Hilbert Transform and Error

[andrew_JKTA]

Hi,

I found this VI on the NI discussion forums whilst trying to determine the phase angle between a voltage and current signal and it has proved a great help.

However, I don't quite understand how the VI works (mainly what the Hilbert function and the error clusters actually do and what effect they have on the VI). Could anyone explain to be how these functions work? I have attached a picture of the VI to clarify my question.

Thanks very much.

Andrew

[GerdW]

Hi Andrew,

what the Hilbert transform do: see wikipedia.org or here

error clusters: this function (Error clusters from error code) adds a new error cluster in case the Hilbert transform gives one i.e. the error code is unequal to zero...

You should use error clusters in all your functions as they easily provide means for dataflow programming!

Message Edited by GerdW on 09-11-2007 11:44 AM

[andrew_JKTA]

GerdW

Thanks for your swift reply.

So what would actually happen or what would be the disadvantages of not having this error code/error cluster combination?

Sorry if the question is very basic, I am an absolute beginner at LabView and programming altogether.

Thanks again,

Andrew

[GerdW]

Hi Andrew,

not having this error cluster would mean:
1) if needed you have to do some other things to get proper dataflow (ever tried to get proper timing using "wait" function without using error cluster? - you have to use a sequence structure then...)
2) you don't recognize errors unless you wire the error code from the hilbert transform
3) you cannot use LabView primitives to test for errors (error merging functions; directly wire the error cluster to a case structure / stop terminal of while loops / select function)

You know you should test for errors as often as possible in software programming?