1. Introduction
This manual provides detailed instructions for the installation, operation, and maintenance of your ComWinTop 2-Channel PT100/PT1000 RS485 Modbus Output Temperature Acquisition Module. This device is designed for precise temperature measurement using PT100 or PT1000 sensors and communicates data via the RS485 Modbus RTU protocol.
Figure 1: ComWinTop 2-Channel PT100/PT1000 RS485 Transmitter Module
Video 1: Product Overview
2. Specifications
The following table outlines the key technical specifications of the module:
| Parameter | Description |
|---|---|
| Power Supply | DC8-30V |
| Power Consumption | 9mA@30V, 12mA@24V, 23mA@12V, 33mA@8V |
| Input Sensor Type | PT100 or PT1000 |
| Measure Range | -180°C ~ +650°C |
| Resolution | 0.1°C |
| Accuracy | 0.25°C |
| Input Connections | Supports two and three wire connections |
| Input Features | Supports disconnection and short circuit detection |
| Output | RS485 (Modbus RTU protocol), isolation design |
| Working Environment | -30 ~ +55°C / 0-95%RH |
| Material | ABS |
| Mounting Type | 35mm Din-rail |
| Dimensions | 88*72*59mm |
Figure 2: Basic Parameters Table
3. Setup
3.1 Terminal Description
Understand the function of each terminal before wiring:
| Terminal | Description |
|---|---|
| +V | Power + |
| GND | Power - |
| RTDx+ | PT100/1000 + |
| RTDx- | PT100/1000 - |
| GND (Sensor) | PT100/1000 GND |
| A (D+) | RS485 + |
| B (D-) | RS485 - |
Figure 3: Terminal Description Table
3.2 PT100/PT1000 Wiring
The module supports both three-wire and two-wire connections for PT100/PT1000 sensors. Refer to the diagram below for correct wiring:
Figure 4: PT100/PT1000 Wiring Diagram
- Three-wire connection: Connect RTD1+, RTD2+, RTD3+, RTD4+, PGND, and RTD1- as shown.
- Two-wire connection: Connect RTD1+, RTD2+, RTD3+, RTD4+, PGND, and RTD1-. For two-wire connections, you need to short RTD(n)- and GND.
3.3 Mounting
The module is designed for 35mm Din-rail mounting.
4. Operating Instructions
4.1 RS485 Communication (Modbus RTU Protocol)
The module communicates using the Modbus RTU protocol over RS485. The default communication parameters are:
- Baud Rate: 9600 bps
- Parity: None (n)
- Data Bits: 8
- Stop Bits: 1
- Default Device Address: 1
4.1.1 Modbus Register Map - Parameter Register (Function Code: 03H Read, 06H Write)
This register allows configuration of communication parameters and device address.
| Address (hex) | Byte Order | Meaning | Description | Property |
|---|---|---|---|---|
| 10 | LO | Communication parameters | BIT<7:5> reserve BIT<4:3> 00=none, 01=even, 10=odd, 11=odd BIT<2:0> Baud Rate: 000=9600, 001=1200, 010=2400, 011=4800, 100=9600, 101=14400, 110=19200 Initial Value: 00 | RW |
| Hi | Address | 1-250 Initial Value: 01 | RW |
Figure 5: Modbus Parameter Register Map
4.1.2 Modbus Register Map - Data Register (Function Code: 03H Read)
This register provides the measured temperature data from each channel.
| Address (hex) | Description | Format | Number of bytes | Property |
|---|---|---|---|---|
| 40H | Channel 1 | Float | 4 | R |
| 42H | Channel 2 | Float | 4 | R |
| 20H | Channel 1 | UINT (Scale: 0.1) | 2 | R |
| 21H | Channel 2 | UINT (Scale: 0.1) | 2 | R |
Figure 6: Modbus Data Register Map
4.2 Configuration Tool
A dedicated configuration tool is provided to easily set up the module's parameters, such as slave address, baud rate, and to read sensor data. The tool offers a user-friendly interface for managing the device.
Figure 7: Configuration Tool Interface
5. Maintenance
- Keep the module clean and free from dust and moisture.
- Ensure proper ventilation around the device to prevent overheating.
- Avoid exposing the module to extreme temperatures or corrosive environments.
- Regularly check wiring connections for tightness and integrity.
6. Troubleshooting
- No communication: Verify RS485 wiring (A/B lines), power supply, and ensure communication parameters (baud rate, parity, address) match between the module and your master device.
- Incorrect temperature readings: Check sensor wiring (two-wire vs. three-wire), ensure the correct sensor type (PT100/PT1000) is selected in your system, and inspect the sensor for damage.
- Module not powering on: Confirm the DC8-30V power supply is connected correctly and providing the specified voltage.
7. User Tips
- For stable readings, ensure your PT100/PT1000 sensors are properly insulated and protected from environmental interference.
- When using the configuration tool, always verify the COM port settings match your PC's serial port connection.
- If experiencing issues, consult the full user manual PDF for more in-depth information: Download User Manual (PDF).
8. Support
For technical assistance or further inquiries, please contact your seller or refer to the official product documentation.