TPI 505 Combination Digital Photo / Contact Tachometer - Use the 505 photo / contact tachometer to determine RPM and surface speed. The 505 is a combination photo and contact tachometer that also measures surface speeds of belts and wheels.
Field Testing the TPI 505 Photo Tachometer
1. Point the 505 at the palm of your hand and press the on button. You should see light on your hand from the lens of the 505. If you do not, replace the batteries and test again.
2. Point the 505 at a fluorescent light (closer to the light is better). Press the on button. The displayed reading should be 7200RPM +/- 10 RPM.