A33422 — Encoder 3: Pulses per revolution square-wave encoder outside tolerance bandwidth

Encoder 3, a square-wave encoder, is monitored for the distance between its zero marks. Alarm A33422 comes up when the measured zero mark distance no longer corresponds to the parameterized zero mark distance — the pulses per revolution of the square-wave encoder are then outside the tolerance bandwidth. The drive only raises the alarm when square-wave encoder PPR correction is active and fault 31131 has been re-parameterized, and the accumulator contains larger values than the tolerance thresholds p4683 or p4684. For a rotary encoder, the zero mark distance used for zero mark monitoring is set in p0425. Depending on the drive configuration, the same condition can also be output as a fault or as a message without a reaction.

• The measured zero mark distance does not correspond to the parameterized zero mark distance.
• With active square-wave encoder PPR correction and re-parameterized fault 31131, 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 parameter for the distance between zero marks (p0424, p0425).
5. Replace the encoder or the encoder cable.

• The drive stores the alarm value in r2124; interpret the value as a decimal number.
• It contains the accumulated differential pulses in encoder pulses.

• p0425 (Encoder rotary zero mark distance, Enc rot dist ZM) — sets the zero mark distance for zero mark monitoring of a rotary encoder; adapt it here when the measured distance does not match.
• p0424 (Encoder linear zero mark distance, Enc lin ZM_dist) — the linear counterpart; the manual names p0424 and p0425 together for adapting the distance between zero marks.
• p4683 (Zero mark monitoring tolerance window alarm threshold positive, ZM tol A_thr pos) — positive threshold of the tolerance window; the alarm triggers when the accumulator contains larger values.
• p4684 (Zero mark monitoring tolerance window alarm threshold negative, ZM tol A_thr neg) — negative threshold of the tolerance window, complementing p4683.
• r2124 (Alarm value) — read the accumulated differential pulses here, interpreted as a decimal value, to see the deviation in encoder pulses.

As an alarm, A33422 requires no acknowledgement and the drive performs no automatic reaction while it is active. If the drive configuration outputs the same condition as a fault instead, the message must be acknowledged IMMEDIATELY.