Rockwell Automation AADvance Controller Demo Unit - Manual (Page 84)

Demo Unit User Manual (AADvance Controller)
5-18 Document: 553850 Issue 1.2: March 2011
Configuring Analogue Inputs
You can wire analogue input channels to the following variable type and data
structures:
 REAL (the <variable_name> gives a floating-point value representing 4 to 20mA)
 TK9_AI_Compact (provides three elements)
 TK9_AI_Full (six elements)
The structures provide additional information about the input, such as discrepancy
status. You can also configure analogue inputs to operate with HART devices, and
define custom thresholds.
TK9_AI_COMPACT and TK9_AI_FULL (Analogue Inputs)
The two data structures for analogue inputs (TK9_AI_COMPACT and
TK9_AI_FULL) provide the elements detailed in the tables.
Table 12: TK9_AI_COMPACT Structure for Analogue Inputs
Identifier Type Description Remarks
<tagname>.PV REAL PV Process Value. A scaled, floating-point value
representing the analogue loop current.
Default scaling factor is 0 to 100% representing
4 to 20mA
<tagname>.CNT INT Raw count A count representing the current on the
channel in units of 1/256mA
0 represents 0mA
5,120 represents 20mA
Accurate to within ± 13 counts, equivalent to
± 0.05mA
<tagname>.DIS BOOL Discrepancy TRUE: there is a discrepancy in current
greater than 2% between the channels of two
or three modules in a redundant configuration
(†)
Table 13: TK9_AI_FULL Structure for Analogue Inputs
Identifier Type Description Remarks
<tagname>.PV REAL PV Process Value. A scaled, floating-point value
representing the analogue loop current.
Default scaling factor is 0 to 100% representing
4 to 20mA