Sensor Technology has extended its new range of torque sensors with a model that has the sensing head and electronics in separate housings. This has two advantages: the sensing head can fit into very confined spaces, and the electronics can be located in a position where they are protected from physical damage, dust, dirt, moisture, electromagnetic forces, etc.
The new TorqSense SGR530/540 series operates on the same principle as all the other SGR510/520 units, namely a full four-element strain gauge bridge. This uses four individual strain gauges affixed to the drive shaft; each measures the deflection of the shaft in a different direction as it rotates under load. The electronics collect readings from all four gauges and calculate the torque value.
Sensor Technology launched the TorqSense SGR510/520 range in 2020 as the successor to its RWT range which worked on the surface acoustic wave (SAW) measurement and detection. It has specialized in real-time torque measurement for over forty years and pioneered the development of wireless technologies that use radiofrequency pickups rather than hard-wired solutions involving delicate and unreliable slip rings.
Initially launched in sizes up to 500Nm, interest in the SGR sensors was so high that the introduction of larger sizes up to 13,000Nm was brought forward 6-12 months to December 2020.
The new range is designed to meet emerging user requirements, notably accurately recording transient torque spikes. In the past transducers didn’t have the bandwidth to capture these spikes, so they were ignored. However, advances in automation, continuous operation, and the increasing need for accurate track and trace data have led to the need for more detailed measurement and analysis.
In use, 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 transducers then use state-of-the-art strain gauge signal conditioning techniques to provide high bandwidth, low-cost torque measuring solution with high over range and overload capabilities.
An advantage of the design of the SGR torque sensors is that they automatically compensate for any extraneous forces, such as bending moments, inadvertently applied to the sensor. They also offer high sensitivity and have a wide temperature tolerance, attributes that are required more and more and production machinery becomes more and more sophisticated and performance demands increase.
Other advantages of the SGR range include elimination of noise pickup and signal corruption associated with slip rings and hard-wired solutions, a 400% mechanical overload limit with accurate torque measurement even at these extremes, and multipoint calibration to eliminate linearity errors within the sensor.
All units are accurate to +/-0.1% and resolution to +/-0.01% of the transducer’s full scale. Other features include an adjustable moving average filter, power supply range from 12VDC to 32VDC, user-settable analog output voltages, and RS232, USB, CANbus, and Ethernet comms options.