ProSoft Technology MVI56-AFC - Manual (Page 75)

MVI56-AFC ♦ ControlLogix Platform Modbus Database
Liquid and Gas Flow Computer User Manual
ProSoft Technology, Inc. Page 75 of 316
February 25, 2011
5.3.1 Virtual Slave Example Application
Assume that an application requires a remote Modbus Master to poll the orifice
diameters for the first 5 channels. Continuing the previous example, the holding
register addresses are listed again the following table.
Meter Registers
1 8162 and 8163
2 10162 and 10163
3 12162 and 12163
4 14162 and 14163
5 16162 and 16163
Because these addresses are not contiguous, the Modbus Master would have to
use five commands to poll all the data directly from the Primary Modbus Slave as
follows:
However, using the Virtual Modbus Slave optimizes the polling of data because
the registers can be remapped in any order using the AFC Manager (Site
Configuration window). The following illustration shows how the orifice diameter
registers could be remapped to the Virtual Slave starting at address Vh00100: