Siemens Sinamics G120 CU240E Operating Instructions Manual page 205

Reasons for inconsistent input signals
With electromechanical sensors (e.g. EMERGENCY STOP buttons or door switches), the
contacts may bounce briefly at the moment switching takes place. The two sensor contacts
never switch at exactly the same time either. As a result, the frequency converter responds
with a fault and indicates signal inconsistencies.
To prevent this, the input signals in the frequency converter must be filtered.
Figure 5-47
Setting the signal filters in the frequency converter
Set the debounce time (P9650 and P9850) to such a level that faults caused by contact
bounce or signal faults cannot occur.
Note
Short response times are essential for ensuring the functional safety of machines. The filter
times increase the time required by the frequency converter to respond to fail-safe signals.
For this reason, do not set the filter times any longer than required.
Completing the commissioning of the safety functions
1. Click on the button
2. If the default password has not been changed, you are prompted to change it.
3. In the following dialog box, confirm the checksums of the safety-related parameters. This
Frequency inverter
Operating Instructions, 08.10. 2008, t.b.d.
Debouncing and filtering the signals at the fail-safe inputs
made.
concludes the process of changing the safety settings.
5.12 Safety-related applications
to complete all of the settings that you have
Functions
205