Siemens SINAMICS G120 Operating Instructions Manual page 309

If the fail-safe input signals too many signal changes within a certain time, then the inverter
responds with a fault.
Figure 8-36
An adjustable signal filter in the inverter suppresses temporary signal changes using bit
pattern test or contact bounce.
The filter increases the inverter response time. The inverter only selects its safety function
after the debounce time has elapsed.
Figure 8-37
Parameter
p9650
p9651
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB
Inverter response to a bit pattern test
Filter for suppressing temporary signal changes
Description
F-DI changeover tolerance time (factory setting: 500 ms)
Tolerance time to change over the fail-safe digital input for the basic functions.
STO debounce time (factory setting: 1 ms)
Debounce time of the fail-safe digital input for the basic functions.
8.8 Safe Torque Off (STO) safety function
Setting functions
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