
7.3 Modbus Protocol
The Centurion configurable controller was programmed with the Modbus protocol which is a system is based on a “master” and “slave” relationship. With Modbus protocol, the master and slave are able to continue to com- municate with each other through defined messages over a variety of network types. The master initiates the queries or commands, and the slave responds to the query with a message or takes action based on the query. In this case, the master is either MConfig (or another Modbus client software), or
The Centurion system communicates through Modbus using Remote Terminal Unit (RTU) transmission mode to maximize data processing.
As with all numeric data defined within Modbus, the programming is limited to accepting integers (whole num- bers only, no decimals). This is important whenever a decimal point is defined for analog inputs.
For example, for the controller to properly read “100.0” with an implied decimal point of 1, the user would need to enter “1000” and 1000 would be stored in the appropriate Modbus register. From the
For additional information, please refer to the Centurion Configurable Controller Programming Manual.
7.4 Features of Transferring Data in Modbus
Note that text visible in the MConfigPro software and on the
Parameter changes made in the
7.5 Modbus Register Address Listings
For a complete MODBUS address map, please refer to The Centurion MODBUS reference document.