How to use the Leica MD40 Laser Sensor

Basic Instructions for using the Leica MD40 Laser Sensor

  1. Plug your laser sensors into the junction box making note to plug them into the correct ports.  Select Laser Mode using the Sensor selection button on the control panel on each side.
    **From the internal Grading System Window, Press configure on the Left or Right side to select the method for elevation control for that side. Items in Red are un-selectable.
  2. Press corresponding "F" key below to Reset (Removes an existing offset applied to sensor)
  3. Put the blade on the ground at the height you want to grade at (i.e. your benchmark).  Keep the blade near to level.
  4. Put the MD40 laser sensor on the mast and move it up or down until you find the laser beam (laser should be min 600rpm head speed).  Set it near the middle (very roughly) and ignore the LEDs. It is not necessary to centre the MD40 perfectly as the on-grade point is adjustable on the MD40 (see next steps).
  5. Press and HOLD the corresponding “F” key below SEEK. You will now see the LED on the MD40 turn green.  You have now set the height for grading. You’ll see 0.0cm at the top of the screen in black.  You have now zeroed off the sensor offsets on the control panel.
  6. Repeat steps 2-5 on the other side.


You are now ready to grade and will be grading to your benchmarked level using the MD40’s on both sides when you put the system into AUTO on the panel or using the external switches. To alter the grading depth use the UP or DOWN arrows. Any alterations you make using the UP and DOWN arrows will appear on the control panel and alter the cutting depth.