What this controller does on the line
The Omron 61F-G3N AC110/220 is a conductive-type level controller that detects high or low liquid levels through electrode probes. It switches three SPDT relays (2 Form C each) rated at 3A @ 200VAC, giving you independent alarm and pump-control contacts from a single unit. Sensitivity is adjustable from 0 to 4 kΩ, which means it works with water, weak acids, and other conductive liquids — the probe resistance threshold is set to match the fluid's conductivity. The control-to-sensor distance can run up to 1 km, so the controller can sit in a panel far from the tank. Power supply is 110/220VAC selectable — no separate control transformer needed if your panel already carries line voltage. The screw terminals accept standard panel wiring, and the DIN-rail mount clips into the enclosure without drilling.
The alarm-high contact feature means one relay energizes when the level exceeds the high probe; the other two relays can be wired for low-level alarm and pump control. Standard SPDT (Form C) wiring applies — common, normally-open, normally-closed per relay.