ProSoft Technology MVI46-DFCM - Manual (Page 62)

MVI46-DFCM ♦ SLC Platform Reference
DF1 Communication Module
Page 62 of 103 ProSoft Technology, Inc.
October 20, 2008
Word one of the block can be used by the ladder logic to determine if the
command was added to the command queue of the module. The command will
only fail if the command queue for the port is full (100 commands for each queue)
or the command requested is invalid.
Command Control
Command control blocks place commands in the command list into the
command queue. Each port has a command queue of up to 100 commands. The
module services commands in the queue before the master command list. This
gives high priority to commands in the queue. Commands placed in the queue
through this mechanism must be defined in the master 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 list with an Enable
parameter set to zero. 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 format of the block is displayed below:
M1 Offset Description Length
7800 5001 to 5006 or 5101 to 5106 1
7801 Command index 1
7802 Command index 1
7803 Command index 1
7804 Command index 1
7805 Command index 1
7806 Command index 1
Blocks in the range of 5001 to 5006 are used for Port 1, and blocks in the range
of 5101 to 5106 are used for Port 2. 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 used with Port 1. The Command
index parameters in the block have a range of 0 to 99 and correspond to the
master 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 format of
the block is displayed below:
M0 Offset Description Length
0 5000 to 5006 or 5100 to 5106 1
1 Number of commands added to command queue 1