The **61F-G2-R/Q** (often referenced within the Omron 61F series) is a high-performance, plug-in **Floatless Level Controller**. These devices are used primarily to control water levels in tanks, reservoirs, and sewage systems using electrodes rather than mechanical floats. --- ## 1. Technical Specifications The "R" and "Q" designations typically refer to specific regional standards or enhanced features like tropical treatment or high-temperature resilience. | Feature | Specification | | :--- | :--- | | **Supply Voltage** | 110/220 VAC (Selectable via wiring) | | **Operating Voltage Range** | 85% to 110% of rated voltage | | **Inter-electrode Voltage** | 8 VAC | | **Power Consumption** | Approx. 3.5 VA | | **Response Time** | Operate: 80 ms max; Release: 160 ms max | | **Control Output** | 5 A at 250 VAC (Resistive load) | | **Ambient Temperature** | -10°C to 55°C | --- ## 2. Key Electronic Components Inside the 61F-G2 unit, the circuitry is designed for stability and protection against electrical noise: ### A. The Transformer * **Isolation:** The unit uses an internal transformer to step down the mains voltage to a safe **8 VAC** for the electrodes. This ensures that the water being measured is not under high voltage, preventing electrocution hazards. ### B. Sensing Circuit (Comparator) * The electronics detect the **impedance** between the electrodes. When water touches the electrode, it completes a low-voltage AC circuit. * The AC signal is rectified and compared against a reference threshold to trigger the internal relay. ### C. Output Relay * A mechanical electromagnetic relay (SPDT) provides the switching power to start/stop pumps or activate solenoid valves. ### D. Tropical/Environmental Protection (R/Q Models) * **Corrosion Resistance:** The "R" and "Q" variants often feature **conformal coating** on the internal PCB to prevent failure due to high humidity, condensation, or corrosive gases commonly found in sewage environments. --- ## 3. Electrode Configuration The 61F-G2 series typically uses a **three-electrode** setup for automatic supply and drainage: 1. **E1 (Short):** The high-level stop point. 2. **E2 (Medium):** The low-level start point. 3. **E3 (Long):** The common/ground electrode (always submerged). --- ## 4. Application Logic The controller operates on a **Hysteresis** principle to prevent "chattering" (rapid cycling of the pump): * **Drainage:** The pump turns ON when water reaches **E1** and turns OFF only when it drops below **E2**. * **Supply:** The pump turns ON when water drops below **E2** and turns OFF when it reaches **E1**. ---