ProSoft Technology MVI69-MCM - Manual (Page 131)

MVI69-MCM ♦ CompactLogix or MicroLogix Platform Reference
Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 131 of 167
March 22, 2011
Function 6 and 16
Here is the structure of the input image write block for Formatted Pass-Through
Control Block IDs 9956 and 9957.
For MVI69-MCM firmware versions 1.21 and newer only:
Offset Description Length (words)
0 9956/9957 1
1 9956/9957 (floating-point) 1
2 Length 1
3 Data Address 1
4 to ( n + 1 ) Data ( n - 2 )
For MVI69-MCM firmware versions earlier than 1.21:
Offset Description Length (words)
0 0 1
1 9956/9957 (floating-point) 1
2 Number of words 1
3 Data Address 1
4 to ( n + 1 ) Data ( n - 2 )
The ladder logic will be responsible for parsing and copying the received
message and performing the proper control operation as expected by the Master
device. The processor must then respond to the pass-through control block with
an output image write block with the following format.
Offset Description Length (words)
0 9956/9957 1
1 to ( n ) Spare ( n - 2)
This will inform the module that the command has been processed and can be
cleared from the pass-through queue.
( n ) = 60, 120, or 240 depending on the Block Transfer Size parameter (refer to the configuration file).