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Can 2 comm ports be enabled when using the RTU Xdriver and are there any issues with this?

Issue

Can 2 comm ports be enabled when using the RTU Xdriver?

Environment

Continuum

9680

99xx

9640

4040

Xdriver

Modbus RTU

Cause

At times it's necessary to have multiple ports enabled for Xdrivers

Resolution

The ability to enable 2 comm ports using Xdrivers can be done, but is not recommended by the Xdriver developers or supported by PSS.

The RTU Xdriver is poll on demand. This type of driver can request a lot of data and starve the CPU on the controller which then makes the polling irregular. If 2 ports are being used then there are typically more devices being added and therefore more points increasing the requests and demand on the controller's CPU.

Use one program to control the polling on both ports. Two programs attempting to control the polling asynchronously will cause communication issues.

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Revision #:
1 of 1
Last update:
‎2018-09-06 01:07 PM
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