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Alarm 1325: Encoder communication error

On an English-language pendant this is displayed as "COMMUNICATION ERROR (ENCODER)".

Class: major alarm (power cycle required) · Sub code: the axis where communication failed

What it means​

The controller talks to every motor encoder over a serial link. On many robots the encoders are wired in a multidrop chain: the servo board talks to them one after another in the order they are connected. If the link breaks, the controller reports the failing axis and all axes after it in the chain.

Tip: the first axis listed in the sub code is where to start looking – the real fault is usually there or at the axis just before it.

Checks on the manipulator side​

  1. Inspect the cable between the encoder and the multi-port connector, and the IN/OUT cables of the multi-port connector, for the first reported axis and the axis before it.
  2. If the first reported axis is the first encoder in the chain, check the internal +5 V supply line for a short circuit or ground fault.

Checks on the controller side​

  1. Switch power off and on.
  2. If it repeats, check the manipulator cable and the encoder connector on the servo control board. For external axes check the encoder cables and the board's external-axis connectors.
  3. Systems with an external force-monitoring board (collaborative robots) or an encoder converter board have additional connectors to check.

Component replacement order​

  1. Encoder of the reported axis, then the encoder one position before it.
  2. Multi-port connector.
  3. Servo control board – only if the sub code points at the first encoder of the chain or at a single serial-encoder external axis. Save CMOS.BIN first.

Source: Based on YASKAWA manual RE-CER-A600.