ProSoft Technology MVI56E-MCM/MCMXT - Manual (Page 124)

Reference MVI56E-MCM ♦ ControlLogix Platform
User Manual Modbus Communication Module
Page 124 of 199 ProSoft Technology, Inc.
June 18, 2014
The following table describes the format of these blocks.
Block Request from Processor to Module
Word Offset Description Length
0 3002 to 3003 or 3102 to 3103 1
1 to 247 Spare 246
The module will recognize the request by receiving the special write block code
and respond with a read block with the following format:
Block Response from Module to Processor
Word Offset Description Length
0 Reserved 1
1 Write Block ID 1
2 to 129 Slave Poll Status Data 128
130 to 248 Spare 119
249 3002 to 3003 or 3102 to 3103 1
Ladder logic can be written to override the value in the Slave status table. It can
disable (state value of 3) by sending a special block of data from the processor to
the Slave. Port 1 Slaves are disabled using block 3000, and Port 2 Slaves are
disabled using block 3100. Each block contains the Slave node addresses to
disable. The following table describes the structure of the block.
Block Request from Processor to Module
Word Offset Description Length
0 3000 or 3100 1
1 Number of Slaves in Block 1
2 to 201 Slave indexes 200
202 to 247 Spare 46
The module will respond with a block with the same identification code received
and indicate the number of Slaves acted on with the block. The following table
describes the format of the response block.
Block Response from Module to Processor
Word Offset Description Length
0 Reserved 1
1 Write Block ID 1
2 Number of Slaves processed 1
3 to 248 Spare 246
249 3000 or 3100 1