PLC Pneumatic Solenoid Valve Circuit

PLC Solenoid Valve Output

PLC-controlled pneumatic machines use digital outputs to energize the coils on directional control valves. This diagram shows one protected 24 VDC output path: the PLC output drives an interface relay, the relay supplies a 5/2 valve coil, and a diode suppresses the inductive voltage spike when that coil turns off. The isolation relay is useful when the PLC output current or wiring practice calls for an interface. In a complete machine schematic, add the matching retract coil, cylinder sensors, terminal numbers, and the PLC input circuit. Confirm whether the output is sinking or sourcing before wiring the installed hardware. Verify the valve coil polarity before adding suppression.

種類 回路図規格 IEEE Std 315 / ANSI Y32.2エンジン schematex-circuit更新日 2026/9/24

依頼内容

“Draw a 24 V PLC output circuit with a fused supply, PLC output Q0.0, output relay, 5/2 pneumatic valve coil, and a flyback diode.”

次はこちらAdd a second PLC output for the retract coil.Change the valve coil label to Clamp extend.

この図に含まれるもの

図の背後にある意思決定を読み解く。

01Output

Use a PLC output or interface relay to switch the coil.

02Suppression

Put a flyback diode across a DC valve coil.

03Protection

Fuse the valve supply separately.

Use for one DC solenoid valve controlled from a PLC output.

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よくある質問

Why use a flyback diode on a valve coil?

It limits the voltage spike created when current through the DC coil is interrupted.

Can a PLC output drive a valve directly?

Yes if its voltage, current, and output type match the coil; otherwise use an interface relay.

What is a 5/2 valve coil?

It is the electrical actuator on a five-port, two-position directional valve commonly used with double-acting cylinders.