This TIL is about a legacy interface no longer compatible with modern computers. It probably does not apply to you.
To calibrate your motion detector with the (MPLI, discontinued), do the following:
1) Start up the program and open a file that uses a motion detector.
2) Since the Motion Detector is plugged into A, click on the A icon for the sensor.
3) Choose Calibrate Now.
4) Enter a label (like Distance) and a unit (like Meters), and then select the Vernier Motion Detector icon.
5) Set the motion detector at a known, measured distance from a reflecting object, such as a wall. You should see a number displayed on the screen, under the A. The motion detector should be clicking. Type in the Raw Reading, which is the distance measured with a meter stick or tape measure, then click on OK.
6) Repeat the step above with a different measured distance, say twice as long or so.
7) You will be asked if you want to save this calibration file. You can if you wish to, but make sure that you save the Experiment File. When you save the Experiment file, it will contain the new calibration for the Motion Detector.