Siemens SINAMICS G120 Operating Instructions Manual page 308

Setting functions
8.8 Safe Torque Off (STO) safety function
The tolerance time does not extend the inverter response time. The inverter selects its safety
function as soon as one of the two F-DI signals changes its state from high to low.
Figure 8-35
Filter to suppress short signals
The inverter normally responds immediately to signal changes at its fail-safe inputs. This is
not required in the following cases:
● When you interconnect a fail-safe input of the inverter with an electromechanical sensor,
contact bounce may result in signal changes occurring, to which the inverter responds.
● Several control modules test their fail-safe outputs using bit pattern tests (on/off tests), in
order to identify faults due to either short-circuit or cross-circuit faults. When you
interconnect a fail-safe input of the inverter with a fail-safe output of a control module, the
inverter responds to these test signals.
A signal change during a bit pattern test usually lasts:
– On test: 1 ms
– Off test: 4 ms
308
Tolerance regarding discrepancy
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB