The Omron 61F-G2NL AC110/220 4KM is a High/Low level controller from the 61F series, designed for conductive liquid level detection in tanks, sumps, or reservoirs. It operates on a 110/220VAC supply and drives two SPDT relays (Form C) rated at 3A @ 200VAC, providing alarm-high contact output. The unit mounts on a standard DIN rail and connects via screw terminals — no special tooling needed for panel integration.
The standout spec here is the 4 km maximum distance between the controller and the sensor probe — that's the '4KM' in the order code. For a level controller, this means you can place the electronics in a central panel and run the probe out to a remote tank or well without worrying about signal drop. The sensitivity adjustment (0 to 0.7 kΩ) lets you tune the detection threshold for different liquid conductivities, from clean water to process fluids.
Mounts on a standard 35 mm DIN rail — snaps on without tools, but leave a finger's width of clearance above and below for the screw terminals. The two SPDT relays give you independent high- and low-level alarm outputs, or you can wire them for pump-up / pump-down control. Operating range is -10°C to 55°C, so it's fine for indoor panel environments but not for direct outdoor exposure without an enclosure.