F31100 — Encoder 1: Zero mark distance error

F31100 reports that the measured zero mark distance does not correspond to the parameterized zero mark distance on Encoder 1. The distance the monitoring expects is set in p0425 for a rotary encoder and in p0424 for a linear encoder. For distance-coded encoders, the drive forms the distance from pairs of detected zero marks; depending on how the pairs are generated, a single missing zero mark does not raise this fault and has no effect in the system. How the drive behaves when the fault trips follows the motor encoder fault response set in p0491, and the fault must be acknowledged before the drive restarts. Depending on the drive configuration, the same condition can also be output as an alarm or with no reaction at all.

• The zero mark distance measured by Encoder 1 deviates from the distance parameterized for the zero mark monitoring (p0425 rotary, p0424 linear).
• For distance-coded encoders, the distance is built from pairs of detected zero marks; depending on the pair generation, a missing zero mark may not be detected and then has no effect in the system.
• The parameterized zero mark distance does not match the encoder actually fitted.

1. Check that the encoder cables are routed in compliance with EMC.
2. Check the plug connections.
3. Check the encoder type — an encoder with equidistant zero marks.
4. Adapt the parameter for the distance between zero marks: p0424 for a linear encoder, p0425 for a rotary encoder.
5. If the message is output above a speed threshold, reduce the filter time in p0438 if necessary.
6. Replace the encoder or the encoder cable.

• The drive stores the last measured zero mark distance in r0949; read the value as a decimal number.
• The value is given in increments — 4 increments correspond to 1 encoder pulse.
• The sign of the value designates the direction of motion when the zero mark distance was detected.

• p0424 — zero mark distance of the linear encoder: enter here the actual distance between zero marks of the linear encoder connected.
• p0425 — zero mark distance of the rotary encoder: enter here the actual distance between zero marks of the rotary encoder connected.
• p0438 — square-wave encoder filter time: reduce it if F31100 is only output above a speed threshold.
• r0949 — fault value: shows, interpreted as a decimal number, the last measured zero mark distance in increments, with its sign giving the direction of motion.
• p0491 — motor encoder fault response ENCODER: named by the manual for this fault; it defines how the drive responds when the encoder monitoring trips.

Once the cause has been removed, acknowledge the fault at the operator panel or in the commissioning tool and restart the drive. Acknowledgement is only possible when pulses are inhibited (PULSE INHIBIT), so bring the drive into a pulse-inhibited state first, then acknowledge. If the condition is configured as an alarm or as a message without reaction, no acknowledgement is required.