ProSoft Technology MVI56E-MCM/MCMXT - Manual (Page 64)

Configuration as a Modbus Slave MVI56E-MCM ♦ ControlLogix Platform
User Manual Modbus Communication Module
Page 64 of 199 ProSoft Technology, Inc.
June 18, 2014
Once again, the COP statement will take as many of the Source elements
required to fill the Dest tag for the length specified. Therefore, the COP statement
will take MCM.DATA.R
EAD D ATA [0] TO [19] to fill the MCM_R EAD _F LOATS [0] TO
[9].
3.4.1 Enron/Daniel Float Configuration
Sometimes it is necessary for the module to emulate Enron or Daniel floating-
point addressing.
Copying the data to the MCM.DATA.W RITE D ATA array and from the
MCM.DATA.R EAD D ATA array is the same as described in the section above. The
main difference is the addressing of the module.
For example, an Enron Float device is required to access address 47001 for
floating-point data, and each Modbus register would emulate a single float value
(does not require 2 Modbus addresses for 1 float value).
A Master device requiring this type of addressing, would require that for every
count of 1, the MVI56E-MCM module responds to the request message with 4
bytes (one 32-bit REAL) value.
To emulate this addressing, the module has the parameters
MCM.CONFIG.P
ORT X.F LOAT F LAG , F LOAT S TART , and F LOAT O FFSET .
Value Description
FloatFlag Tells the module to use the FloatStart and FloatOffset parameters
listed below
FloatStart Determines what starting address on the Modbus network to treat
as floating-point data. A value of 7000 will signal the module that
address 47001 on the Modbus network is the starting location for
Modbus floating-point data. Every address will occupy 2 registers
within the modules database
FloatOffset Determines the address within the module to which to associate
the data from the FloatStart section.
Here is a sample configuration for the module.
With the above configuration, this would be the addressing for the module.
Module Address Modbus Address Tag Address
100 47001 MCM.DATA.WriteData[100]
102 47002 MCM.DATA.WriteData[102]
104 47003 MCM.DATA.WriteData[104]
110 47006 MCM.DATA.WriteData[110]
120 47011 MCM.DATA.WriteData[120]
200 47051 MCM.DATA.WriteData[200]
300 47101 MCM.DATA.WriteData[300]
500 47201 MCM.DATA.WriteData[500]