Displacement Sensors Explained: Working Principle, Usage, Common Faults, and Repair Guide

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Displacement sensors, also known as linear sensors, are devices used to measure the position changes of objects or structures. They convert the displacement of an object relative to a reference point into electrical signals, enabling monitoring and control of position changes. Displacement sensors are widely used in industrial automation, structural monitoring, healthcare, automotive engineering, and more.

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I. Working Principle of Displacement Sensors

Displacement sensors consist of a sensing element and a conversion element. The sensing element detects the position change of the measured object, while the conversion element translates this change into electrical signals or other forms of output. Based on their working principles, displacement sensors are classified into several types:

1. Inductive Displacement Sensors: Measure position changes by detecting variations in inductance. Typically composed of a fixed coil and a movable coil, where the inductance changes as the movable coil approaches or recedes from the fixed one.
2. Capacitive Displacement Sensors: Measure position changes by detecting variations in capacitance between two parallel plates, one of which is movable.
3. Photoelectric Displacement Sensors: Utilize light reflection and transmission to detect position changes, using a light source, receiver, and movable reflector.
4. Hall Effect Displacement Sensors: Rely on the Hall effect, where a magnetic field change induces a measurable voltage in a semiconductor material, indicating position changes.

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II. How to Use Displacement Sensors

Using the 4000TDZ-A displacement sensor as an example, it is mainly used to measure radial and axial displacements of shafts to monitor vibrations during equipment operation. The steps for proper use are as follows:

1. Identify the Measurement Points: Select appropriate measurement points based on equipment and vibration requirements. Measurement points should generally be along the centerline of the equipment.
2. Install the Sensor: Fix the sensor securely at the measurement point, ensuring correct orientation and stable attachment.
3. Connect Cables: Connect the sensor cables to the data acquisition system for transmitting the vibration data for processing.
4. Start the Equipment: Once the equipment is running, the sensor automatically starts measuring vibrations.
5. Data Collection and Analysis: Use the data acquisition system to gather and analyze the vibration data, adjusting and maintaining the equipment accordingly.
6. Periodic Calibration: Regular calibration ensures accurate and reliable measurements.

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III. Common Faults and Repair Methods for Displacement Sensors

1. Inaccurate Measurements:

• Causes: Laser beam obstruction, surface reflectivity changes, ambient light interference, or electronic noise.
• Repair: Check the laser beam path for obstructions, ensure stable reflectivity, reduce ambient light interference, and verify proper grounding of electronic devices.

1. Unstable Measurement Values:

• Causes: Calibration errors, temperature fluctuations, mechanical vibrations, or optical contamination (e.g., dirty lenses).
• Repair: Check calibration certificates, ensure environmental temperature and vibration are within sensor specifications, and clean lenses regularly.

1. No Signal Output:

• Causes: Damaged cables, loose connections, communication protocol mismatch, or power issues.
• Repair: Inspect cable integrity, secure connections, verify communication protocol and baud rate settings, and ensure stable power supply.

1. Sensor Damage:

• Causes: Accidental impact, overuse, or improper installation.
• Repair: Inspect the sensor casing for cracks or deformation, ensure proper installation to avoid external force damage, and use suitable mounting accessories for stability.

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IV. Conclusion

Displacement sensors play a vital role in various industries. Understanding their working principles, mastering correct usage methods, and diagnosing common faults is crucial for ensuring the accuracy of measurement data and the safe operation of equipment. Regular calibration and maintenance of sensors are essential for maintaining performance and accuracy.

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V. Displacement Sensors Repaired by Longi Electromechanical – Brands and Models

Rongji Electromechanical has extensive experience in repairing various brands and models of displacement sensors, including:

1. Keyence:

• LVDT Series:
• GT2 Series: GT2-A12, GT2-A32, GT2-H12, GT2-H32
• GT-7000 Series: GT-701, GT-703, GT-706
• Laser Displacement Sensors:
• LK-G5000 Series: LK-G502, LK-G507, LK-G508
• IL Series: IL-030, IL-065, IL-100

1. Micro-Epsilon:

• Eddy Current Displacement Sensors:
  • eddyNCDT 3001: EDS-05, EDS-10
  • eddyNCDT 3100: EDS-18, EDS-28
• Laser Displacement Sensors:
  • optoNCDT 1420: ILD1420-10, ILD1420-200
  • optoNCDT 2300: ILD2300-2, ILD2300-10

1. SICK:

• OD Precision Series:
  • OD2-P20W10 (10mm measuring range)
  • OD2-P30W15 (15mm measuring range)
• OD Value Series:
  • OD2-B160 (60mm measuring range)
  • OD2-B210 (100mm measuring range)

1. Omron:

• ZX2 Series: ZX2-LD50, ZX2-LD100
• ZX-E Series: ZX-E010, ZX-E025
• LVDT Series:
• E2E-X Series: E2E-X5ME1, E2E-X8ME1

1. Baumer:

• Eddy Current Displacement Sensors:
  • WFM Series: IWFM 12P1701/S35A, IWFM 18P1701/S35A
• Laser Displacement Sensors:
  • OADM Series: OADM 12I6440/S14F, OADM 20I4470/S14F

1. Banner Engineering:

• Laser Displacement Sensors:
  • L-GAGE LE Series: LE250, LE550
• Ultrasonic Displacement Sensors:
  • T30UX Series: T30UX1, T30UX2

1. HBM (Hottinger Baldwin Messtechnik):

• Eddy Current Displacement Sensors:
  • C2/C3 Series: C2-100, C2-200
  • WPS Series: WPS-100, WPS-200
• Laser Displacement Sensors:
  • T100 Series: T100-100, T100-200

1. Novotechnik:

• Rotary Displacement Sensors:
  • RFC4800 Series: RFC4800-6, RFC4800-8
  • RFX6900 Series: RFX6900-6, RFX6900-8
• Linear Displacement Sensors:
  • LWH Series: LWH-100, LWH-200
  • TR Series: TR-100, TR-200

1. Lion Precision:

• Capacitive Displacement Sensors:
  • CPL190 Series: CPL190-5, CPL190-10
  • CPL490 Series: CPL490-20, CPL490-50
• Eddy Current Displacement Sensors:
  • ECL101 Series: ECL101-5, ECL101-10
  • ECL150 Series: ECL150-20, ECL150-50

1. Kaman Precision Products:

• Eddy Current Displacement Sensors:
  • KD-2306 Series: KD-2306-5, KD-2306-10
  • KD-5100 Series: KD-5100-20, KD-5100-50
• Capacitive Displacement Sensors:
  • DIT-5200 Series: DIT-5200-5, DIT-5200-10
  • DIT-5300 Series: DIT-5300-20, DIT-5300-50

1. OMEGA Engineering:

• LVDT Series:
  • LD610 Series: LD610-50, LD610-100
  • LD620 Series: LD620-200, LD620-300
• Laser Displacement Sensors:
  • LD702 Series: LD702-50, LD702-100
  • LD752 Series: LD752-200, LD752-300

1. Solartron Metrology:

• Orbit ACS Series:
  • D6P (6mm displacement)
  • D10P (10mm displacement)

1. Linear Displacement Sensors Series:

• DP/2S: 2mm displacement
• DP/10S: 10mm displacement

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Balluff:

• Magnetostrictive Displacement Sensors:
  • BIL Series: BIL PA0, BIL SA1
• Inductive Displacement Sensors:
  • BES Series: BES 516-100, BES 517-105
• Optical Displacement Sensors:
  • BOH Series: BOH 0012, BOH 0025

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Longi Electromechanical has 30 years of experience in repairing and troubleshooting displacement sensors and other industrial components. In addition to repairs, the company also provides purchasing and sales services for second-hand displacement sensors. Feel free to contact us for more information.

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