RT Timestamp Analysis VI

Owning Palette: RT Utilities VIs

Requires: RT Module

Analyzes the array of timestamps returned by the RT Get Timestamp VI.

Details  Example

	timestamp array specifies the array of 64-bit timestamps returned from the RT Get Timestamp VI that you want to analyze.
	calibration array is an array used to remove the overhead associated with the RT Get Timestamp VI. The RT Timestamp Analysis VI subtracts the mean value of all elements in calibration array from each element in timestamp array to remove the overhead incurred when the RT Get Timestamp VI adds the element to the timestamp array in memory on the RT target.
	Warmup iterations specifies the number of timestamps to ignore from the beginning of timestamp array. Use Warmup iterations to remove initial timestamps from the beginning of timestamp array that might have been affected during the initial execution of the application on an RT target.
	error in (no error) describes error conditions that occur before this node runs. This input provides standard error in functionality.
	mean time returns the average execution time for the values in the execution times array.
	standard deviation returns the standard deviation for the values in the execution times array.
	execution times returns the execution time, in microseconds, between each element of timestamp array.
	execution histogram returns histogram values for the elements of execution times.
	max jitter returns the maximum deviation between elements of execution time and the value of mean time. The value can represent a positive or negative deviation.
	error out contains error information. This output provides standard error out functionality.

RT Timestamp Analysis Details

The RT Get Timestamp VI returns a timestamp array that you can use to benchmark code. The timestamps returned in the array contain additional overhead incurred when the RT Get Timestamp VI adds timestamp values to the array in memory on an RT target. You can run the RT Get Timestamp VI alone for several iterations and add the timestamps to a calibration array. You then can use the calibration array input of the RT Timestamp Analysis VI to remove the overhead from the timestamp values. The RT Timestamp Analysis VI subtracts the mean value of the calibration array from all timestamps provided in timestamp array to calculate the actual execution times for the code that you benchmark.

Example

Refer to the Benchmark Project.lvproj in the labview\examples\Real-Time\RT Benchmarking directory for an example of using the RT Timestamp Analysis VI.