F31121 — Encoder 1: Coarse position error

F31121 reports that the drive detected an error in the actual value sensing of Encoder 1, so the position information delivered by this encoder can no longer be trusted. The manuals print two titles for the same fault number: Encoder 1: Coarse position error (an error was detected on the module during actual value sensing, so the coarse position must be assumed to be incorrect) and Encoder 1: Determined commutation position incorrect (an error in the commutation position actual value sensing was detected). Depending on how the drive is configured, the same condition can also be output as an alarm (A) or with no reaction (N).

• An error was detected on the module during actual value sensing; as a result, the sensing must be assumed to supply an incorrect coarse position (G130/G150 wording of the fault).
• An error was detected in the commutation position actual value sensing (S120/S150 wording of the fault).
• In both cases the affected component is Encoder 1.

1. Replace the motor with DRIVE-CLiQ interface or the appropriate Sensor Module — the manuals print this as the only remedy for this fault.
2. Note that p0491 (motor encoder fault response ENCODER) governs how the drive responds to this encoder fault.
3. After the replacement, acknowledge the fault with the pulses inhibited and restart the drive.

• p0491 — motor encoder fault response (ENCODER); both entries for F31121 refer to this parameter for the drive's response to the Encoder 1 error.

This fault is cleared with pulse inhibit acknowledgement: the drive must first be brought into a pulse-inhibited state, the fault is then acknowledged, and only afterwards can the drive be restarted. Since the printed remedy is hardware replacement, acknowledge only after the motor with DRIVE-CLiQ or the appropriate Sensor Module has been exchanged. Where the condition is configured as an alarm or without reaction, the manuals specify no acknowledgement.