The MVI56E-MCMR Enhanced Modbus Master/Slave Communication Module with Reduced Data Block allows Rockwell Automation® ControlLogix® processors to easily interface with devices using the Modbus RTU/ASCII serial communications protocol. Compatible devices include a wide variety of instruments. process measurement devices. popular brands of programmable logic controllers (PLCs) and programmable automation controllers (PACs). The MVI56E-MCMR acts as an input/output module on the ControlLogix backplane. making Modbus data appear as I/O data to the processor. Backplane data transfers to and from the processor are asynchronous from communications on the Modbus network. Two independently-configurable serial ports can operate on the same or different Modbus networks. Each port can be configured as a Modbus Master or Slave. sharing the same user-controlled 5000-word database.