LDM41A and LDM42A

Robust and precise laser distance sensors up to 100 m

The LDM41A is an optoelectronic distance measuring device for industrial applications with an analogue interface (4 mA to 20 mA).
It works contact-free on the principle of comparative phase measurement (amplitude modulation) and facilitates precisely accurate measurement of distances.


It distinguishes itself through high precision as well as high independence from the surface of the measuring object. The red, visible laser beam allows for easy alignment. The sister model LDM42A has been further developed for fast distance measurements on white surfaces.

  • Distance measurement and determination of position
  • Diameter measurement of rolls / coils
  • Fill level measurement
  • Position control
  • Monitoring of safety-relevant parts
  • Monitoring of lifting plants / lifting height measurement and positioning of elevators
  • Monitoring and positioning of cranes and conveyor systems


  • Millimeter precise measurement on various surfaces
  • Long range reflector-less distance measurement
  • With additional reflectors on the target object measurements over 100 m
  • Operation in extreme ambient temperatures with high precision and range
  • High supply voltage range between 10 V and 30 V DC with low power consumption
  • Safe operation through laser class 2
  • Easy adjustment through visible laser beam
  • One connection cable for supply voltage, serial data interface, switching and analog output
  • Customized parameterization via PC
  • Display of measured values in meters, feet, inches and others due to free scaling
  • Robust, compact housing, easy to install, protection standard IP 65

Technical Data

Measuring range1

0.2 m ... 30 m on almost all natural surfaces, over 100 m achievable depending on the degree of reflection of surfaces

Measuring uncertainty2 ±2 mm under defined measuring conditions3
±3 mm (+15 °C ... +30 °C)
±5 mm (-10 °C ... +50 °C)

0.1 mm, freely scalable

Reproducibility4 0.5 mm
Measuring time

0.24 s ... 6 s adjustable or automatically in mode DT
0.1 s in mode DW on white surface
20 ms in mode DX on white surface (only LDM42A)

Laser divergence5 0.6 mrad
Laser class

Laser class 2 acc. to DIN EN 60825-1:2001-11 (650 nm, red)

Operating temperature -10 °C ... +50 °C
Storage temperature -40 °C ... +70 °C
Supply voltage

10 V ... 30 V direct currents

Power consumption Ca. 1.5 W
Serial interface6 RS232 or optional RS422, max. Baud rate 38400, ASCII, setting of measuring functions, scaling, measuring time via commands, display of measured values, internal temperature and error code
Switching output

Programmable switching threshold and hysteresis, "high side" switch, maximum load 0.5 A

Analog output

Programmable distance range limits,
4 mA to 20 mA, adjustable reaction on error (3 mA, 21 mA or last valid measured value)

Housing material

Aluminum anodized

Size (LxBxH) 187 mm x 96 mm x 50 mm
Weight 850 g
Protection class IP 65
Shock resistance 10 g / 6 ms (DIN ISO 9022-3-31-01-1)

30,000 hours at 25 °C


4 drill holes for M6 screws, 100 mm x 85 mm

Remarks on the technical data of the LDM41A and LDM 42A

1 Dependent on target reflectance, influence of extraneous light and atmospheric conditions
2 Statistical spread of 95 %
3 Measurement on planar, vertical white surface at standstill or in continuous movement, + 15 °C to +30 °C
4 Dependent on target reflectance, influence of extraneous light and atmospheric conditions
5 At a distance of 10 m the beam diameter is 6 mm, at 100 m it is 6 cm
6 Please specify option RS422 when placing the order


Mr. Daniel Strandt

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