Maximum TCP Connections for I/A Series R2 UNC with Modbus TCP Driver

[Product_Support]

Issue

What is the maximum number of TCP connections supported on an I/A Series R2 UNC running a Modbus TCP driver?

Product Line

TAC IA Series

Environment

I/A Series R2 UNC

Cause

The system needs to support multiple Modbus TCP devices or gateways simultaneously. Each device or gateway uses a separate processing thread, and the platform has a finite number of threads available.

Resolution

• The recommended maximum number of Modbus TCP connections is 24 for JACE-4 (UNC-410) and JACE-5 (UNC-510/UNC-520).
• Default setting for maximumConnections is 1.
• If multiple Master TCP devices need simultaneous access to the station as a Modbus slave, increase maximumConnections accordingly.
• Important: Each Modbus TCP device or gateway shadowed in the station consumes a separate processing thread. Exceeding the recommended limit may impact performance.