Knowledge Base / Rockwell In-chassis / ControlLogix / MVI56 Series / MVI56-MCM

Bulletin 1-5165141 MVI56-MCM getting intermittent communications errors when operating on both ports

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Version 1.26 of the MVI56-MCM module firmware has been created to address this issue. This new version of code uses interrupt timing, to drop the RTS line as quick as possible, and enable the module to be ready to receive messages as fast as it can. All previous versions of the module should be flash updated to this new version, as this has been proven to increase reliability of all modbus master and modbus slave applications at all baud rates. this will also eliminate the need for customer's to setup the guard band parameter for issuing write messages as a master, or on multi-drop slave applications.