Siemens SINAMICS G120 Function Manual page 200

Alarms, faults and system messages
6.2 Reaction of the safety functions to faults
Response in the event of a discrepancy
A discrepant signal at a fail-safe input, e.g. caused by a cable break, results in safety
function SS1 being selected. After the tolerance time has expired, the inverter signals the
discrepancy (alarm C01770 or C30770) but does not interrupt the braking operation for the
motor.
Figure 6-6
To switch the motor on again, you must proceed as follows:
1. Rectify the discrepancy.
2. Acknowledge the active messages (see Section Acknowledging with a fail-safe signal or
3. Issue an OFF1 command.
4. Switch the motor on again (ON command).
198
Response of safety function SS1 in the event of a discrepancy (as example: SS1 in
mode 1)
with a power on reset (Page 191)).
Note: In this case, it is not possible to acknowledge by selecting and deselecting STO.
Safety Integrated Function Manual, SINAMICS G120 and G120C
Function Manual, 01/2011, FW 4.4, A5E03052391B AB