What it means
A03550 reports a speed setpoint filter whose natural frequency, set in p1417, has reached or gone past the Shannon frequency. The drive derives that limit from the sampling time of the TM31 inputs/outputs and calculates it as 0.5 / p4099[3]. The filter concerned is a PT2 low pass in the speed setpoint path, so its setting in p1417 must stay under this limit.
Why it appears
- The natural frequency stored in p1417 for the speed setpoint filter has reached or exceeded the Shannon frequency, which the drive calculates as 0.5 / p4099[3] from the TM31 inputs/outputs sampling time.
What to check
- Read p4099[3], the TM31 inputs/outputs sampling time, and work out the Shannon frequency as 0.5 divided by this value.
- Compare that limit with the natural frequency currently set in p1417 for the speed setpoint filter.
- Set a lower natural frequency for the PT2 low pass in p1417 so that it stays below the Shannon frequency.
Parameters the manual names
- p1417 — natural frequency (denominator) of velocity setpoint filter 1: the value to turn down until it lies below the Shannon frequency.
- p4099 — sampling time of the TM31 inputs/outputs: its value at index [3] fixes the Shannon frequency (0.5 / p4099[3]) that p1417 must remain under.
Acknowledging and restarting
Correcting p1417 is all that is needed: once the natural frequency lies below the Shannon frequency, the alarm clears by itself and no reset has to be performed.
What differs between the drive families
Straight from the manuals' own fields — A03550 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | NONE | NONE | Error in the parameterization / configuration / commissioning procedure (18) | None | SINAMICS G130, G150 List Manual · p. 1517 |
| S120, S150 | — | — | Error in the parameterization / configuration / commissioning procedure (18) | None | SINAMICS S120, S150 List Manual · p. 2744 |
The drives this code lives on
A03550 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 A03550 mean in SINAMICS?
The natural frequency set in p1417 for the speed setpoint filter has reached or exceeded the Shannon frequency, which the drive calculates as 0.5 / p4099[3].
How do I fix alarm A03550?
Set a lower natural frequency for the PT2 low pass in p1417 so it stays below the Shannon frequency; the alarm then clears by itself.
What is the Shannon frequency that A03550 refers to?
It is the limit the drive derives from the TM31 inputs/outputs sampling time: 0.5 divided by the value in p4099[3].
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 A03xxx group · SINAMICS manuals · Siemens manuals