Leuze electronic MLC 500 - Transmission channel and range selection

Functions
Leuze electronic MLC 520 Host/Guest 19
The “contactor monitoring” function monitors the contactors, relays or valves connected downstream of the
safety sensor. Prerequisite for this are switching elements with positive-guided feedback contacts (normally
closed contacts).
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 receiver can be switched by changing the supply voltage polarity
(MLC520 receiver).
NOTICE
Faulty function due to incorrect transmission channel!
Select the same transmission channel on the transmitter and corresponding receiver.
4.4 Operating range selection
In addition to selecting the suitable transmission channels (see chapter 4.3 "Transmission channel
changeover"), the operating range selection also serves to prevent mutual interference of adjacent safety
sensors. At reduced operating range the light power of the transmitter reduces, so that around half of the
nominal range is reached.
Select operating range:
Ä Wire pin4 (see chapter 7.1 "Pin assignment transmitter and receiver").
ð The wiring of pin4 determines the transmitting power and thereby the range.
WARNING
Impairment of the protective function due to incorrect transmitting power!
The light power emitted from the transmitter is reduced through a single channel and without
safety-relevant monitoring.
Ä Do not use this configuration option for safety purposes.
Ä Note that the distance to reflective surfaces must always be selected so that no reflection
bypass can occur even at maximum transmitting power (see chapter 6.1.4 "Minimum dis-
tance to reflective surfaces").