Industrial RS485 MODBUS Temperature & Humidity Sensor
🔹 Overview
An Industrial RS485 MODBUS Temperature & Humidity Sensor is a rugged digital environmental sensing device used in industrial automation systems.
- Measures:
- Temperature
- Relative Humidity
- Outputs data via:
- RS485 communication
- MODBUS RTU protocol
👉 Designed for PLC, SCADA, and industrial IoT systems
🔹 Working Principle
- Uses:
- Capacitive humidity sensor (polymer-based)
- Bandgap / thermistor temperature sensor
- Internal system:
- Signal conditioning
- ADC conversion
- Digital processing
- Data is transmitted via:
- RS485 differential communication
- MODBUS RTU registers
👉 Host device reads values using Modbus function codes (e.g., 0x03)
🔹 Measurement Characteristics
🌡️ Temperature
- Typical Range: –40°C to +125°C
- Accuracy:
- ±0.1°C to ±0.5°C (high-precision models)
💧 Humidity
- Range: 0% to 100% RH
- Accuracy:
- ±1% to ±3% RH
📊 Resolution
- Typically:
- 0.1°C
- 0.1% RH
🔹 Electrical Characteristics
- Supply Voltage:
- 5V – 30V DC (common)
- Industrial range: 9V – 36V DC
- Power Consumption:
- Low (typically <10 mA)
🔹 Communication Interface
🔌 RS485 Interface
- Differential signal (A+, B– lines)
- Long-distance communication:
- Up to ~1000 meters
🔄 MODBUS RTU Protocol
- Industrial standard protocol
- Features:
- Device addressing (1–247 or more)
- Configurable baud rate (9600–115200)
- Register-based data reading
👉 Fully compatible with:
- PLC
- SCADA
- Industrial controllers
🔹 Physical & Mechanical Design
🔧 Housing
- Industrial-grade materials:
- ABS plastic
- Aluminum alloy
- Features:
- Dust-proof
- Waterproof (IP-rated in many models)
- Corrosion-resistant
🔌 Probe Design (common type)
- Stainless steel probe
- Breathable membrane
- Cable length: ~1–2 meters
🔹 Internal Features
- Factory calibration
- Digital filtering and compensation
- Temperature compensation for humidity
- Configurable parameters:
- Address
- Baud rate
🔹 Functional Behavior
- Continuously measures environmental data
- Sends values via MODBUS registers
- Typical reading:
- Temperature = register value ÷ 10
- Humidity = register value ÷ 10
🔹 Key Technical Features
- Industrial-grade reliability
- Long-distance communication (RS485)
- Standard MODBUS RTU protocol
- High accuracy and stability
- Wide operating range
- Easy integration with automation systems
- Configurable communication parameters
🔹 Applications
- HVAC systems
- Industrial automation
- Greenhouses & agriculture
- Cold storage monitoring
- Data centers
- Smart buildings
- Weather stations
- Environmental monitoring systems
🔹 Advantages
- Robust communication over long distances
- Noise immunity (RS485 differential signaling)
- Easy integration with industrial systems
- High accuracy and stability
- Suitable for harsh environments
🔹 Limitations
- Requires:
- RS485 interface / converter (for MCU use)
- MODBUS protocol handling needed
- Slightly higher cost than basic sensors
- Slower compared to direct analog sensors (due to protocol overhead)
🔹 Technical Summary
An Industrial RS485 MODBUS Temperature & Humidity Sensor is a professional environmental sensing solution that:
- Combines high-accuracy sensing + industrial communication
- Enables long-distance, reliable data transmission
- Is optimized for PLC, SCADA, and industrial IoT systems
👉 It is best classified as a temperature-humidity transmitter (industrial-grade) rather than a simple sensor module.
