What it means
A31470 is an alarm from Encoder 1: the encoder signals an internal error, and what it is actually reporting is soiling — the encoder is dirty. The manuals title the message Encoder 1: Encoder signals an internal error (X521.7)
and Encoder 1: Soiling detected
; both describe the same condition. On the Sensor Module Cabinet 30 (SMC30) the dirty-encoder signal reaches the drive as a 0 signal at terminal X521.7 — in the G130/G150 manual for the alternative encoder system interface on the SMC30, in the S120/S150 manual stated generally for the SMC30. Depending on how the drive is configured, the same condition can also be issued as a fault or as a message without any reaction.
Why it appears
- The encoder reports an internal error to the drive: the encoder is dirty (soiling detected).
- The report arrives at the Sensor Module Cabinet 30 (SMC30) as a 0 signal at terminal X521.7; the G130/G150 manual ties this to the alternative encoder system interface on the SMC30, while the S120/S150 manual states it generally for the SMC30.
What to check
- Check the plug connections.
- If the alarm persists, replace the encoder or the encoder cable.
Acknowledging and restarting
No acknowledgement is required for this alarm; the fix is to remove the cause — check the plug connections and, if required, replace the encoder or the encoder cable. If the drive is configured to output the same condition as a fault instead, the manuals list its acknowledgement as IMMEDIATELY.
The same on every family
Every manual that describes A31470 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. 3058 |
| G130, G150 | NONE | NONE | Actual position/speed value incorrect or not available (11) | Encoder 1 | SINAMICS G130, G150 List Manual · p. 1743 |
The drives this code lives on
A31470 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 A31470 mean?
Encoder 1 signals an internal error: the encoder is dirty (soiling detected). On the Sensor Module Cabinet 30 (SMC30) the condition is reported to the drive as a 0 signal at terminal X521.7.
Does A31470 stop the drive?
No. As an alarm it requires no acknowledgement, and the drive does not trip. Depending on the drive's configuration, the same condition can also be issued as a fault or as a message without any reaction.
How do I clear alarm A31470?
Check the plug connections and, if the alarm persists, replace the encoder or the encoder cable. The alarm itself needs no acknowledgement; when issued as a fault, it is acknowledged immediately.
Which terminal signals a dirty encoder on the SMC30?
Terminal X521.7. The encoder signals the soiling as a 0 signal at this terminal on the Sensor Module Cabinet 30 (SMC30).
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