Operation Principle; Type Ip5000 - SMC Networks IP5000 Operation Manual

2.Operation Principle

2 - 1 Type IP5000

When the input pressure to SIG port of a positioner increase, bellows push balance-lever to the left.
Since this movement moves flapper to the left via joint spring, there appear a gap between nozzle and
flapper and nozzle back pressure of pilot valve drops.Consequently, the pressure balance of constant
pressure chamber is destroyed and exhaust valve push supply valve B to the right, and then the supply
valve B is opened. As a result of this function, the output pressure of OUT1 increase and then diaphragm
moves downwards.
The motion of diaphragm make feedback arm wave to the right via feedback lever, transmission lever
and roller. Because of this wave, the tension of feedback spring increase and work on balance lever.
Since diaphragm keeps moving untill the tension of feedback spring and bellows become equal, it is
constantly adjusted at the place where is proportioned to the input pressure.
When a signal air pressure decrease , the movement goes contrariwise.
Fig. 3 Block diagram of Type IP5000
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