Sensorer og Aktuatorer


The principle of Optically sensors based on either reflections of a lightsource (Source and detector integrated in the same unit) An alternative method could be a separate lightsource and detector which activated by a object between them.

The electric propertie of a coil (Self-induction coefficient - L) depends of the presence by iron. A special design electric circuit (based on AC voltage) will be able to detect changes of the self-induction. The figure presents a system for measurement of speed and motion of a shaft. Each shaft turn will produce 4 pulses.

Reed-relays a good alternative to mechanic switches. A magnet will magnetize the iron-contacts inside and hence forcing then together. After the magnet removed will a spring-effect of the contacts pull them apart.