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Function description
Operating Manual PSEN op2B/1 Series
1003357-EN-02
16
t
Test/Start
button
1
0
Status of
safety light
grid
Error
Normal
operation
5 s
5 s
Fig.: Timing diagram - Reset after malfunction
4.4
EDM
Contactors outside the safety light grid
can be monitored (External Device Monitoring =
EDM, also known as feedback loop monitoring).
EDM only needs to be activated if the contactors are controlled directly.
A test is performed to see that the N/C contacts switch if the state of the OSSD changes
and so is used to monitor and detect malfunctions on the contactors. If a malfunction is de-
tected, the safety light grid switches
to a safe condition and stops the connected machine.
This check is carried out each time the OSSD is triggered and before restarting.