What it means
On Encoder 1, the drive monitors the voltage of the analog spindle sensor S1. A31940 is signalled when this voltage leaves the permissible range; the signal level measured at that moment is available in r2124. The same condition can also be issued as a fault (F) or as a message without any reaction (N) — the drive's configuration decides which variant appears.
Why it appears
- The voltage of the analog spindle sensor S1 lies outside the permissible range.
What to check
- Check the clamped tool.
- Check the tolerance and, if required, adapt p5040.
- Check the thresholds and, if required, adapt p5041.
- Check analog sensor S1 and its connections.
Reading the message value
- The drive stores the alarm value in r2124; interpret the number as decimal — it is the signal level from sensor S1.
A signal level of 500 mV corresponds to the numerical value 500 dec.
Parameters the manual names
- r2124 — alarm value: read the signal level that sensor S1 delivered when the message was raised; interpret the number as decimal.
- p5040 — spindle voltage threshold values tolerance: adapt it here if checking shows the tolerance does not suit the signal from sensor S1.
- p5041 — spindle voltage threshold values: adapt the thresholds here if they do not match the signal delivered by sensor S1.
Acknowledging and restarting
As an alarm, A31940 requires no acknowledgement and the drive does not execute a stop reaction on account of it; once the voltage of sensor S1 is back inside the permissible range, the condition for the message is gone. If your drive is configured to signal this same condition as a fault instead, the fault must be acknowledged immediately before the drive can start again.
The same on every family
Every manual that describes A31940 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Application/technological function faulted (17) | Encoder 1 | SINAMICS S120, S150 List Manual · p. 3080 |
| G130, G150 | NONE | NONE | Application/technological function faulted (17) | Encoder 1 | SINAMICS G130, G150 List Manual · p. 1763 |
The drives this code lives on
A31940 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 A31940 mean?
The voltage of the analog spindle sensor S1 on Encoder 1 is outside the permissible range. The signal level measured at that moment is stored in r2124 and is interpreted as a decimal number.
How do I read the alarm value of A31940?
Open r2124 and read the number as decimal: it is the signal level from sensor S1. A signal level of 500 mV corresponds to the numerical value 500 dec.
Does A31940 have to be acknowledged?
Not while it stands as an alarm — no acknowledgement is required. If the drive is configured to report the same condition as a fault, it must be acknowledged immediately before the drive can start again.
Which parameters belong to A31940?
p5040 holds the tolerance and p5041 the threshold values of the spindle voltage monitoring; adapt them if the checks on this page show the settings do not fit sensor S1. r2124 shows the measured signal level.
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