El escenario
A PLC relay output energizes a 24VDC interposing relay coil; its normally open contact switches 120VAC to a hydraulic directional control valve solenoid.
Qué hay en este dibujo
Lee las decisiones que hay detrás.
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.