Description The working prince of the automatic constant tension control system in automatic mode is that:compared with the man-made setting tension(the setting tension in LC displayer),if the actual measured tension between two tension detectors (measuring tension in LCD)is not equal the controller will adjust the output proportion(output proportion in LCD)to make magnetic powder clutch brake or servomotor change their torque;if the setting tension is equal to measuring tension,the controller will keep the output proportion to make the balance between the measuring tension an the setting tension.