In-cylinder sensor offers flexibility and zero wear

Dean Palmer reports on a new sensor that uses patented non-contacting technology giving users a reliable position measurement device

A new sensor has been launched in the UK which benefits from patented non-contacting technology offering hydraulic and pneumatic cylinder manufacturers reliable position measurement. Novotechnik's TLI In-Cylinder sensor (distributed in the UK by Variohm-EuroSensor) uses 'Indres' non-contact technology which has no sliding contact and so wear is negligible. It can be used inside the pressure chamber of hydraulic or pneumatic cylinders. The sensor can be supplied in a dual redundant version for use on safety critical applications such as vehicle steering. It has two complimentary outputs that can be used for performance monitoring. Mechanically, the TLI is designed to simplify retrofitting as the flanged design is interchangeable with other monitoring systems. Linearity is 0.2% and the sensor is sealed to IP67. Temperature range is from -40°C up to 125°C and all the unit meets all the relevant EMC requirements. Also worth checking out is Variohm's new intelligent vibration transmitter from Wilcoxon. This converts traditional accelerometer signals to 4-20mA data for use in existing PLC/DCS networks for condition trending, while still providing a buffered dynamic output for more extensive vibration analysis. Pairing an existing vibration sensor with the iT Series gives users one sensor that accomplishes both tasks. By using the existing sensor infrastructure, the expense of online monitoring can be reduced. RML Motorsport, a UK-based racing car constructor, used data logging and control sensors from Variohm on the recent MG Lola car for the Le Mans 24 Hour race. Sensor reliability was a major factor in the team's choice of supplier and Variohm was eventually chosen to supply four functions on the MG Lola: suspension height monitoring; steering position; gear selection control; and brake pressure. The first three functions used potentiometers and the fourth utilised a strain gauge pressure transducer. All the devices are absolute insofar as they do not use any memory function, they can be switched off or disconnected and will know precisely where they are or the pressure they are seeing the moment power is restored.