MVI56E-MCMR ♦ ControlLogix Platform
Reference
Modbus Communication Module with Reduced Data Block
User Manual
ProSoft Technology, Inc.
Page 161 of 223
Command Error List Blocks (9950, 9951)
The
Get Command Error List
special function is applicable only when the
module's port is configured as a Modbus Master. Use block identification codes
9950 for Port 1 or 9951for Port 2 anytime you want to request the
Command
Error List
for the 100 user-configurable commands that may be sent by that port.
There is a one-to-one correspondence between the position of a command in the
Command List
and its corresponding execution status in the
Command Error
List
. Each word in the
Command Error List
holds the most recent execution
status of each corresponding command in the
M
ODBUS
P
ORT
1
C
OMMANDS
or
M
ODBUS
P
ORT
2
C
OMMANDS
lists, which were configured in the PCB module
configuration file and downloaded to the module. As each command is executed,
whether as part of normal, repetitive polling or if triggered by
Command Control
,
the status of the most recent execution will be placed in the appropriate word of
the 100-word
Command Error List
.
The
Command Error List
is requested using a "Get Attribute Single" service type
MSG instruction. The following illustration shows the MSG instruction
configuration for a
Get Command Error List
MSG.
The format of the data returned by the
Get Command Error List
MSG is shown in
the following table.
