The **HMS-2-R/K** is a high-performance **Magnetic Stirrer with Heating** (Hotplate Stirrer) commonly used in laboratory environments. It is engineered to provide precise temperature control and consistent stirring speeds for chemical and biological solutions. --- ### Core Electronic Components and Specifications The device integrates several key electronic systems to ensure safety and accuracy during operation. | Component | Description | Function | | :--- | :--- | :--- | | **Control System** | Microprocessor-based PID controller | Regulates temperature and speed with high precision. | | **Display** | Dual Digital LED/LCD Display | Shows real-time temperature (PV) and set values (SV). | | **Heating Element** | High-density ceramic or alloy plate | Provides rapid heating up to 340°C - 400°C. | | **Motor Type** | Brushless DC Motor (BLDC) | Ensures long life, low noise, and stable torque at low speeds. | | **Sensor Port** | External PT1000 connection | Allows for direct liquid temperature monitoring. | --- ### Technical Features #### 1. Temperature Management The "K" in the model often refers to the **K-type thermocouple** compatibility or specific controller variants. * **Accuracy:** Typically within $\pm 1^\circ C$. * **Safety Circuit:** Independent safety hardware cuts power if the temperature exceeds a fixed limit (usually around 350°C - 420°C). #### 2. Stirring Mechanism * **Speed Range:** 100 to 1500+ RPM. * **Magnetic Drive:** Utilizes high-strength Neodymium magnets to prevent "de-coupling" of the stir bar during high-viscosity applications. #### 3. Protection Systems * **Residual Heat Warning:** A "Hot" light stays on after switching off until the plate drops below 50°C. * **Enclosure:** Rated for IP42 or higher to protect internal electronics from accidental spills. --- ### Internal Wiring & Control Logic The electronic architecture follows a standard power-regulation loop: ```mermaid graph LR A[Power Input] --> B[Transformer/Rectifier] B --> C[Microprocessor] C --> D[TRIAC/Relay for Heater] C --> E[PWM Controller for Motor] F[PT1000 Sensor] --> C ``` 1. **PID Feedback:** The processor calculates the power needed to reach the target temperature without overshoot. 2. **PWM Speed Control:** Pulse Width Modulation is used to maintain constant RPM even as the liquid's viscosity changes.