What it means
A01940 is an alarm reporting a PROFIBUS (PB) or PROFINET (PN) synchronization problem. The bus is in the data exchange state and clock synchronous operation was selected via the parameterizing telegram, but it was not possible to synchronize to the clock cycle specified by the master.
Why it appears
- The master does not send a clock synchronous global control telegram, although clock synchronous operation was selected when configuring the bus.
- The master is using another clock synchronous DP clock cycle than the one transferred to the slave in the parameterizing telegram.
- At least one drive object has a pulse enable, even though that pulse enable is not controlled from PROFIBUS/PROFINET.
What to check
- Check the master application and the bus configuration.
- Check the consistency between the clock cycle entered when configuring the slave and the clock cycle setting at the master.
- Check that no drive object has a pulse enable;
Only enable the pulses after synchronizing the PROFIBUS/PROFINET drives.
Acknowledging and restarting
No acknowledgement is required for this alarm, and the drive takes no automatic action in response to it. There is no separate reset step: the remedy is to remove one of the causes listed above.
The same on every family
Every manual that describes A01940 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | NONE | NONE | Communication error to the higher-level control system (9) | None | SINAMICS G130, G150 List Manual · p. 1493 |
| S120, S150 | NONE | NONE | Communication error to the higher-level control system (9) | None | SINAMICS S120, S150 List Manual · p. 2717 |
The drives this code lives on
A01940 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 SINAMICS alarm A01940 mean?
The drive is connected via PROFIBUS or PROFINET in clock synchronous operation and could not synchronize to the clock cycle specified by the master while the bus is in the data exchange state.
Does A01940 trip the drive?
No. The alarm triggers no automatic drive response and does not have to be acknowledged.
Why does A01940 appear even though the bus is communicating?
Data exchange can already be running while synchronism is still missing — for example because the master sends no clock synchronous global control telegram, or uses another clock synchronous DP clock cycle than the one transferred to the slave in the parameterizing telegram.
Can I enable the pulses while A01940 is active?
No. Check that no drive object has a pulse enable, and only enable the pulses after the PROFIBUS/PROFINET drives have synchronized.
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 A01xxx group · SINAMICS manuals · Siemens manuals