I have an air line here that I can’t connect
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This post was last edited by Red Coral Fish on 2016-8-13 09:03. It’s a single-acting valve equipped with a solenoid valve and a positioner; the system operates normally. When the solenoid valve is powered, the shutter closes. At this point, the opening degree of the shutter can be adjusted using the positioner. When the solenoid valve loses power, the shutter opens. If the air supply is cut off, the shutter also opens. How should this be connected? First, no signal should be sent to the positioner; the solenoid valve must be able to control the opening and closing of the valve on its own
This post was last edited by ylb913 on 2016-8-13 09:06. Connection sequence: locator, solenoid valve (installed on the air line at the locator’s output), cylinder or diaphragm head. By the way, this should be an air release valve. When the solenoid valve is powered, air is supplied to the cylinder or diaphragm head ； In the event of a power loss, the supply of air from the locator to the cylinder or diaphragm head is cut off, and the outlet of the solenoid valve is connected to the vent.
This air circuit should be quite simple, right?
The positioner outputs to the solenoid valve, which is a two-position three-way type with electric actuation; the output from the solenoid valve connects to the air inlet on the side of the actuator that controls closure.
If that locator doesn’t have a gas supply, the solenoid valve won’t be able to close the valve when powered
If that’s the case, the locator won’t send any signals, and then the solenoid valve will also be ineffective, right?
This post was last edited by ylb913 on 2016-8-13 09:25. 1. Under normal conditions, this valve (shutter) is controlled by a positioner; the solenoid valve is used only when necessary to quickly cut off the air supply. Regardless of the opening degree of the shutter, the valve will open rapidly as a result. The main function of this solenoid valve is to enable faster valve opening compared to the positioner, and it also facilitates the setup of interlocks. 2. Since the positioner no longer provides any air output, the solenoid valve loses its function; at this point, the valve can only remain in its naturally closed state from the time of manufacture.
Your requirement is that the valve should open in the event of a loss of pressure or power; as long as either of these conditions occurs, the valve will open. There is a problem with the description in your second sentence. What you mean is to set the positioner at 0%, so that the solenoid valve can open and close the valve – this is feasible. When the solenoid valve loses power, the valve opens due to the force of the spring; when the solenoid valve is powered, the valve closes