ProSoft Technology MVI94-MCM-MHI - Manual (Page 32)

Configuration MVI94-MCM ♦ Flex I/O Platform
User Manual Serial Communications Modbus Communication Module
Page 32 of 109 ProSoft Technology, Inc.
March 29, 2011
Based on the IntAddress and the configuration within the
MCM.CONFIG.M
OD D EF
section for WriteStartReg and WriteRegCount, the data
from the tag MCM.DATA.W
RITE D ATA [0] TO [6]
will be written to Modbus
addresses 47001 to 47007 of the Slave device node #1.
Note: A swap code may be required to put the data in the proper format for the Slave device.
3.5.2 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 MVI94-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 FLEX 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.