ProSoft Technology MVI56E-MCM/MCMXT - Manual (Page 63)

MVI56E-MCM ♦ ControlLogix Platform Configuration as a Modbus Slave
Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 63 of 199
June 18, 2014
Value Description
StopBits Valid values are 1 or 2
SlaveID Valid values are 1 to 247
3.4 Floating-Point Data Handling (Modbus Slave)
In most applications, the use of floating-point data requires no special handling.
1 Copy the data to and from the MVI56E-MCM module with a tag configured as
a data type REAL in the ControlLogix processor.
Each floating-point value will occupy 2 registers on the Modbus network.
Some Master devices use Enron or Daniel Float data. These types of floats
require one Modbus register for each float in the module memory. If your
Master requires this addressing, refer to the following section.
For standard floating-point data handling, the following is an example of
copying 10 floats to the module.
2 First, configure a tag within the ControlLogix processor.
3 Then configure a COP statement within the main routine to copy this tag to
the module's MCM.DATA.W RITE D ATA array.
The length of the copy statement is determined by the Dest file size. To copy 10
floats from the MCM_Write_Floats array to the MCM.DATA.W
RITE D ATA array,
the length of the COP statement must be set to a value of 20.
To copy data from the MVI56E-MCM module to a floating-point tag within the
ControlLogix processor
1 Configure a tag within the ControlLogix processor as shown.
2 Then configure the COP statement to move data from the
MCM.DATA.R EAD D ATA array, and over to the new tag MCM_R EAD _F LOATS
tag as shown here.