The **MH22TBD-R** is a specific model of a **Magnetic Proximity Sensor** (often referred to as a Reed Switch or Magnetic Switch), typically manufactured by companies like **Azbil** (formerly Yamatake). These sensors are widely used for cylinder position sensing in pneumatic and hydraulic systems. --- ## 1. Technical Specifications The "TBD" suffix usually denotes a specific wiring and output configuration (2-wire vs. 3-wire). Below are the typical electronic characteristics for this series: | Parameter | Specification | | :--- | :--- | | **Sensor Type** | Magnetic Proximity (Reed or Solid State) | | **Operating Voltage** | 10 to 30V DC / 100V AC (model dependent) | | **Load Current** | 5 to 40 mA | | **Internal Voltage Drop** | ≤ 4V | | **Indicator Light** | Red LED (turns on when activated) | | **Response Time** | ≤ 1 ms | | **Enclosure Rating** | IP67 (Dust-tight and waterproof) | --- ## 2. Key Electronic Components ### A. The Sensing Element The core of the MH22TBD-R is either a **Reed Switch** or a **Hall Effect Sensor**: * **Reed Switch:** Two ferrous reeds in a glass capsule that close when a magnetic field (from a cylinder piston) is present. * **Solid State (Hall Effect):** Uses a semiconductor to detect the magnetic field. This is more durable as it has no moving parts. ### B. LED Indicator It features a built-in **Light Emitting Diode**. When the magnetic field is detected and the circuit completes, the LED illuminates, allowing technicians to verify the sensor's state visually without using a multimeter. ### C. Protection Circuitry Standard versions include: * **Reverse Polarity Protection:** Prevents damage if the positive and negative wires are swapped. * **Surge Suppression:** Protects the internal switch from voltage spikes caused by inductive loads. --- ## 3. Wiring Configuration The MH22TBD-R generally follows a **2-wire** or **3-wire** DC configuration. ### 2-Wire Connection (Typical) In this setup, the sensor is wired in series with the load (e.g., a PLC input or a relay). 1. **Brown Wire:** Connects to the Positive (+) supply. 2. **Blue Wire:** Connects to the Load (which then connects to 0V/Ground). ```text [ + VDC ] ---- (Brown) [ Sensor ] (Blue) ---- [ Load/PLC ] ---- [ 0V ] ``` --- ## 4. Application Use-Case These parts are almost exclusively used for **Cylinder Stroke Detection**. * **Mounting:** It is slid into a "T-slot" or "C-slot" on the side of a pneumatic cylinder. * **Trigger:** A permanent magnet mounted on the internal piston of the cylinder triggers the sensor as it passes by.