Multiple light beam safety devices

The multiple light beam safety devices of the MLD 300 (type 2) and MLD 500 (type 4) series are used for access guarding at machines and systems. The devices are available as 2-, 3- and 4-beam transmitter-receiver systems for large operating ranges up to 70 m and as cost-efficient 2- and 3-beam transceiver systems for operating ranges up to 8 m.

Economical access guarding

Advantages for you

  • With 2, 3 and 4‑beam versions and operating ranges up to 70 m, the MLD family always offers the right solution
  • Together with the UMC mirror columns, multi‑sided safeguarding is easy to implement
  • The integrated muting functions ensure easy setup of access guarding on conveyor lines
  • Practical swivel mounts and clamp brackets for quick installation and alignment


Efficient solutions for any operating range

The transceiver systems consist of an active transmitter/receiver and a passive deflecting mirror without electrical connection. This allows cost‑effective solutions with low installation effort.
The transmitter-receiver systems consist of a separate transmitter and receiver for applications with large operating ranges up to 70 meters. Deflecting mirrors can be added for multi‑sided safeguarding.

Simple and error-free configuration

All settings on the device can be configured by means of pin assignment. This saves time and money when commissioning and ensures error‑free configuration. A device can be swapped out easily by means of plug-and-play without reconfiguration.

Quick and easy alignment

The practical swivel mounts and clamp brackets make the MLD easy to align. Thanks to the integrated laser alignment aid, alignment can be performed quickly and easily even over large distances and with multi‑sided safeguarding.

Clearly visible status

The integrated, multi‑color indicator lights clearly show the status of the OSSD outputs at all times. Reset requests are also indicated if required.

Free-standing mounting

The DC and UDC device columns enable easy, freestanding mounting of the MLD multiple light beam safety devices. Special mounting brackets ensure simple installation and fast alignment of the devices.
The UMC mirror columns ensure simple and reliable set-up of multi-sided access guarding.
The spring elements in the foot of the columns absorb mechanical impacts and reset the columns automatically into their initial position. Alignment or repair work is unnecessary.

Quickly installed with preconfigured sets


With their pre-mounted and ready‑to‑use setup, the Set-AC muting sensor sets ensure fast and error‑free commissioning. They work together with MLD multiple light beam safety devices. They are mounted easily to the side of the UDC device columns or directly to the MLD devices.

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The MLDSET protective sensor sets offer complete solutions for access guarding with muting function. Thanks to the ready‑to‑use design with pluggable connections, the pre-mounted sets guarantee efficient setup and fast commissioning.

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Access guarding

Access to a dangerous area at a machine or system is to be guarded. To enable simple entry and exit of material, optoelectronic safety sensors are to be used.

The MLD 300/500 multiple light beam safety devices offer affordable access guarding solutions. The transceiver models with an operating range of up to 8 m are especially easy to install. For wide-area guarding, transmitter/receiver models are available with a range of up to 70 m.

Multi-sided access guarding

Access to the working range is to be guarded while the machine is in operation. To enable material entry and exit, the machine must be easily accessible from multiple sides.

The MLD 300/500 multiple light beam safety devices in combination with the UMC mirror columns safeguard access to the machine on multiple sides and over lengths of up to 70 m. The integrated laser alignment aid makes installation quick and easy.

Access guarding on conveyor lines, with muting function

Access guarding on conveyor lines is to prevent persons from accessing the danger zone, while at the same time allowing the transported goods to pass through.

The muting function bridges the safety sensor in a controlled manner to allow the transported goods to pass through. Various muting functions are already integrated in the MLD multiple light beam safety devices:
- 2‑sensor muting, timing controlled (MLD 330 / 530)
- 2‑sensor muting, sequence controlled (MLD 330 / 335 / 530 / 535)
- 4‑sensor muting, timing controlled (MLD 335 / 535)

Technical properties

  MLD 300: type 2, performance Level PL c, SIL 1
MLD 500: type 4, performance Level PL e, SIL 3
2 and 3‑beam transceiver systems for operating ranges up to 8 m
2, 3 and 4‑beam transmitter-receiver systems for operating ranges up to 70 m
Integrated 2‑sensor muting, timing controlled and sequence controlled
Integrated 4‑sensor muting, timing controlled
Integrated laser alignment aid
Mirror columns for multiple-side guarding
Device status can be read off from 7‑segment display at all times
Variant with AS‑i Safety interface for direct integration into AS‑i bus systems
Wide temperature range from -30 … 55°C

Safety - Product overview (PDF, ~7 MB)
Safety Solutions - Flyer (PDF, ~0.8 MB)
Optical safety sensors for point-of-operation and access guarding - Product overview (PDF, ~ 3 MB)