The Omron 61F-GP-N8 AC200 is a High/Low Level controller from the 61F series, designed for conductive liquid level sensing in tanks, sumps, and process vessels. It operates on a 200VAC supply and uses a relay output (SPDT, 2 Form C) rated at 3A @ 250VAC to drive pumps, valves, or alarms. Sensitivity is adjustable from 0 to 4kOhm, which covers most conductive liquids including water, weak acids, and alkaline solutions. The 1km maximum distance between controller and sensor electrodes means the control unit can sit in a panel remote from the tank — useful for large sites where the tank farm is separate from the MCC room.
The 0-4kOhm sensitivity range is the key spec for the buyer: it determines what liquids the controller can reliably detect. Clean water (tap, deionized) typically reads 10-100 kOhm depending on conductivity — this unit won't trigger on deionized water. Wastewater, process water, or coolant mixtures with dissolved solids fall well within the 4kOhm range. If your application involves ultrapure water or non-conductive fluids (oils, hydrocarbons), this controller won't work — you'd need a capacitive or ultrasonic level sensor instead. The SPDT (2 Form C) relay contacts give you both normally-open and normally-closed switching per pole. That lets one set of contacts drive the fill pump and the other drive a high-level alarm, all from the same controller. The 3A @ 250VAC contact rating handles small pumps and solenoid valves directly; for larger motor loads, interpose a contactor. The 1km control-to-sensor distance is a practical advantage. In a typical plant layout, the controller mounts in the main panel while the electrodes sit at the tank. That 1km reach covers even the largest single-building installations without needing a remote I/O or signal repeater.
Socketable with an 8-pin octal base — the controller plugs into a standard relay socket, which simplifies replacement and panel wiring. The termination style is plug-in via the octal pins, so the controller can be swapped without disturbing the field wiring.