Troubleshooting Guide

Modbus Connections‍

Sometimes a Modbus device may fail to connect or return a FAILED status. Here are common issues and how to fix them:‍

Controller IP Issues‍

• Problem: The Modbus controller’s IP is incorrect or not accessible.
• Fix: Double-check the device IP in your BAS or device front-end.

Port Configuration

• Problem: Port is closed or incorrect.
• Fix: Default Modbus TCP port is 502. Confirm this port is open and accessible.

Unit Identifier (Slave ID)

• Problem: Wrong unit ID entered.
• Fix:
  • Verify the unit identifier in the device’s configuration or vendor manual.
  • If multiple devices share the same controller IP, each must have a unique unit ID.

Unsupported Vendor Device

• Problem: Device not listed in Onboard’s Modbus templates.
• Fix:
  • Check the Connectivity Requirements documentation for supported models.
  • If unsupported, request a template in the Online Community with vendor name and model.