What it means
A07851 is the alarm External alarm 2. The drive sets it when a 1/0 edge arrives at binector input p2116 — in other words, when the binary signal at this input changes from state 1 to state 0. Because p2116 is a binector input (BI), the edge comes from whatever signal source has been interconnected there. Depending on the drive's configuration, the same condition can also be issued as fault F07851.
Why it appears
- A 1/0 edge — the binary signal at binector input p2116 changing from state 1 to state 0 — has arrived at the input. This edge is what fulfils the alarm condition.
- The edge comes from the signal source interconnected at p2116, so its practical meaning is defined by that interconnection.
What to check
- Call up p2116 to establish which signal source is interconnected there for External alarm 2.
- Clarify why this signal went from 1 to 0 and remove that cause. The remedy the manuals give, in their own words:
Eliminate the causes of this alarm.
Parameters the manual names
- p2116 — binector input (BI) for External alarm 2; it determines the signal source whose 1/0 edge initiates this alarm.
Acknowledging and restarting
A07851 requires no acknowledgement step of its own; eliminating the cause of the 1/0 edge at p2116 is what clears the alarm. If the drive is configured to output the same condition as fault F07851 instead, the fault must be acknowledged immediately (POWER ON).
What differs between the drive families
Straight from the manuals' own fields — A07851 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | External measured value / signal state outside the permissible range (16) | None | SINAMICS S120, S150 List Manual · p. 2870 |
| G130, G150 | NONE | NONE | External measured value / signal state outside the permissible range (16) | None | SINAMICS G130, G150 List Manual · p. 1601 |
| G120 | NONE | NONE | External measured value / signal state outside the permissible range (16) | — | SINAMICS G120 · p. 883 |
| G120XA | NONE | NONE | — | — | SINAMICS G120XA PN converter · p. 1134 |
| G115D | — | — | — | — | SINAMICS G115D distributed drive · p. 394 |
The drives this code lives on
A07851 is described for G115D, G120, G120XA, G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does A07851 External alarm 2 mean?
The drive has registered a 1/0 edge at binector input p2116 — the binary signal there changed from state 1 to state 0 — and this fulfils the condition for External alarm 2. What the edge means in practice depends on the signal source interconnected at p2116.
How do I acknowledge A07851?
The alarm itself requires no acknowledgement; eliminate the cause of the edge at p2116. If the same condition is configured as fault F07851, it must be acknowledged immediately (POWER ON).
Which parameter belongs to A07851?
p2116 (BI: External alarm 2). It is the binector input whose 1/0 edge initiates this alarm.
Can A07851 also appear as a fault?
Yes — depending on the drive's configuration, the same condition can also be issued as fault F07851.
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 A07xxx group · SINAMICS manuals · Siemens manuals