What it means
A49938 reports that the uninterruptible power supply (UPS) is in battery operation
— the UPS is currently running on its battery. The drive picks the message up as a status signal: it is output via the signal source of binector input p6577[26] of the Control Unit, and no message value is transmitted with it. Depending on how the drive is configured, the same condition can also be issued as a fault instead of as an alarm.
Why it appears
- The uninterruptible power supply (UPS) is in battery operation.
What to check
- Check the power supply of the control cabinet.
Parameters the manual names
- p6577 (BI: Circuit monitoring functions signal source) — the Control Unit outputs this message via the signal source of binector input p6577[26]; p6577 is where the signal sources of the circuit monitoring functions are interconnected.
Acknowledging and restarting
As an alarm, A49938 requires no acknowledgement and the drive does not trigger an automatic response to it. If the drive configuration raises the same condition as a fault instead, the preset response is OFF1 for the infeed and for the SERVO, VECTOR and HLA drive objects; the reactions that can be selected instead are shown in brackets in the manual.
The same on every family
Every manual that describes A49938 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | General drive fault (19) | None | SINAMICS S120, S150 List Manual · p. 3296 |
The drives this code lives on
A49938 is described for S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does alarm A49938 mean on a SINAMICS drive?
It reports that the uninterruptible power supply (UPS) is in battery operation. The drive outputs the message via the signal source of binector input p6577[26] of the Control Unit.
Does A49938 have to be acknowledged?
No. As an alarm the message requires no acknowledgement and the drive does not react to it automatically; only if it is configured as a fault does the preset OFF1 response apply.
What should I check when A49938 appears?
Check the power supply of the control cabinet, which is the remedy the manual gives for this message.
Can A49938 also appear as a fault?
Yes — depending on the drive configuration, the same condition can be issued as a fault. The manual then prescribes OFF1 as the preset reaction for the infeed and for the SERVO, VECTOR and HLA drive objects.
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