Overview
The MODBUS Trigger node listens to MODBUS TCP events by polling a specified memory address (register index) on a MODBUS device at a defined interval. It reads data from the device using parameters such as memory address, unit ID, data type, and quantity of data to read. When a change in the data is detected, the node triggers a workflow execution, making it useful for monitoring MODBUS devices in real-time, such as industrial sensors or controllers.
Use Case Examples
- Monitoring temperature or pressure sensors connected via MODBUS and triggering workflows when values change.
- Polling a MODBUS device to track status registers and automate alerts or actions based on the data.
Properties
| Name | Meaning |
|---|---|
| Memory Address | The memory address (register index) to read from. |
| Unit-ID | Unit-ID to address devices behind modbus-bridges. |
| Data Type | The data type of the values read from the memory address, such as signed or unsigned integers of various bit lengths. |
| Quantity | The number of data values to read from the memory address. |
| Polling | The polling interval in milliseconds to repeatedly read data from the MODBUS device. |
| Options | Additional options for the MODBUS client, currently empty but can be extended. |
Output
JSON
data- The array of data values read from the MODBUS device, converted according to the selected data type.
Dependencies
- An API key credential for MODBUS TCP connection
Troubleshooting
- Common issues include invalid memory address input (must be a valid number).
- Errors from the MODBUS client such as connection failures or read errors will stop the polling and throw errors.
- Ensure the MODBUS device is reachable and the unit ID and memory address are correctly configured.