A31811 — Encoder 1: Encoder serial number changed

A31811 is the message Encoder 1: Encoder serial number changed: the drive has detected that the serial number of the motor encoder of a synchronous motor no longer matches the serial number it has stored. The check is only performed for encoders that supply a serial number and for built-in motors (p0300 = 401) or third-party motors (p0300 = 2).

Depending on the drive configuration, the same condition can also be issued as a fault or with no reaction. With closed-loop position control, the serial number is accepted when the adjustment is started (p2507 = 2); while the encoder is adjusted (p2507 = 3), the serial number is checked for changes and the adjustment is reset (p2507 = 1) if required.

• The encoder was replaced.
• A third-party, built-in or linear motor was re-commissioned.
• The motor with its integrated and adjusted encoder was replaced.
• The firmware was updated to a version that checks the encoder serial number.

1. Establish which cause applies: a replaced encoder, a re-commissioned third-party, built-in or linear motor, a replaced motor with integrated and adjusted encoder, or a firmware update that now checks the serial number.
2. For causes 1 and 2, carry out an automatic adjustment using the pole position identification routine: acknowledge the fault, initiate the routine with p1990 = 1 and then check that it was executed correctly. On SERVO, the routine starts automatically if a pole position identification technique is selected in p1980 and p0301 does not contain a motor type with an encoder adjusted in the factory.
3. For causes 1 and 2, the manual allows two alternatives instead: set the adjustment via p0431, in which case the new serial number is accepted automatically, or mechanically adjust the encoder and accept the new serial number with p0440 = 1.
4. For causes 3 and 4, accept the new serial number with p0440 = 1.
5. If serial number monitoring is not wanted, hide it: set p0441 = FF, p0442 = 0, p0443 = 0, p0444 = 0, p0445 = 0 as the serial number in the applicable encoder data set, and parameterize F07414 as message type N via p2118 and p2119.

• p0300 — Motor type selection: the serial number check only concerns built-in motors (p0300 = 401) and third-party motors (p0300 = 2).
• p0301 — Motor code number selection: on SERVO, p1990 activates automatically when p0301 does not contain a motor type with an encoder adjusted in the factory.
• p0431 — Angular commutation offset: setting the adjustment here makes the drive accept the new serial number automatically.
• p0440 — Copy encoder serial number: set to 1 to accept the new serial number.
• p0441 to p0445 — Encoder commissioning serial number parts 1 to 5: set p0441 = FF and p0442 = 0, p0443 = 0, p0444 = 0, p0445 = 0 to hide serial number monitoring.
• p0491 — Motor encoder fault response ENCODER: the manual's cross-reference for the response when the condition is output as a fault.
• p1980 — PolID technique: if a technique is selected here, p1990 starts automatically on SERVO.
• p1990 — Encoder adjustment, determine angular commutation offset: start the pole position identification routine with p1990 = 1 and verify that it executed correctly.
• p2118 / p2119 — Change message type message number and type: use them to parameterize F07414 as message type N.
• p2507 — LR absolute encoder adjustment status: the serial number is accepted when starting the adjustment (p2507 = 2); when adjusted (p2507 = 3) it is checked and the adjustment reset (p2507 = 1) if the serial number has changed.

As an alarm, A31811 requires no acknowledgment; handling ends with one of the remedies above. Where the drive is configured to issue the condition as a fault, the fault must be acknowledged: for causes 1 and 2 the remedy acknowledges the fault and then initiates the pole position identification routine with p1990 = 1, and for causes 3 and 4 accepting the new serial number with p0440 = 1 completes the procedure.