I’ve got a problem by building up a
vibration analysing test site. First I want to give you an overview over my test
equipment. I am using a PXI RT Controller (PXI-8196) and the DSA-Card NI 4461,
which is mounted in Slot 8 of the PXI-Chassis NI-1042. I have installed LabView
8.0.1, the Sound and Vibration Toolkit and the Order Analysing Toolkit.
I want to generate a sweeping sinus
from 1000 Hz down to 50 Hz (with the Swept sine VI´s of Sound and Vibration
Toolkit) on analogue output port a0 of the DSA-Card. The output signal is routed
back to the ai0 port of the same device. The sweeping sinus is used for
controlling a power amplifier which is connected to a non-rotating electrical
machine. The current of the power amplifier creates a magnetic field, which
excite vibrations of a special part in this machine. This vibrations are
measured with a laser measurement system (doppler effect) and it delivers a
voltage signal, which is proportional to vibration velocity. This voltage is
acquired with an sample rate up to 35 kHz on input port ai1 of the DSA-Card.
With the answer of the laser measurement system, I’d like to compute the rms
response level of the laser signal. Therefore I use the SVT Read Swept Sine RMS
Level VI at the moment and it work actually fine. But I need more Information’s
about the measured signal. I also want to compute the mechanical orders of this
process, which are typically even multiples of the exciting electrical
frequency. I want to get out the waveforms of every order (up to the
12th order) and create an order spectrum and the “Klirrfaktor” which
is similar to THD for each frequency.
I found out, that there is a toolkit
for analysing orders, but only for rotating machines. So I installed the Order
Analysing Toolkit and try to adapt it to the described problem above but I can’t
solve the problem yet. Is there a way for adapting the block set of this toolkit
for my problem? Especially I am interesting in how to rebuild a speed profile
for this case. Can I use the blocks of OAT in parallel and/or combination with
the swept sine engine VI of the SVT?
I also want to collect the measured
data. What is the best way to store it? Is an online computation of the
requested parameters possible, or should the data first stream to disk and
compute it subsequent to the measurement? I hope you can give me some hint’s.
Perhaps you can give me an example VI ?
