Reference
MVI56E-MNETR ♦ ControlLogix Platform
User Manual
Modbus TCP/IP Interface Module with Reduced Data Block
Page 114 of 175
ProSoft Technology, Inc.
June 14, 2011
Module’s Internal Database Structure
5000 registers for user data
0
Register Data
4999
Data contained in this database is paged through the input and output images by
coordination of the ControlLogix ladder logic and the MVI56E-MNETR module's
program. Up to 40 words of data can be transferred from the module to the
processor at a time. Up to 40 words of data can be transferred from the
processor to the module. Each image has a defined structure depending on the
data content and the function of the data transfer. The module uses the following
block numbers:
Block Range
Descriptions
-1
Status block
0
Status block
1 to 125
Read or write data
1000 to 1124
Output Initialization Blocks
2000
Event Command Block
5001 to 5006
Command Control
9956
Formatted pass-through block from function 6 or 16 with word data.
9957
Formatted pass-through block from function 6 or 16 with floating-point data.
9958
Formatted pass-through block from function 5.
9959
Formatted pass-through block from function 15.
9960
Formatted pass-through block from function 22.
9961
Formatted pass-through block from function 23.
9970
Function 99 indication block.
9996
Unformatted Pass-through block with raw Modbus message.
9998
Warm-boot control block
9999
Cold-boot control block
These block identification codes can be broken down into a few groups: Normal
data transfer blocks (-1 to 125), Initialization blocks (1000 to 1124), Command
control blocks (2000, 5001 to 5006, 9998 and 9999) and pass-through function
blocks (9956 to 9961, 9970 and 9996).
Normal Data Transfer Blocks
Normal data transfer includes the paging of user data from the module’s internal
database (registers 0 to 4999), as well as paging of status data. These data are
transferred through read (input image) and write (output image) blocks.
The following topics describe the function and structure of each block.
