The **RHP-20D-R02FNT** is a high-precision digital temperature and humidity transmitter, typically used in industrial automation, HVAC systems, and environmental monitoring. It is part of the RHP series produced by manufacturers like **Dwyer Instruments**. --- ### 1. Component Overview This device is a **duct-mount transmitter** that converts environmental readings into standardized electrical signals. It utilizes a capacitive polymer sensor for humidity and a thermistor or RTD for temperature. | Feature | Specification | | :--- | :--- | | **Primary Functions** | Relative Humidity (RH) & Temperature Sensing | | **RH Accuracy** | ±2% (indicated by the "2" in the part number) | | **Output Signal** | Dual 4-20 mA loops (current outputs) | | **Mounting Type** | Duct Mount | | **Filter Type** | Sintered Filter (indicated by "FNT") | --- ### 2. Key Electronic Characteristics The internal electronics are designed for stability and noise immunity in industrial environments. * **Current Loop (4-20 mA):** The "R02" designation typically refers to the dual output configuration. One loop represents 0-100% RH, and the other represents a specific temperature range. * **Power Supply:** Usually operates on a wide DC range (10-35 VDC). * **Sensor Technology:** * **Humidity:** Uses a thin-film polymer capacitor that changes capacitance based on water vapor absorption. * **Temperature:** Employs a solid-state bandgap sensor or a platinum RTD for linear output. * **Protection:** The "FNT" suffix usually indicates a **Sintered Nylon Filter**. This protects the electronic sensor elements from dust and high-velocity air particles while allowing gas to permeate. --- ### 3. Wiring Diagram (Conceptual) The device typically uses a terminal block for field wiring. ```mermaid graph LR A[Power Supply +] --> B[Transmitter V+] C[RH Output] --> D[Controller/PLC Input 1] E[Temp Output] --> F[Controller/PLC Input 2] G[Common/Ground] --> H[Power Supply -] ``` --- ### 4. Technical Specifications Table | Parameter | Value | | :--- | :--- | | **RH Range** | 0 to 100% RH | | **Temp Range** | -40 to 140°F (-40 to 60°C) | | **Input Voltage** | 10 - 35 VDC | | **Enclosure Rating** | NEMA 4X (IP66) for the housing | | **Response Time** | ~15 seconds |