Woodward 9907-838 Load Sharing Module

Abnormal input voltage (below 20VDC or above 30VDC).

Loose, short-circuited power cables, or blown internal fuse.

Damaged power module (e.g., bulging capacitor, burnt chip).

Use a multimeter to check input voltage, ensuring it is within 24VDC±15%. Inspect the power supply circuit (e.g., circuit breakers, cables).

Tighten power terminals, replace fuses (if replaceable). Contact the manufacturer for repair or replacement if the internal power module is damaged

Open circuit, short circuit, or poor contact in sensor cables (e.g., oxidized connectors).

Improper sensor installation gap (magnetic probe to gear gap exceeds 0.5~2mm range).

Damaged sensor (e.g., coil failure, distorted signal output).

Measure sensor cable resistance with a multimeter (normal should be several hundred ohms). Replace faulty cables or connectors, ensuring shielded grounding.

Re-calibrate sensor installation gap, measure and fix with a feeler gauge to avoid vibration-induced offset.

Test with a same-model sensor replacement; if the signal recovers, replace the sensor.

Poor contact in output cables, or load exceeding rated value (e.g., high actuator impedance).

Faulty output drive circuit (e.g., triode breakdown, op-amp failure).

Incorrect internal configuration (e.g., uncalibrated output range).

Check output cable connections, use an oscilloscope to measure output signal waveform, replace cables if abnormal.

View output channel status via controller diagnostic functions (e.g., upper computer software). Repair the circuit board or replace the module if hardware failure occurs.

Re-calibrate analog outputs (e.g., set 4mA/20mA corresponding values via panel buttons or software).

Frequent load mutations, or actuator response lag (e.g., stuck electro-hydraulic servo valve).

Speed feedback signal affected by electromagnetic interference (e.g., unshielded cables near high-power equipment).

Re-tune PID parameters: first increase integral time, decrease proportional gain, and optimize step-by-step for stability (refer to the manufacturer's debugging manual).

Check smooth actuator operation, clean or replace the servo valve, ensure no hydraulic system leaks.

Install shielded sleeves for speed sensor cables, keep away from power cables, and ground at a single point.

Incorrect communication cable wiring (e.g., reversed RS-485 positive/negative), or mismatched parameters like baud rate and data bits.

Damaged communication interface chip, or incompatible controller firmware version with the software.

On-site electromagnetic interference causing signal distortion (e.g., near frequency converters, motors).

Confirm communication cable wiring (A/B lines corresponding to RS-485±). Check controller communication parameters (baud rate, parity) via panel menu to match the upper computer settings.

Try replacing the communication interface (e.g., use a USB-RS485 converter). Return for repair if the chip is damaged.

Install isolators or surge protectors in the communication line, keep away from interference sources.

Too low overspeed threshold setting, or momentary abnormal speed sensor signal (e.g., missing gear teeth, vibration-induced pulse misreading).

Abnormal internal speed calculation logic (e.g., software bug).

Check overspeed protection parameters (e.g., set threshold to 110%~115% of rated speed), re-calibrate speed sensor signals (e.g., verify correct gear tooth count settings).

Upgrade controller firmware to the latest version. If false trips persist, contact the manufacturer to investigate algorithm issues.