SMC IP5000-030 POSITIONER

When the input pressure applied to the SIG port of the positioner increases, bellows press balance lever to the left. As this movement moves flapper to the left through connecting spring, the gap between nozzle and flapper widens, and the nozzle back pressure of pilot valve drops. As a result, the pressure balance in the constant pressure chamber is broken, and exhaust valve presses inlet valve B to the right, thus opening inlet port B. Then, output pressure OUT1 rises, and driven diaphragm moves downward. The movement of diaphragm valve deflects feedback arm to the right through feedback lever, transmission lever and roller. Such deflection increases the tension of feedback spring and acts on balance lever.Since driven diaphragm moves until the tensile force of feedback spring and the force generated by bellows balance, it is always set in the position proportional to the input pressure. When the signal air pressure decreases, the operation is reversed.