Rotary position sensor is reliable, accurate and low cost

By sourcing low cost rotary position sensors, a sequential gearbox indicator manufacturer has been able to pass on cost savings to end users, writes Dean Palmer

"There are few rotary position sensor manufacturers who offer such a reliable and accurate sensor at such a reasonable low price at the volumes I require," explained Neil Wallace, owner of Geartronics, a manufacturer of sequential gearbox indicators. He continued: "I have been able to reduce costs significantly and pass on those savings to customers, making our products an attractive choice for gearbox manufacturers and end users alike." The sensor Wallace is talking about is the SRS280 rotary position sensor from Penny + Giles. Suitable for motorsport and industrial use, the sensor is designed for high reliability in extreme temperature, high vibration and shock environments. At Geartronics, it is fitted to the selector barrel of the company's sequential indicators. The action of the gear stick rotates this barrel to set a position corresponding to the selected gear and the sensor measures this position precisely, enabling the electronic control unit to calculate and display which gear is selected. This method of sensing the selected gear offers very reliable, repeatable results compared with micro switches, which count the number of times the gear stick has been knocked forwards or backwards by the driver. Using traditional sensors often leads to problems with signal continuity as a result of broken casings, intermittent shaft contact or ingress of dust or fluids. The SRS280 can be sealed to IP66. Ray New, managing director at Penny + Giles commented: "We've conducted research in Formula One to identify these issues and develop solutions. The SRS280 is based on our proven hybrid potentiometer track technology, which is widely used in linear position sensing systems globally. The technology is known for its stability in extreme environments, its virtually infinite resolution and its durability - in excess of 50 million operations." The sensor has an integral moulded cable assembly which negates the need for a heat shrink boot. It also has crush-proof mounting flanges with steel inserts that protect the casing from damage from mounting bolts. As a result, the sensor can be re-positioned as many times as necessary, rather than discarded after only one use. According to New, the SRS280 was the first rotary sensor of its kind to offer a range of 35 different models with angles from 10° to 350°, allowing users to match the sensitivity of the system to the application, for improved data acquisition and closer control.