Signal Filter For Sto Selection - Siemens SINAMICS G120C Operating Instructions Manual

Advanced commissioning
8.16 Safe Torque Off (STO) safety function
8.16.4.5

Signal filter for STO selection

Overview
Two filters are available for a failsafe digital input:
• When the discrepancy time is active, the converter tolerates input signals that briefly differ.
• When the debounce time is active, the converter suppresses brief signal changes.
Function description
Discrepancy time
The converter checks that the two input signals of the failsafe digital input always have the
same signal state (high or low).
With electromechanical sensors (e.g. emergency stop buttons or door switches), the two
sensor contacts switch, but never at exactly the same time, and are therefore temporarily
inconsistent (discrepancy).
Only a permanent discrepancy signifies a fault in the failsafe digital input circuit, e.g. wire
breakage.
You must set the discrepancy time to ignore signals that are briefly inconsistent.
Figure 8-28
The discrepancy time does not extend the converter response time. The converter activates
the safety functions as soon as one of the two F-DI signals changes its state from high to low.
262
Discrepancy time
Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK
SINAMICS G120C Converters