What it means
F07905 is raised when the drive commands the contactor of the external armature short-circuit to open and the contactor feedback signal configured in p1235 does not report the state "Open" (r1239.1 = 0) within the monitoring time set in p1236. The manuals describe this identically for the drive objects of the G130, G150, S120 and S150, so the behaviour below applies to all of them. Depending on the drive configuration, the same condition can also be output as an alarm (A) or with no reaction (N).
Why it appears
- When the contactor was opening, its feedback signal (p1235) did not issue the signal "Open" (r1239.1 = 0) within the monitoring time (p1236).
What to check
- Check that the contactor feedback signal is correctly connected and assigned in p1235.
- Check the logic of the contactor feedback signal: r1239.1 = 1 means "Closed", r1239.1 = 0 means "Open".
- Increase the monitoring time in p1236 if the feedback does not make it into the monitored window.
- If required, operate the external armature short-circuit without a contactor feedback signal by setting p1231 = 2.
Parameters the manual names
- p1235 (BI: External armature short-circuit contactor feedback signal / ASC ext feedback) — the input at which the drive expects the contactor feedback; verify here that the feedback is correctly connected.
- p1236 (Ext. armature short-cct. contactor feedback signal monit. time / ASC ext t_monit) — the monitoring time within which the feedback must report "Open"; increasing it gives the feedback more time.
- p1231 (Armature short-circuit / DC braking configuration / ASC/DCBRK config) — setting p1231 = 2 runs the external armature short-circuit without a contactor feedback signal.
Acknowledging and restarting
The drive coasts down when this fault trips and must be acknowledged before it will restart. Remove the cause first, then acknowledge the fault immediately at the operator panel or in the commissioning tool. Where the condition is configured as an alarm or without reaction, the manual specifies no automatic reaction and no acknowledgement.
The same on every family
Every manual that describes F07905 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | OFF2 (NONE) | IMMEDIATELY | Application/technological function faulted (17) | None | SINAMICS G130, G150 List Manual · p. 1607 |
| S120, S150 | OFF2 (NONE) | IMMEDIATELY | Application/technological function faulted (17) | None | SINAMICS S120, S150 List Manual · p. 2877 |
The drives this code lives on
F07905 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 fault F07905 mean?
The contactor of the external armature short-circuit was commanded to open, but its feedback signal (p1235) did not report "Open" (r1239.1 = 0) within the monitoring time (p1236).
How do I clear F07905?
Check the connection and logic of the contactor feedback signal (r1239.1 = 1: "Closed", r1239.1 = 0: "Open"), increase the monitoring time p1236 if needed, or set p1231 = 2 to run the external armature short-circuit without a feedback signal. Then acknowledge the fault immediately.
Can F07905 also appear as a warning?
Yes. Depending on the drive's configuration, the same condition can also be issued as an alarm (A) or with no reaction (N).
How does F07905 differ from F07904?
F07904 (External armature short-circuit: Contactor feedback signal "Closed" missing) is the neighbouring message for the opposite signal state, while F07905 concerns the missing "Open" signal.
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 F07xxx group · SINAMICS manuals · Siemens manuals