ProSoft Technology MVI71-MCM - Manual (Page 68)

MVI71-MCM ♦ PLC Platform Reference
Modbus Communication Module
Page 68 of 111 ProSoft Technology, Inc.
December 28, 2007
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 structure of the block is displayed in the following table:
Offset Description Length
0 3000 or 3100 1
1 Number of Slaves in Block 1
2 to 61 Slave indexes 60
62 to 63 Spare 2
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 format of this
response block is displayed in the following table:
Offset Description Length
0 3000 or 3100 1
1 Write Block ID 1
2 Number of slaves processed 1
3 to 63 Spare 61
Ladder logic can be written to override the value in the slave status table to
enable the slave (state value of 1) by sending a special block. Port 1 slaves are
enabled using block 3001, and Port 2 slaves are enabled using block 3101. Each
block contains the slave node addresses to enable. The following table describes
the format for this block.
Offset Description Length
0 3001 or 3101 1
1 Number of Slaves in Block 1
2 to 61 Slave indexes 60
62 to 63 Spare 2
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 format of this
response block is displayed in the following table:
Offset Description Length
0 Reserved 1
1 Write Block ID 1
2 Number of slaves processed 1
3 to 63 Spare 61