Your torque sensor’s output will typically go to some sort of instrumentation, such as a strain gauge conditioner or data acquisition (DAQ) system. On reaction torque sensors - or older-model, slip-ring-type torque sensors - the outputs are usually millivolt per volt, which is a strain gauge output. When using such an output, typically an AC or DC strain gauge conditioner is used to power the sensor and then condition the output to a usable signal, usually analog or digital. Plus or minus 10 volts DC amplitude signals are often more susceptible to noise than a frequency or digital output.
Frequency outputs are a time base signal and are less susceptible to noise than amplitude outputs. So more-modern torque sensors also give a frequency output:
- 10 kilohertz +/-5 kilohertz
- 60 kilohertz +/-30 kilohertz
- 240 kilohertz +/-120 kilohertz
The lower the frequency, the better the resolution. In other words, a 10 kilohertz output will typically have more resolution than a 240 kilohertz output. This is because raising the frequency usually generates more noise down at the low end. However, the advantage of a higher-frequency output is that it can increase the response time and lower the propagation delay - the time it takes for a torque event to happen on the input and then be seen on the output of the torque sensor.
It’s good to note that digital torque sensors can come with outputs such as CAN, ProfiBus, ProfiNet and EtherCAT. Because of fewer signal conversions, the overall performance can improve. If a torque sensor isn’t equipped with digital outputs, you can usually purchase a separate device to achieve digital communication.