Tension sensor, English: tension pick-up. Tension sensor is an instrument used to measure the tension value of coil during tension control. The strain gauge type used in pharmacy and pharmacy is that the tension strain gauge and the compression strain gauge are connected together in a bridge mode, and the resistance value of the strain gauge will also change when it is subjected to external pressure, and the change value will be proportional to the tension; Micro-displacement type is called micro-displacement type tension detector because the load is applied by external force, and then the tension is detected by differential transformer. The displacement of the leaf spring is extremely small, about 200 μ m. In addition, from the external structure, it can be divided into: shaft-type, through-shaft type, cantilever type, etc.