A 3/2 solenoid valve has 3 ports and 2 switching positions. A 5/2 solenoid valve has 5 ports and 2 switching positions. The port count is what determines which actuator type each valve can drive.
A 3/2 valve has one air-supply port, one output port and one exhaust port - enough to pressurize and vent a single actuator chamber. This makes it the standard choice for single-acting (spring-return) actuators, which only need air pushed in one direction; the internal spring handles the return stroke.
A 5/2 valve has one supply port, two output ports (one to each side of the actuator) and two exhaust ports. This lets it alternately pressurize either side of a double-acting actuator while venting the other - which is exactly what a double-acting actuator needs, since it has no spring and relies on air pressure for both strokes.
The symbol, switching
- Type
- 3/2, spring return
- Coil
- De-energised
- Flow path
- P blocked, A exhausts to R
At a glance
| 3/2 Valve | 5/2 Valve | |
|---|---|---|
| Ports | 3 | 5 |
| Positions | 2 | 2 |
| Drives | Single-acting (spring-return) actuators | Double-acting actuators |
| Typical use | Fail-safe applications needing a defined position on air loss | Applications where the actuator should hold its last position on air loss |
Which one do I need?
Check the actuator, not the valve, first. If the actuator has a visible spring housing (usually a longer body on one end), it's single-acting and needs a 3/2 valve. If it's a symmetric dual-rack body with no spring housing, it's double-acting and needs a 5/2 valve.
Related
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