Rockwell Automation AADvance Controller Demo Unit - Manual (Page 96)

Demo Unit User Manual (AADvance Controller)
5-30 Document: 553850 Issue 1.2: March 2011
Digital Output Advanced Channel Settings
Each output channel from the 9451 digital output module supports the set of control
parameters detailed in the table.
Table 18: Digital Output Control Parameters
Description Value(s) Default Remarks
Shutdown State Off, Hold Last State
(†) None specified 'Off' de-energizes the output during
a shutdown
'Hold Last State' forces the output
to remain in its last commanded
state, during a shutdown
Disable Line Test Yes, No None specified 'Yes' disables reporting of the status
variable (STA) state 3; in a no-load
condition, the Channel LED will not
go amber
'No' is equivalent to the default
setting, which enables the line test
Note: (†) The option labelled 'Default' does nothing. Do not choose this option.
Disabling the Line Test for a Digital Output
The 9451 digital output module checks for a no-load condition on each output. The
AADvance Workbench refers to the check as the 'Line Test'.
A no-load condition occurs when the controller cannot detect a load connected to the
field wiring, or the load current is below 20mA when the output is commanded TRUE.
You can disable the check for a no-load condition, for example if you want to connect
a low load to an output, or if the output is unused and you do not want to fit a dummy
load.
The module reports a no-load condition by setting the state variable (<tagname>.STA)
to the value 3, and by setting the channel LED to amber. If you disable the line test,
then assuming there are no other faults present, the state variable will continue to
show 2 or 4 (depending on the commanded value) instead of 3, and the channel LED
will show off or green instead of amber.
Note: There are other scenarios (such as no field voltage) that still result in an amber
LED, even if you disable the line test.