Das Szenario
A PLC relay output energizes a 24VDC interposing relay coil; its normally open contact switches 120VAC to a hydraulic directional control valve solenoid.
Was diese Zeichnung zeigt
Die dahinterstehenden Entscheidungen verstehen.
01
Use an interposing relay to isolate the PLC output from the 120VAC solenoid load.
02
Include a slow-blow fuse on the hot line to protect the solenoid circuit.
03
Keep the 24VDC control return isolated from the AC neutral.
Reuse when a PLC discrete output must drive a higher-voltage solenoid valve with galvanic isolation and fused protection.