Can the SC-2345 be used as the basis of a vibration control system

[Wentworth]

I am in the begining stage of putting together a small vibration control and measurement system for one of our Professors.  I have a small MB shaker and amplifier, accelerometers, an SC-2345 based system and 2 SCC-ACC01 accelerometer modules.  Before I commit to going forward can I assume that this assortment of hardware is adequate for a simple vibration control system?  If so, is there a set of .vi's available such that I could show a simple demonstration of the unit?

Thanks in advance,

Chuck

[preston_johnson]

Thanks for your posting,

By using an acelerometer or two, you will be able to measure the stimulus (shaker) and the response (vibration transferred thru the unit under test) with the two accelerometers.  By analyzing the vibration, you can determine whether to increase or decrease the vibration level.  You may want to perform vibration level measurements, or vibration measurements at specific frequencies.  Either way, the output of your analysis should be a scaler value which you can use as  a process value for a PID algorithim or other control algorithim.  The output of the control algorithim would control for example the magnitude of the vibration signal fed to the shaker. 

So the diagram is really 1) measure vibration leve 2) pass level thru control algorithim and 3) adjust amplitude of signal fed to shaker. 

Does this make sense?

[Wentworth]

Yes that does make sense.  I understand the basics, having worked in a Vib test lab for a number of years.  I am more interested in knowing if the specific hardware that I have at hand is suitable for the task. Can I turn the SC-2345 into an actual Vibration Controller?   I see the need for an output module to feed a signal to the amp.  I want to have a closed loop system, where the control continuously checks the signal on the shaker head, and corrects the signal going to the amp.  My goal is to be able to A)sweep a sine wave at either a constant displacement, constant acceleration, or a combination using a crossover frequency

and

B) run a random profile with a controlled frequency spectrum.

 Basicly, we have almost all of the hardware here except for the output module.  Since I orked in Vibration/Modal analysis for a long time, I was asked if I could come up with a vibration system, and was hoping to use the NI equipment that we have on hand.

[Nick_F1]

Hi Chuck,

It sounds like all that you are missing is the SCC-AO10 or SCC-CO20 which are analog output and current output modules.  Once you have that, you will be able to make the control system in LabVIEW.

[Scott C]

Wentworth - were you successful in using the SC2345?  Could you share your program?  I need the same radom vibration type control with a small shaker and amplifier with cut-off frequencies on the input.

[Wentworth]

Scott,

I am getting closer, but have just ordered the hardware, and have not yet started writing the program(s).  When I have anything, I will post here.

[Scott C]

Chuck:
Thanks.  Email me directly (scopeland80@hotmail.com).  I have a piece of equipment thta you might be able to use.

[Scott C]

Chuck - haven't checked in for awhile.  Did you ever get your software written and system working?

[yogi_patel]

Hey,

I know this is a complete long shot but has anyone actually figured out how to do what Preston proposed. Either have the acceleration stay steady as you sweep through frequencies or the ability to sweep through accelerations at steady frequencies such that you can directly adjust acceleration, not just the amplitude of your signal, so that you do not have to guess how much you have to change your output signal to step up a certain ammount in accleration.

Sincerely,

Yogi Patel

[yogi_patel]

The only example on the net that I have found involved the use of shift registers.  The code should be attached below, I was just wondering if there was a more elegant way of creating this system.  Code was written by Dave Duimistra at GVSU in 1997 so the code is a little outdated