Configuration as a Modbus Master
MVI56-MCM
♦
ControlLogix Platform
Modbus Communication Module
ProSoft Technology, Inc.
Page 29 of 159
July 24, 2008
For modifying the WriteData array, change the High Limit value of the LIM
statement in rung #3 of the
WriteData
ladder. Also make sure that the ReadData
and WriteData arrays do not overlap in the module memory. If you have an
application that requires 2000 words of WriteData, starting at register 0, then
your MCM.CONFIG.ModDef.ReadStartReg should be set to a value of 2000 or
greater.
4.2.1 Port
Setup
The following section describes the parameters necessary within the
MCM.CONFIG.PortX section of the controller tags that are used when the
module is setup as a Modbus Master device. Port 1 and Port 2 each have their
own set of parameters to configure.
Note: Any changes made within either the MCM.CONFIG array must be downloaded to the
MVI56MCM module by setting either the WarmBoot, ColdBoot, or cycling power to the module.
Any parameters not mentioned in this section are not used when the module is
configured as a Modbus Master. Parameters in
BOLD
are required for all
applications as a master.
Verify you are in Monitor Tags mode. Then use scroll bar at bottom to view
description of each parameter. The following table uses that information.
Label Description
Enabled
1 = enable port, 0 = disable port
Type
Master = 0
FloatFlag
0 = No Floating point data, 1 = Use Floating point data. See "Floating
Point Support (page 40)" for more information.
FloatStart
Register offset in message for floating data point. See "Floating Point
Support (page 40)" for more information.
Protocol
0 = Modbus RTU mode, 1 = Modbus ASCII mode
Baudrate
Sets the baud rate that the port will operate at. Valid values for this field
are 110, 150, 300, 600, 1200, 4800, 9600, 19200, 384 or 3840 (for
38,400 baud), 576 or 5760 (for 57,600 baud) and 115,1152, or 11520
(for 115,200 baud)
Parity
0 = None, 1 = Odd, 2 = Even
DataBits
Modbus RTU mode = 8 Modbus ASCII mode = 8 or 7
StopBits
Valid values are 1 or 2.
RTSOn
0 to 65535 milliseconds delay before data
RTSOff
0 to 65535 milliseconds delay after data
UseCTS
0 = No, 1 = Yes to use CTS modem line
CmdCount
Command list count
