ABB PQFM Instruction Manual page 206

When pressing 'ACK. FAULT' the filter will display a message relevant to the problem.
It also shows a list of the most recent critical faults that have been recorded.
If the filter is in remote control operation and the message 'ACK. FAULT' is present on
the PQF-Manager, the fault can be acknowledged by sending a 'STOP' command by
remote control (low signal). Alternatively, the remote control functionality can be
disabled by disabling the corresponding digital input functionality. Then, the fault can
be acknowledged locally.
Figure 105 shows the error treatment procedure in flowchart format.
206 Troubleshooting guide ç Manual Power Quality Filter PQFM