ProSoft Technology MVI56-AFC - Manual (Page 77)

MVI56-AFC ♦ ControlLogix Platform Modbus Communication
Liquid and Gas Flow Computer User Manual
ProSoft Technology, Inc. Page 77 of 316
February 25, 2011
6 Modbus Communication
In This Chapter
 Communication Parameters .................................................................. 78
 Port Options .......................................................................................... 79
 Modbus Master ...................................................................................... 80
 Modbus Pass-Through .......................................................................... 82
A remote Modbus Master device can be connected to any one of the
communication ports for data polling. The module accepts the following Modbus
command functions according to the Modbus protocol specification:
Modbus Function Code Description
3 Read Holding Registers
4 Read Input Registers
6 Preset (Write) Single Register
16 Preset (Write) Multiple Registers
Ports 2 and 3 support RS-232, RS-422, or RS-485 communications. The
Configuration/Debug port (Port 1) supports RS-232 only.
Refer to Cable Connections (page 299) for wiring instructions.
The Modbus Master command can be sent to either the Primary or Virtual
Modbus Slaves in the module. Each slave has individual Modbus addresses that
you can configure (Project / Site Configuration). The Primary Slave address is
configured as 244 by default.