The **Omron E5C2-R20G** is a basic, analog-set temperature controller known for its reliability and simplicity. It is widely used in industrial applications such as plastic extrusion, packaging, and heat treatment. --- ## 1. Core Technical Specifications | Feature | Specification | | :--- | :--- | | **Input Type** | Thermocouple Type J (Iron-Constantan) | | **Control Mode** | ON/OFF Control | | **Output Type** | Relay Output (SPDT) | | **Rated Voltage** | 100 to 240 VAC (50/60 Hz) | | **Temperature Range** | Typically 0 to 300°C (Varies by model suffix) | | **Mounting** | DIN Track or Flush mounting (via 8-pin socket) | --- ## 2. Key Electronic Components & Interfaces ### A. The Input Stage (Thermocouple J) The "G" in the model name indicates that this specific unit is calibrated for a **Type J Thermocouple**. * **Cold Junction Compensation:** The internal circuitry compensates for the ambient temperature at the controller terminals to ensure accurate readings from the thermocouple. * **Sensor Error Detection:** If the thermocouple wire breaks, the controller usually defaults to an "OFF" state to prevent overheating. ### B. Control Mechanism (Analog Dial) Unlike digital controllers, the E5C2 uses a potentiometer connected to the front-facing knob. * **Setting Method:** The user turns the dial to the desired temperature. * **Internal Comparator:** An operational amplifier (Op-Amp) compares the millivolt signal from the thermocouple against the voltage level set by the potentiometer. ### C. Output Relay The "R" in the model name stands for **Relay**. * **Switching Capacity:** Usually rated at 3A at 250 VAC. * **Action:** When the measured temperature is below the set point, the relay energizes (closing the circuit to the heater). Once the set point is reached, the relay de-energizes. --- ## 3. Terminal Connection Diagram (8-Pin) The device typically uses a standard P2CF-08 or P3G-08 circular socket. | Pin Number | Function | Description | | :--- | :--- | :--- | | **1 & 8** | Power Supply | 100-240 VAC Input | | **3, 4, 5** | Relay Output | 3 (Common), 4 (NC), 5 (NO) | | **6 (+)** | Sensor Input | Thermocouple Positive (White for Type J) | | **7 (-)** | Sensor Input | Thermocouple Negative (Red for Type J) | --- ## 4. Advantages and Limitations ### Advantages * **Ease of Use:** No complex menus or programming; just turn the dial. * **Durability:** Analog circuits are often more resilient to certain types of electronic noise compared to cheap microprocessors. * **Maintenance:** Easy to swap out due to the plug-in socket design. ### Limitations * **Hysteresis:** Being an ON/OFF controller, it has a fixed "dead band" (usually 2°C), which can lead to temperature overshoot. * **Precision:** Not suitable for applications requiring PID (Proportional-Integral-Derivative) control for extremely stable temperatures. ---