Transmission Channel Changeover; Range Reduction - Leuze electronic MLC 520 EX Series Original Operating Instructions

Implement the contactor monitoring function:
• through appropriate wiring of the MLC 520 safety sensors (see table 7.2).
• 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.
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, there-
by 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").
Faulty function due to incorrect transmission channel!
Select the same transmission channel on the transmitter and corresponding receiver.
4.4

Range reduction

In addition to selecting the suitable transmission channels (see chapter 4.3 "Transmission channel
changeover"), the range reduction also serves to prevent mutual interference of adjacent safety sensors.
Activating the function reduces the light power of the transmitter so that around half of the nominal range
is reached.
Reducing range:
 Wire pin 4 (see chapter 7.1 "Pin assignment transmitter and receiver").
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-rele-
vant monitoring.
 Do not use this configuration option for safety purposes.
 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 distance to reflective surfac-
es")
Leuze electronic MLC 520 EX
Functions
16