Siemens SINAMICS G120 CU240B-2 Operating Instructions Manual page 217

Figure 7-24
The filter does not increase the inverter response time. The inverter activates its safety
functions as soon as one of the two F-DI signals changes its state from high to low.
Bit pattern test of fail-safe outputs and contact bounces of sensors
The inverter normally responds immediately to signal changes at its fail-safe input. This is
not required in the following cases:
1. When you interconnect the fail-safe input of the inverter with an electromechanical
2. Several control modules test their fail-safe outputs using bit pattern tests (on/off tests), in
Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
Filter for suppressing discrepancy monitoring
sensor, contact bounce may result in signal changes occurring, to which the inverter
responds.
order to identify faults due to either short or cross circuiting. When you interconnect the
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 1 ms.
Figure 7-25 Inverter response to a bit pattern test
7.10 Safe Torque Off (STO) safety function
Functions
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