The Omron 61F-HSL AC110 is a High/Low Level controller from the 61F series, designed for tank fill-and-drain logic with a single relay output. It operates on 110VAC supply and provides SPDT (2 Form C) contacts rated at 5A @ 220VAC — enough to drive a small pump contactor or solenoid valve directly. The adjustable sensitivity range of 0 ~ 5MOhm means it can detect anything from tap water (low resistance) to demineralized water or certain chemicals (high resistance), making it a flexible fit for process tanks, sumps, and cooling towers.
The High/Low Level type gives you two setpoints from one controller: a high-level stop and a low-level start (or reverse, depending on wiring). That's the standard pump-down or pump-up sequence — no separate low-level relay needed. The SPDT (2 Form C) output provides both normally-open and normally-closed contacts, so you can wire fail-safe logic (pump off on fault) without an extra interposing relay. Sensitivity adjustment from 0 to 5MOhm covers most conductive liquids. At the low end (0 ohms), it triggers on any conductive path; at 5MOhm, it can detect high-resistivity fluids like deionized water or certain alcohols. If you're switching between product runs with different liquid types, you dial the sensitivity per batch — no probe swap. The 8-pin octal socket is a standard industrial footprint.