Serial Pulse Coder is Abnormal

What does 351 mean?

Similar to Alarm 350, this alarm indicates an abnormal condition or communication error specifically related to a serial pulse coder (encoder) on the Fanuc Series 20 CNC. It signifies a problem with the digital data transfer from the encoder to the servo system.

• Loose or damaged serial communication cable between the pulse coder and the servo amplifier.
• Electrical noise interfering with the serial data transmission.
• Malfunction of the serial pulse coder itself.
• Faulty serial interface on the servo amplifier.
• Incorrect parameter settings for the serial pulse coder.

Click steps to track your progress.

1. 1

   Inspect the serial pulse coder cable for physical damage, loose connections, or improper shielding.

2. 2

   Verify proper termination of the serial communication line if applicable.

3. 3

   Check for sources of electromagnetic interference (EMI) near the cable runs and ensure proper grounding.

4. 4

   Examine diagnostic data related to the serial pulse coder for specific error sub-codes or communication status.

5. 5

   Temporarily swap the suspected pulse coder or servo amplifier with a known good one if feasible to isolate the fault.