Leuze electronic MLC 520 - EDM contactor monitoring

Functions
Leuze electronic MLC 520 15
4.2 EDM contactor monitoring
NOTICE
The contactor monitoring of the MLC520 safety sensors can be activated through appropriate
wiring (see chapter 7.1.1 "MLC500 transmitter")!
The “contactor monitoring” function monitors the contactors, relays or valves connected downstream of the
safety sensor. Prerequisites for this are switching elements with positive-guided feedback contacts (nor-
mally closed contact).
Implement the contactor monitoring function:
• through appropriate wiring of the MLC520 safety sensors (see chapter 7.1.1 "MLC500 transmitter").
• through the external contactor monitoring of the downstream safety relay, (e.g. MSI series from Leuze
electronic)
• or through contactor monitoring of the downstream safety PLC (optional, integrated via a safety bus)
If contactor monitoring is activated (see chapter 7 "Electrical connection"), it operates dynamically, i.e., in
addition to monitoring the closed feedback circuit every time before the OSSDs are switched on, it also
checks whether the release of the feedback circuit opened within 500 ms and, after the OSSDs are
switched off, whether it has closed again within 500 ms. If this is not the case, the OSSDs return to the
OFF state after being switched on briefly. An error message appears on the 7-segment display (E30, E31)
and the receiver switches to the fault interlock state from which it can only be returned to normal operation
by switching the supply voltage off and back on again.
4.3 Transmission channel changeover
Transmission channels are used to prevent mutual interference of safety sensors which are located close
to each other.
NOTICE
To guarantee reliable operation, the infrared beams are modulated so they can be discerned
from the ambient light. Welding sparks or warning lights, e.g. from passing high-lift trucks,
thereby do not influence the protective field.
With the factory setting, the safety sensor works in all operating modes with transmission channelC1.
The transmission channel of the transmitter can be switched by changing the supply voltage polarity (see
chapter 7.1.1 "MLC500 transmitter").
The transmission channel of the receiver can be switched by changing the supply voltage polarity (see
chapter 7.1.2 "MLC520 receiver").
NOTICE
Faulty function due to incorrect transmission channel!
Select the same transmission channel on the transmitter and corresponding receiver.