Sensor Technology TorqSense SGR510/520 series non-contact torque sensors

Sensor Technology has launched a range of non-contact torque sensors based on a full four element strain gauge bridge design, complementing its existing non-contact sensors that use surface acoustic wave (SAW) detection.

Designated the TorqSense SGR510/520 series, the units have a 250% overrange reading capacity, allowing sudden spikes in torque to be measured and recorded accurately. The design also compensates for any extraneous forces (such as bending moments inadvertently applied to the sensor), improves sensitivity and has a wide temperature tolerance.

The bridge is essentially four strain gauges glued onto the shaft that is to be monitored in a square formation set at 45° to the axis of rotation. Thus, when torque is applied to the shaft, two gauges are stretched into tension and two go into compression.

A rotor mounted ultra-miniature microcontroller, powered by an inductive coil, measures the differential values in each strain gauge and transmits them back to the stator digitally, via the same coil. The SGR510/520 series transducer then uses state-of-the-art strain gauge signal conditioning techniques to provide a high bandwidth, low-cost torque measuring solution with high overrange and overload capabilities.

The measuring range of the series is 1 to 500 Nm (with models up to 13,000 Nm available shortly), accurate to +/-0.1% and with a resolution to +/-0.01% of the transducer’s full scale The digital transmission between rotor and stator cuts out all cyclic fluctuation of the signal due to shaft rotation and generates a digital sample rate of 4000 samples per second.

Other features include an optional adjustable moving average filter, power supply range from 12 to 32 VDC, user configurable analog output voltages, a choice of RS232 communications, USB interface, CANbus interface, external Ethernet gateway and LabView virtual instruments.