Operation Principle; Type Ip8000 - SMC Networks IP8000 Operation Manual

2.Operation Principle

2-1 Type IP8000

When the input current increases, armature (13) receives counter-clockwise rotating torque with
leaf-spring (11) of torque motor (12) functioning as the support, counter-weight (4) is pushed
towards left, the space between nozzle (6) and flapper (5) opens and the nozzle back pressure
decreases. As the result, exhaust valve (7) of pilot valve (1) moves to right, the output pressure
of OUT1 increases and diaphragm valve (15) moves downward. The movement of diaphragm
valve (15) acts on feedback spring (10) through feedback lever (8), transmission lever (14) and
span adjusting lever (9) and the actuator is balanced at the position where it is balanced with the
force generated by the input current.
feedback the movement of exhaust valve (7) to counter-weight (4) and it increases the loop
stability. For zero-point adjustment, change the tension of zero-adjust spring (3).
Zero
adjusting
spring
IN current Torque
motor
Gain suppression spring (2) is used to immediately
Restrictor
) (
Nozzle
+ +
Diaphragm
- - flapper
Gain
suppression
spring
Feedback
spring
Fig. 1 Block diagram of Type IP8000
SUP
Exhaust
Inlet
valve
valve
Span
Feedback
adjusting
lever
lever
7
Stem stroke
Driven
OUT
diaphragm