What it means
A06904 signals that the internal Braking Module is currently inhibited. The inhibit is applied through the binector input p3680, which is carrying a 1 signal. While the module is inhibited, energy cannot be dissipated using the braking resistor. Depending on how the drive is configured, the same condition can also be output as a message without a reaction. The neighbouring Braking Module messages A06900, A06901, A06905 and A06921 are described on their own pages.
Why it appears
- A 1 signal is present at binector input p3680, and this signal inhibits the internal Braking Module.
- As long as the inhibit is active, energy cannot be dissipated using the braking resistor.
What to check
- Release the internal Braking Module by applying a 0 signal to p3680 (BI: p3680 = 0 signal).
Parameters the manual names
- p3680 (BI: Braking Module internal inhibit / BM int inhib) — the binector input through which the internal Braking Module is inhibited and released for this message: a 1 signal inhibits the module, a 0 signal releases it.
Acknowledging and restarting
No acknowledgement is required, and the drive takes no protective reaction while A06904 is active. The condition ends as soon as the internal Braking Module is released with a 0 signal at p3680.
The same on every family
Every manual that describes A06904 gives it the same reaction, acknowledgement and message class.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| G130, G150 | NONE | NONE | Braking Module faulted (14) | None | SINAMICS G130, G150 List Manual · p. 1531 |
| S120, S150 | NONE | NONE | Braking Module faulted (14) | None | SINAMICS S120, S150 List Manual · p. 2774 |
The drives this code lives on
A06904 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 A06904 mean on a SINAMICS?
It means the internal Braking Module is inhibited: a 1 signal at binector input p3680 has switched the module off, and in this inhibited state energy cannot be dissipated using the braking resistor.
How do I clear alarm A06904?
Release the internal Braking Module by applying a 0 signal to p3680 (BI: p3680 = 0 signal). No acknowledgement of the message is needed.
Does A06904 stop or trip the drive?
No. The message triggers no protective reaction, but while the inhibit is active the braking resistor cannot dissipate energy.
Why is A06904 displayed without any reaction?
Depending on the drive configuration, the same condition can also be output as a message without a reaction; the message itself does not force any protective response.
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 A06xxx group · SINAMICS manuals · Siemens manuals