A31443 — Encoder 1: Signal level track C/D outside tolerance (alarm)

A31443 reports that the unipolar signal level of encoder 1 is outside the permissible tolerance: the unipolar level (CP/CN or DP/DN) has left the allowed band. The manuals print the code as Encoder 1: Signal level track C/D outside tolerance (alarm) and also as Encoder 1: Unipolar CD signal level outside specification — different wording, same condition. The unipolar nominal signal level of the encoder must lie in the range 2500 mV +/- 500 mV; the drive responds when the level falls below 1700 mV or rises above 3300 mV. Depending on how the drive is configured, the same condition can also be issued as a fault (F) or as a message without reaction (N). The signal level is only evaluated when the Sensor Module properties are available (r0459.31 = 1) and monitoring is active (p0437.31 = 1).

• The unipolar level (CP/CN or DP/DN) for encoder 1 is outside the permissible tolerance: the nominal signal level must lie in the range 2500 mV +/- 500 mV, and the response thresholds are below 1700 mV and above 3300 mV.

1. Check that the encoder cables and shielding are routed in compliance with EMC.
2. Check the plug connections and contacts of the encoder cable.
3. Check that the C/D tracks are connected correctly — have the signal cables CP and CN or DP and DN been interchanged?
4. Replace the encoder cable.

The message value is the alarm value stored in r2124, interpreted binary ("Fault cause: %1 bin").

• Bit 0 = 1: either CP or CN outside the tolerance.
• Bit 16 = 1: either DP or DN outside the tolerance.

• r2124 — holds the alarm value for this message; read it as a binary pattern to see which pair is affected (bit 0: CP/CN, bit 16: DP/DN).
• r0459 — Sensor Module properties extended; the signal level is only evaluated when r0459.31 = 1 (Sensor Module properties available).
• p0437 — Sensor Module configuration extended; monitoring of the signal level is only active when p0437.31 = 1.
• p0491 — motor encoder fault response ENCODER; sets how the drive reacts if the same condition is raised as a fault.

As an alarm, A31443 triggers no automatic response and needs no acknowledgement: it clears itself once the unipolar level is back inside the tolerance. If the drive is configured to raise the same condition as a fault (response set in p0491), the fault must be acknowledged immediately before the drive can be restarted.