The **LCS-70-R** is an industrial-grade Liquid Capacitive Sensor typically used for non-contact level detection of liquids through non-metallic tank walls (like plastic or glass). It is commonly manufactured by companies like **Rechner Sensors**. Below is a breakdown of its electronic components, specifications, and wiring structure. --- ### 1. Technical Specifications The core electronics are designed for high sensitivity and stability in industrial environments. | Feature | Specification (Typical) | | :--- | :--- | | **Operating Voltage** | 10 — 35 V DC | | **Output Type** | PNP (Normally Open / Normally Closed selectable) | | **Mounting** | Non-flush (usually via a mounting bracket) | | **Sensing Distance** | Adjustable (optimized for liquid detection) | | **Frequency of Operating Cycle** | 50 Hz | | **Enclosure Rating** | IP 67 (Dust tight and water immersion resistant) | --- ### 2. Key Electronic Components #### A. Capacitive Sensing Element The "head" of the sensor contains an electrode that forms one plate of an open capacitor. When liquid approaches the sensor, the dielectric constant changes, increasing the capacitance and triggering the internal circuit. #### B. Integrated Potentiometer Located at the rear of the sensor, this is a variable resistor used to adjust the sensitivity. * **Function:** It allows the user to "tune out" the container wall so the sensor only reacts to the liquid inside. #### C. Signal Converter & Schmidt Trigger The internal circuitry converts the analog change in capacitance into a digital signal. A **Schmidt Trigger** is used to ensure clean switching and prevent "chatter" (rapid flickering) when the liquid level is right at the threshold. #### D. LED Indicator Most LCS-70-R models include an integrated LED: * **Yellow/Red:** Indicates the switching state (on/off). * **Green (Optional):** Indicates power supply is active. --- ### 3. Wiring Diagram (Electronic Interface) The sensor typically uses a standard 3-wire or 4-wire DC configuration. ```markdown Color Code | Function | Connection -----------|----------------|-------------------------- Brown | +VDC | Positive Supply (10-35V) Blue | -VDC (GND) | Ground Black | Output (NO) | Load / PLC Input White | Output (NC)* | Optional (if 4-wire) ``` *\*Note: Some models use the white wire for programming or selecting the NO/NC state.* --- ### 4. Application Electronic Logic The LCS-70-R is electronically "blind" to the container material if the dielectric constant of the liquid is significantly higher than the wall material. * **Plastic/Glass ($\epsilon \approx 2-7$):** Ignored by the sensor. * **Water/Aqueous Liquids ($\epsilon \approx 80$):** Detected instantly.