What it means
A01977 signals that the alarm threshold for overtemperature of the Communication Board Ethernet 41 (CBE41) has been reached. The drive raises the condition as an alarm; depending on the drive configuration, it can also be output with no reaction (N). While the alarm is active, the drive takes no protective action and no acknowledgment is needed — the message clears itself. The current temperature of the board can be followed in r8828 (CBE41 temperature).
Why it appears
- The alarm threshold for the overtemperature of the Communication Board Ethernet 41 (CBE41) has been reached — the current temperature is visible in r8828 (CBE41 temperature).
What to check
- Check the air intake for the Control Unit.
- Check the Control Unit fan.
Parameters the manual names
- r8828 — CBE41 temperature: read this value to see how hot the CBE41 currently is, whether the alarm threshold is still exceeded, and when the temperature has fallen below the limit value again.
Acknowledging and restarting
No acknowledgment is required. The alarm is automatically withdrawn once the limit value has been fallen below.
r8828 (CBE41 temperature) shows when the CBE41 temperature has dropped below the limit value again.
The same on every family
Every manual that describes A01977 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | NONE | NONE | Communication error to the higher-level control system (9) | None | SINAMICS S120, S150 List Manual · p. 2721 |
The drives this code lives on
A01977 is described for S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does alarm A01977 mean on SINAMICS S120/S150?
It means the alarm threshold for overtemperature of the Communication Board Ethernet 41 (CBE41) has been reached. The drive takes no protective action and withdraws the alarm automatically once the temperature falls below the limit value again.
How do I clear A01977 CBE41 overtemperature?
No acknowledgment is needed: the alarm is automatically withdrawn once the limit value has been fallen below. Check the air intake for the Control Unit and the Control Unit fan so the temperature actually drops.
Which parameter shows the CBE41 temperature for A01977?
r8828 (CBE41 temperature). It displays the current temperature of the CBE41, so you can see whether the alarm threshold is still exceeded and when it has fallen below the limit value again.
Does A01977 stop the drive?
No. The drive takes no protective action for this condition, and the alarm is withdrawn automatically once the limit value has been fallen below.
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