Rockwell Automation FactoryTalk Metrics User Guide - Manual (Page 107)

Collecting Performance Data Chapter 3
Use the following data point functions:
Item Description
SUM() Returns the sum of multiple parameters for data points, ranges,
numbers, or numeric expressions.
DIFF() Uses two parameters to return the difference between the previous
value and the current value. The first parameter is a data point,
usually a counter accumulator. The second parameter is a rollover
value and is used when the current value is less than the previous
value. This function has built in rollover logic used when the current
value is less than the previous value. This logic calculates the
difference between the rollover value and the previous value and
adds the current value.
• If current value > previous value, then Diff = (current value -
previous value)
• If current value < previous value, then Diff = (rollover value -
previous value) + current value
AVG() Returns the average of multiple parameters for data points, ranges,
numbers, or numeric expressions.
MIN() Returns the minimum value of multiple parameters for data points,
ranges, numbers, or numeric expressions.
MAX() Returns the maximum value of multiple parameters for data points,
ranges, numbers, or numeric expressions.
NameOf() Returns a string that contains the name of a single data point as a
parameter.
ItemOf() Returns a string that contains the item or tag name of a single data
point as a parameter.
StationOf() Returns a string that contains the topic name of a DDE data point as
a parameter. If the data point was retrieved from RSView32, the
resulting string contains the project name. If the data point was
retrieved from FactoryTalk, the resulting string contains the
application area and server information.
Rockwell Automation Publication PLTMT-UM001M-EN-P-June 2014 107