A31422 — Encoder 1: Pulses per revolution square-wave encoder outside tolerance bandwidth

A31422, printed by the drive as Encoder 1: Pulses per revolution square-wave encoder outside tolerance bandwidth, reports that the measured distance between the zero marks of encoder 1 does not correspond to the distance parameterized for it. With active square-wave encoder PPR correction — including a re-parameterized fault 31131 — the drive accumulates the differential pulses and raises the message once the accumulator contains larger values than the tolerance thresholds. Depending on the drive configuration, the same condition can also be issued as a fault or with no reaction.

• The measured zero mark distance does not correspond to the parameterized zero mark distance; for zero mark monitoring of a rotary encoder this distance is set in p0425.
• With active square-wave encoder PPR correction and a re-parameterized fault 31131, the message is triggered when the accumulator contains larger values than p4683 or p4684.

1. Check that the encoder cables are routed in compliance with EMC.
2. Check the plug connections.
3. Check the encoder type — it must be an encoder with equidistant zero marks.
4. Adapt the parameters for the distance between zero marks (p0424, p0425).
5. Replace the encoder or the encoder cable.

• The drive writes the alarm value to r2124 — interpret it as a decimal number.
• The value is the accumulated differential pulses in encoder pulses.

• p0425 (encoder rotary zero mark distance): sets the zero mark distance used for zero mark monitoring on a rotary encoder — adapt it when the measured distance differs from the setting.
• p0424 (encoder linear zero mark distance): the zero mark distance for a linear encoder — adapt it together with p0425 when the parameterized distance needs correcting.
• p4683 / p4684 (zero mark monitoring tolerance window alarm threshold positive / negative): with active square-wave encoder PPR correction, the message triggers once the accumulated value exceeds one of these thresholds.
• r2124 (alarm value): read here, interpreted decimal, to see the accumulated differential pulses in encoder pulses.
• p0491 (motor encoder fault response ENCODER): the manual cross-references this parameter — it matters when the condition is issued as a fault, since it sets the encoder fault response.

As an alarm, A31422 requires no acknowledgment and the drive executes no automatic response while the condition is present only as an alarm. Remove the cause (see the checks above) and observe r2124 to see whether differential pulses are still accumulating. If the drive is configured to issue the same condition as a fault, that fault is acknowledged immediately once the cause has been corrected.