The main difference is whether the actual tension is worth feedback, not indirect measurement. With tension value detection, we become a fully automatic tension system, also known as a fully closed-loop control system; The control method of calculating the coil diameter by other means, such as measuring the number of turns and filling in the thickness, is called semi-automatic tension, also known as semi-closed loop control system; Without signal feedback, manual tension control is realized by manual adjustment.
Tension system is mainly used in coil, wire and other application environments. Widely used in lithium battery, packaging, printing, paper processing, textile, tire rubber, cord fabric and other industries. At present, China is doing better. I recommend you to know about "ABO Intelligent Control". There are patents, technical teams and production plants.