Configuring WirenBoard WB-MIO-E v1 Device via Modbus Registers

Problem Statement

When using WirenBoard devices—specifically the WB-MIO-E v1 gateway—to interface with WBIO expansion modules such as WBIO-DI-WD-14, WBIO-DO-R10R-4, and others, you must ensure the communication speed on the WB-MIO-E for WBIO bus is correctly set. By default, the WB-MIO-E v1 operates at 9600 baud. If you wish to run at any other speed, you must explicitly change the Modbus register responsible for speed (register 110).

Failing to match the correct speed leads to No communication with attached WBIO modules.

Hence, the problem is:

1. The WB-MIO-E v1 WBIO bus speed defaults to 9600 but may need to be changed to a higher or lower baud rate (e.g., 115200).
2. The only way to do this is by writing to Modbus registers (e.g., register 110 for speed).
3. Some firmware revisions apply speed changes only after writing 1 to the reboot register (120).

Proposed Solution: An Interactive Bash Script

To address this, we provide a Bash script that:

1. Stops any service holding the RS-485 port (like wb-mqtt-serial on Wiren Board).
2. Creates a TCP↔PTY bridge using socat.
3. Reads and writes the Modbus registers (address, speed, reboot) on the WB-MIO-E via modbus_client.
4. Prompts you interactively for the new speed, making it easy to switch away from the default 9600 if needed.

Key Steps in the Script

1. Stop wb-mqtt-serial:

   • Ensures no conflicts for the serial port.
   • Allows socat to establish a clean connection.

2. Launch socat:

   • Bridges a TCP connection (IP_ADDRESS:TCP_PORT) to a local virtual device (DEV_PORT).
   • Essential if the WB-MIO-E is behind a network or RS-485→TCP converter.

3. Check & Set Registers:

   • Register 128: Modbus Address (verifies you are talking to the right MIO-E).
   • Register 110: Speed (baud/100). By default 9600 → 96, but you can change to e.g. 1152 for 115200.
   • Register 120: Reboot control (1 triggers a reboot if required to finalize speed changes).

4. Interactive Prompt:

   • Reads the current speed from register 110.
   • Asks if you want to switch to a new baud rate.
   • Validates your choice (e.g., 19200, 115200) and writes the correct code to the register.
   • Optionally reboots the WB-MIO-E.

5. Stop socat & Restart wb-mqtt-serial:

   • Closes the connection after configuration.
   • Restores normal operation on Wiren Board.

Why This Script Matters

• Default Speed Caveat: The WB-MIO-E v1 ships with 9600 baud for WBIO bus. Changing it to a different speed must be done in the register.
• No Manual Switches: You cannot switch speeds via hardware DIP settings; it must be done by Modbus write.
• Ensures WBIO Compatibility: By aligning the MIO-E speed with your host and your WBIO modules’ expected parameters, you enable stable polling and communication.

Example Usage

1. Clone the repository:

   git clone https://github.com/kvakirsanov/wb-mio-v1-change-wbio-speed.git
   cd wb-mio-v1-change-wbio-speed

2. Edit the script parameters:
   • IP_ADDRESS, TCP_PORT, CURRENT_ADDR
   • DEV_PORT,
   • CURRENT_BAUD, CURRENT_PARITY, CURRENT_STOPBITS,
   • SPEED_MAP.
3. Run the script:

   sudo ./wb-mio-change-speed.sh

4. Follow prompts to:
   • Read current speed,
   • Change speed (if desired, e.g. from 9600 to 115200),
   • Write to register 110,
   • Reboot (register 120) if needed.

Table of Important Registers

Register	Hex	Meaning	R/W	Notes
110	0x006E	Speed (baud/100)	R/W	Default is 96 (→9600). For 115200, set 1152. Needed to switch from default speed.
128	0x0080	Modbus Address	R/W	Confirms the target device address.
120	0x0078	Reboot Register	R/W	Write 1 to reboot if firmware requires this to apply the new speed.

For more details on registers, refer to the official WB-MIO Modbus Registers documentation.

Conclusion

By default, the WirenBoard WB-MIO-E v1 runs at 9600 baud. If you require a different speed (e.g., 115200) to match your host or your WBIO modules' communication needs, you must write the new speed code into Register 110. Some devices also need a reboot via Register 120. This interactive script automates the entire process, ensuring you can easily manage the module’s speed, address, and reboot steps without manual confusion or conflicts with wb-mqtt-serial.

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Happy configuring!
If you have suggestions, questions, or issues, open an Issue or submit a Pull Request in the repository.