The Omron 61F-GP-N8H AC240 is a conductive liquid level controller from the 61F series, designed for high/low level detection in tanks, sumps, and process vessels. It operates on a 240VAC supply and uses the conductivity of the liquid (sensitivity range 15kOhm ~ 70kOhm) to detect level changes, switching a SPDT (2 Form C) relay rated at 3A @ 250VAC.
The socketable design with plug-in, 8-pin octal termination means this unit mounts onto a standard 8-pin octal relay socket (sold separately), not directly to a DIN rail. For a panel build, you'll wire the socket once and the controller swaps out in seconds — handy for line-down replacement without pulling wires. The max control-to-sensor distance of 50m gives you flexibility to place the controller away from the tank in a drier panel location.
The sensitivity adjustment (15kOhm ~ 70kOhm) is the key tuning parameter: lower settings work for high-conductivity liquids like salt water or acids; higher settings handle low-conductivity fluids like deionized water or light oils. If the liquid won't conduct enough to trigger the 70kOhm threshold, this controller won't see it — you'd need a different sensing method (float, ultrasonic).