The Omron 61F-G3-AC110/220 is a conductive level controller for high/low detection in tanks, sumps, and process vessels. It operates on a dual-range 110/220VAC supply, sensing level through probe resistance from 0 up to 4kOhm — covering most water-based and mildly conductive liquids. Three relay outputs (2 Form C SPDT) rated at 5A @ 220VAC handle the alarm and pump-control logic directly, no interposing relay needed for moderate loads.
The 0~4kOhm sensitivity range is the key selection parameter: it determines the minimum conductivity the controller can detect. For clean water (typically 10–50 kOhm/cm), set the sensitivity near the upper end; for process fluids like coolant emulsions or dilute acids (lower resistance), dial it down. The 1km maximum distance between controller and sensor head means the 61F-G3-AC110/220 can serve remote tank farms or elevated reservoirs without a local amplifier — just run the probe wires. Chassis-mount form factor with screw terminals suits panel integration; no DIN-rail adapter is included, so plan for a backplate or enclosure mounting.
Deployment context
Chassis-mount with screw terminals — this lands on a backplate or inside a junction box near the tank, not on a DIN rail. Three SPDT relays give independent high and low alarm contacts plus one spare for a pump start/stop or remote annunciator.