The Omron 61F-G AC100/200 is a conductive-type liquid level controller from the 61F series, configured for High/Low Level detection — meaning it maintains a fill level between two probe points, not just a single overflow alarm. It accepts a dual-range supply of 100 or 200 VAC, so the same unit works on either a 100 V or 200 V line without rewiring. The sensing circuit triggers when the liquid resistance between probes falls within the adjustable 0 to 4 kOhm range. That covers most conductive liquids — water, weak acids, coolants — but not deionized water or hydrocarbons. The SPDT relay output (2 Form C) switches 5 A at 220 VAC, enough to drive a contactor or small pump directly.
Deployment context
The 61F-G AC100/200 mounts to a chassis or panel backplate via its integral mounting holes. Screw terminals accept field wiring directly — no socket required. The control-to-sensor distance can run up to 1 km from the controller to the probe electrodes, which suits tank farms or remote sumps where the controller sits in the MCC room and the probes are at the vessel.