Techdrives is now offering sensors from the Italian position measurement specialist FIAMA srl. FIAMA is known for digital and clock-type position indicators, plus it manufactures wire operated transducers ('string pots') and non-contacting linear encoders. Combined with a matching display, these low-voltage devices can give high resolution on strokes of up to 12m. Wire transducers are lower in cost and flexible to use, being suitable for linear speeds up to 500mm/s. Non-contacting position transducers are effectively encoders; both incremental and absolute versions are available.
Wire-operated linear transducers (also known as draw wire displacement sensors) are simply devices that turn linear motion into a variation in resistance of a potentiometer. The cable housing with spring retraction of the cable is mounted in a fixed position with a low-voltage DC supply and gives outputs of 4-20mA or 0-10V. The cable can be supplied in standard lengths starting at 50mm stroke and running up to 12.2m. Operating speeds are limited to 500mm/s but accuracy is good, with repeatability at about 0.2mm depending on the model. Options include a battery-powered, self-contained model, and pulse outputs for serial transmission by RS485 or Profibus.
Where higher speeds and accuracy are needed, FIAMA offers a non-contacting system in which a magnetised plastic ferrite strip is sensed by a DC-powered transducer. Linear speeds up to 3m/s are possible. This is effectively an incremental encoder system with push-pull or TTL line-driver outputs in two channels. The magnetised strip can be supplied for measuring lengths up to 25m with a position measurement accuracy of 0.1mm. A further option is an absolute encoding system available up to 10m.
Follow the link for more information about FIAMA position measurement systems for linear motion.