Category: Mitsubishi

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Operation Guide for Mitsubishi VFD FR-D700 （D740,D720）Series User Manual

I. Introduction to VFD Operation Panel Functions
The operation panel of the Mitsubishi VFD FR-D700 series(D740,D720) is straightforward, facilitating various settings and operations for users. The panel primarily includes the following buttons and a rotary potentiometer:

Mitsubishi VFD FR-D700 Operation Panel Function Diagram

RUN: Press this button to start the VFD.
STOP/RESET: Press this button to stop the VFD or reset alarms.
MODE: Mode switching button used to toggle between different setting and display modes.
SET: Confirmation button used to confirm current settings or enter the next menu level.
PU/EXT: Operation mode switching button used to switch between PU (operation panel) mode and EXT (external terminal) mode.
Rotary Potentiometer: Used to manually adjust the output frequency of the VFD.

Setting Operation Modes
The VFD offers multiple operation modes, which can be set via parameter P79:

P79=0: PU operation mode, controlled via buttons and the rotary potentiometer on the operation panel.
P79=2: External operation mode, receiving start, stop, and speed commands via external terminals.

II. Terminal Start/Stop and External Potentiometer Speed Adjustment
Wiring Instructions
To achieve terminal start/stop and external potentiometer speed adjustment, proper wiring to the corresponding terminals of the VFD is required. Typically, the wiring is as follows:

STF (Forward Start): Connect to the normally open contact of an external start button or relay.
STR (Reverse Start): If reverse function is needed, connect to the normally open contact of an external reverse start button or relay.
SD (Stop): Connect to the normally closed contact of an external stop button or relay.
RH, RM, RL (Speed Setting): These terminals are typically used to connect an external potentiometer for speed adjustment. Among them, RH and RL are connected to the two ends of the potentiometer, and RM is connected to the sliding contact of the potentiometer.

Parameter Settings
Apart from proper wiring, relevant parameters need to be set to ensure the VFD operates as expected:

P79: Set to 2 to select external operation mode.
Pr7, Pr8: Set acceleration and deceleration times respectively to suit different application needs.
Pr9: Set the electronic overcurrent protection parameter to protect the VFD and motor from overcurrent damage.

Mitsubishi VFD FR-D700 Series External Wiring Diagram

III. VFD Fault Code Analysis and Solutions
When faults occur in the Mitsubishi VFD FR-D700 series, corresponding error codes are displayed, allowing users to analyze and resolve the faults. Below are some common fault codes and their solutions:

ER1: Overcurrent during acceleration. Check if the motor is overloaded, if there is a short circuit in the output, and if the acceleration time is set too short.
ER2: Overcurrent during constant speed. Check for sudden changes in load, and if there is a short circuit in the output.
ER3: Overcurrent during deceleration. Check for rapid deceleration, if there is a short circuit in the output, and if the motor’s mechanical brake is applied too early.
OL: Overspeed prevention (overcurrent). Check if the motor is overloaded.
TH: Motor overheat. Check if the motor is operating overloaded for a long time, if the ambient temperature is too high, and if the cooling system is functioning properly.
PS: PU stop. Check if the STOP button on the operation panel is pressed.
MT: Main circuit terminal abnormality. Check if the connections of the main circuit terminals are loose or damaged.
uV: Undervoltage protection. Check if the power supply voltage is too low, and if there is a large-capacity motor starting up causing instantaneous voltage drop.

Solutions
For overcurrent faults (ER1, ER2, ER3, OL): First, check if the motor and load are normal, then adjust acceleration time, deceleration time, and electronic overcurrent protection parameters.
For overheating faults (TH): Improve the motor’s cooling conditions, such as adding fans or lowering the ambient temperature.
For PU stop (PS): Confirm if the STOP button was pressed by mistake; if not, check the related control circuits.
For main circuit terminal abnormality (MT): Check and tighten the connections of the main circuit terminals, and replace if damaged.
For undervoltage protection (uV): Check if the power supply voltage is stable, and consider adding a power supply voltage stabilizing device.

The above is the operation guide for the Mitsubishi VFD FR-D700 series user manual, hoping to assist users in practical operations. If encountering other issues during use, it is recommended to refer to the detailed user manual of the VFD or contact professional technicians of longi for consultation.

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Mitsubishi FX1S Switching Power Supply Maintenance and STRG6551 Chip Circuit Analysis and Circuit Diagram

This article presents an in-depth analysis of the Mitsubishi FX1S PLC switching power supply board, focusing on its circuit schematic diagram and the STRG6551 chip. The power supply board features two isolated 24V outputs and provides a 5V supply for the motherboard through voltage reduction. These outputs are isolated via L2 bidirectional filters, which also serve to block high-frequency interference pulses, enhancing system stability.

Mitsubishi FX1S PLC switching power supply board

Circuit Working Principle:
The 220V power supply enters the power board through the L and N terminals. C1, C2, C4, and L1 form a bidirectional low-pass filtering network, with L1 and L2 performing similar functions. Dual fuses F1 and TH1 protect the circuit, with F1 serving as an overload protection quick fuse and TH1 as a temperature fuse. After rectification, the mains power is converted to a DC voltage of about 280V, which is then applied to the primary switch transformer TB1’s oscillation and voltage stabilization circuit, centered around the STRG6551 power oscillation module.

STRG6551 Chip Analysis:
Despite limited available information on the STRG6551 chip, its pin functions can be inferred from the circuit structure. Pins 4 and 3 are used for power supply, while pins 1 and 2 are internally connected to the source and drain of a power switch (MOS) transistor. Pin 5 introduces feedback voltage. The STRG6551 functions similarly to the common U3844 switch mode power supply oscillator.

Circuit Analysis:
The circuit can be divided into three main branches: (1) the oscillation circuit, (2) the voltage stabilizing circuit, and (3) the protection circuit.

  1. Oscillation Circuit: The rectified 280V DC voltage is reduced to 30V through R1, R11, and D5, and then supplied to pin 4 of STRG6551. The secondary winding of TB1 provides the working power supply for STRG6551.
  2. Voltage Stabilizing Circuit: TB1’s winding 2 induces voltage, which is rectified and filtered by D4 and C10. This voltage serves as the overall working power supply for the PLC. The stability of this voltage is crucial for the PLC’s performance. R9, IC2, and the PC1 output voltage sampling circuit are used to maintain voltage stability.
  3. Protection Circuit: R2 serves as the sampling resistance for the internal MOCS switching tube’s working current. In case of abnormal load or input, the protection circuit will disconnect the driving circuit of the switch tube, stopping oscillation and protecting the circuit. Additionally, D6 provides a discharge path for the magnetic field energy stored in the transformer, protecting the switch tube from overvoltage breakdown.
Mitsubishi FX1S PLC Switching Power Supply Circuit Schematic

Repairing the Switching Power Supply:
A common fault in switching power supplies is the lack of output voltage. This can be caused by various reasons, including blown fuses, abnormal load, or circuit malfunctions. To troubleshoot, it is important to first distinguish whether the fault lies in the oscillation circuit or the voltage stabilization circuit. By disconnecting the PLC motherboard and using a voltage regulator to set the input voltage below AC100V, one can test the circuit’s response and identify the faulty component.

In conclusion, understanding the working principle and circuit structure of the Mitsubishi FX1S PLC switching power supply board, as well as the function of the STRG6551 chip, is crucial for effective troubleshooting and repair. By adopting reasonable maintenance steps and scientific methods, one can improve maintenance efficiency and ensure the stable operation of the PLC system.

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Testing Method for Offline Operation of Mitsubishi MR-J3 Servo Driver Maintenance Board

When repairing Mitsubishi servo drives, encountering damaged modules is common. After repairing such modules, it’s crucial to test the drive board’s output function offline before reinstallation. This article provides a detailed guide for testing a repaired Mitsubishi MR-J3-350A/3.5KW servo module.

Mitsubishi Servo MR-J3 Circuit Board Maintenance Test Diagram

Preparation for Offline Testing:

  1. Power Connection: Connect 300V DC voltage to power boards P2 and N to avoid E9 fault after power-on.
  2. Module Pad Hole Shielding:
    • Connect the 10 pins of the module pad hole to N.
    • Connect pad holes U, V, W to N to prevent AL24 fault.
    • Connect pad holes EV, EU, EW (upper axle drive trigger) to N.

Parameter Setting Before Running:

  1. Change PA01: Set PA01 to 0002.
  2. Change PD01: Set PD01 to 0000.
  3. Power Board Connection: Connect P and D on the power board.
  4. Additional Power Board Connections: Connect L1 to L11 and L2 to L12 on the power board.
    • If PD parameters are not visible, change PA19 to 000C and power on again.
Mitsubishi servo MR-J3 drive circuit actual pulse state

Testing Process:

  • After following the above steps, power on and run the servo to test its 6-way waveform.
  • During parameter waveform testing, manually rotate the motor shaft to observe changes in pulse width and phase in the waveform. Note that this machine does not have a static cut-off negative voltage.

By following this comprehensive guide, you can effectively test the offline operation of a repaired Mitsubishi MR-J3 servo driver maintenance board, ensuring its functionality before reinstallation.