Pneumatic valve position between electric brake pneumatic valve?

some electric pneumatic valve can only be fully open or close, a pair of electric pneumatic valve handwheel by handwheel, control, for example, % %? Large diameter electric brake pneumatic valve is suitable for liquid, usually stop, flow, pressure control flow and control flow is called as electric switch pneumatic valve ( Some can only open or close, because some can only stop in the middle have a rough adjustment, e. g. , %, %, %, %) , flow, pressure control of the so-called electric regulating pneumatic valves, electric pneumatic valve can be opened, the fulfillment of the principle of the rough control, is in the process of machine stop running. Mainly depends on your choice of electric actuators, choose the type of switch, if so, can only be pneumatic valve fully open or close, of course, you can also manually. If the monitoring of electrical equipment, to meet this requirement. However, if we don't suggest you use high pressure pneumatic valve pneumatic valve position. You can be in any one station middle position switch signal to it, as long as a timely cut off power supply cut off long, pneumatic valve will not stop in that position? Of course, you need to add a pneumatic valve electric actuator position feedback signal, to indicate the pneumatic valves open, the better. Add in DCS controller time calculating all the choice of travel time and flow characteristics of pneumatic valve, switch to ON Half OFF, it should be stopped in the middle of the right time. This is not so high pressure. What is the purpose of you want to stop in the middle? Ventilation rate of the control?