System design and selectable functions
16
SOLID-2
Leuze electronic
Review-Stand, , 8. April 2015
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3.4.2
Contactor monitoring (EDM)
If the “Contactor monitoring” function is activated, it dynamically monitors contactors,
relays or valves downstream from the SOLID-2. Precondition here are switching elements
with positive-guided feedback contacts (normally closed).
You can implement the contactor monitoring function with:
✟
The internal contactor monitoring in the Receiver Extended (see Chapter 6.1.3)
✟
or via a downstream safety PLC
If the internal contactor monitoring function is activated, it works dynamically, i.e. in
addition to verifying that the feedback loop is closed before turning on the OSSDs the
system checks whether the feedback circuit has opened within 500 ms of being enabled
and whether it has closed again within 500 ms when turning off the OSSDs. If this is not
the case, the OSSDs will assume an OFF state again shortly after turning on. A error
message appears at the 7-segment display, E 30.
Fig. 3.4-3:
Contact monitoring function, combined in this example with a start/
restart interlock
