Length

LENGTH MEASUREMENT USING LASER DOPPLER

Laser Doppler sensors can measure the length even of hot surfaces without contact. They may also be protected by an adequate housing including air purge.

Principle:
A laser spot is projected on the moving surface. Depending on reflection in or against movement direction, the reflected beam has a different phasing. Using this phasing difference, the speed, and by a certain period the length, can be calculated.