Level Controller for Remote Tank Monitoring
The Omron 61F-G4NL AC110/220 4KM is a high/low level controller designed for conductive liquid detection in the 61F series. Its standout spec is the 4 km maximum distance between the controller and the remote sensor probe, making it suited for widely spaced tank farms or elevated reservoirs where running long cable runs is the norm. The dual-voltage supply (110/220 VAC) simplifies panel wiring across sites with different line voltages — one part number covers both.
The Type High/Low Level means the controller energizes or de-energizes the relay outputs based on whether the liquid level is above (high) or below (low) the probe setpoint — standard for fill/empty control in sumps, tanks, or cooling towers. The sensitivity range of 0 to 0.7 kOhm sets the threshold at which the controller detects liquid conductivity; adjust it to match the specific water or process fluid resistivity on site. The 3 A @ 200 VAC contact rating on the SPDT relays is sufficient for pilot-duty solenoid valves or alarm indicators, but for direct motor switching you will want an interposing contactor.
Screw terminals accept up to 2.5 mm² wire — strip 8 mm, torque to 0.5 Nm. The six relay outputs (2 Form C + 3 Form C) occupy the terminal rows; label each output clearly during commissioning to avoid confusion between the high-level and low-level circuits.