Issue
This resolution explains System Words %SW82 and %SW83 in a Unity Momentum PLC.

Product Line
171CBU98090
171CBU98091.

Resolution
The explanation of %SW82 and %SW83 in Unity Pro Help is incorrect.  This is a Unity Help documentation issue.

Unity Pro V11 Help incorrectly states System Words %SW82 and %SW83 are used for Message Management in the M340, M580, Unity Momentum, Atrium, Premium, and Quantum ranges.   Where,
%SW82 = Number of Modbus messages sent or received on serial port 1, updated at 1 second period.
%SW83 = Number of Modbus messages sent or received on serial port 2, updated at 1 second period.

The correct definition of System Words %SW82 and %SW83 are:
For the ranges M340, M580, and Unity Momentum, these system words are routing message counters.
For the Quantum product range, these system words contain serial port counters.