1. Introduction
This manual provides detailed instructions for the installation, operation, and Modbus communication of the Betterbeita Modbus RS485 Temperature and Humidity Sensor. This device is designed for accurate measurement of temperature and humidity in various indoor and industrial environments, communicating data via the RS485 interface using the Modbus-RTU protocol.
2. Package Contents
The package includes:
- 1 x Betterbeita Modbus RS485 Temperature and Humidity Sensor
3. Specifications
| Feature | Description | |
|---|---|---|
| Auxiliary Power Supply | DC5-36V | |
| Measure Range | Temperature: -40 ~ +120°C | Humidity: 0-100%RH |
| Accuracy | Temperature: ±0.5°C | Humidity: ±3% |
| Stability | Temperature: ≤0.1°C | Humidity: ≤1%RH |
| Operation Environment | -20 ~ +70°C, 0-85%RH, non-corrosive gas air environment | |
| Installation | 35mm DIN rail or wall hanging | |
| Communication Protocol | RS485, Modbus-RTU | |
| Device Address | 1-247 (Default: 1) | |
| Baud Rate | 0-4 (Default: 3) (0: 1200, 1: 2400, 2: 4800, 3: 9600, 4: 19200) |
|
| Communication Check Method | 0-2 (Default: 0) (0: None, 1: Odd, 2: Even) |
|
| Display Type | Analog | |
| Theory | Thermometer Hygrometer | |
| Use | Indoor | |
Dimensions
4. Installation
The sensor supports two installation methods: 35mm DIN rail mounting or wall hanging.
4.1 DIN Rail Mounting
Align the sensor's clips with a standard 35mm DIN rail and press firmly until it clicks into place.
4.2 Wall Hanging
Use appropriate screws to mount the sensor directly to a wall through the designated mounting holes.
5. Wiring
Connect the sensor to the power supply and RS485 communication lines as shown in the diagram below. Ensure correct polarity for the power supply.
Terminal Connections:
- V+: DC5-36V Power Input (Positive)
- -: DC5-36V Power Input (Negative)
- A+: RS485 Data Line A
- B-: RS485 Data Line B
6. Operation and Modbus Communication
The sensor communicates using the Modbus-RTU protocol over RS485. Below are the register definitions and communication frame structures.
6.1 Registers Address Form and Descriptions
| Register Address | Descriptions | Data Format | Data Length | Read/Write | Commentary |
|---|---|---|---|---|---|
| 00 | Measure temperature value | INT16 | 2 | R | Actual measured value (Expand 10 times) |
| 01 | Measure humidity value | INT16 | 2 | R | Actual measured value (Expand 10 times) |
| 02 | Adjustment value for temperature | INT16 | 2 | R/W | Range 0-10 (Transmit temperature value = Measure temperature value + adjustment value) |
| 03 | Adjustment value for humidity | INT16 | 2 | R/W | Range 0-10 (Transmit humidity value = Measure humidity value + adjustment value) |
| 04 | Sensor address | INT16 | 2 | R/W | Range 1-247 |
| 05 | Baud rate | INT16 | 2 | R/W | Range 0-4 |
| 06 | Check method | INT16 | 2 | R/W | Range 0-2 |
6.2 Host Inquiry Frame Structure
| Address Code | Function Code | Register Start Address | Register Numbers | Low Bit Check Code | High Bit Check Code |
|---|---|---|---|---|---|
| 1 byte | 1 byte | 2 byte | 2 byte | 1 byte | 1 byte |
6.3 Slave Machine Response Frame Structure
| Address Code | Function Code | Effective Bytes | Data Area | Second Data Area | N Data Area | Check Code |
|---|---|---|---|---|---|---|
| 1 byte | 1 byte | 1 byte | 2 bytes | 2 bytes | 2 bytes | 2 bytes |
6.4 Communication Examples
Example 1: Read Measure Temperature and Humidity Value
Scenario: Read temperature and humidity from sensor with address 1.
Send Code: 01 03 00 00 00 02 C4 0B
| Sensor Address | Function Code (Read) | Register Start Address | Register Numbers | Low Bit Check Code | High Bit Check Code |
|---|---|---|---|---|---|
| 01 | 03 | 00 00 | 00 02 | C4 | 0B |
Reaction Code: 01 03 04 01 3C 02 DE BA FB
| Sensor Address | Function Code (Read) | Effective Bytes | First Data Area (Temperature) | Second Data Area (Humidity) | Low Bit Check Code | High Bit Check Code |
|---|---|---|---|---|---|---|
| 01 | 03 | 04 | 01 3C | 02 DE | BA | FB |
Interpretation:
- Temperature value = 013C (Hex) = 316 (Decimal). Actual temperature = 316 / 10 = 31.6°C
- Humidity value = 02DE (Hex) = 734 (Decimal). Actual humidity = 734 / 10 = 73.4%RH
Example 2: Write Sensor Address
Scenario: Change sensor address from 1 to 3.
Send Code: 01 06 00 04 00 03 88 0A
| Sensor Address | Function Code (Write) | Register Address | Write Value | Low Bit Check Code | High Bit Check Code |
|---|---|---|---|---|---|
| 01 | 06 | 00 04 | 00 03 | 88 | 0A |
Reaction Code: 03 06 00 04 00 03 89 E8
| Sensor Address | Function Code (Write) | Effective Bytes | Write Value | Low Bit Check Code | High Bit Check Code |
|---|---|---|---|---|---|
| 03 | 06 | 00 04 | 00 03 | 89 | E8 |
7. Manufacturing Process Overview
The following video provides a brief look into the manufacturing process of the sensor, showcasing the assembly of the circuit boards and the final casing.
8. Troubleshooting
- No Power: Ensure the DC5-36V power supply is correctly connected to the V+ and - terminals and is within the specified voltage range. Check for loose connections.
- No Communication: Verify the RS485 A+ and B- connections are correct. Check the baud rate and communication check method settings (parity) to ensure they match your Modbus master device. Confirm the sensor address is unique on the bus.
- Incorrect Readings: Ensure the sensor is installed in an environment within its specified operating conditions (-20~+70°C, 0-85%RH, non-corrosive gas). Check for any physical obstructions or sources of interference near the sensor.
9. User Tips
No specific user tips were available from reviews or Q&A for this product at this time. For optimal performance, ensure the sensor is placed away from direct heat sources, strong air currents, or areas with high concentrations of corrosive gases.
10. Support
For further assistance or technical inquiries, please contact Betterbeita customer support. Refer to the official product page or your purchase documentation for contact details.