4WRA6EA30-2X/G24K4/V2FRE16-4X/125LBK4M 4WRPEH6C3B04L-2X/G24K0/A1M 4WRA6EA30-2X/G24N9K4/V2FRE16-4X/125LBK4V

Follow the "safety first, external first then internal" principle for troubleshooting:

• Power supply inspection: Use a multimeter to measure the power terminal voltage of the amplifier, which should be 22.8~25.2V. If the voltage is 0V, check whether the fuse is blown and whether the power line is open; if the voltage is too low, check whether the wire diameter is insufficient or the connector is oxidized.
• Signal inspection: Measure the input signal of the amplifier. The current signal should be stable at 4~20mA (fluctuation ≤±0.1mA), and the voltage signal should be stable at 0~10V (fluctuation ≤±0.05V). If the signal is abnormal, check whether the PLC/DCS output is normal and whether the signal line is connected incorrectly.
• Solenoid inspection: Cut off the power and measure the coil resistance. If the resistance is 0Ω (short circuit) or infinite (open circuit), the solenoid needs to be replaced. When energized, use a screwdriver to approach the solenoid, and there should be obvious suction.
• Spool inspection: If the emergency button can be operated manually, the spool may be stuck by impurities. At this time, the hydraulic oil and filter should be replaced, and the valve core and valve cavity should be cleaned; if the emergency button cannot be operated, check whether the return spring is broken and replace it if necessary.

The main reasons are related to oil quality, pressure compensation and feedback signals:

• Oil pollution or viscosity abnormality: Check the oil sample. If there are visible particles, replace the oil and clean the filter (it is recommended to install a 10μm precision filter); if the oil viscosity is too high (such as low temperature), heat the oil to 40~50℃.
• Pressure compensation failure: Disassemble the valve body to check whether the pressure compensator is stuck by impurities or worn. Clean the compensator or replace the worn parts. Ensure that the stroke limiter is in the correct position (the flat nut is at the left limit stop when not limited).
• Feedback signal interference: Use an oscilloscope to measure the feedback signal of the inductive position sensor. If the signal fluctuates greatly (>±0.1V), check whether the sensor wiring is loose and whether the shield layer is grounded reliably. The length of the feedback signal line should not exceed 5m, otherwise a signal amplifier needs to be added.

• External leakage (valve body surface/joint): If the shaft oil seal leaks, replace the damaged oil seal and check whether there are scratches on the shaft; if the pipe joint leaks, re - tighten it with a torque wrench or replace the aging gasket; if the valve body bolt is loose, re - tighten it evenly to avoid deformation of the valve body.
• Internal leakage (abnormal pressure drop): Detect the internal leakage on the test bench. If the leakage exceeds the manual limit (such as ≤1.5L/min for 100L/min specification valve), it is usually caused by wear of the valve core/valve sleeve or damage to the seal. At this time, the valve body should be disassembled to replace the worn parts, and the matching gap between the valve core and the valve sleeve should be ensured to be ≤0.01mm.
• Valve body defect: If the above measures are ineffective, the valve body may have sand holes or cracks, and the valve body should be replaced in time and the supplier should be contacted for detection.

Focus on checking the following points:

• Oil liquid problem: The oil viscosity is too high at low temperature, resulting in poor fluidity. The oil should be heated to the normal working temperature; the filter is blocked, resulting in insufficient oil supply. The filter should be cleaned or replaced.
• Parameter deviation: The dead zone compensation is too small or the gain is too low. Use VT - Soft software to re - calibrate: if the input signal exceeds 1% and there is still no action, increase the dead zone compensation value; if the action is slow, appropriately increase the gain parameter.
• Mechanical wear: The valve core and valve sleeve are worn, resulting in increased internal leakage and slow response. Disassemble the valve body to check the wear, and replace the valve core/valve sleeve if necessary.