How do I successfully do order tracking when having to create the speed profile from a generic waveform that contains speed.

[randy1815]

We use frequency boards to condition speed into a condidtioned number during acquisition so the pulses to speed profile vi won't work for me.  I need to convert waveform containing speed sampled at same time as signals to be processed into workable speed profile. Many approaches tried generally nothing works either profile not generated or the one that is generated produces error in the tracking vi's.  Most just cause the tracking vi's to output blank arrays with no errors or one stating input array is empty when it is not.  Any help much appreciated.

[JK1]

Hai,

1. Speed profile can be generated using count or the pulse period as input.  Which type of input you are using for generating spd profile.

2. What is meant by the conditioned output??could you add some more information on the nature of the output from the frequency boards.

[randy1815]

We use a PXI/SCXI combo chassis to record all of our strain and vibration data. An SCXI 1126 is used to measure speed. A frequency channel is setup in Max along with many other channels and everything ends up in a tdm file.  The vi that I am attempting to write reads that tdm file and processes for several order cuts.  Problem is around the creation and use of a speed profile.  I have yet to find a workable way to turn the waveform read from tdm containing measured speed into a speed profile for use in the tracking vi's.

[preston_johnson]

There are a couple of choices.

1) You can tap into your input to the 1126 and bring it in as an analog input.  This would be the easiest from a software perspective.  Then use analog tach vi on the analog pulsing waveform to create the speed profile. 

2) you can use the speed number you get from the 1126 to generate a continious square wave at the same frequency.  Combine this waveform with your vibration and other waveforms, then use this created channel to generate the speed profile.  This works fine when the speed is constant.  If speed is changing rapidly, you'll need to dig down into the generation functions to find a point where you can change frequency while maintaining a continious output. 

[randy1815]

I finally got it to work by using newer subs from the sound and vibration tool kit and adding decimation to the signal while creating the speed profile.