The meaning of the actuator legend

This post was last edited by ylb913 on 2018-9-3 09:42. The pneumatic valve controls the regulating valve through the position of the solenoid valve; X is an arbitrary initial letter added without meaning, while C and O at the end represent the closed and open states respectively. Z stands for drive, S for switch, and I for indication. XY appears to refer to the solenoid valve. In the diagram, there is a regulating valve (XV), a solenoid valve that controls the opening and closing of the regulating valve (XY), a switch that controls the state of the solenoid valve (XS), feedback switches that display the opening and closing state of the regulating valve (XSO and XSC), as well as feedback indicators (*O and *C). The electric valve (MV) uses switches (MZO and MZC) to control the on/off state of the motor (M), as well as its forward and reverse rotation, in order to directly drive the control valve; M stands for electric, Z for driving (switch), and A for alarm.

Double-acting piston pneumatic actuator with ball valve

May I ask what is the difference between having two solenoid valves and just one?

Ensure interlocking in the event that an electromagnetic valve is damaged

Does it mean that the area with two solenoid valves is more important, indicating that these valves are more significant?

Basically, that’s what it means: if the solenoid valve does not have a SIL certification, installing two solenoid valves should result in a safety circuit of SIL2 level. There are also those with 3 solenoid valves.

This post was last edited by ylb913 on 2018-9-7 06:21. Two solenoid valves are used here, which shows that this switch valve is very important; the two solenoid valves provide a double safety mechanism to prevent accidental operation. If either solenoid valve fails (due to poor contact or power loss), it will not cause the valve to open accidentally.

From a fail-safe perspective, using dual solenoids presents two scenarios: one is to prevent the valve from acting erroneously, and the other is to prevent it from failing to act. Analyzing the diagram of the dual solenoid valves shown by the poster, if the principles of fail-safe design are followed – with power supplied under normal conditions and the interlock de-energized – it is clear that the valves will only engage in interlocked operation when both solenoid valves lose power. Therefore, if any solenoid valve fails and loses power, the valve will not move.

With normal power supply, the valves will only engage in interlocking action when both solenoids lose power, thereby preventing accidental operation of the solenoids