Specifications

Reference Manual
00809-0200-4801, Rev CA
July 2010
6-15
Rosemount 3051S
Figure 6-12. Example AI
Function Block for Trending
Standard Deviation in DeltaV
Set the units and scaling for the function block as follows:
XD_SCALE = 0 to 1 in H
2
O (68 °F)
OUT_SCALE = 0 to 1 in H
2
O (68 °F)
L_TYPE = Indirect
Note that the range set in the OUT_SCALE parameter will be the range that is
shown by default when the variable is trended in the DeltaV Process History
View. Standard deviation typically has a range much narrower than the
process measurement, and so the scaling should be set accordingly. Also
note that the units for XD_SCALE must be set to in H
2
O (68 °F), but the units
for OUT-SCALE can be set to any desired engineering unit.
If you want the standard deviation to be logged to DeltaV Continuous
Historian, you need to add the appropriate parameter to the historian.
Right-click on the OUT parameter of the AI Block, and select the option “Add
History Recorder …” (Figure 6-13)
Figure 6-13. Adding History
Recorder from DeltaV Control
Studio