1. Introduction
This manual provides instructions for the WITMOTION USB to RS485 Modbus RTU UART Converter Cable. This device offers a straightforward method to connect RS485 Modbus level serial interface devices to a computer via USB. It supports various operating systems and is designed for reliable data transfer.
1.1 What's in the Box
- 1 x WitMotion USB-RS485 serial cable (1 meter)
- 1 x Welcome guide
Image 1: The WITMOTION USB to RS485 Converter Cable, showing the USB-A connector and the 4-way female socket header.
2. Features
- Robust Design: Provides a fast, simple way to connect devices with an RS485 Modbus level serial interface to USB.
- Modbus RTU Access: Offers access to Modbus RTU A (RS485 A), B (RS485 B), VCC (5V), and GND connections.
- Plug and Play: USB specification 2.0 compliant, supporting the CH340 driver for convenient setup and connections.
- Operating System Compatibility: Compatible with Windows XP/7/8/10 (32-bit/64-bit), Linux, Wince, Mac, and Vista.
- Adjustable Baud Rates: Supports baud rates from 300 bps to 1.5 Mbps.
3. Setup and Installation
3.1 Driver Installation
The converter cable utilizes a CH340 chip. Before connecting the cable, ensure the appropriate CH340 driver is installed on your operating system. Drivers are typically available from the manufacturer's website or can be found by searching for 'CH340 driver download'.
3.2 Connecting the Cable
- Connect the USB-A end of the cable to an available USB port on your computer.
- Identify the 4-way female socket header. This header provides the following connections for your RS485 device:
- A (RS485 A): Data A line for RS485 communication.
- B (RS485 B): Data B line for RS485 communication.
- VCC (5V): 5 Volt power supply output.
- GND: Ground connection.
- Connect the 4-way female socket header to your RS485 Modbus device, ensuring correct pin assignments (A to A, B to B, VCC to VCC, GND to GND). Refer to your device's documentation for its specific pinout.
Video 1: Official product video demonstrating the WITMOTION USB to RS485 Converter Cable and its connections.
4. Operating Instructions
Once the cable is physically connected and the drivers are installed, your computer will recognize the device as a virtual COM port. You can then use serial communication software (e.g., PuTTY, RealTerm, or custom applications) to interact with your RS485 Modbus device.
- Open your preferred serial communication software.
- Select the COM port assigned to the WITMOTION USB to RS485 converter. You can find this in your computer's Device Manager (Windows) or by listing serial devices (Linux/Mac).
- Configure the serial port settings to match your RS485 Modbus device's requirements. Key settings include:
- Baud Rate: Set between 300 bps and 1.5 Mbps (e.g., 9600, 19200, 115200).
- Data Bits: Typically 8.
- Parity: None, Even, or Odd.
- Stop Bits: Typically 1 or 2.
- Initiate communication with your RS485 Modbus device according to its protocol specifications.
5. Specifications
| Feature | Specification |
|---|---|
| Brand | WITMOTION |
| Model Name | USB to RS485 Modbus RTU UART Converter Cable |
| Item Model Number | RS485 line |
| Connector Type | USB |
| Cable Type | USB |
| Compatible Devices | Industrial Equipment, Modbus Devices, Sensors |
| Special Feature | Data Transfer |
| Recommended Uses | Connecting devices with RS485 Modbus level serial interface to USB |
| Color | Black |
| Connector Gender | Male-to-Male (USB-A to 4-way header) |
| Data Transfer Rate | Up to 1.5 Megabits Per Second |
| Number of Pins | 4 (on socket header) |
| Maximum Voltage | 5 Volts (VCC output) |
| Cable Length | 1 meter (3.28 feet) |
| Item Weight | 0.04 Kilograms (1.44 ounces) |
| Indoor/Outdoor Usage | Indoor |
6. Troubleshooting
- Device Not Recognized: Ensure the CH340 driver is correctly installed. Check your computer's Device Manager for any unknown devices or COM port errors. Try a different USB port.
- Communication Errors: Verify that the baud rate, data bits, parity, and stop bits in your serial communication software match the settings of your RS485 Modbus device. Incorrect settings are a common cause of communication failure.
- Incorrect Wiring: Double-check the connections between the converter cable's 4-way header and your RS485 device. Ensure A connects to A, B to B, VCC to VCC (if powering the device), and GND to GND.
- No Data Transmission: Confirm that your RS485 device is powered on and functioning correctly. Test with a known working RS485 device if possible.
- Intermittent Connection: Ensure all connections are secure. Avoid excessively long or unshielded RS485 bus lines, which can introduce noise.
7. Warranty and Support
WITMOTION provides a 12-month warranty for this product, along with lifetime friendly customer service.
7.1 Obtaining Support
If you require assistance or have questions, please use one of the following methods:
- Guiding Card: Refer to the tutorial link printed on the guiding card included in the product package.
- Online Tutorials: Visit wit-motion.com and navigate to the support page to download complete tutorials and documentation.
- Email Support: Contact the WITMOTION support team directly via email at support@wit-motion.com.