What it means
A49942 reports that the protective breaker for the SITOP 24 V circuit has tripped. The Control Unit generates the message through the signal source of binector input p6577[21] (circuit monitoring functions). Depending on how the drive is configured, the same condition can also be issued as a fault.
Why it appears
- The protective breaker for the SITOP 24 V circuit has tripped.
What to check
- Check the SITOP power supply.
Parameters the manual names
- p6577 (BI: Circuit monitoring functions signal source) — signal source of the circuit monitoring functions; this message is output via binector input p6577[21] of the Control Unit.
Acknowledging and restarting
The alarm itself requires no acknowledgement. If the drive is configured to raise this condition as a fault, the affected drive objects are switched off with OFF1 — the manual lists the possible alternative reactions for each drive object type — and the fault must be acknowledged immediately before the drive will start again.
The same on every family
Every manual that describes A49942 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. 3298 |
The drives this code lives on
A49942 is described for S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does SINAMICS alarm A49942 mean?
It reports that the protective breaker for the SITOP 24 V circuit has tripped. The Control Unit outputs the message via the signal source of binector input p6577[21].
How do I fix alarm A49942 on an S120 or S150?
Check the SITOP power supply — that is the remedy the manual gives for this message. As an alarm, the message requires no acknowledgement.
What happens when A49942 is issued as a fault instead of an alarm?
The affected drive objects are switched off with OFF1, and the manual lists the possible alternative reactions for each drive object type. The fault must be acknowledged immediately before the drive will start again.
Which parameter is linked to A49942?
p6577 (BI: Circuit monitoring functions signal source). The message is output through binector input p6577[21] of the Control Unit.
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