I am using the Order Analysis Toolkit and want to get more information about the compensation for "Reference Signal Processing", which is scarce in the manuals, the website and the examples installed with the toolkit.

[CracKatoA]

I am using the Order Analysis Toolkit and want to get more information about the compensation for "Reference Signal Processing", which is scarce in the manuals, the website and the examples installed with the toolkit.

In particular, I am analyzing the example "Even Angle Reference Signal Processing (Digital Tacho, DAQmx).vi", whose documentation I am reproducing in the following:

<B>DESCRIPTIONS</B>:
This VI demonstrates how to extract even angle reference signals and remove the slow-roll errors. It uses DAQmx VIs to acquire sound or vibration signals and a digital tachometer signal. This VI includes a two-step process: acquire data at low rotational speed to extract even angle reference; use the even angle reference to remove the errors in the vibration signal acquired at normal operation.

<B>INSTRUCTIONS</B>:
1. Run the VI.
2. On the <B>DAQ Configurations</B> tab, specify the <B>sample rate</B>, <B>samples per channel</B>, device and channel configurations, and tachometer channel information.
<B>NOTE</B>: You need to use DSA PXI-447x/PXI-446x and PXI TIO device in a PXI chassis to run this example. The DSA device must be in slot 2 of the PXI chassis.
3. Switch to <B>Extract Even Angle Reference</B> tab. Specify the <B>number of samples to acquire</B> and the <B># of revs in reference</B> which determines the number of samples in even angle reference. Click <B>Start</B> to take a one-shot data acquisition of the vibration and tachometer signals. After the acquisition, you can see the extracted even angle references in <B>Even Angle Reference</B>.
4. Switch to the <B>Remove Slow-roll Errors</B> tab. Click <B>Start</B> to acquire data continuously and view the compensate results. Click <B>Stop</B> in this tab to stop the acquisition.

<B>ORDER ANALYSIS VIs USED IN THIS EXAMPLE</B>:
1. SVL Scale Voltage to EU.vi
2. OAT Digital Tacho Process.vi
3. OAT Get Even Angle Reference.vi
4. OAT Convert to Even Angle Signal.vi
5. OAT Compensate Even Angle Signal.vi

My question is: How is the synchronization produced at the time of the compensation ? How is it possible to eliminate the errors in a synchronized fashion with respect to the surface of the shaft bearing in mind that I am acquired data at a low rotation speed in order to get the "even angle reference" and then I use it to remove the errors in the vibration signal acquired at normal operation. In this application both operations are made in different acquisitions, therefore the reference of the correction signal is lost. Is it simply compensated without synchronizing ?

Our application is based on FPGA and we need to clarity those aspects before implementing the procedure.

[Filipe Silva · Accepted solution]

Hi CracKatoA.
Take a look at the link bellow:

http://forums.ni.com/ni/board/message?board.id=170&message.id=255126&requireLogin=False

Regards,
Filipe Silva