ProSoft Technology MVI56E-MNETR - Manual (Page 110)

MVI56E-MNETR ♦ ControlLogix Platform Reference
Modbus TCP/IP Interface Module with Reduced Data Block User Manual
Page 110 of 153
ProSoft Technology, Inc.
August 31, 2009
Command Control
Command control blocks place commands in the command list into the command
queue. The client has a command queue of up to 100 commands. The module
services commands in the queue before the user defined command list. This
gives high priority to commands in the queue. Commands placed in the queue
through this mechanism must be defined in the module's command list. Under
normal command list execution, the module will only execute commands with the
Enable parameter set to one or two. If the value is set to zero, the command is
skipped. Commands may be placed in the command queue with an Enable
parameter set to zero using this feature. These commands can then be executed
using the command control blocks.
One to six commands can be placed in the command queue with a single
request. The following table describes the format for this block.
Offset Description Length
0 5001 to 5006 1
1 Command index 1
2 Command index 1
3 Command index 1
4 Command index 1
5 Command index 1
6 Command index 1
7 to 41 Spare 35
The last digit in the block code defines the number of commands to process in
the block. For example, a block code of 5003 contains 3 command indexes that
are to be placed in the command queue. The Command index parameters in the
block have a range of 0 to 99 and correspond to the module's command list
entries.
The module responds to a command control block with a block containing the
number of commands added to the command queue for the port. The following
table describes the format for this block.
Offset Description Length
0 Write Block ID 1
1 Number of commands added to command queue 1
2 to 40 Spare 39
41 5001 to 5006 1
Warm Boot
This block is sent from the ControlLogix processor to the module (output image)
when the module is required to perform a warm-boot (software reset) operation.
The following table describes the format of the control block.
Offset Description Length
0 9998 1
1 to 41 Spare 41