Reer MZERO Installation, Use And Maintenance Manual page 77

The time after which the electromagnet is activated depends entirely on the technical/physical
characteristics of the specific device and may therefore vary according to the type of guard lock
used. Thus, since the LockOut signal controls the activation of this device, the status of the
Lock_Fbk feedback signal will change at different times, depending on the type of guard lock.
This variability can be avoided by changing the value of the Feedback Time parameter, which is the
maximum delay accepted by the "Guard_Lock" operator before the Lock_Fbk signal switches
status following a request to activate the electromagnet. Clearly, the following condition must be
met:
This will now be explained using a practical example.
Example of operation in the "with Gate" mode
In this example the user unlocks the guard lock with the "SWITCH" block. The "LockOut" signal
controls an "STATUS" SIL 1/PL c output that controls the guard lock electromagnet, the status of
which is detected by the "Lock_fbk" input via the "LOCK FEEDBACK" input block. "Output1"
indicates the status of the operations.
The status of the safety gate is monitored by the "Gate" input via the "E_GATE" input.
The guard lock used in the example continues to be locked when the electromagnet is not
energised. Hence the "Interlock spring" option must be selected.
➔
The Guard Lock operator parameters are shown on the right. On the left there is an example
of an application diagram. The electromagnet feedback consists of two contacts, one
normally closed and one normally open. When the electromagnet is energised the two
contacts switch status. The gate feedback consists of two normally closed contacts.
8541403 • 19/07/2021 • Rev.1
STAND ALONE PROGRAMMABLE SAFETY CONTROLLER
Feedback Time ≥ Electromagnet activation time
Figure 35 – Example of operation in the with Gate mode
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