Light curtains MLD

Multiple Light Beam Safety Devices and transceiver with integrated muting

The Multiple Light Beam Safety Devices of the MLD 300 and MLD 500 series are active opto-electronic protective devices for persons at access points or at hazard locations of machines and plants. They are available as 2-, 3- and 4-beam transmitter-receiver systems as well as 2- and, for the first time, 3-beam transceiver systems. The user can select from the several function classes of the MLD series to get the optimal model for the application and respective requirements. In addition to the start/restart interlock and contactor monitoring functions, various muting modes can be selected. No PC is necessary for configuration, as the functions are set via the pin assignments at the connection of the devices. Thus, no additional modules are required and, should it be necessary to exchange a device, the sensor does not need to be reconfigured.

Access  guarding,  perimeter  guarding, muting – your requirements are decisive

  • Transceiver innovation:
    The 3-beam transceiver can replace more complex systems;
  • Suitable for low temperature environment:
    Completely functional up to -30 °C;
  • Simple start-up:
    All settings, e.g. configuration of the muting modes, are made without the use of a PC; a device can be replaced by means of Plug & Play via M12 connection technology without any programming;
  • Device versions with integrated AS-i Safety interface:
    Direct connection to the AS-i bus without additional coupling modules;
  • Muting without additional devices:
    Integrated muting functions, configurable via pin assignments. Status indicators optionally included in the receiver. Pre-mounted Muting Sensor Sets for L- and T-designs enable sequential and parallel muting;
  • Fast and precise laser alignment:
    Integrated laser alignment aid (option) for easy and fast alignment for long distances;
  • 7-segment display:
    Easy determination of the sensor behavior and appropriate countermeasures.

Whether transceiver or transmitter-receiver system – the MLD advantages are always included

The respective equipment (function class) of the MLD series can be selected depending on the application. This applies not only to integrated muting functions, but also to other optional performance characteristics. The MLD 330 and MLD 530 series has, for example, a 7-segment display, which you can use to immediately determine the cause of sensor behavior and initiate the proper countermeasures.

Transceiver system

This system consists of an active transceiver (transmitter/ receiver in one housing) and a passive Deflecting Mirror without electrical connection.

  • 2- and 3-beam systems available Operating range from 0.5 to 8 m;
  • M12 connection technology, also with integrated AS-i Safety interface;
  • High robustness against interference through multiple scanning.

Transmitter-receiver  system

Systems consisting of transmitter and receiver are well-suited for high operating ranges.

  • 2-, 3- and 4-beam systems available;
  • Operating range type 1 (MLD…-R /-T): 0.5 to 50 m;
  • Operating range type 2 (MLD…-xR /-xT): 20 to 70 m M12 connection technology, also with integrated AS-i Safety interface;
  • High robustness against interference through multiple scanning.

Alignment and mounting – a child's play

Easy alignment

with integrated laser alignment aid. The series is predestined for wide-area perimeter guarding, which is realized with Deflecting Mirrors. With the integrated laser alignment aid, adjustment of such safeguards is noticeably simplified. A reflective element integrated in the cap on the receiver side of the system ensures clear visibility of the alignment laser spot, even over long distances. The Deflecting Mirror columns necessary for perimeter guarding are simply and quickly aligned, step-by-step. The setup time is considerably reduced.

BT-240 swivel mount (optional)

With the swivel mount, the safety sensor can be flexibly turned 240° on its own axis, easily aligned and reliably mounted – an extremely practical solution for further simplifying use of the devices and for accelerating the installation.

BT-P40 clamp bracket (optional)

With the clamp brackets, the safety sensor can, when used in device columns, be flexibly adjusted in height and easily aligned in its vertical position.

Multicolored status indicator

The practical aid for daily operation: the colored indicator displays the respective sensor operating state, even over large distances - and during muting, of course.

Configure muting modes without a PC

Вith the Multiple Light Beam Safety Devices of the MLD series, a total of 6 different muting operating modes can easily be set. Configuration is performed by means of wiring or pin assignments at the plug and socket. Further auxiliary equipment, such as a PC, software etc., is no longer required and additional muting devices are not required. When setting up the muting application, this considerably simplifies the overall construction.

Freely confiгuration and muting!

With the individual operating modes, the sensor is well equipped for a wide range of muting applications. In addition to 2- and 4-sensor muting (timing controlled, sequence controlled), partial muting is, for example, also possible. In this case, the lower beams can be muted while the upper beam remains active. As a result, a safeguard that would otherwise be necessary, e.g. by means of guards or other protective sensors, can be eliminated.

Helps reduce cabling!

If a muting signal comes from a system control, the user can use the 8-pin plug (machine interface) directly on the sensor for this signal. This reduces cabling requirements. Further-more, the muting enable function can be used to enable or disable the muting sequence via an external signal. This increases security against tampering.


In cooperation with the Leuze electronic Safety Monitor ASM-m, the MLD Multiple Light Beam Safety Devices permit the easy construction of access guarding with muting based on AS-i Safety at Work.

Fewer addresses – more slaves.

The ASM-m Safety Monitor takes care of controlling the muting process, including driving the muting indicator integrated into the MLD via AS-interface. It is now no longer necessary to assign an AS-i slave address specifically for the muting indicator. This also applies to an external muting indicator connected to the local socket of the safety sensor. This saving allows even more AS-i slaves, such as safety sensors, to be connected to an AS-i network for each AS-i Safety Monitor.


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