Configure Minimum Send Interval for ModbusAsync Driver in I/A Series R2

[Product_Support]

Issue

Can the I/A Series R2 ModbusAsync driver be configured to control the minimum send time between Modbus messages on the bus?

Product Line

TAC IA Series

Environment

• I/A Series R2
• Modbus

Cause

Some Modbus devices cannot process messages at normal transmission rates and require a delay between consecutive messages to avoid communication errors.

Resolution

Yes, the minimum send time between Modbus messages can be controlled by adding a parameter in the drivers.properties file:

1. Ensure you have modbusAsync-2.302.514.v1 or higher installed.
2. Open the UNC using the Admin Tool and navigate to the Installation tab.
3. Edit the drivers.properties file.
4. Add the following property on its own line:

   modbusAsync.minSendInterval=1000
   

   (Value is in milliseconds; adjust as needed, e.g., 1000 = 1 second delay)
5. Save the file and reboot the station.
6. Important: Backup the station when prompted during the process.