Waldkirch, November 2008 – The linear measuring MPS Magnetic Position Sensor from SICK is a solution for the analogue querying of piston position on pneumatic cylinders combining flexibility with user-friendliness and maximum precision. Maximum resolution and accuracy, a variety of housing lengths for differing measurement ranges, as well as suitability for the high velocities of cylinder pistons make the MPS a multitalent for many applications.

According to the automation task, the MPS series covers measurement ranges of 32 mm, 64 mm, 96 mm or 128 mm. The corresponding differing housing lengths of the MPS are achieved by lengthening the extruded plastic housing profile. In practical use, the flexibility of this analogue path measurement system means that, on the one hand, the T-slots on the cylinder need not be occupied with sensors for individual switching points and, on the other hand, the teach-in function does away with the need for mechanical sensor adjustment – and thus optimises product or process changes. Zero- and end-point adjustment offers users maximum resolution of the measurement range.

Simple integration, maximum precision

In order to ensure that installation is as simple and reliable as possible, the housing of the MPS has been designed in such a way that it allows rapid drop-in mounting from above into all common T-slots, and fixing with just two screws. The IP67-protected sensor housing contains, among other things, Hall sensors (for non-contact position detection), the controller and the teach-in element on two circuit boards. The zero- and end-point, i.e. the actual desired measurement range, can be taught-in via the teach button regardless of the piston position and the magnetic field pole. The intermediate piston positions are transmitted as analogue signals that are available as 4 - 20 mA current output and as a 0 - 10 V voltage signal. The querying of piston position takes place at piston speeds of up to 3 m/s and always with maximum precision. The resolution is 0.05 mm, the linearity error is only 0.3 mm for any measurement range, and the repeatability accuracy is 0.1 mm. With the help of MPS, a pneumatic drive now achieves a level of accuracy that is suitable for numerous tasks that have hitherto been solved with linear motors.

MPS opens up new applications for pneumatic cylinders

Pneumatic cylinders are considerably more rapid and economical than equally powerful linear drives, and are thus very popular as drive elements in assembly and handling technology. The use of MPS devices has substantially reduced the accuracy advantage of linear motors compared to pneumatic drives. Therefore numerous applications can now be solved “pneumatically” for which there were only “linear” approaches in the past. As a result of the four different measurement ranges, the advantages of the MPS are not restricted to ultra-short movement applications with measurement ranges of just a few millimetres, but generally benefit compact cylinder applications with measurement ranges of up to 128 mm. Future device features such as additional programmable switching points or IO Link capability will further improve the range of functions of the MPS and appropriately equipped pneumatic drives.