Posted on by

Error Analysis and Optimization Strategies for Calibration of Handheld XRF Analyzers in Iron Ore Testing

Introduction

X-ray fluorescence (XRF) spectroscopy technology is widely applied in geological exploration and mineral analysis due to its advantages of rapidness, non-destructiveness, and simultaneous multi-element determination. Handheld XRF analyzers are particularly crucial for on-site testing of iron ores, enabling quick determination of ore grades, on-site screening of element contents, and monitoring of mining production processes. However, the test results from handheld XRF do not always align with laboratory chemical analyses, with deviations often stemming from improper sample preparation or inaccurate calibration. Therefore, a thorough understanding of the instrument’s calibration methods and analytical conditions is essential to avoid reporting erroneous results.

Overview of the Principles and Calibration Mechanisms of Handheld XRF Analyzers

Handheld XRF analyzers operate based on the X-ray fluorescence effect: an X-ray tube emits primary X-rays to irradiate the sample, exciting characteristic X-rays (fluorescent rays) from the elements in the sample. The detector receives and measures the energy and intensity of these characteristic X-rays, and the software identifies the element types based on the characteristic energy peaks of different elements and calculates the element contents according to the peak intensities. Handheld XRF uses energy-dispersive spectroscopy analysis, acquiring signals from elements ranging from magnesium (Mg) to uranium (U) through a built-in silicon drift detector (SDD), enabling simultaneous analysis of major and minor elements in iron ores, such as iron, silicon, aluminum, phosphorus, and sulfur.

To convert the detected X-ray intensities into accurate element contents, XRF analyzers need to establish a calibration model. Most handheld XRF analyzers come pre-calibrated by the manufacturer, combining the fundamental parameters method and empirical calibration. The fundamental parameters method (FP) uses physical models of X-ray interactions with matter for calibration, allowing simultaneous correction of geometric, absorption, and secondary fluorescence effects over a wide range of unknown sample compositions. The empirical calibration method establishes an empirical calibration curve by measuring a series of known standard samples for quantitative analysis of specific types of samples. Handheld XRF also generally incorporates an energy calibration mechanism to align the spectral channels and ensure stable identification of element peak positions.

Error Issues Based on Calibration Using 310 Stainless Steel

In practical applications, some operators may calibrate handheld XRF using metal standards (e.g., 310 stainless steel) and then directly apply it to the compositional analysis of iron ores. However, this approach can introduce significant systematic errors due to the mismatch between the calibration standard and the sample matrix. 310 stainless steel is a high-alloy metal, differing greatly from iron ores (which are oxide-based non-metallic mineral matrices) in terms of physical properties and matrix composition.

Matrix effects are the primary cause of these errors. When the calibration reference of XRF differs from the actual sample matrix, it can lead to changes in the absorption or enhancement of the X-ray signals of the elements to be measured, causing deviations from the calibration curve. For example, when an instrument calibrated with 310 stainless steel is used to measure iron ores, since stainless steel contains almost no oxygen and has a high-density metal matrix, the excitation and absorption conditions of the Fe fluorescence signal in this matrix are entirely different from those in iron ores, causing the instrument to tend to overestimate the iron content.

In addition to matrix absorption differences, systematic errors can also arise from inappropriate calibration modes, linear shifts caused by single-point calibration, differences in geometry and surface conditions, and other factors. The combination of these factors can result in significant errors and biases in the results of iron ore measurements calibrated with 310 stainless steel.

Calibration Modes of XRF Analyzers and Their Impact on Results

Handheld XRF analyzers typically come pre-programmed with multiple calibration/analysis modes to accommodate the testing needs of different types of materials. Common modes include alloy mode, ore/geological mode, and soil mode. Improper mode selection can significantly affect the test results.

  • Alloy Mode: Generally used for analyzing the composition of metal alloys, assuming the sample is a high-density pure metal matrix. Using alloy mode to measure iron ores can lead to deviations and anomalies in the results because ores contain a large amount of oxygen and non-metallic elements.
  • Soil Mode: Mainly used for analyzing environmental soils or sediments, employing Compton scattering internal standard correction methods. It is suitable for measuring trace elements in light-element-dominated matrices. For iron ores, if only impurity elements are of concern, soil mode can provide good sensitivity, but problems may arise when the major element contents are high.
  • Ore/Mining (Geological) Mode: Specifically designed for mineral and geological samples, often using the fundamental parameters method (FP) combined with the manufacturer’s empirical calibration. It can simultaneously determine major and minor elements. For iron ores, which have complex compositions and a wide range of element contents, ore mode is the most suitable choice.

Principles and Examples of Errors Caused by Matrix Inconsistency

When the matrix of the standard material used for calibration differs from that of the actual iron ore sample to be measured, matrix effect errors can occur in XRF quantitative analysis. Matrix effects include absorption effects and enhancement effects, that is, the influence of other elements or matrix components in the sample on the fluorescence intensity of the target element.

For example, if a calibration curve for iron content is established using pure iron or stainless steel as standards and then used to measure iron ore samples mainly composed of hematite (Fe₂O₃), the metal matrix has strong absorption of Fe Kα fluorescence, while in the ore sample, Fe atoms are surrounded by oxygen and silicon and other light elements, which have weaker absorption of Fe Kα rays. Therefore, the Fe peak intensity produced by the ore sample is higher than that in the metal matrix. However, the instrument’s calibration curve is based on metal standards and still converts the content according to the metal matrix relationship, thus interpreting the stronger signal in the ore as a higher Fe content, leading to a systematic overestimation of Fe.

Calibration Optimization Methods for Iron Ore Testing

For iron ore samples, adopting the correct calibration strategy can significantly reduce errors and improve testing accuracy. The following calibration optimization methods are recommended:

  • Calibration Using Ore Standard Materials: Use iron ore standard materials to establish or correct the instrument’s calibration curve to minimize systematic errors caused by matrix mismatch.
  • Multi-Point Calibration Covering the Concentration Range: Perform multi-point calibration covering the entire concentration range instead of using only a single point for calibration. Use at least 3-5 standard samples with different compositions and grades to establish an intensity-content calibration curve for each element.
  • Correct Selection of Analysis Mode: Select the ore/mining mode for analyzing iron ore samples and avoid using alloy mode or soil mode.
  • Application of Compton Scattering Correction: Use the Compton scattering peak as an internal standard to correct for matrix effects and compensate for overall scattering differences between samples due to differences in matrix composition and density.
  • Regular Calibration and Quality Control: Establish a daily calibration and quality control procedure for handheld XRF. After each startup or change in the measurement environment, use stable standard samples for testing to check if the instrument readings are within the acceptable range.

Other Factors Affecting XRF Testing of Iron Ores

In addition to the instrument calibration mode and matrix effects, the XRF testing results of iron ores are also influenced by factors such as sample particle size and uniformity, surface flatness and thickness, moisture content, probe contact method, measurement time and number of measurements, and environmental and instrument status. To obtain accurate and consistent measured values, these factors need to be comprehensively controlled:

  • Sample Particle Size and Uniformity: The sample should be ground to a sufficiently fine size to reduce particle size effects.
  • Sample Surface Flatness and Thickness: The sample surface should be as flat as possible and cover the instrument’s measurement window. The pressing method is an optimal choice for sample preparation.
  • Moisture Content: The sample should be dried to a constant weight before testing to avoid the influence of moisture.
  • Probe Contact Method: The probe should be pressed tightly against the sample surface for measurement to avoid air gaps in between.
  • Measurement Time and Number of Measurements: Appropriately extend the measurement time and repeat the measurements to take the average value to improve precision.
  • Environmental and Instrument Status: Ensure that the instrument is in good calibration and working condition and avoid the influence of extreme environments.

Precision Optimization Suggestions and Operational Specifications

To integrate the above strategies into daily iron ore XRF testing work, the following is a set of optimized operational procedures and suggestions:

  • Instrument Preparation and Initial Calibration: Check the instrument status and settings, ensure that the battery is fully charged, and the instrument window is clean and undamaged. Use reference standard samples with known compositions for calibration verification to confirm that the readings of major elements are accurate.
  • Sample Preparation: Dry the sample to a constant weight, grind it into fine powder, and mix it thoroughly. Prepare sample pellets using the pressing method to ensure density, smoothness, no cracks, and sufficient thickness.
  • Measurement Operation: Place the sample on a stable supporting surface, ensure that the probe is perpendicular to and pressed tightly against the sample. Set an appropriate measurement time, and measure each sample for at least 30 seconds. Repeat the measurements 2-3 times to evaluate data repeatability and calculate the average value as the final reported value.
  • Result Correction and Verification: Perform post-processing corrections on the data as needed, such as dry basis conversion or oxide form conversion. Compare the handheld XRF results with known reference methods for verification and establish a calibration curve for correction.
  • Quality Control and Record-Keeping: Strictly implement quality control measures and keep relevant records. When reporting the analysis results, note key information to facilitate result interpretation and reproduction.

Conclusion

Handheld XRF analyzers have become powerful tools for on-site testing of iron ores, but the quality of their data highly depends on correct calibration and standardized operation. This paper analyzes the errors that may arise when using metal standards for calibration, elucidates the principles of systematic deviations caused by matrix effects, and compares the impacts of different instrument calibration modes on the results. Through discussion, a series of optimized calibration strategies for iron ore samples are proposed, and the significant influences of factors such as sample preparation, probe contact, and measurement time on testing accuracy are emphasized.

Overall, proper calibration of the instrument is the foundation for ensuring testing quality. Only by doing a good job in standard material selection, mode setting, and matrix correction can handheld XRF发挥 (fully leverage) its advantages of rapidness and accuracy to provide credible data for iron ore composition analysis. Mineral analysts should attach great importance to the control of calibration errors, combine handheld XRF measurements with necessary laboratory analyses, and establish calibration correlations for specific ores to enable mutual verification and complementarity between on-site and laboratory data. Through continuous improvement of calibration methods and strict quality management, handheld XRF is expected to achieve more precise and stable measurements in iron ore testing, providing strong support for geological prospecting, ore grading, and production monitoring.

Posted on by

Comprehensive Analysis of AL-09 Overload Fault Diagnosis and Solutions for LS Servo Drive APD-VP Series

Table of Contents

  1. Introduction
  2. Basic Concept of AL-09 Overload Fault 2.1 What is AL-09 Overload Fault? 2.2 Common Manifestations of AL-09 Fault
  3. Structure and Working Principle of LS Servo Drive APD-VP Series 3.1 Hardware Structure of APD-VP Series Servo Drive 3.2 Control Logic and Feedback Mechanism of Servo Drive 3.3 Working Principle of Overload Protection Mechanism
  4. Causes of AL-09 Fault 4.1 Mechanical Load Abnormalities 4.2 Electrical Parameter Setting Errors 4.3 Motor or Encoder Failures 4.4 Power Supply Issues 4.5 Environmental Factors
  5. Diagnostic Steps for AL-09 Fault 5.1 Preliminary Inspection 5.2 Mechanical System Inspection 5.3 Electrical Parameter Inspection 5.4 Motor and Encoder Inspection 5.5 Power Supply and Wiring Inspection
  6. Solutions for AL-09 Fault 6.1 Optimization and Adjustment of Mechanical Load 6.2 Reconfiguration of Electrical Parameters 6.3 Maintenance and Replacement of Motor and Encoder 6.4 Improvement of Power Supply Stability 6.5 Control of Environmental Factors
  7. Preventive Measures for AL-09 Fault 7.1 Regular Maintenance and Upkeep 7.2 Parameter Backup and Optimization 7.3 Runtime Monitoring and Alarm System
  8. Case Studies 8.1 Case Study 1: AL-09 Fault Caused by Mechanical Jamming 8.2 Case Study 2: AL-09 Fault Caused by Parameter Setting Errors 8.3 Case Study 3: AL-09 Fault Caused by Unstable Power Supply
  9. Conclusion and Recommendations
  10. References

1. Introduction

In the field of modern industrial automation, servo drives are core components for precise motion control, widely used in robotic arms, CNC machines, packaging machinery, and other equipment. The LS Electric APD-VP series servo drives are renowned for their high performance, reliability, and flexible control methods. However, in practical applications, servo drives may encounter various faults, with AL-09 overload faults being one of the most common issues. AL-09 faults not only cause equipment downtime but also severely impact the continuity and quality of production lines. Therefore, a deep understanding of the causes, diagnostic methods, and solutions for AL-09 faults is of significant practical importance for engineers and technicians.

This article comprehensively analyzes the causes, diagnostic steps, solutions, and preventive measures for AL-09 overload faults in the LS servo drive APD-VP series. It also validates these through practical case studies, aiming to provide a systematic and practical reference guide for relevant technical personnel.

2. Basic Concept of AL-09 Overload Fault

2.1 What is AL-09 Overload Fault?

AL-09 is an alarm code for LS servo drives, indicating an overload fault (Over Load). When the load on the servo motor exceeds its rated capacity during operation, the drive triggers the overload protection mechanism and displays the AL-09 alarm. Overload faults can be caused by various factors, including mechanical load abnormalities, electrical parameter setting errors, motor or encoder failures, and power supply issues.

2.2 Common Manifestations of AL-09 Fault

When a servo drive encounters an AL-09 fault, the following phenomena typically occur:

  1. The drive’s display shows the “AL-09” alarm code.
  2. The servo motor stops operating and cannot continue executing motion commands.
  3. The alarm indicator light turns on, usually red or yellow.
  4. The system may be accompanied by abnormal noises, such as motor humming or mechanical friction sounds.
  5. The upper-level machine or PLC may receive alarm signals, causing the entire control system to shut down.

3. Structure and Working Principle of LS Servo Drive APD-VP Series

3.1 Hardware Structure of APD-VP Series Servo Drive

The LS servo drive APD-VP series adopts a modular design, primarily consisting of the following components:

  1. Main Circuit Board: Includes IGBT inverters, PWM control circuits, current/voltage detection circuits, etc., responsible for converting input AC power into controllable three-phase AC power to drive the servo motor.
  2. Control Circuit Board: Contains core control chips such as DSP (Digital Signal Processor) and FPGA (Field-Programmable Gate Array), responsible for motion control algorithms, parameter settings, communication interfaces, etc.
  3. Interface Board: Provides various input/output interfaces, including analog input/output, pulse input, encoder feedback interfaces, etc., for communication with upper-level machines, PLCs, sensors, and other devices.
  4. Power Supply Module: Supplies stable DC power to the internal circuits of the drive.
  5. Cooling System: Includes heat sinks and fans to ensure stable operation of the drive under high loads.

3.2 Control Logic and Feedback Mechanism of Servo Drive

The APD-VP series servo drive employs a closed-loop control method, achieving precise motion control through the following steps:

  1. Command Input: The upper-level machine (such as PLC or motion controller) sends motion commands (position, speed, or torque commands) to the drive.
  2. Control Algorithm: The internal DSP of the drive calculates the control output based on the commands and feedback signals (such as encoder pulses and current sensor signals).
  3. PWM Modulation: The control algorithm outputs PWM signals to drive the IGBT inverter, converting the DC bus voltage into variable frequency and amplitude three-phase AC power.
  4. Motor Drive: The three-phase AC power drives the servo motor.
  5. Feedback Detection: The encoder detects the motor’s position and speed in real-time, and the current sensor detects the actual current of the motor, sending feedback signals to the drive.
  6. Closed-Loop Adjustment: The drive compares the commands and feedback signals and adjusts the output through the PID controller to achieve precise control.

3.3 Working Principle of Overload Protection Mechanism

The APD-VP series servo drive is equipped with an overload protection mechanism, which operates as follows:

  1. Current Detection: The drive monitors the phase current of the motor in real-time. When the current exceeds the rated value, it triggers overload protection.
  2. Torque Calculation: The drive calculates the actual output torque based on the current and motor parameters (such as torque constant). When the torque exceeds the set torque limit ([PE-205], [PE-206]), it triggers overload protection.
  3. Load Monitoring: The drive calculates the actual load on the motor through encoder feedback and current detection. When the load exceeds the rated load (typically 300% of the rated torque), it triggers the AL-09 alarm.
  4. Protection Action: Once overload protection is triggered, the drive immediately cuts off the PWM output, stopping the motor and displaying the AL-09 alarm code.

4. Causes of AL-09 Fault

The causes of AL-09 overload faults are diverse and can be categorized as follows:

4.1 Mechanical Load Abnormalities

Mechanical load abnormalities are the most common cause of AL-09 faults, including:

  1. Mechanical Jamming: Transmission mechanisms (such as gears, guides, and screws) may jam or experience excessive friction, preventing the motor from rotating normally.
  2. Excessive Load: The actual load exceeds the motor’s rated load capacity, such as overweight workpieces or unreasonable mechanical design.
  3. Coupling Misalignment: The motor shaft and load shaft are misaligned, resulting in additional radial or axial forces that increase the motor load.
  4. Insufficient Lubrication: Transmission components lack lubrication, increasing friction and motor load.

4.2 Electrical Parameter Setting Errors

Incorrect parameter settings in the drive can directly affect the motor’s operating state. Common parameter setting errors include:

  1. Torque Limit Set Too Low: [PE-205] (CCW Torque Limit) and [PE-206] (CW Torque Limit) are set too low, causing the motor to trigger overload protection under normal loads.
  2. Incorrect Gain Parameter Settings: Speed proportional gain ([PE-307], [PE-308]) or position proportional gain ([PE-302], [PE-303]) are set too high, leading to system oscillation or overload.
  3. Electronic Gear Ratio Error: [PE-701] (Electronic Gear Ratio) is set incorrectly, causing a mismatch between pulse commands and actual positions, resulting in overload.
  4. Encoder Pulse Number Setting Error: [PE-204] (Encoder Pulse Number) does not match the actual encoder, leading to incorrect feedback signals and triggering overload protection.

4.3 Motor or Encoder Failures

Failures in the motor or encoder can also cause AL-09 alarms:

  1. Motor Winding Short Circuit or Open Circuit: Internal winding damage in the motor causes abnormal current increases.
  2. Encoder Signal Loss or Error: Encoder damage or loose wiring causes interruption or error in feedback signals.
  3. Motor Bearing Damage: Worn or jammed bearings increase the motor’s rotational resistance.

4.4 Power Supply Issues

The stability of the power supply directly affects the operation of the drive and motor:

  1. Voltage Fluctuations: Unstable input voltage, such as overvoltage or undervoltage, causes abnormal drive output.
  2. Poor Power Line Contact: Loose or oxidized power lines cause excessive voltage drops.
  3. Regenerative Resistor Failure: Damaged regenerative resistors or incorrect parameter settings prevent effective absorption of regenerative energy, leading to overvoltage or overload.

4.5 Environmental Factors

Environmental factors can indirectly cause AL-09 faults:

  1. High Temperature: Operation of the drive or motor in high-temperature environments leads to poor heat dissipation and performance degradation.
  2. Humidity or Corrosive Gases: Moisture or corrosive environments may cause short circuits or poor contact in the circuit board.
  3. Vibration or Impact: Mechanical vibration or impact may loosen or damage internal components of the drive.

5. Diagnostic Steps for AL-09 Fault

When the APD-VP series servo drive displays an AL-09 fault, follow these steps for diagnosis:

5.1 Preliminary Inspection

  1. Confirm Alarm Code: Verify that the alarm code displayed on the drive is AL-09.
  2. Check Mechanical Load: Manually rotate the motor shaft to confirm if there is jamming or abnormal resistance.
  3. Check Power Supply: Ensure the input voltage is within the allowed range (AC200-230V) and the power line is normal.

5.2 Mechanical System Inspection

  1. Inspect Transmission Mechanism:
    • Ensure gears, guides, screws, and other transmission components are well-lubricated and free from jamming.
    • Check if the coupling is aligned and free from offset or deformation.
  2. Check Load:
    • Confirm that the load is within the motor’s rated range, such as workpiece weight and mechanical friction.
    • Reduce the load and observe if the fault disappears.

5.3 Electrical Parameter Inspection

  1. Check Torque Limit:
    • Enter menus [PE-205] and [PE-206] to confirm if the torque limit is set too low.
    • If the torque limit is too low, increase the setting appropriately (usually not exceeding 300%).
  2. Check Gain Parameters:
    • Check if the speed proportional gain ([PE-307], [PE-308]) and position proportional gain ([PE-302], [PE-303]) are too high.
    • If the gain is too high, gradually reduce the gain value and observe if the fault disappears.
  3. Check Electronic Gear Ratio:
    • Ensure [PE-701] (Electronic Gear Ratio) matches the mechanical transmission ratio.
  4. Check Encoder Settings:
    • Ensure [PE-204] (Encoder Pulse Number) matches the motor nameplate.

5.4 Motor and Encoder Inspection

  1. Inspect Encoder:
    • Ensure encoder wiring is secure and free from breaks or short circuits.
    • Use an oscilloscope to check encoder signals (A, B, Z phases) for normality.
  2. Inspect Motor:
    • Measure the insulation resistance of the motor windings to ensure no short circuits or open circuits.
    • Manually rotate the motor shaft to ensure bearings are free from abnormal noises or jamming.

5.5 Power Supply and Wiring Inspection

  1. Check Power Supply:
    • Use a multimeter to measure the input voltage, ensuring it is within the AC200-230V range.
    • Check the power line for poor contact or oxidation.
  2. Check Regenerative Resistor:
    • Ensure the regenerative resistor is connected correctly and parameters are set reasonably.
    • Check if the regenerative resistor is damaged and if the resistance value is normal.

6. Solutions for AL-09 Fault

Based on the diagnostic results, the following solutions can be implemented:

6.1 Optimization and Adjustment of Mechanical Load

  1. Reduce Load:
    • Lighten the workpiece weight or optimize the mechanical structure to reduce the motor load.
  2. Lubricate Transmission Components:
    • Regularly add lubricating oil or grease to gears, guides, screws, and other transmission components.
  3. Adjust Coupling:
    • Ensure the motor shaft and load shaft are aligned to avoid radial or axial forces.

6.2 Reconfiguration of Electrical Parameters

  1. Adjust Torque Limit:
    • Based on the actual load, appropriately increase the torque limit values in [PE-205] and [PE-206].
  2. Optimize Gain Parameters:
    • Gradually reduce the speed proportional gain ([PE-307], [PE-308]) and position proportional gain ([PE-302], [PE-303]) to avoid system oscillation.
  3. Recalibrate Electronic Gear Ratio:
    • Reset [PE-701] (Electronic Gear Ratio) according to the mechanical transmission ratio.

6.3 Maintenance and Replacement of Motor and Encoder

  1. Replace Damaged Encoder:
    • If the encoder signal is abnormal, replace it with a new one and ensure correct wiring.
  2. Repair or Replace Motor:
    • If the motor windings or bearings are damaged, send them for repair or replace them with new ones.

6.4 Improvement of Power Supply Stability

  1. Stabilize Power Voltage:
    • Use a voltage regulator or UPS (Uninterruptible Power Supply) to ensure stable input voltage.
  2. Check Power Line:
    • Ensure the power line is in good contact and free from oxidation.

6.5 Control of Environmental Factors

  1. Improve Cooling Conditions:
    • Ensure the cooling fans of the drive and motor operate normally to avoid high-temperature environments.
  2. Prevent Moisture and Corrosion:
    • In humid or corrosive environments, take protective measures such as sealing the drive cabinet.

7. Preventive Measures for AL-09 Fault

To prevent the occurrence of AL-09 faults, the following measures can be taken:

7.1 Regular Maintenance and Upkeep

  1. Regularly Inspect Mechanical Transmission Components:
    • Check the wear and lubrication of gears, guides, screws, and other components.
  2. Regularly Clean Drive and Motor:
    • Remove dust and debris to ensure good heat dissipation.
  3. Regularly Check Electrical Connections:
    • Ensure all terminal connections are secure and free from oxidation or loosening.

7.2 Parameter Backup and Optimization

  1. Backup Drive Parameters:
    • Regularly back up the drive’s parameter settings for quick recovery after faults.
  2. Optimize Parameter Settings:
    • Optimize parameters such as gain and torque limit based on actual load and operating conditions.

7.3 Runtime Monitoring and Alarm System

  1. Real-Time Monitoring of Operating Status:
    • Use upper-level machines or PLCs to monitor motor current, speed, position, and other parameters in real-time.
  2. Set Alarm Thresholds:
    • Set reasonable alarm thresholds in the drive to detect and handle abnormalities promptly.

8. Case Studies

8.1 Case Study 1: AL-09 Fault Caused by Mechanical Jamming

Fault Phenomenon: A CNC machine suddenly stopped during operation, and the drive displayed an AL-09 alarm. Manual rotation of the motor shaft revealed significant jamming in the screw transmission.

Diagnostic Process:

  1. Inspected the mechanical transmission and found that the screw guide lacked lubrication, causing excessive friction.
  2. Checked the drive parameters and found that the torque limit settings were normal.

Solution:

  1. Added lubricating oil to the screw guide.
  2. Adjusted the coupling alignment to reduce radial forces.
  3. Reset the alarm, and the equipment resumed normal operation.

Experience Summary: Mechanical jamming is a common cause of AL-09 faults. Regular maintenance and lubrication of transmission components are crucial.

8.2 Case Study 2: AL-09 Fault Caused by Parameter Setting Errors

Fault Phenomenon: An automated production line frequently displayed AL-09 alarms during debugging, and the motor failed to start normally.

Diagnostic Process:

  1. Inspected the mechanical load and found no abnormalities.
  2. Checked the drive parameters and found that the speed proportional gain ([PE-307]) was set too high, causing system oscillation.

Solution:

  1. Gradually reduced the speed proportional gain until the system stabilized.
  2. Optimized other control parameters, such as the integral time constant ([PE-309]).
  3. Reset the alarm, and the equipment operated normally.

Experience Summary: Parameter setting errors are another significant cause of AL-09 faults. During debugging, parameters should be adjusted gradually to avoid excessive settings.

8.3 Case Study 3: AL-09 Fault Caused by Unstable Power Supply

Fault Phenomenon: A packaging machine suddenly stopped during operation, and the drive displayed an AL-09 alarm. Inspection revealed significant voltage fluctuations in the input power.

Diagnostic Process:

  1. Used a multimeter to measure the input voltage, which fluctuated between 180V and 250V.
  2. Inspected the power line and found poor contact causing excessive voltage drops.

Solution:

  1. Replaced the power line to ensure good contact.
  2. Added a voltage regulator to stabilize the input voltage.
  3. Reset the alarm, and the equipment resumed normal operation.

Experience Summary: Unstable power supply can cause abnormal drive output, triggering overload protection. Ensuring power stability is key to preventing AL-09 faults.

9. Conclusion and Recommendations

AL-09 overload faults are common issues in the LS servo drive APD-VP series in practical applications. Through this analysis, we can draw the following conclusions:

  1. AL-09 faults have diverse causes, including mechanical load abnormalities, electrical parameter setting errors, motor or encoder failures, power supply issues, and environmental factors.
  2. Diagnosing AL-09 faults requires a systematic approach, involving inspections from mechanical, electrical, and environmental perspectives.
  3. Solving AL-09 faults requires targeted measures, such as optimizing mechanical loads, adjusting electrical parameters, maintaining motors and encoders, and stabilizing power supplies.
  4. Preventing AL-09 faults requires proactive measures, including regular maintenance, parameter optimization, and runtime monitoring.

Recommendations:

  1. Establish Equipment Maintenance Records: Document the equipment’s operating status, fault history, and maintenance activities.
  2. Regularly Train Operators: Enhance their ability to diagnose and handle servo drive faults.
  3. Introduce Remote Monitoring Systems: Monitor equipment operating status in real-time to detect and address abnormalities promptly.
Posted on by

Yokogawa Optical Spectrum Analyzer AQ6370D Series User Manual: Usage Guide from Beginner to Expert

Introduction

The Yokogawa AQ6370D series optical spectrum analyzer is a high-performance and multifunctional testing instrument widely used in various fields such as optical communication, laser characteristic analysis, fiber amplifier testing, and WDM system analysis. With its high wavelength accuracy, wide dynamic range, and rich analysis functions, it has become an indispensable tool in research and development as well as production environments.

This article, closely based on the content of the AQ6370D Optical Spectrum Analyzer User’s Manual, systematically introduces the device’s operating procedures, functional modules, usage tips, and precautions. It aims to help users quickly master the device’s usage methods and improve testing efficiency and data reliability.

I. Device Overview and Initial Setup

1.1 Device Structure and Interfaces

The front panel of the AQ6370D is richly laid out, including an LCD display, soft key area, function key area, data input area, optical input interface, and calibration output interface. The rear panel provides various interfaces such as GP-IB, TRIGGER IN/OUT, ANALOG OUT, ETHERNET, and USB, facilitating remote control and external triggering.

Key Interface Descriptions:

  • OPTICAL INPUT: This is the optical signal input interface that supports common fiber connectors such as FC/SC.
  • CALIBRATION OUTPUT: Only the -L1 model has this built-in reference light source output interface for wavelength calibration.
  • USB Interface: Supports external devices such as mice, keyboards, and USB drives for easy operation and data export.

1.2 Installation and Environmental Requirements

To ensure normal operation of the device, the installation environment should meet the following conditions:

  • Temperature: Maintain between 5°C and 35°C.
  • Humidity: Not exceed 80% RH, and no condensation should occur.
  • Environment: Avoid environments with vibrations, direct sunlight, excessive dust, or corrosive gases.
  • Space: Provide at least 20 cm of ventilation space around the device.

Note: The device weighs approximately 19 kg. When moving it, ensure two people operate it together and that the power is turned off.

II. Power-On and Initial Calibration

2.1 Power-On Procedure

  1. Connect the power cord to the rear panel and plug it into a properly grounded three-prong socket.
  2. Turn on the MAIN POWER switch on the rear panel. The POWER indicator on the front panel will turn orange.
  3. Press the POWER key to start the device, which will enter the system initialization interface.
  4. After initialization, if it is the first use or the device has been subjected to vibrations, the system will prompt for alignment adjustment and wavelength calibration.

2.2 Alignment Adjustment

Alignment adjustment aims to calibrate the optical axis of the built-in monochromator to ensure optimal optical performance.

Using Built-in Light Source (-L1 Model):

  1. Connect the CAL OUTPUT and OPTICAL INPUT using a 9.5/125 μm single-mode fiber.
  2. Press SYSTEM → OPTICAL ALIGNMENT → EXECUTE.
  3. Wait approximately 2 minutes, and the device will automatically complete alignment and wavelength calibration.

Using External Light Source (-L0 Model):

  1. Connect an external laser source (1520–1560 nm, ≥-20 dBm) to the optical input port.
  2. Enter SYSTEM → OPTICAL ALIGNMENT → EXTERNAL LASER → EXECUTE.

2.3 Wavelength Calibration

Wavelength calibration ensures the accuracy of measurement results.

Using Built-in Light Source:
Enter SYSTEM → WL CALIBRATION → BUILT-IN SOURCE → EXECUTE.

Using External Light Source:
Choose EXECUTE LASER (laser type) or EXECUTE GAS CELL (gas absorption line type) and input the known wavelength value.

Note: The device should be preheated for at least 1 hour before calibration, and the wavelength error should not exceed ±5 nm (built-in) or ±0.5 nm (external).

III. Basic Measurement Operations

3.1 Auto Measurement

Suitable for quick measurements of unknown light sources:

  1. Press SWEEP → AUTO, and the device will automatically set the center wavelength, scan width, reference level, and resolution.
  2. The measurement range is from 840 nm to 1670 nm.

3.2 Manual Setting of Measurement Conditions

  • Center Wavelength/Frequency: Press the CENTER key to directly input a value or use PEAK→CENTER to set the peak as the center.
  • Scan Width: Press the SPAN key to set the wavelength range or use Δλ→SPAN for automatic setting.
  • Reference Level: Press the LEVEL key to set the vertical axis reference level, supporting PEAK→REF LEVEL for automatic setting.
  • Resolution: Press SETUP → RESOLUTION to choose from various resolutions ranging from 0.02 nm to 2 nm.

3.3 Trigger and Sampling Settings

  • Sampling Points: The range is from 101 to 50,001 points, settable via SAMPLING POINT.
  • Sensitivity: Supports multiple modes such as NORM/HOLD, NORM/AUTO, MID, HIGH1~3 to adapt to different power ranges.
  • Average Times: Can be set from 1 to 999 times to improve the signal-to-noise ratio.

IV. Waveform Display and Analysis Functions

4.1 Trace Management

The device supports 7 independent traces (A~G), each of which can be set to the following modes:

  • WRITE: Real-time waveform update.
  • FIX: Fix the current waveform.
  • MAX/MIN HOLD: Record the maximum/minimum values.
  • ROLL AVG: Perform rolling averaging.
  • CALCULATE: Implement mathematical operations between traces.

4.2 Zoom and Overview

The ZOOM function allows local magnification of the waveform, supporting mouse-drag selection of the area. The OVERVIEW window displays the global waveform and the current zoomed area for easy positioning.

4.3 Marker Function

  • Moving Marker: Displays the current wavelength and level values.
  • Fixed Marker: Up to 1024 can be set to display the difference from the moving marker.
  • Line Marker: L1/L2 are wavelength lines, and L3/L4 are level lines, used to set scan or analysis ranges.
  • Advanced Marker: Includes power spectral density markers, integrated power markers, etc., supporting automatic search for peaks/valleys.

4.4 Trace Math

Supports operations such as addition, subtraction, normalization, and curve fitting between traces, suitable for differential measurements, filter characteristic analysis, etc.

Common Calculation Modes:

  • C = A – B: Used for differential analysis.
  • G = NORM A: Normalize the display.
  • G = CRV FIT A: Perform Gaussian/Lorentzian curve fitting.

V. Advanced Measurement Functions

5.1 Pulsed Light Measurement

Supports three modes:

  • Peak Hold: Suitable for repetitive pulsed measurements.
  • Gate Sampling: Synchronized sampling with an external gate signal.
  • External Trigger: Suitable for non-periodic pulsed measurements.

5.2 External Trigger and Synchronization

  • SMPL TRIG: Wait for an external trigger for each sampling point.
  • SWEEP TRIG: Wait for an external trigger for each scan.
  • SMPL ENABLE: Perform scanning when the external signal is low.

5.3 Power Spectral Density Display

Switch to dBm/nm or mW/nm via LEVEL UNIT, suitable for normalized power display of broadband light sources (such as LEDs, ASE).

VI. Data Analysis and Template Judgement

6.1 Spectral Width Analysis

Supports four algorithms:

  • THRESH: Threshold method.
  • ENVELOPE: Envelope method.
  • RMS: Root mean square method.
  • PEAK RMS: Peak root mean square method.

6.2 Device Analysis Functions

  • DFB-LD SMSR: Measure the side-mode suppression ratio.
  • FP-LD/LED Total Power: Calculate the total optical power through integration.
  • WDM Analysis: Simultaneously analyze multiple channel wavelengths, levels, and OSNR.
  • EDFA Gain and Noise Figure: Calculate based on input/output spectra.

6.3 Template Judgement (Go/No-Go)

Upper and lower limit templates can be set for quick judgement in production lines:

  • Upper limit line, lower limit line, target line.
  • Supports automatic judgement and output of results.

VII. Data Storage and Export

7.1 Storage Media

Supports USB storage devices for saving waveform data, setting files, screen images, analysis results, etc.

7.2 Data Formats

  • CSV: Used to store analysis result tables.
  • BMP/PNG: Used to save screen images.
  • Internal Format: Supports subsequent import and re-analysis.

7.3 Logging Function (Data Logging)

Can periodically record WDM analysis, peak data, etc., suitable for long-term monitoring and statistical analysis.

VIII. Maintenance and Troubleshooting

8.1 Routine Maintenance

  • Regularly clean the fiber end faces and connectors.
  • Avoid direct strong light input to prevent damage to optical components.
  • Use the original packaging for transportation to avoid vibrations.

8.2 Common Problems and Solutions

Problem PhenomenonPossible CausesSolutions
Large wavelength errorNot calibrated or temperature not stablePerform wavelength calibration and preheat for 1 hour
Inaccurate levelFiber type mismatchUse 9.5/125 μm SM fiber
Scan interruptionExcessive sampling points or high resolutionAdjust sampling points or resolution
USB drive not recognizedIncompatible formatFormat as FAT32 and avoid partitioning

IX. Conclusion

The Yokogawa AQ6370D series optical spectrum analyzer is a comprehensive and flexible high-precision testing device. By mastering its basic operations and advanced functions, users can efficiently complete various tasks ranging from simple spectral measurements to complex system analyses. This article, based on the official user manual, systematically organizes the device’s usage procedures and key technical points, hoping to provide practical references for users and further improve testing efficiency and data reliability.

Posted on by

Fixturlaser NXA Series Laser Alignment Instrument: In-Depth Analysis and Operation Guide

Chapter 1 Product Overview and Technical Specifications

1.1 Introduction to the Product System

The Fixturlaser NXA series laser alignment instrument is the flagship product of ACOEM AB (formerly ELOS Fixturlaser AB). Since its establishment in 1984, the company has established a complete professional service system in over 70 countries. As an industry-leading solution for shaft alignment, this system is designed based on innovative measurement technology and is widely used in various industrial equipment maintenance fields.

1.2 Core Technical Specifications

Display Unit NXA D Parameters

  • Two operating modes: On and Off
  • Dust and water resistance rating: IP65
  • Processor: 1GHz dual-core main processor
  • Memory: 256Mb, Flash storage: 8Gb
  • Operating temperature range: -10 to 50℃
  • Weight: Approximately 1.2kg (including battery)

Sensor Unit Technical Specifications

  • Weight: Approximately 192 grams (including battery)
  • Operating temperature: -10 to 50℃
  • Protection rating: IP65

Compliance Certifications

  • Complies with EMC Directive 2004/108/EC
  • Complies with Low Voltage Directive 2006/95/EC
  • Complies with RoHS Directive 2011/65/EU

Chapter 2 Analysis of Core System Components

2.1 Functional Characteristics of the Display Unit

  • 6.5-inch touchscreen display
  • On/off button with status LED
  • Battery status check button
  • Built-in 256Mb memory and 8Gb flash storage

Sensor Unit Configuration

  • M3 and S3 sensors: Anodized aluminum frame design, high-impact ABS plastic casing, TPE rubber overmolding process

2.2 Power Management System

  • Built-in high-capacity rechargeable lithium-ion battery pack
  • Sustainable usage for approximately 2-3 years under normal operating temperatures

Chapter 3 Safety Operation and Maintenance Procedures

3.1 Laser Safety Operation Standards

  • Uses laser diodes with a power output of <1.0mW
  • Laser classification: Class 2 safety level

Chapter 4 Core Principles of Laser Alignment Technology

4.1 Theoretical Basis of Alignment Technology

The system utilizes measurement units installed on two shafts. After rotating the shafts to different measurement positions, the system calculates the relative distances between the two shafts in two planes. It is necessary to accurately input the distances between the measurement planes, to the coupling, and to the machine feet.

4.2 System Measurement Advantages

Accuracy Advantages

  • 6-axis MEMS inertial motion sensors provide precise data acquisition
  • Automatic drift compensation ensures measurement stability
  • On-site calibration capability guarantees measurement reliability

Chapter 5 Detailed Practical Operation Procedures

5.1 Preparation Requirements

Pre-Alignment Checklist

  • Determine required tolerance specifications
  • Check for dynamic movement offsets
  • Assess system installation environment limitations
  • Confirm shaft rotation feasibility
  • Prepare compliant shim materials

5.2 Sensor Installation Specifications

Specific Installation Steps

  • The sensor marked “M” is installed on the movable machine, while the sensor marked “S” is installed on the fixed machine.
  • Assemble the sensors on their V-block fixtures, precisely placing the fixtures on both sides of the coupling.
  • Hold the V-block fixtures upright and correctly install them on the shaft of the measurement object.
  • Lift the open end of the chain, tighten the chain to eliminate slack.
  • Securely tighten the chain using tension screws, and use dedicated tension tools if necessary.

Installation Accuracy Control Points

  • Adjust the sensor height by sliding it on the column until a clear laser line is obtained.
  • Lock the final position using the clamping devices on the backs of both units.

Chapter 6 Measurement Methods and Technology Selection

6.1 Rapid Mode Method

Technical Characteristics

  • Calculates alignment status by recording three points
  • Requires a minimum rotation angle of 60°
  • The system automatically records each measurement point

6.2 Three-Point Measurement Method

  • Performs alignment calculations by manually acquiring three points
  • All measurement points must be manually collected

6.3 Clock Method Technique

  • Acquires three measurement points through 180° rotation
  • Computes accurate mechanical position information
  • Suitable for comparison and analysis with traditional methods

Chapter 7 Data Processing and Quality Management

7.1 Measurement Result Evaluation

  • Angle and offset values jointly determine alignment quality
  • Compare actual values with preset tolerance standards for analysis
  • Evaluation results directly determine whether further corrections are needed

Chapter 8 Analysis of Professional Application Technologies

8.1 Softcheck Soft Foot Detection

  • Uses the built-in Softcheck program system for detection
  • Provides precise measurements and displays results for each foot (in millimeters or mils)

8.2 OL2R Application Technology

Measurement Condition Requirements

  • Must be performed under both operating and cold conditions
  • The system automatically calculates and evaluates process variables

8.3 Target Value Presetting Technology

Preset Condition Analysis

  • Most equipment generates heat changes during operation
  • Ideally, the driven and driving equipment are affected to the same extent
  • Enables target value presetting under cold conditions

Chapter 9 Professional Maintenance Requirements

9.1 Cleaning Operation Procedures

  • The system surface should be wiped with a damp cotton cloth or swab
  • Laser diode apertures and detector surfaces must be kept clean
  • Do not use any type of paper towel material
  • Strictly prohibit the use of acetone-based organic solvents

9.2 Power Management Maintenance

Battery Service Life

  • Under normal usage conditions, the battery life is typically valid for approximately 2-3 years

9.3 Battery Charging Specifications

  • Full charging time is approximately 8 hours
  • When not in use for an extended period, charge to 50-75% capacity
  • It is recommended to perform maintenance charging every 3-4 months

Chapter 10 Fault Diagnosis and Repair Procedures

10.1 System Anomaly Detection

  • Check battery level
  • Confirm good charging status
  • Ensure Bluetooth device connection is normal

Chapter 11 Quality Assurance System

11.1 Repeatability Testing

  • Must be performed before each measurement
  • Establish correct sampling time parameter settings
  • Effectively avoid the influence of external environmental factors

Chapter 12 Technological Development Trends

12.1 Intelligent Development Directions

  • Integration of Internet of Things (IoT) technology
  • Remote monitoring and diagnostic capabilities
  • Application of digital twin technology

12.2 Precision Development Directions

  • Continuous improvement in measurement accuracy
  • Optimization and improvement of operational procedures
  • Expansion and enhancement of system functions

Through an in-depth technical analysis of the Fixturlaser NXA series products, operators can fully grasp the core technological points of the equipment, thereby fully leveraging its significant value in the field of industrial equipment maintenance. This enables a notable increase in equipment operational efficiency and reasonable control over maintenance costs.

Posted on by

Easy-Laser E420 Laser Alignment System User Guide

I. Product Overview

The Easy-Laser E420 is a laser-based shaft alignment system designed specifically for the alignment operations of horizontally and vertically installed rotating machinery, such as pumps, motors, gearboxes, etc. This system utilizes high-precision laser emitters and Position Sensitive Detectors (PSDs) to capture alignment deviations in real-time and guides users through adjustments with intuitive numerical and graphical interfaces. This guide combines the core content of the user manual and provides detailed explanations on equipment composition, operation procedures, functional settings, and maintenance to help users fully master the usage methods of the device.

II. Equipment Composition and Key Components

System Components

  • Measurement Units (M Unit and S Unit): Installed on the fixed end and the movable end respectively, transmitting data via wireless communication.
  • Display Unit E53: Equipped with a 5.7-inch color backlit display, featuring a built-in lithium battery that supports up to 30 hours of continuous operation.
  • Accessory Kit: Includes shaft brackets, chains, extension rods (60mm/120mm), measuring tapes, power adapters, and data management software, etc.

Technical Specifications

  • Resolution: 0.01 mm (0.5 mil)
  • Measurement Accuracy: ±5µm ±1%
  • Laser Safety Class: Class 2 (power <0.6mW)
  • Operating Temperature Range: -10°C to +50°C
  • Protection Rating: IP65 (dustproof and waterproof)

III. Equipment Initialization and Basic Settings

Display Unit Operation

  • Navigation and Function Keys: Use the directional keys to select icons or adjust values, and the OK key to confirm operations. Function key icons change dynamically with the interface, with common functions including returning to the previous level, saving files, and opening the control panel.
  • Status Bar Information: Displays the current unit, filtering status, battery level, and wireless connection status.
  • Screen Capture: Press and hold the “.” key for 5 seconds to save the current interface as a JPG file, facilitating report generation.

Battery and Charging Management

  • Charging Procedure: Connect the display unit using the original power adapter and charge up to 8 measurement units simultaneously via a distribution box.
  • Low Battery Alert: An LED red light flashes to indicate the need for charging, a green light flashes during charging, and remains lit when fully charged.
  • Temperature Considerations: The charging environment should be controlled between 0°C and 40°C, with faster charging speeds in the off state.

System Settings

  • Language and Units: Supports multiple languages, with unit options for metric (mm) or imperial (mil).

IV. Detailed Measurement Procedures

Horizontal Alignment (Horizontal Program)

  • Installation Steps: Fix the S unit on the stationary machine and the M unit on the movable machine, ensuring relative positional offset. Align the laser beams with the targets on both sides using adjustment knobs. When using wireless functionality, search for and pair the measurement units in the control panel.
  • Measurement Modes:
    • EasyTurn™: Allows recording three measurement points within a 40° rotation range, suitable for space-constrained scenarios.
    • 9-12-3 Mode: Requires recording data at the 9 o’clock, 12 o’clock, and 3 o’clock positions on a clock face.
  • Result Analysis: The interface displays real-time horizontal and vertical offsets and angular errors, with green indicators showing values within tolerance ranges.

Vertical Alignment (Vertical Program)

  • Applicable Scenarios: For vertically installed or flange-connected equipment.
  • Key Parameter Inputs: Include measurement unit spacing, bolt quantity (4/6/8), bolt circle diameter, etc.
  • Adjustment Method: Gradually adjust the machine base height and horizontal position based on real-time values or shim calculation results.

Softfoot Check

  • Purpose: To check if the machine feet are evenly loaded, avoiding alignment failure due to foundation distortion.
  • Operation Procedure: Tighten all anchor bolts. Sequentially loosen and retighten individual bolts, recording detector value changes.
  • Result Interpretation: Arrows indicate the machine tilt direction, requiring shim adjustments for the foot with the largest displacement.

V. Advanced Functions and Data Processing

Tolerance Settings (Tolerance)

  • Preset Standards: Based on rotational speed分级 (e.g., 0–1000 rpm corresponds to a 0.07mm offset tolerance), users can also customize tolerance values.

File Management

  • Saving and Exporting: Supports saving measurement results as XML files, which can be copied to a USB drive or associated with equipment data via barcodes.
  • Favorites Function: Save commonly used machine parameters as “FAV” files for direct recall later.

Filter Adjustment (Filter)

  • Function: Suppresses reading fluctuations caused by temperature variations or vibrations.
  • Setting Recommendations: The default value is 1, typically using levels 1–3 for filtering, with higher values providing greater stability but taking longer.

Thermal Compensation (Thermal Compensation)

  • Application Scenarios: Compensates for height changes due to thermal expansion during machine operation. For example, when thermal expansion is +5mm, a -5mm compensation value should be preset in the cold state.

VI. Calibration and Maintenance

Calibration Check

  • Quick Verification: Use a 0.01mm tolerance to lift the measurement unit by 1mm using shims and verify if the readings match the actual displacement.

Safety Precautions

  • Laser Safety: Never look directly into the laser beam or aim it at others’ eyes.
  • Equipment Warranty: The entire unit comes with a 3-year warranty, but the battery capacity warranty period is 1 year (requiring maintenance of at least 70% capacity).
  • Prohibited Scenarios: Do not use in areas with explosion risks.

VII. Troubleshooting and Technical Support

Common Issues

  • Unstable Readings: Check for environmental temperature gradients or airflow influences, and increase the filtering value.
  • Unable to Connect Wireless Units: Ensure that the units are not simultaneously using wired connections and re-search for devices in the control panel.

Service Channels

  • Equipment must be repaired or calibrated by certified service centers. Users can query global service outlets through the official website.

VIII. Conclusion

The Easy-Laser E420 significantly enhances the efficiency and accuracy of shaft alignment operations through intelligent measurement procedures and intuitive interactive interfaces. Users should strictly follow the manual steps for equipment installation, parameter input, and result analysis, while making full use of advanced functions such as file management and thermal compensation to meet complex operational requirements. Regular calibration and standardized maintenance ensure long-term stable operation of the equipment, providing guarantees for industrial equipment safety.

Posted on by

A Comprehensive Guide to Fault Diagnosis and Troubleshooting for ER.C90 in VEICHI SD700 Servo Drives

Introduction

In the realm of modern industrial automation, servo drives, as the core components of precision control systems, play a pivotal role. The VEICHI SD700 series servo drives are highly regarded for their high performance and reliability, finding widespread applications in fields such as CNC machine tools, robots, printing machinery, and packaging equipment. However, various faults may occur during the use of these products, among which the ER.C90 fault is relatively common, manifesting as encoder communication abnormalities. If not addressed promptly, such faults can not only disrupt production processes but also potentially lead to equipment damage or safety hazards.

Based on the detailed version of the VEICHI SD700 servo system manual and practical engineering experience, this article provides an in-depth analysis of the ER.C90 fault and offers a comprehensive and practical guide for diagnosis and troubleshooting. The aim is to assist engineers and technicians in quickly locating problems and enhancing system stability.

Overview of the SD700 Servo System

The VEICHI SD700 series servo drive is a high-performance AC servo system suitable for 200V and 400V voltage classes, supporting servo motors with power ranges from 100W to 7.5kW. This system employs advanced vector control technology, combined with high-resolution encoder feedback, to achieve closed-loop control, ensuring high precision and high dynamic response of the system.

Main Component Names and Functions of the System

  • Servo Drive Main Body: Includes a display panel, CHARGE indicator light, and CN series interfaces (such as CN1 control terminals, CN2 encoder interface, and CN7 USB communication terminal). The display panel is used to display status codes, fault codes, and parameter settings.
  • Servo Motor: Equipped with incremental or absolute encoders, supporting multi-turn absolute position feedback.
  • Encoder: The core feedback component, typically with a resolution of 17 or 24 bits, used to provide motor position and speed information.
  • System Block Diagram: The main circuit includes power input, regenerative resistor, and motor output; the control circuit involves PLC upper computers, I/O signals, and communication modules. The SD700 supports multiple communication protocols, such as RS485, CANopen, and EtherCAT, facilitating integration into industrial networks. An example of system composition includes an upper computer (such as a PLC), servo drive, motor, and load, forming a closed-loop control link.

Role of the Encoder in the Servo System

The encoder serves as a bridge connecting mechanical and electrical components, converting the physical motion of the motor into digital signals and providing real-time feedback to the drive. The SD700 servo system mainly uses optical incremental or absolute encoders with resolutions as high as 16,777,216 pulses per revolution (24 bits).

Working Principle of the Encoder

The encoder generates A, B, and Z phase signals (for incremental types) or multi-turn absolute position data (for absolute types) through optical or magnetic grating disks. These signals are transmitted to the drive via the CN2 interface, and the drive calculates the motor position, speed, and torque deviations accordingly to achieve PID closed-loop regulation. If communication is interrupted, the drive cannot obtain accurate feedback, leading to system out-of-control and triggering the ER.C90 fault.

Description of the ER.C90 Fault

The ER.C90 is a specific fault code for the VEICHI SD700 servo drive, displayed on the panel, such as a red LED showing “ER.C90”. This fault is classified as a “Class 1” alarm, meaning “encoder communication fault: disconnection.”

When the drive detects a loss or abnormality in the encoder signal, it immediately stops the motor output and triggers this alarm. Symptoms include:

  • The motor fails to start or stops suddenly.
  • The system reports an error and cannot enter the enabled state.
  • The upper computer monitoring shows zero or abnormal values for position feedback.

Analysis of Fault Causes

The root cause of the ER.C90 fault lies in the interruption of the communication link between the encoder and the drive. The main reasons include:

  • Signal wire disconnection or poor connection: Cable breakage due to bending, pulling, or aging during use. Loose or oxidized CN2 plugs can also cause poor contact.
  • Incompatible cable specifications: Using non-original cables or improper shielding layers can lead to signal distortion.
  • Excessive cable length: Exceeding the recommended length causes significant signal attenuation.
  • External interference: Electromagnetic interference from devices such as frequency converters and welding machines. Improper shielding grounding exacerbates the problem.
  • Motor or encoder damage: Failure of the internal photoelectric components of the encoder or wear of the motor bearings leading to unstable signals.
  • Incorrect parameter settings: Mismatched motor group parameters or incorrect drive power ratings.
  • Drive hardware failure: Damage to the communication module on the main board.

Diagnostic Steps

Diagnosing the ER.C90 fault requires a systematic approach, starting from simple to complex. Ensure that power is disconnected before operation to avoid the risk of electric shock.

  • Preliminary Inspection: Observe the panel display to confirm it is an ER.C90 fault. Use the manual FN000 to view the alarm records.
  • Cable Integrity Test: Use a multimeter to measure each signal wire of the CN2 interface to check for continuity and short circuits.
  • Connection Inspection: Check the CN2 and motor-end plugs for dust, dirt, or oxidation. Re-plug and test.
  • Cable Specification Verification: Measure the cable length and confirm that the model matches the requirements in the manual.
  • Interference Investigation: Check the shielding layer grounding and keep away from interference sources. Try adding magnetic rings for filtering.
  • Parameter Confirmation: Check parameters such as Pn000 (encoder type) and Pn100 (inertia ratio) for correctness.
  • Hardware Testing: Replace with spare cables or motors for testing.
  • Advanced Diagnosis: Connect the CN7 USB and use upper computer software to monitor Un003 (rotor position).

Solutions

Provide specific solutions for each cause:

  • Disconnection/poor connection: Replace the cable or tighten the plugs.
  • Incompatible specifications: Select the correct cable model and shorten the length.
  • Excessive cable length: Optimize the layout to reduce the length.
  • Interference: Improve grounding and add magnetic rings.
  • Hardware damage: Replace the encoder or motor.
  • Parameter errors: Reset the Pn parameters and restore factory settings before reconfiguration.
  • Drive failure: Contact VEICHI after-sales service to replace the unit.

Preventive Measures

Prevention is better than cure. The following strategies can reduce the incidence of the ER.C90 fault:

  • Regular maintenance: Check cables and connections every quarter and clean dust.
  • Environmental optimization: Install in ventilated cabinets to avoid high temperatures. Use EMI filters.
  • Cable management: Use fixed clips to secure cables and prevent pulling.
  • Parameter backup: Use the upper computer to export parameters for easy restoration.
  • Training: Train operators on correct installation to avoid misoperations.
  • Redundancy design: In critical applications, use dual encoders or wireless feedback.

Case Studies

  • Case 1: A printing factory using an SD700 servo drive for roller positioning suddenly encountered an ER.C90 fault, and the motor stopped. Diagnosis revealed a broken A-phase wire of the CN2 interface. Replacing the cable and adding a magnetic ring resolved the issue.
  • Case 2: A factory had a welding machine nearby with poor grounding, causing interference. Adding shielding resolved the ER.C90 fault.

Advanced Debugging Techniques

For stubborn faults, use the upper debugging tools in Chapter 14 of the manual:

  • Upper computer connection: Connect via the CN7 USB, install the driver, and open the software.
  • Real-time monitoring: View Un140 bus voltage and Un003 position feedback.
  • Digital oscilloscope: Capture the encoder signal waveform and analyze distortion.
  • Auxiliary functions: Perform FN105 vibration initialization and use EASYFFT to eliminate mechanical interference.

Conclusion

Although the ER.C90 fault is common, it can be efficiently resolved through systematic diagnosis and guidance from the manual. The VEICHI SD700 servo system is renowned for its high reliability, and correct maintenance can ensure long-term stable operation. This article provides a comprehensive reference, hoping to be of assistance. For more details, refer to the official manual or contact support.

Posted on by

Comprehensive Analysis of the Yaskawa Varispeed F7 PG Feedback Card — A Practical Study on the SI-P1 Ver 3.04

1. Introduction: The Role of the PG Card in Inverter Control Systems

In modern vector-control inverters, the PG card (Pulse Generator card) plays a central role.
It acts as an interface between the inverter and the motor encoder, acquiring high-precision rotational signals from the motor shaft and feeding them back to the inverter’s control CPU.
Through this feedback, the inverter can precisely detect speed, position, and rotational phase, enabling closed-loop vector control, zero-servo holding, stable-speed regulation, and torque compensation.

In Yaskawa’s Varispeed F7 series, the PG feedback card is not just an accessory—it is the core component that transforms the inverter from a standard open-loop V/f device into a high-performance vector drive.
With accurate speed feedback, the F7 achieves servo-level control precision, excellent dynamic response, and high stability even under heavy load variations.

This paper focuses on the SI-P1 Ver 3.04 PG card (code 73600-C0333 / SIP-901), an OEM version widely used in the F7 family.
By comparing it with the official PG-A2/B2/D2/X2 cards described in Yaskawa’s manuals, we analyze its structure, compatibility, wiring method, parameter configuration, and field performance in real industrial applications.

2. Technical Background — Function and Principle of PG Feedback

2.1 Basic Function of the PG Card

The PG card’s primary function is to receive incremental encoder signals (A, B, Z phases) and convert them into the internal pulse format that the inverter’s CPU can process.
Based on these pulses, the inverter continuously calculates the rotational speed, direction, and position deviation of the motor.

This closed-loop feedback enables several advanced control modes:

  • Speed Feedback Control — maintains a precise target RPM regardless of load fluctuation.
  • Torque Compensation — improves low-speed torque stability.
  • Zero-Servo Control — holds the motor shaft at a fixed mechanical position.
  • Regenerative Braking Control — enhances braking torque using feedback phase information.

The accuracy and signal integrity of the PG card determine the overall response time, torque precision, and stability of the system.

2.2 Common PG Cards Used with the Varispeed F7

ModelSignal TypeSupply VoltageTypical ApplicationRemarks
PG-A2Differential TTL (A/A¯, B/B¯, Z/Z¯)+5 VStandard incremental encodersMost widely used type
PG-B2Open-collector (single-ended A/B)+12 VNPN output encodersFor environments with higher noise
PG-D2Push-pull (A/B/Z quadrature)+15 VHeavy industrial, long-distance feedbackExcellent noise immunity
PG-X2High-speed TTL differential+5 VHigh-resolution / high-speed vector controlUsed in advanced servo applications

All four cards share the same mechanical interface and CN5 connector, but differ in electrical levels and signal types.
Among them, PG-A2 is the standard type used in most F7 applications.

3. Identifying the SI-P1 Ver 3.04 and Its Compatibility

Although the SI-P1 Ver 3.04 is not explicitly listed in the official F7 manual, practical testing and circuit comparison confirm that:

The SI-P1 Ver 3.04 is an OEM-equivalent version of the PG-A2 card.

The justification is as follows:

  1. Identical Signal Architecture
    The SI-P1 accepts differential inputs for A, /A, B, /B, Z, /Z, which perfectly matches the TTL line-driver interface of PG-A2.
  2. Same Power Requirements
    It provides an internal +5 V DC output (maximum 200 mA) for encoder supply—exactly like the PG-A2—and does not support 12 V or 15 V encoders.
  3. Same Physical Connector
    The card plugs directly into the F7 control PCB via the CN5 slot. Pin layout and dimensions are identical to the PG-A2.
  4. Firmware Generation
    The “Ver 3.04” label corresponds to the firmware generation period of early-2000s Yaskawa F7 inverters, when PG-A2 was the default model.

Hence, the SI-P1 card can be treated as functionally identical to PG-A2.
All wiring, parameter settings, and diagnostic methods described for PG-A2 apply equally to SI-P1.

4. Detailed Wiring between the SI-P1 and the Encoder

4.1 Terminal Definitions

PinSignal NameFunctionDescription
1+5 VEncoder Power SupplyProvides +5 V DC (≤ 200 mA)
20 VPower GroundCommon reference for encoder
3APhase A positiveForward rotation signal
4/APhase A negativeDifferential complement
5BPhase B positive90° shift from A
6/BPhase B negativeDifferential complement
7ZZero-mark signalOnce-per-revolution pulse
8/ZZero-mark complementOptional connection
FGFrame GroundConnect to shield of cable

Use twisted-pair shielded cable for each differential pair (A/A¯, B/B¯, Z/Z¯).
Connect the cable shield to FG at the inverter side only.

4.2 Typical Wiring Diagram

Encoder Side               SI-P1 PG Card
+5 V  ───────────────────────→  Pin 1 (+5 V)
0 V   ───────────────────────→  Pin 2 (0 V)
A    ───────────────────────→  Pin 3 (A)
A¯   ───────────────────────→  Pin 4 (/A)
B    ───────────────────────→  Pin 5 (B)
B¯   ───────────────────────→  Pin 6 (/B)
Z    ───────────────────────→  Pin 7 (Z)
Z¯   ───────────────────────→  Pin 8 (/Z)
Shield layer ─────────────→  FG (Ground)

This standard differential connection ensures noise immunity and reliable high-speed feedback, even under strong EMI conditions.

4.3 Electrical Precautions

  • Keep the encoder cable shorter than 20 m; for longer runs, use a differential line driver (RS-422 standard).
  • Never connect both ends of the shield to ground—do so only on the inverter side.
  • Verify the A/B phase shift (90° ± 10°) using an oscilloscope; reversed A/B causes inverted rotation detection.
  • Avoid running encoder cables in parallel with power cables.

5. Parameter Configuration and Commissioning

To enable the feedback loop, several parameters must be configured in the Varispeed F7:

ParameterDescriptionTypical SettingNotes
A1-02Control Mode Selection3“Vector control with PG”
F1-01Encoder Pulses per Revolutione.g., 1024 PPRMatch actual encoder
F1-03PG Input Type0Differential TTL input
E1-04Rotation Direction Logic0 or 1Depends on wiring
U1-05Monitor Speed Feedback–Used for verification

Commissioning Steps

  1. Open-loop Test
    Run the inverter without enabling PG feedback. Verify that the motor runs smoothly and direction matches your system.
  2. Enable Closed-Loop Mode
    Set A1-02 = 3 and cycle the power. The inverter now reads encoder feedback. Observe that the motor starts softly and maintains constant speed.
  3. Zero-Servo or Position Hold
    For applications requiring shaft holding, fine-tune parameters F1-05 to F1-07.
  4. Verification
    Check parameter U1-05 to ensure displayed speed matches the actual RPM measured by a tachometer.

6. Practical Field Experience and Case Studies

Case 1: Speed Feedback Optimization

A 37 kW Varispeed F7 inverter driving a conveyor motor used a 1024 PPR encoder.
After replacing a damaged PG-A2 with an SI-P1 Ver 3.04, the system was configured with:

  • A1-02 = 3
  • F1-01 = 1024
  • F1-03 = 0

Result:
Acceleration response improved from 100 ms to 40 ms, and steady-state speed fluctuation dropped below 0.3%.
The SI-P1 performed identically to the original PG-A2.

Case 2: Direction Error due to Reversed Phases

In a hoisting control system, swapping A/B signal pairs caused the inverter to misinterpret rotation direction, leading to oscillation.
After interchanging the A and B channels, feedback direction was corrected, and stability restored.

Case 3: Noise Interference and Shielding

A 15 m unshielded encoder cable caused ±5% speed variation due to EMI.
Replacing it with twisted-pair shielded cable and grounding only at the inverter side reduced fluctuation to ±0.2%.
Proper shielding proved critical for feedback reliability.

7. Signal Verification and Maintenance

Regular inspection of the PG system is essential for long-term stability.

7.1 Oscilloscope Test

Check A/B waveforms at the PG card input:

  • Duty cycle ≈ 50%
  • Phase shift ≈ 90°
    Distorted or noisy waveforms indicate cable damage or grounding issues.

7.2 Feedback Speed Monitoring

Under no-load constant-speed operation, monitor U1-05.
If speed fluctuates, inspect PG connections, encoder bearings, and connector pins.

7.3 Cleaning and Care

The PG card contains sensitive CMOS components.
Avoid dust or moisture.
Clean contacts periodically with isopropyl alcohol and ensure firm seating in the CN5 slot.

8. Signal Mapping Comparison: SI-P1 vs PG-A2

FunctionSI-P1 PinPG-A2 PinRemark
+5 V Supply11Encoder Power
0 V Ground22Common Ground
A Signal33Differential +
/A Signal44Differential –
B Signal55Differential +
/B Signal66Differential –
Z Signal77Zero Pulse
/Z Signal88Complement Zero
FG ShieldFGFGCable Shield Ground

The one-to-one correspondence confirms that SI-P1 can replace PG-A2 without modification.

9. Engineering Discussion and Technical Insights

  1. Functional Equivalence
    The SI-P1 Ver 3.04 is a fully compatible PG-A2 card, supporting all F7 feedback control modes including vector, torque, and zero-servo functions.
  2. Signal Quality is Paramount
    Differential signal integrity and proper grounding are more critical than parameter tuning.
    Incorrect grounding can produce random “PG Loss” or “OV” faults.
  3. Parameter Matching
    Always set the correct encoder PPR (F1-01) and direction logic (E1-04) to avoid instability or reverse torque.
  4. Maintenance Importance
    Connector oxidation and vibration loosening are common causes of intermittent speed errors.
    Regular re-seating of the card ensures reliability.
  5. Cost-Effective Substitution
    For legacy F7/G7 systems, the SI-P1 serves as an excellent, low-cost replacement for discontinued PG-A2 cards without any firmware or wiring change.

10. Conclusion

The Yaskawa Varispeed F7 remains one of the most reliable inverter platforms in industrial automation.
As the key interface between the drive and the motor’s feedback device, the PG card is indispensable for achieving high-performance vector control.

Through detailed examination, this study confirms that SI-P1 Ver 3.04 is technically equivalent to the PG-A2 model.
It shares the same wiring, electrical characteristics, and parameter settings.
When properly connected and configured (A1-02 = 3), it enables full closed-loop operation with high accuracy and stability.

For field engineers, understanding this equivalence provides a major advantage—allowing quick replacement, reduced downtime, and seamless integration in maintenance or retrofit projects.

11. Summary of Best Practices

  • Always use shielded twisted-pair cable, one pair per differential channel.
  • Ground the shield at one end only (inverter side).
  • Verify A/B phase direction before enabling closed-loop mode.
  • Configure feedback parameters carefully according to the encoder specifications.
  • Periodically check the CN5 slot and card contacts for corrosion or dust.

By following these practices, the SI-P1 PG feedback system can deliver long-term precision and reliability comparable to servo-class control systems.

Author’s Note

This article is written as an original technical analysis for maintenance engineers, automation specialists, and industrial electronics technicians who maintain or retrofit Yaskawa Varispeed F7 inverters.
It integrates both manual specifications and real-world experience gathered from field repairs and performance testing.

Posted on by

Technical Analysis and Application of Startup Display Diagnosis from “1.d002” to “00ST” in Leadshine L7 Series Servo Drives

Abstract
The Leadshine L7 series AC servo drives are crucial components in the field of industrial automation. The startup display sequence reflects the device’s initialization status and operational readiness. This paper provides an in-depth analysis of the phenomenon where users observe a brief display of “1.d002” followed by a switch to “00ST,” indicating a normal initialization process. By interpreting the manual, safety precautions, and incorporating online resources from similar EL7 series, it explores the meanings of display codes, diagnostic methods, potential causes, and optimization strategies, aiming to offer comprehensive guidance to engineers and technicians.

Introduction
In modern industrial automation systems, servo drives play a pivotal role. The Leadshine L7 series AC servo drives utilize the latest DSP from Texas Instruments (TI), featuring high integration and reliability. Users often encounter startup display issues, such as the display showing “1.d002” briefly after power-on, followed by a switch to “00ST.” This paper centers on this phenomenon, conducting a systematic analysis by combining excerpts from the user manual and online resources, aiming to assist users in understanding the technical implications of the display sequence and providing practical diagnostic steps.

Servo Drive Fundamentals

Basic Principles

Servo drives drive servo motors to achieve precise motion by receiving command signals from an upper-level controller. The fundamental principles include triple-loop control (position loop, speed loop, and current loop), with PID algorithms at the core.

L7 Series Characteristics

The L7 series belongs to AC servo drives, supporting 220VAC input and a wide power range. The manual emphasizes that improper operation can lead to severe consequences, and users must adhere to safety precautions.

Key Components and Initialization

The key components of a servo system include the drive, motor, and encoder. The drive integrates a DSP processor, and the initialization process involves self-tests, parameter loading, and status monitoring.

Display Panel Basics

The display panel employs a seven-segment LED digital tube, supporting status display, parameter settings, and alarm prompts. Understanding these codes is crucial for diagnosing device status.

Control Modes and Parameter Settings

Servo drives offer control modes including position, speed, and torque modes. Parameter settings are achieved through panel buttons or MotionStudio software.

Safety Guidelines

The manual stresses that product storage and transportation must comply with environmental conditions, and user modifications will void the warranty.

Overview of the L7 Series

Product Features and Updates

The Leadshine L7 series is a fully digital AC servo drive, utilizing TI DSP, supporting stiffness tables, inertia identification, and vibration suppression. The version has evolved from V1.00 to V2.10 with continuous updates.

Application Areas and Manual Structure

The L7 series finds wide applications in PLC control, robotic arms, and other fields. The manual structure covers the preface, safety matters, specifications, installation, wiring, commissioning, and maintenance.

Wiring and Version Descriptions

Wiring includes power, motor, encoder, and I/O ports. The version description indicates program compatibility and content updates.

Display Panel in Detail

Operation Interface and Key Functions

The L7 drive’s operation interface consists of a 6-digit LED digital tube and 5 keys for status display and parameter settings.

Initialization and Monitoring Mode Codes

Upon power-on, the panel first displays initialization codes. “1.d002” may be a custom or transient display, and switching to “00ST” indicates a standby state. Monitoring mode codes include position deviation, motor speed, etc.

Alarm Code Interpretation

Alarm codes start with “Er,” and the absence of “Er” indicates normal operation.

Diagnostic Analysis

Core Phenomenon Interpretation

The display showing “1.d002” briefly followed by a switch to “00ST” is a normal sequence. The initialization process includes self-tests and parameter loading.

Potential Causes Explored

Potential causes include normal boot-up, configuration influences, and external factors.

Diagnostic Steps and Methods

Diagnostic steps include checking the display history, software verification, and factory reset.

Troubleshooting

Non-Normal Situation Exclusion Methods

If non-normal, exclusion methods include power supply checks, wiring verification, parameter resets, and software tuning.

Common Faults and Solutions

Common faults such as overcurrent and overload are unrelated to the display sequence.

Applications and Optimization

Case Studies: CNC Machine Tools and Robotic Arms

Case 1: A CNC machine tool uses the L7 to control axes, and a normal startup sequence ensures precision. Case 2: A robotic arm in bus mode uses EtherCAT synchronization to avoid delays.

Optimization Strategies and Future Trends

Optimization strategies include adjusting control modes and vibration suppression. Future trends involve integrating AI tuning.

Conclusion
The transition from “1.d002” to “00ST” indicates a normal state. Mastering diagnostic methods can enhance application efficiency. It is recommended to refer to the manual and technical support to ensure stable system operation.

Posted on by

In-Depth Analysis and Maintenance Practices for Mitsubishi FR-A700 Inverter “E.7” CPU Error

I. Introduction: When the Brain of the Drive Crashes

The Mitsubishi FREQROL-A700 inverter series is renowned for its high-performance vector control, stable communication capabilities, and comprehensive protection functions. It is widely used in CNC machines, plastic molding equipment, air compressors, hoists, and a variety of industrial automation lines.

However, when the display shows “E.7” or “E.CPU”, the inverter immediately halts output, and the entire system comes to a standstill. This is often referred to by technicians as a “brain crash,” as it indicates a critical failure of the inverter’s central processing unit (CPU).

Among all protection codes, E.7 is one of the most severe. It typically signals that internal communication between control units has failed, logic processes have become unstable, or the CPU hardware itself has malfunctioned.
This article offers a comprehensive technical exploration of the E.7 (CPU Error) fault — its causes, diagnostic methods, hardware implications, repair solutions, and preventive measures — supported by real industrial case studies.

II. Understanding the Fault and System Logic

According to the FR-A700 User Manual (page 397):

E.6 / E.7 / E.CPU – CPU Error
When an internal CPU communication error occurs, the inverter stops output.
Inspection Point: Check if there are devices around the inverter that generate strong electrical noise.
Measure: If no external interference is found, contact the supplier or Mitsubishi service center.

This indicates that E.7 is a system-level protection event.
The inverter’s internal logic continuously monitors communication between the main CPU, gate driver interface, and memory/control buses. If any communication timeout or checksum failure occurs, the CPU triggers a protective shutdown to prevent unpredictable IGBT switching or hardware damage.

The main CPU fault logic in the FR-A700 involves:

  1. Abnormal communication between the main processor and gate drive circuits.
  2. Data corruption or response failure in EEPROM, ADC, or communication ICs.
  3. Watchdog timer reset caused by logic hang or power fluctuation.

When the watchdog detects that the CPU fails to respond within its monitoring period, the system declares a “CPU Communication Error” and displays E.7.

III. Technical Causes of the CPU Error

The E.7 fault generally stems from three major categories of issues:

  1. Electromagnetic interference (EMI)
  2. Power supply instability
  3. Internal control board failure

1. Electromagnetic Interference (EMI)

Industrial sites are rich in high-frequency noise sources — welding machines, large contactors, induction heaters, and switching power supplies. These generate voltage spikes and transient electromagnetic waves that couple into the control board’s circuits, disturbing the CPU clock or data bus.

Typical EMI sources include:

  • Arc welders or high-frequency induction furnaces
  • Contactors or solenoid valves switching nearby
  • Control signal lines routed in parallel with power cables
  • Improper or floating grounding systems

In such cases, E.7 may occur intermittently, often clearing after power cycling — a sign that transient interference is affecting the CPU.

Technical Recommendations:

  • Separate control wiring from power cables (minimum 10 cm apart).
  • Use twisted shielded cables for control and communication lines.
  • Ground all shields at one single point only.
  • Install proper EMI filters and ferrite cores on input lines.

2. Power Supply Fluctuations or Grounding Issues

The FR-A700 series contains multiple voltage rails — DC bus (≈540 VDC), control voltage (24 VDC), and logic voltage (5 VDC).
When any of these experience transient drops due to unstable input voltage, aging capacitors, or poor grounding, the CPU watchdog may trigger an internal reset, leading to an E.7 CPU Error.

Typical symptoms:

  • E.7 appears immediately upon power-up
  • Random alternation between E.6 and E.7
  • Display flickering or panel freezing

Diagnostic Points:

  1. Measure three-phase input balance and verify stable voltage.
  2. Check DC bus voltage ripple — excessive ripple suggests degraded capacitors.
  3. Measure 24V and 5V supply rails; ensure no drop below tolerance.
  4. Inspect the grounding system — avoid shared return paths with external PLCs or IO devices.

3. Hardware Failure on Control or Power Board

If E.7 persists after confirming stable power and minimal EMI, the most likely cause is a hardware fault.

Common hardware-related sources:

  • Damaged main CPU (e.g., Renesas or Mitsubishi custom MCU)
  • Failed EEPROM or memory IC communication
  • Broken optocouplers (HCPL-2631, etc.) between logic and driver circuits
  • Poor connection between control board and power board
  • Feedback interference caused by a shorted IGBT module

Observable signs:

  • Instant E.7 alarm at power-up
  • Unable to reset via panel or RES signal
  • FR-Configurator2 communication fails
  • No clock signal detected on the CPU oscillator

In this situation, replacing the control PCB or even the entire inverter is often the most efficient solution.

IV. Step-by-Step Diagnostic Procedure

A systematic diagnostic process can help quickly isolate the E.7 cause.

Step 1: Record and Observe

  • Note when the error occurs (during start, stop, idle, or communication).
  • Observe whether the fault happens after brief power loss.
  • Check ambient temperature (CPU overheating can cause instability).

Step 2: Insulation and Ground Testing

  • After disconnecting power and waiting at least 10 minutes, measure insulation resistance (>5 MΩ) between main terminals and ground.
  • Ensure no short between control circuits and main circuit.

Step 3: Check for Interference and Grounding Issues

  • Verify that PE grounding resistance is below 10 Ω.
  • Ensure all power cables are symmetrical (balanced three-phase).
  • Avoid “loop grounds” by ensuring star-point grounding topology.
  • For RS-485 or CC-Link communication, ground the shield at one end only.

Step 4: Monitor Power Rails

  • Use an oscilloscope to monitor 24V and 5V supplies; ensure minimal ripple (<100 mV).
  • Confirm the DC bus is steady without oscillation when idle.

Step 5: Module-Level Inspection

  • Re-seat the operation panel and connectors between boards.
  • Examine ribbon cables for oxidation or loose pins.
  • Swap with a known-good control board if available.
  • If error persists → replace power board or complete drive.

V. Repair and Replacement Strategies

1. Component-Level Control Board Repair

Qualified service technicians can:

  • Verify CPU clock oscillator output (16–20 MHz typical).
  • Check watchdog timer pulse (ICs like 74HC123).
  • Replace EEPROM, voltage regulators, or capacitors.
  • Re-solder cracked joints and clean carbon residue.
  • Add low-ESR capacitors (e.g., 47 µF × 2) near CPU power pins to enhance filtering.

2. Inverter Replacement and Parameter Recovery

When the board is irreparable:

  • Use FR-Configurator2 to back up parameters before removing the unit.
  • Install the new inverter, then restore parameters via copy function (Pr.990–Pr.999).
  • Run auto-tuning (Pr.71, Pr.80–Pr.84) to recalibrate motor characteristics.

3. Environmental Hardening

For long-term stability:

  1. Add EMI filters or isolation transformers on input side.
  2. Install surge absorbers (MOVs) between R/S/T lines.
  3. Route control and power cables separately.
  4. Maintain good cabinet ventilation and cleanliness.

VI. Case Study: CPU Error in Injection Molding Machine

An FR-A740-22K-CHT inverter was used as the main drive in a plastic injection molding machine. The unit displayed E.7 intermittently; resetting restored operation temporarily.

Investigation findings:

  • Three inverters were installed side-by-side in the same panel.
  • Control signal cables ran parallel to motor leads.
  • Ground connections were multi-pointed, creating loops.
  • Heavy dust on control board and fan filter.

Corrective actions:

  1. Re-routed control cables with shielded twisted pairs.
  2. Implemented star-point grounding.
  3. Added 100 µF capacitor to 5V rail on control board for ripple suppression.
  4. Cleaned dust and re-seated connectors.

After these measures, the machine ran for 72 hours continuously without reoccurrence.
Conclusion: E.7 was caused by EMI-induced communication loss rather than true CPU failure.

VII. Relationship Between Related Error Codes

CodeDescriptionMeaningCorrelation
E.6CPU Communication Error ACommunication loss in main logic channelOften co-occurs with E.7
E.7CPU Communication Error BInternal bus or logic timing faultMay escalate to E.CPU
E.CPUCPU Hardware FaultCPU self-check failure or watchdog timeoutSevere or persistent E.6/E.7

If E.6, E.7, and E.CPU alternate rapidly, it typically indicates either a logic power fault or crystal oscillator failure.

VIII. Preventive Engineering Practices

1. During Electrical Design

  • Provide dedicated grounding bars (no shared returns).
  • Use separate grounding cables for each inverter.
  • Add RC snubber circuits or line filters on power input.
  • Use crimp terminals for all wiring to prevent loose contacts.

2. During Installation and Commissioning

  • Test motor insulation before wiring to inverter.
  • Avoid long, unshielded communication lines.
  • Use optical isolation modules when interfacing PLCs.

3. During Routine Maintenance

  • Clean cooling channels and fans every 6 months.
  • Check fan bearings and noise levels.
  • Measure DC bus capacitor ESR annually.
  • Use heaters or dehumidifiers in damp environments.

4. Backup and Record Management

  • Regularly back up parameters via FR-Configurator2 or PU unit.
  • After replacing the control board, verify calibration parameters.
  • For aging units, perform preventive replacement of capacitors and relays.

IX. Technical Insights and Summary

The E.7 fault in the Mitsubishi FR-A700 series is a CPU communication error — a high-level protection mechanism that prevents erratic operation when the internal logic loses synchronization.
It does not relate to mechanical load or overcurrent events, but rather to the integrity of digital control.

Based on field experience, E.7 can be categorized into three scenarios:

TypeRoot CauseSolution
IntermittentElectrical noise or unstable powerImprove grounding and filtering
RecurrentLoose connectors, aged componentsMaintenance and board cleaning
PersistentDamaged CPU or control boardReplace control board or full unit

Following the logical troubleshooting flow — external causes → power check → control circuit diagnosis — enables engineers to identify the root problem quickly and avoid unnecessary replacements.

In preventive terms, a robust EMC design and proper grounding layout remain the most effective strategies to eliminate CPU communication errors in high-frequency drive systems.

X. Practical Recommendations

  • For environments with frequent E.7 errors, consider using a 1:1 isolation transformer (2 kVA or above) for the inverter’s control supply.
  • In high-temperature cabinets (>45°C), add external forced-air cooling.
  • For long-distance communication, use optical fiber isolation modules instead of RS-485 copper lines.
  • For multi-inverter systems, use independent control power supplies for each unit.

Conclusion

The E.7 CPU Error is not simply a nuisance fault — it is an intelligent self-protection feature designed to prevent catastrophic failure in the Mitsubishi FR-A700 inverter series.
Understanding its electrical, logical, and environmental causes allows engineers to perform accurate diagnostics, avoid misjudgment, and reduce downtime.

In today’s automation landscape, where system reliability and electromagnetic compatibility (EMC) are paramount, addressing E.7 is not merely about fixing an error — it’s about building resilience into every layer of the control system.

Posted on by

User Guide for EST900 Series Inverter from Yiste: A Comprehensive Analysis from Operation to Troubleshooting

The EST900 series inverter from Yiste, as a high-performance vector inverter, is widely applied in the control and speed regulation of three-phase asynchronous motors. This article, based on the official manual, will elaborate in detail on its operation panel functions, parameter setting methods, external terminal control and speed regulation implementation, as well as handling measures for common fault codes, helping users quickly master the usage skills.

I. Introduction to Operation Panel Functions and Parameter Settings

(A) Overview of Operation Panel Functions

The EST900 series inverter comes standard with an LED operation panel, which offers a variety of functions:

  • Status Monitoring: It can display key information such as operating frequency, current, voltage, and fault codes in real time.
  • Parameter Setting: It supports viewing and modifying functional parameters.
  • Operation Control: Control commands such as start, stop, and forward/reverse rotation can be executed through the panel.
  • Indicator Lights: It is equipped with indicator lights including RUN (operation), LOCAL/REMOT (control source), FWD/REV (direction), and TUNE/TC (tuning/torque/fault), which visually reflect the equipment status.

(B) Factory Parameter Settings

During debugging or when parameters are in disarray, a factory reset operation can be performed:

  • Steps:
    • Enter the FP – 01 parameter.
    • Set it to 1 (restore factory parameters, excluding motor parameters).
    • Press the ENTER key to confirm.
    • Wait for the display to restore, indicating parameter initialization is complete.
  • Notes:
    • FP – 01 = 2 can clear fault records and other information.
    • FP – 01 = 4 can back up the current parameters.
    • FP – 01 = 501 can restore the backed-up parameters.

(C) Password Setting and Clearing

To prevent misoperation, a user password can be set:

  • Setting a Password:
    • Enter FP – 00 and set it to a non-zero value (e.g., 1234).
    • After exiting, the password needs to be entered when accessing parameters again.
  • Clearing a Password:
    • Set FP – 00 to 0.

(D) Parameter Access Restrictions

Parameter access can be restricted in the following ways:

  • Parameter Group Display Control:
    • Set the FP – 02 parameter to control whether Group A and Group U parameters are displayed.
    • For example, setting it to “11” can hide some parameter groups to prevent mismodification.
  • Prohibition of Modification during Operation:
    • Some parameters marked with “★” cannot be modified during operation and need to be set after shutdown.

II. External Terminal Forward/Reverse Rotation Control and Potentiometer Speed Regulation

(A) External Terminal Forward/Reverse Rotation Control

  • Wiring Terminals:
    • D11: Forward rotation (FWD)
    • D12: Reverse rotation (REV)
    • COM: Digital input common terminal
  • Parameter Settings:
    | Parameter Code | Name | Setting Value | Description |
    | —- | —- | —- | —- |
    | F0 – 02 | Operation Command Selection | 1 | Terminal control |
    | F4 – 00 | D11 Function Selection | 1 | Forward rotation |
    | F4 – 01 | D12 Function Selection | 2 | Reverse rotation |
    | F4 – 11 | Terminal Command Mode | 0 | Two-wire type 1 |
  • Note: If a three-wire control system is used, set F4 – 11 = 2 or 3 and cooperate with other DI terminals.

(B) External Potentiometer Speed Regulation

  • Wiring Terminals:
    • +10V: Positive pole of potentiometer power supply
    • GND: Negative pole of potentiometer power supply
    • A11: Analog voltage input (0 – 10V)
  • Parameter Settings:
    | Parameter Code | Name | Setting Value | Description |
    | —- | —- | —- | —- |
    | F0 – 03 | Main Frequency Command Selection | 2 | A11 |
    | F4 – 13~F4 – 16 | A11 Curve Settings | Adjust according to actual conditions | Minimum/maximum input corresponds to frequency |
  • Tip: It is recommended that the potentiometer resistance be between 1kΩ and 5kΩ to ensure that the current does not exceed 10mA.

III. Common Fault Codes and Handling Methods

The EST900 series inverter has a comprehensive fault diagnosis function. The following are common faults and their handling methods:

(A) Overcurrent Faults

Fault CodeNamePossible CausesHandling Measures
Err02Acceleration OvercurrentMotor short circuit, too short acceleration timeCheck motor insulation, increase acceleration time
Err03Deceleration OvercurrentShort deceleration time, large load inertiaIncrease deceleration time, install a braking resistor
Err04Constant-speed OvercurrentLoad mutation, mismatched motor parametersCheck the load, perform motor tuning again

(B) Overvoltage Faults

Fault CodeNamePossible CausesHandling Measures
Err05Acceleration OvervoltageHigh input voltage, external force during accelerationCheck power supply voltage, enable overvoltage suppression
Err06Deceleration OvervoltageShort deceleration time, energy feedbackIncrease deceleration time, install a braking unit
Err07Constant-speed OvervoltageExternal force dragging during operationCheck the mechanical system, enable overvoltage suppression

(C) Other Common Faults

Fault CodeNamePossible CausesHandling Measures
Err09Undervoltage FaultLow power supply voltage, rectifier bridge faultCheck the power supply, measure the bus voltage
Err10Inverter OverloadExcessive load, undersized selectionCheck the load, replace with a higher-power inverter
Err11Motor OverloadExcessive motor load, improper protection parameter settingAdjust the F9 – 01 motor overload gain
Err14Module OverheatingPoor heat dissipation, fan faultClean the air duct, replace the fan
Err16Communication FaultWiring error, improper parameter settingCheck the communication line, set FD group parameters

(D) Fault Reset Methods

  • Press the STOP/RESET key on the panel.
  • Set a DI terminal to the “Fault Reset” function (F4 – xx = 9).
  • Write “2000H = 7” through communication.
  • Power off and restart (wait for more than 10 minutes).

IV. Conclusion

The Yiste EST900 series inverter is powerful and flexible in operation, capable of adapting to various industrial scenarios. Through the introduction in this article, users can master the following key contents:

  • Basic usage methods of the operation panel and parameter setting skills.
  • How to control and regulate the speed of the motor using external terminals and a potentiometer.
  • Diagnostic ideas and handling skills for common faults.
  • Effective use of password management and parameter protection mechanisms.
    During actual use, it is recommended that users strictly follow the manual specifications for wiring and parameter setting, and regularly carry out maintenance work to ensure the long-term stable operation of the equipment.