The relationship between the positive and negative effects of the electric valve positioner and the positive and negative effects of the valve actuator
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Do the positive and negative actions of the positioner correspond to the positive and negative actions of the actuator, that is, the positive action of the positioner corresponds to the positive action of the actuator, and the reverse action corresponds to the reaction of the actuator? For double-acting positioners used for pneumatic piston actuators (without return springs), which output is used to define the positive and negative effects of the positioner, OUT1 or OUT2?
In other words, for piston actuators, changing the cam A and B surfaces of the positioner can change the positive and negative effects of the actuator. Personally, I feel that changing the cam A and B surfaces of the positioner also changes the running direction of the valve stem, that is, changing the positive and negative effects of the actuator at the same time.
The positive and negative effects of the positioner and the positive and negative effects of the actuator are independent of each other and can be combined according to actual needs. For the two air source outputs of the double-acting valve positioner, if you want to change the valve action direction, simply changing the A and B sides of the cam will not work. You also need to change the air source pipeline of the actuator.
What is said above is correct. The positive and negative effects of the actuator can determine the fault state of the valve (FC or FO). The positive and negative effects of the positioner determine the relationship between the adjustment deviation and the output signal size. There is no positive and negative effect on the double-acting cylinder. If you want to separate it, it is generally* Inertia turns open as the positive direction of action.