Special considerations for upgrading existing installations

Upgrading from version 1.4.x or older to version 1.5.x or newer

Input32 and Holding32 Register Types

In alignment with the Modbus specification, direct support for 32-bit registers has been removed from AVEVA Adapter for Modbus TPC 1.5.x and later. Collecting 32-bit (or larger) values is still possible with AVEVA Adapter for Modbus TPC 1.5.x by configuring different data type codes, where the values collected will be made up of two (or more) 16-bit registers.

Connect Timeout

AVEVA Adapter for Modbus TCP maintains a TCP connection without requiring specific timeout configurations. Typically, a configurable application-layer level timeout (such as the RequestTimeout in the data source configuration) is sufficient to account for any special cases a modbus device may require.

However, if specific timeout settings at the TCP layer must be made, please refer to the OS documentation for potential adjustments.

Simultaneous Requests

AVEVA Adapter for Modbus TPC 1.5.x and later no longer supports a configurable number of simultaneous requests, as many Modbus devices do not allow multiple connections. In consideration of this change, AVEVA Adapter for Modbus TPC 1.5.x and later includes significant performance improvements for single connections. Alternatively, users may configure multiple adapter components with the same device configuration or configure multiple devices with different hostnames that all resolve to the same physical Modbus device.