What it means
A49940 reports that the protective breaker in the 400 V AC supply circuit of the power unit (PU) has tripped. The Control Unit outputs the message via the signal source of binector input p6577[28]; p6577 is the signal source of the circuit monitoring functions. Depending on how the drive is configured, the same condition can also be raised as a fault (F) instead of an alarm.
Why it appears
- The protective breaker in the 400 V AC supply circuit of the power unit has tripped.
What to check
- Check the 400 V AC supply voltage for the power unit.
Parameters the manual names
- p6577 — BI: Circuit monitoring functions signal source. For this code the message is output via the signal source interconnected at index p6577[28], so this parameter identifies where the protective-breaker signal of the 400 V power unit supply enters the Control Unit.
Acknowledging and restarting
The manual specifies no acknowledgment for the alarm itself: A49940 triggers no automatic response from the drive and needs no reset action. If the drive is configured to raise the same condition as a fault, the infeed and the servo, vector and HLA drive objects respond with OFF1 by default (the manual lists alternative reactions), and the fault must then be acknowledged IMMEDIATELY.
The same on every family
Every manual that describes A49940 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | External measured value / signal state outside the permissible range (16) | Control Unit (CU) | SINAMICS S120, S150 List Manual · p. 3297 |
The drives this code lives on
A49940 is described for S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does alarm A49940 mean on SINAMICS S120 or S150?
It reports that the protective breaker for the 400 V AC supply of the power unit has tripped. The Control Unit receives the signal via binector input p6577[28].
How is alarm A49940 reset?
As an alarm it needs no acknowledgment and triggers no automatic response from the drive. Check the 400 V AC supply voltage for the power unit, which is the remedial action the manual prescribes.
Can A49940 also appear as a fault?
Yes — depending on the drive configuration the same condition can also be issued as a fault (F). The default response is then OFF1 for the infeed and the servo, vector and HLA drive objects, and the fault must be acknowledged IMMEDIATELY.
Which parameter is associated with A49940?
p6577, the signal source for the circuit monitoring functions (BI: Circuit monitoring functions signal source). The message is output through index p6577[28].
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 A49xxx group · SINAMICS manuals · Siemens manuals