What it means
A01981 is raised when a controller attempts to establish a connection to the drive over PROFINET and, as a consequence, the permitted number of PROFINET connections is exceeded. The drive is not stopped by this alarm: it withdraws it automatically after approx. 30 seconds. The manuals for S120/S150 and for G130/G150 describe the alarm in the same way; the G130/G150 manual additionally names the p8929 setting (PN remote controller number) in its remedy.
Why it appears
- A PROFINET controller is trying to open a connection to the drive, and this would take the number of PROFINET connections above the permitted maximum.
What to check
- Check the configuration of the PROFINET controllers.
- On G130 and G150, the manual additionally says to check the setting of p8929 (PN remote controller number).
Reading the message value
The alarm value is stored in r2124 and must be interpreted as a hexadecimal number of the form yyyyxxxx hex, where yyyy = Info 1 and xxxx = Info 2. The drive also enters Info 1 and Info 2 into the message value (shown as %1 and %2). The manual decodes the value as follows:
- Info 1 = 0: the number of RT connections has been exceeded.
- Info 1 > 0: the number of IRT connections has been exceeded.
- Info 2: the permitted number of connections.
Parameters the manual names
- r2124 (alarm value): read the alarm value here, interpreting it as hexadecimal, to see whether the RT or the IRT connection limit was hit and what the permitted number of connections is.
- p8929 (PN remote controller number): for G130 and G150 the remedy says to check the setting of this parameter when the alarm appears.
Acknowledging and restarting
Nothing has to be acknowledged: the alarm disappears automatically after approx. 30 seconds. If it keeps returning, a controller is still attempting to open more PROFINET connections than the drive permits — correct the PROFINET controller configuration and, on G130/G150, the p8929 setting.
The same on every family
Every manual that describes A01981 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Error in the parameterization / configuration / commissioning procedure (18) | None | SINAMICS S120, S150 List Manual · p. 2723 |
| G130, G150 | NONE | NONE | Error in the parameterization / configuration / commissioning procedure (18) | None | SINAMICS G130, G150 List Manual · p. 1497 |
The drives this code lives on
A01981 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 alarm A01981 mean on a SINAMICS drive?
A PROFINET controller attempted to establish a connection to the drive and the permitted number of PROFINET connections would be exceeded as a result. The drive raises this alarm but does not stop.
How do I clear A01981?
No acknowledgment is needed — the alarm is withdrawn automatically after approx. 30 seconds. If it reappears, a controller is still trying to open more PROFINET connections than permitted, so check the PROFINET controller configuration (and p8929 on G130/G150).
How can I tell whether RT or IRT connections triggered A01981?
Read the alarm value in r2124 as a hexadecimal number of the form yyyyxxxx: if yyyy (Info 1) is 0, the number of RT connections was exceeded; if yyyy is greater than 0, the number of IRT connections was exceeded. Info 2 (xxxx) shows the permitted number of connections.
Which parameter belongs to A01981?
r2124 holds the alarm value to be interpreted as hexadecimal, and on G130 and G150 the remedy additionally names p8929 (PN remote controller number), whose setting should be checked.
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