What it means
A31401 is the zero-mark monitoring alarm for Encoder 1. It appears when the drive has covered more than 1.5 times the parameterized zero mark distance without a zero mark being detected. The distance being watched is the one set in p0425 for a rotary encoder or in p0424 for a linear encoder. Both manuals describe the message the same way for Encoder 1, and depending on the drive configuration the same condition can also be issued as a fault or as a message without any reaction.
Why it appears
- No zero mark was detected although the distance traveled exceeded 1.5 times the zero mark distance set for the monitoring — p0425 for a rotary encoder, p0424 for a linear encoder.
What to check
- Check that the encoder cables are routed in a way that complies with EMC requirements.
- Check the plug connections.
- Check the encoder type — the monitoring expects an encoder with equidistant zero marks.
- Adapt the parameter for the clearance between zero marks (p0425) so it matches the encoder actually fitted.
- Replace the encoder or the encoder cable.
Reading the message value
- The message value is a placeholder; the alarm value behind it sits in r2124 and must be interpreted as a decimal number.
- It holds the number of increments after POWER ON or since the last zero mark that was detected.
- 4 increments correspond to 1 encoder pulse.
Parameters the manual names
- p0425 — zero mark distance of the rotary encoder: this is the value the monitoring compares against for Encoder 1, and the remedy has you adapt it when the actual clearance between zero marks does not match.
- p0424 — zero mark distance of the linear encoder: takes the place of p0425 when a linear encoder is being evaluated.
- r2124 — alarm value: read it here, interpreted as decimal, to see how many increments elapsed after POWER ON or since the last detected zero mark.
Acknowledging and restarting
The drive raises this code as an alarm, so no acknowledgment is required on your part. Depending on the configuration the same condition can also be issued as a fault or without any reaction; if it comes up as a fault, that fault must be acknowledged immediately.
The same on every family
Every manual that describes A31401 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. 3047 |
| G130, G150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 1 | SINAMICS G130, G150 List Manual · p. 1733 |
The drives this code lives on
A31401 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 alarm A31401 mean on a SINAMICS drive?
Encoder 1 has delivered no zero mark although the drive covered 1.5 times the zero mark distance set in p0425 (rotary encoder) or p0424 (linear encoder).
How do I fix A31401?
Work through the manual's checks in order: EMC-compliant encoder cable routing, the plug connections, the encoder type with equidistant zero marks, adapting p0425, and finally replacing the encoder or the encoder cable.
Where can I read how far the drive traveled without a zero mark?
In r2124, interpreted as a decimal alarm value: the number of increments after POWER ON or since the last detected zero mark, where 4 increments equal 1 encoder pulse.
Do I have to acknowledge A31401?
As an alarm it needs no acknowledgment. Only when the configuration raises the same condition as a fault does it have to 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