Forced Dormant Error Detection - Siemens SINUMERIK 808D Function Manual

The wiring for factory setting and using the STO function is shown as follows:
Selecting/deselecting "Safe Torque Off"
The following is executed when "Safe Torque Off" is selected:
● Each monitoring channel triggers safe pulse suppression via its switch-off signal path.
● A motor holding brake is closed (if connected and configured).
Note
If "Safe Torque Off" is selected and de-selected through one channel within 2 seconds, the pulses are suppressed without a
message being output.
Restart after the "Safe Torque Off" function has been selected
1. Deselect the function in each monitoring channel via the input terminals.
2. Issue drive enable signals.
3. Switch the drive back on.
– 1/0 edge at input signal "ON/OFF1"
– 0/1 edge at input signal "ON/OFF1" (switch on drive)
4. Operate the drives again.
Response time for the "Safe Torque Off" function
The worst response time for the STO function is 5 ms.
22.4.2

Forced dormant error detection

Forced dormant error detection or test of the switch-off signal paths for Safety Integrated Basic Functions
The forced dormant error detection function at the switch-off signal paths is used to detect software/hardware faults at both
monitoring channels in time and is automated by means of activation/deactivation of the "Safe Torque Off" function.
To fulfill the requirements of ISO 13849-1:2006 regarding timely error detection, the two switch-off signal paths must be
tested at least once within a defined time to ensure that they are functioning properly. This functionality must be
implemented by means of forced dormant error detection function, triggered either in manual mode or by the automated
process.
A timer ensures that forced dormant error detection is carried out as quickly as possible.
8760 hours for the forced dormant error detection.
Once this time has elapsed, an alarm is output and remains present until forced dormant error detection is carried out.
The timer returns to the set value each time the STO function is deactivated.
When the appropriate safety devices are implemented (e.g. protective doors), it can be assumed that running machinery will
not pose any risk to personnel. For this reason, only an alarm is output to inform the user that a forced dormant error
Function Manual
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