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HP Forum Archive 17

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HP50g (Vibration Analyzer)
Message #1 Posted by Brad Davis on 3 Sept 2007, 1:19 p.m.

I do vibration testing (single channel FFT and multi-channel modal analysis--pretty simple stuff as vibe testing goes) and had an interesting thought a couple of days ago.

Does anyone know of a vibration analyzer developed around the HP50g, single channel or otherwise? I searched briefly online and didn't find anything. Currently, analyzers are heinously expensive for the most part. There is one developed around a Palm device that is only a few thousand bucks, but the Palm has its own problems, IMO.

The 50g has FFT and IFFT and I have to think it's fast enough to at least work as a two channel input-only analyzer.

      
Re: HP50g (Vibration Analyzer)
Message #2 Posted by Donald Williams on 3 Sept 2007, 1:24 p.m.,
in response to message #1 by Brad Davis

What is your highest frequency of interest? Since you are stuck with serial data transfer, that would probably limit your frequency response - unless your sensor/data aquisition device had on board memory.

            
Re: HP50g (Vibration Analyzer)
Message #3 Posted by Brad Davis on 3 Sept 2007, 1:36 p.m.,
in response to message #2 by Donald Williams

20 Hz max, almost never > 10 Hz. Civil engineering applications, mostly floors.

                  
Re: HP50g (Vibration Analyzer)
Message #4 Posted by Donald Williams on 3 Sept 2007, 2:00 p.m.,
in response to message #3 by Brad Davis

This is not a high quality device, but interesting. Cheap price.

Here

I think it can be interfaced to the 50G through a CBL, but I have not personnally attempted this.

                        
Re: HP50g (Vibration Analyzer)
Message #5 Posted by Jeff Kearns on 3 Sept 2007, 2:48 p.m.,
in response to message #4 by Donald Williams

The note on that page reads: "All Vernier products are designed for educational use only. Our equipment is not designed or recommended for research or any apparatus involved with any industrial or commercial process such as life support, patient diagnosis, control of a manufacturing process, or industrial testing of any kind."

I would not recommend using this device for your application. They do refer you to a different website for industrial apps.

Regards,

JeffK

      
Re: HP50g (Vibration Analyzer)
Message #6 Posted by DaveJ on 3 Sept 2007, 5:11 p.m.,
in response to message #1 by Brad Davis

The market for that would be ridiculously small, so I'd be very surprised if there is any commercial product. There is a Compact Flash one for Pocket PC's: http://www.easylaser.com/MicroVibe.htm

Dave.

            
Re: HP50g (Vibration Analyzer)
Message #7 Posted by Brad Davis on 3 Sept 2007, 5:23 p.m.,
in response to message #6 by DaveJ

Yeah, no doubt it would be a small market. Then again, folks have done it for the Palm and I've heard of one that was software only that worked with a high-end notebook computer sound card.

I figured that somebody might've programmed one almost for fun.

Thanks everybody.

                  
Re: HP50g (Vibration Analyzer)
Message #8 Posted by DaveJ on 3 Sept 2007, 6:01 p.m.,
in response to message #7 by Brad Davis

Quote:
Then again, folks have done it for the Palm

Yes, but the Palm is a massive market compared with the 50G though. Plus it has a bigger more suitable screen, is more readily available , development tools are better etc

Quote:
and I've heard of one that was software only that worked with a high-end notebook computer sound card.

Yes, plenty of those around, even Freeware.

Quote:

I figured that somebody might've programmed one almost for fun.


Well, software ain't enough of course, you need a decent hardware front end.

Do you *really* want to see FFT's on that tiny 50G screen?

Dave.

                  
Re: HP50g (Vibration Analyzer)
Message #9 Posted by BruceH on 3 Sept 2007, 6:21 p.m.,
in response to message #7 by Brad Davis

You need to get in touch with Brian McGuire at Saltire Software. They are developing this. The prototype was demonstrated at last year's conference (HHC2006) and it was excellent. Sadly, nothing seems to have happened in the meantime.

He demonstrated an accelerometer attached to a wooden ruler which was "pinged" on the desk. So it is more than capable of picking up your 20Hz max frequency but you would have to ask about the sensitivity. (Although the instrument bit is interchangeable so you could always fit a more sensitive accelerometer.)

Please do get in touch with him (and hassle through Richard Nelson if you don't get anywhere) because if you were willing to be a real-life case-study then that might just give HP the impetus they need to give Saltire a poke and get things going again.

                        
Re: HP50g (Vibration Analyzer)
Message #10 Posted by Matt Kernal on 4 Sept 2007, 5:20 p.m.,
in response to message #9 by BruceH

I want to second Bruce's opinion.. Brian McGuire's demo of the Saltire Data Streamer was impressive! I remember seeing, on more than one occasion, HP representatives talking with Brian outside of the main conference following his presentation. I was glad to see HP's interest in the product. Hopefully we'll see more this "Mobile Digital Laboratory" collaboration soon.

      
Re: HP50g (Vibration Analyzer)
Message #11 Posted by Dave Shaffer (Arizona) on 3 Sept 2007, 7:29 p.m.,
in response to message #1 by Brad Davis

Are you more concerned about price or size/portability?

As others have noted, the price could be quite reasonable if you use a PC sound card, or the Vernier unit referred to by Don Williams.

You'd still need an accelerometer of some kind, but you can get a very simple but adequate A/D convertor from folks like DATAQ (their 240 sample per second unit is well under $100). I've played with it and like it.

By the way, the Vernier unit is part of a very large data collection and analysis system designed primarily for educational labs, and interfaced to either PCs or TI8x calcs (USB or serial). Their warning is mostly a CYA so that somebody (who'd have to be approaching brain-dead himself) doesn't use their stuff for life-critical purposes. For a testing lab, they should be quite OK (that's why they pay us scientists and engineers the big bucks: to decide what kind of lab/test equipment is suitable for the applications at hand!).


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