Custom mods for high-temp position measurement application

As part of a motorised control system that regulates and optimises peak engine performance, Positek's compact pushrod style P103 is mounted near the direct flow hot engine exhaust gases where its specially designed thermal shield allows use at temperatures of up to 160 C (at the inductive sensing element) whilst the conditioning electronics remain at around 125 C.

Positek's patented PIPS inductive technology is based upon a simple, single coil design which facilitates straightforward customisation, often with the benefit of reduced lead times which in some cases can be as short as a few days. Positek states that when compared with other available LVDT and magneto-strictive sensor types, PIPS based displacement sensors can overcome problems such as bulky coils, poor length-to-stroke ratio or the need for special magnetic materials - and for simplified control say that they do not require separate signal conditioning either.

As there is no contact between the moving electrical components, the technology is said to deliver extremely long life when compared to potentiometer based equivalents. Even as standard components Positek says the technology has excellent resilience to shock and vibration with respective specification values of 10g (IEC 68-2-6) and 40g (IEC 68-2-29). These factors combine with typical IP67 protection ratings and full compliance to EN61000 for both susceptibility and radiated EMC.

For the wastegate valve application, the stainless steel housed P103 series sensor includes a special threaded mounting that aided a compact installation for the customer, as well as the standard options of spring-loaded pushrod and cable gland. The electrical characteristics combined a 4.5V DC calibrated output from a +5V DC supply. A wide range of alternative electrical options are available across the standard range along with mechanical options that include flange or body clamp mountings and free or captive push-rods.

The 35 mm diameter P103 series short stroke position sensor has any measurement range up to 50 mm (a version for longer measurements up to 100 mm is also available). With independent linearity to < +/-0.25% (< 0.1% option available) and with essentially infinite resolution and a low temperature coefficient, the sensor is said to provide highly accurate and repeatable position measurement over a wide temperature range.

The P103 is part of a range of linear, rotary and tilt sensors from the ISO9001:2015 designer and manufacturer which includes ATEX, IEC-Ex and CSA certification across many product ranges.