The **W2VS-221-R2** is an industrial-grade signal conditioner/transmitter, specifically a **Potentiometer Transmitter** manufactured by **M-System**. Its primary function is to measure the position of a potentiometer (slidewire) and convert that resistance value into a standard analog signal (like 4-20mA or 0-10V). --- ### ## Technical Specifications The "W2VS" series is known for its dual-output capability. Below is a breakdown of its core electronic parameters: | Component/Feature | Specification | | :--- | :--- | | **Input Type** | Potentiometer (Total resistance: 100 $\Omega$ to 10 k$\Omega$) | | **Output 1** | 4 – 20 mA DC (Standard) | | **Output 2** | 1 – 5 V DC (Standard for R2 configuration) | | **Power Input** | 24V DC (Indicated by the "R" in the model code) | | **Accuracy** | ±0.1% | | **Response Time** | $\leq$ 0.5 seconds (0 – 90%) | | **Isolation** | 3-way isolation (Input to Output to Power) | --- ### ### Key Electronic Parts & Functionality The device is composed of several critical internal stages that ensure precision and safety: 1. **Reference Voltage Circuit:** Since a potentiometer is a passive device, the W2VS-221-R2 provides a stable excitation voltage (typically around 0.5V DC) across the potentiometer. This allows the unit to sense the wiper position as a voltage ratio. 2. **Input Conditioning (High Impedance):** The input stage uses a high-impedance operational amplifier to ensure that the current drawn from the potentiometer wiper is negligible, preventing measurement errors caused by loading effects. 3. **Isolation Barrier:** The "221" designation implies specific isolation protocols. It uses optoisolators or magnetic transformers to separate the input, output, and power circuits. This prevents ground loops and protects sensitive PLC/DCS equipment from field-side surges. 4. **Zero & Span Adjustment:** The front panel typically features multi-turn potentiometers (trimmers) that allow the user to calibrate the 0% and 100% points of the electronic signal output. --- ### ### Model Code Breakdown: W2VS-221-R2 * **W2VS:** Series name (Dual Output Potentiometer Transmitter). * **2:** Output 1 (4 – 20 mA DC). * **2:** Output 2 (1 – 5 V DC). * **1:** Configuration/Output 1 Type. * **R:** Power Input (24V DC). * **2:** Design revision/Version. --- ### ### Wiring Diagram Overview | Terminal No. | Function | Description | | :--- | :--- | :--- | | **1 / 2 / 3** | Input | Connect to Potentiometer (High / Wiper / Low) | | **4 / 5** | Output 1 | 4-20mA (Current Loop) | | **6 / 7** | Output 2 | 1-5V DC (Voltage Signal) | | **8 / 9** | Power | +24V DC / 0V | ---