LevelCrossings (FPScript)

21.09.2021

Searches a data set for level crossings.

Syntax

LevelCrossings(DataSet, Level, Hysteresis, [ Orientation = EVENT_BOTH ] [ , Operation = EVENT_DEFAULT ])

 

The syntax of the LevelCrossings function consists of the following parts:

Part

Description

DataSet

The data set to be searched.

Permitted data structures are data series, data matrix, signal und signal series. All numeric data types are permitted.

For complex data types the absolute value is formed.

If the argument is a list, then the function is executed for each element of the list and the result is also a list.

Level

Specifies the level for which the crossings are to be found.

Permitted data structures are scalar value. All numeric data types are permitted. The unit has to be compatible with that of parameter DataSet.

For complex data types the absolute value is formed.

If the argument is a list, then the function is executed for each element of the list and the result is also a list.

Hysteresis

The hysteresis forms a symmetrical band [level - hysteresis, level + hysteresis] around the specified level. A level crossing is then only accepted if the course of the curve enters the band from one side and then exits on the other side.

Permitted data structures are scalar value. All numeric data types are permitted. The unit has to be compatible with that of parameter DataSet.

For complex data types the absolute value is formed.

If the argument is a list, then the function is executed for each element of the list and the result is also a list.

Orientation

Specifies the orientation of the level crossings to be found.

The argument Orientation can have the following values:

Constant

Meaning

EVENT_POSITIVE

Search for rising level crossings only.

EVENT_NEGATIVE

Search for falling level crossings only.

EVENT_BOTH

Search for falling and rising level crossings.

If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated.

If this argument is omitted, it will be set to the default value EVENT_BOTH.

Operation

Specifies the way the function operates.

The argument Operation can have the following values:

Constant

Meaning

EVENT_INDEX

The indices of the values or points meeting the condition are placed in the result data set.

EVENT_EXTRACT

Only the points or values meeting the condition are transferred into the result data set.

EVENT_SETVOID

The points or values that do not meet the condition are also included in the result data set, but there they are marked as void.

EVENT_DEFAULT

Corresponds to EVENT_SETVOID if a data matrix or signal series is present, and otherwise EVENT_INDEX.

+ EVENT_COMPLEMENT

This constant can be optionally added and then reverses the selected operation. Then, for example, for EVENT_EXTRACT, the points that do not meet the condition are copied.

If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated.

If this argument is omitted, it will be set to the default value EVENT_DEFAULT.

Remarks

Hysteresis prevents level crossings from being detected several times in noisy signals. If the course of the curve oscillates multiple times around the level before leaving the hysteresis band, then the mean value of the first and last crossing through the level is passed as an index.

Available in

FlexPro Basic, Professional, Developer Suite

Examples

LevelCrossings({1, 5, 7, 4, 3}, 5, 0)

Results in {1L, 2L}. Results in the indices of the positions at which the level is crossed.

See Also

NextLevelCrossing Function

ValuesAboveLevel Function

ValuesBelowLevel Function

ValuesInInterval Function

Intersections Function

Event Isolation Analysis Object

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