Wire-draw encoders also measure around corners

The new wire-draw encoders of the BTF/PRF series from SICK-STEGMANN provide a precise and robust solution in many situations where positions are to be determined or paths measured but the measurement section goes round a corner.

>> Elevating platforms, construction machines, or cranes are typical examples of machines whose control systems require precise positional and path information, but which do not have a continuous path – as a result of articulated or hinged mechanisms. The new BTF/PRF wire-draw encoders (a combination of wire-draw mechanism and encoder) provide the solution. They are available for measurement lengths varying from 2–50 m, and are thus also suitable for smaller machines.

Drum rotations are the measure of all things

With wire-draw encoders, a rust-free steel cord is moved between the starting and finishing points of a measurement section and is wound in or out of a drum in a single layer. The number of drum rotations (proportional to the length) is counted by an encoder and converted to a measurement signal. Even without a straight linear path this provides precise positional and path data, and thus information e.g. on the platform height of an elevating platform, the position of a dredging shovel, or that of a crane’s gripper. In order to allow the device to ignore the demanding application conditions, these wire-draw encoders have a robust housing with an enclosure rating of IP 64, a dirt scraper, and a fat chamber for the measurement cord.

Available with absolute or incremental encoder

Depending on the favoured method of determining the number of rotations, and the linear resolution desired, users can choose between wire-draw systems with absolute or incremental encoders. With Profibus, CANopen or DeviceNet fieldbus technologies; the SSI interface; the absolute and HTL or TTL interfaces of incremental wire-draw encoders, the appropriate interface for data transmission is available for any particular application.

Wide range of uses

The wide variety of types of BTF/PRF wire-draw encoders available opens up numerous application opportunities, such as for presses, extrusion machines, high-bay warehouses, theatre stages, medical technology, locks and barrage systems, and in numerous other applications and branches.

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