Adding to the range of simple-to-use transportable sensors in the 300 series of digital readouts is the 362 clip-on sensor. Like the well-established 361 clip-on sensor, it is robustly constructed in a die-cast aluminium box with mounting tube.
Both sensors use standard pipe clips (8mm or 12mm) on the machine, which clip onto the tube on the sensor. This enables the sensors to be moved between machines. The measuring wire entry is sealed with a PTFE bush.
The maximum measuring range of the 361 clip-on sensor is 500mm 20". Its size is 52x38x32mm plus a 8mm diameter mounting tube. The measuring range for the 362 is extended to a maximum of 1200mm 48". The sensor size is 110x60x30mm, with a mounting tube 65mm long and 12.7mm diameter.
All the sensors from BW Electronics use a similar measuring method, based on an extending stranded stainless-steel wire, much like a tape measure. The measuring wire is wound around a small drum inside the sensor, which also has a restoring spring. As the wire is pulled out or returned under the spring tension, the wire winds off or on the drum. The drum has a thread cut on its outside diameter to ensure the wire winds cleanly on and off, with no overlapped turns. Attached to the drum is a rotary optical encoder that measures the rotation; signals from the encoder are counted to give the distance moved.
This method of measuring makes it particularly easy to fit sensors on smaller machine tools.
Some of the sensors available from BW Electronics -- the Micro Position Sensor 2 (MPS2), the 361 clip-on sensor (top right), and the 362 clip-on sensor (bottom). The MPS2 and 361 sensors each have a maximum measuring range of 20" 500mm, making them ideal for the smaller machine tool. The 362's maximum measuring range is 48" 1200mm. Also shown are the standard plastic pipe clips used for mounting the clip-on sensors.
Because the sensors have been expressly designed to be moved from machine to machine, this drastically reduces the cost for equipping a whole workshop with DROs. For example, a small workshop needs only two MPS3s, or one 300 series display and two clip-on sensors, to equip all the machines.
Experience has shown, however, that moving the 362 sensor is not a good idea. There is so much wire in it that it inevitably seems to get caught and damaged. If you can get away with using a 361, then that is to be preferred.
BW Electronics, 12 Mussons Close, Corby Glen, Grantham,
Lincolnshire, NG33 4NY, Great Britain