TimeWeightedAverage_Sampled()

Format

TimeWeightedAverage_Sampled(Expr ,StartTime [,EndTime])

Note: This function was named Hist_TimeWeightedAverage in v2.6.

Returns

Returns the time-weighted average of the values of an expression over a range of time.

Inputs

Expr: The expression whose values should be averaged.
Behaviour: Required
Dimension: Collection
Valid data types: Boolean, Decimal, Integer

StartTime: The start time over which to produce the average. 
Behaviour: Required
Dimension: Collection, SingleValue
Valid data types: DateTime, Decimal, Integer, String

Note: You can use the Time() function to use a valid DateTime argument.

EndTime: The end time over which to produce the average. If not specified, it assumes the current time. 
Behaviour: Optional 
Dimension: Collection, SingleValue
Valid data types: DateTime, Decimal, Integer, String

Note: You can use the Time() function to use a valid DateTime argument.

How to format data types

When to Use

A time-weighted average takes all the values that the expression held during a period of time, multiplies them by the time that the value was in effect, sums them, and then divides by the total time. This is most appropriate when producing averages of sampled continuous functions, such as the temperature of a furnace.

It is possible to retrieve very large volumes of data through indiscriminate use of this function. Retrieving large amounts of Historian data across a slow network can affect system performance for all users of the system.

Examples

Expression: TimeWeightedAverage_Sampled(Expr, Time() - 60, Time())
Result: Average over the last minute (60 seconds).

Expression: TimeWeightedAverage_Sampled(Expr, Time() - 60)
Result: Average over the last minute (60 seconds).

Expression: TimeWeightedAverage_Sampled(Expr, Midnight(Time()))
Result: Average since midnight (the start of the day).

Expression: TimeWeightedAverage_Sampled({tag, sampleMethod = "Raw"}, Time() – 60)
Result: Average of the raw values over the last minute.

Expression: TimeWeightedAverage_Sampled(Sampling(Expr, "raw"), Time() - 60)
Result: Average of the raw values over the last minute.