What it means
A31431 is reported by Encoder 1 when the zero pulse is passed and the drive detects a deviation in the incremental position at that moment. Depending on how the drive is configured, the same condition can also be issued as a fault (F) or with no reaction (N) instead of an alarm.
Why it appears
- When the zero pulse is passed, a deviation in the incremental position of Encoder 1 was detected.
- With equidistant zero marks, the first zero mark passed supplies the reference point for all subsequent checks — every further zero mark must sit at n times the distance referred to the first zero mark.
- With distance-coded zero marks, the first zero mark pair supplies the reference point for all subsequent checks — the other zero mark pairs must keep the expected distance to the first zero mark pair.
What to check
- Check that the encoder cables are routed in compliance with EMC.
- Check the plug connections.
- Replace the encoder or the encoder cable.
- Clean the coding disk, or remove strong magnetic fields.
Reading the message value
- The drive stores the alarm value of this message in r2124; interpret the value as a decimal number.
- The value is the detected deviation in quadrants — one encoder pulse corresponds to 4 quadrants.
Parameters the manual names
- r2124 — read the alarm value of this message here: the position deviation in quadrants, to be interpreted as a decimal number.
- p0491 — Motor encoder fault response ENCODER: the message cross-references this parameter; the response of the drive to a motor encoder fault (ENCODER) is configured here.
Acknowledging and restarting
As an alarm, A31431 triggers no automatic response from the drive and requires no acknowledgement. If the drive is configured to output the same condition as a fault (F), that fault is acknowledged immediately; the manual cross-references p0491 (Motor encoder fault response ENCODER) for the fault response.
The same on every family
Every manual that describes A31431 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 1 | SINAMICS S120, S150 List Manual · p. 3054 |
| G130, G150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 1 | SINAMICS G130, G150 List Manual · p. 1740 |
The drives this code lives on
A31431 is described for G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does SINAMICS alarm A31431 mean?
Encoder 1 has detected a deviation in the incremental position when the zero pulse was passed — the incremental/absolute position deviation is too high. Depending on the drive configuration, the same condition can also appear as a fault or with no reaction.
Where can I read the deviation value of A31431?
The drive stores the alarm value in r2124; interpret it as a decimal number. The value is the deviation in quadrants, where one encoder pulse corresponds to 4 quadrants.
How do I fix alarm A31431?
Check that the encoder cables are routed in compliance with EMC and check the plug connections. Then replace the encoder or the encoder cable, and clean the coding disk or remove strong magnetic fields.
Does A31431 have to be acknowledged?
No — as an alarm it triggers no automatic drive response and needs no acknowledgement. Only if the drive is configured to output the same condition as a fault must it be acknowledged immediately.
Codes next to this one
Source
Written from Siemens' own List Manuals and operating instructions; every number, designation and parameter on this page is checked against them before publication.
All SINAMICS codes: fault and alarm codes · the A31xxx group · SINAMICS manuals · Siemens manuals