362

Power off the machine. Inspect the encoder cable from the motor to the amplifier connector (typically JD1A on αi series amplifiers). Check for physical damage, tight bends, or cable wear at the motor exit point.

Lock out main power before opening amplifier cabinet or touching motor cables

Disconnect and reconnect the encoder cable at both motor and amplifier ends. Inspect connector pins for bent contacts, contamination, or corrosion. Clean with contact cleaner if necessary. Verify connector locking mechanism is secure.

Check encoder cable routing for proximity to power cables or sources of electrical noise. Maintain minimum 100mm separation from motor power lines and verify proper shielding ground connection at amplifier end only.

Access DIAGNOSIS > SERVO screen and monitor parameter 300#0 (serial pulse coder alarm) and diagnostic 200-207 (position deviation) while jogging the axis slowly. Erratic values or alarm bit toggling confirms encoder signal issues.

Check motor encoder battery voltage at the motor connector or amplifier terminal (typically 3.0-3.6V for lithium batteries). If below 2.8V, replace battery immediately. Note that low battery may trigger alarm 362 before alarm 8 (battery low) appears.

Access MAINTENANCE > ABSOLUTE position screen and verify the multi-turn revolution count data changes correctly when rotating the motor manually (power off). Erratic jumping or frozen values indicate encoder failure.

Set parameter 1815#2 (absolute position lost detect) to 0 temporarily if testing requires axis movement with alarm present

Check parameter 1825 (serial encoder type) matches the motor pulse coder model. Verify parameter 1826 (encoder gear ratio) and 1827 (encoder revolution) are correctly set per motor specifications. Incorrect settings cause revolution data calculation errors.

If battery and parameters are correct but alarm persists, the pulse coder internal circuitry has likely failed. Replace the motor or encoder unit. After replacement, execute absolute position establishment via SYSTEM > PMC > SETTING > ABSOLUTE or parameter 1815#0.

Check amplifier LED status codes. αi/βi amplifiers will show alarm LED patterns (refer to amplifier manual). A continuous alarm LED with no other error patterns suggests control board issues rather than motor/cable problems.

Swap the suspect axis amplifier with a known working axis amplifier of the same model. If alarm 362 moves to the new axis, the motor/cable is faulty. If alarm stays with the original axis, the amplifier control board is defective.

Record all servo parameters before swapping amplifiers. Set parameter 11#0 (parameter write enable) to 1 to allow parameter restoration

Check for loose internal connections on the amplifier control PCB, particularly the encoder interface board connections. Reseat all internal connectors and verify proper mounting of circuit boards to backplane.

Only qualified personnel should access amplifier internals. High voltage capacitors remain charged after power-off