Max_Sampled()

Format

Max_Sampled(Expr ,StartTime [,EndTime])

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

Returns

Returns the maximum value of the points in an expression over a range of time.

Inputs

Expr: The expression whose values should be processed to find the maximum.
Behaviour: Required
Dimension: Collection
Valid data types: Boolean, DateTime, Decimal, Integer, String, Duration

StartTime: The start time over which to produce the maximum. 
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 maximum. 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

This is a sample-based maximum, that is, it finds the maximum of all of the values within the time range. This is most appropriate when calculating the maximum of a batch-based quantity, such as the moisture content of coal shipments.

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: Max_Sampled(Expr, Time() - 60, Time())
Result: Maximum over the last minute (60 seconds).

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

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

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

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