Virtual instruments from USB source

[jackinnj]

That's much more useful if you connect it to a chart recorder rather than a scope, but still way less useful than a sound card for SA applications.

Conrad -- I have a USB Datalogger which I programmed in Visual Basic.Net and Softwire -- this makes any wave-analyzer (Like the 3581 or the 3586 receiver0 a much more interesting and useful tool.

In particular, the noise floor of the 3581 is some tens of nano-volts and the RMS detector (it's a hybrid log amp) is almost as good as a thermally based unit.

I'm getting OT, I realize. Sorry I gave away my 535.

 

[Conrad Hoffman]

Way further OT, what I reeeeealy want is the new Agilent USB 2.0-to-GPIB converter, and a laptop. Then I could hook up my various pieces of surplus HP gear in the lab and automate some tests. I could also use the laptop with my E-mu interface for response measurements in the living room- something that's extremely awkward now, since I can't even lift the rack cabinet holding my old GR sound & vib analyzer plus it's synchronized chart recorder. Unfortunately, the USB/GPIB adapter is $499, not to mention the price of a laptop, so it will have to wait a while. Like forever. I rewrote the VB include file for the Agilent I/O suite, so I can program everything directly in PowerBASIC, something I'm much more comfortable with than VB- if I ever get the interface

 

[jackinnj]

Way further OT, what I reeeeealy want is the new Agilent USB 2.0-to-GPIB converter, and a laptop. Then I could hook up my various pieces of surplus HP gear in the lab and automate some tests. I could also use the laptop with my E-mu interface for response measurements in the living room- something that's extremely awkward now, since I can't even lift the rack cabinet holding my old GR sound & vib analyzer plus it's synchronized chart recorder. Unfortunately, the USB/GPIB adapter is $499, not to mention the price of a laptop, so it will have to wait a while. Like forever. I rewrote the VB include file for the Agilent I/O suite, so I can program everything directly in PowerBASIC, something I'm much more comfortable with than VB- if I ever get the interface

Let's split this off -- I have some USB to GPIB/HPIB stuff from National Instruments.

 

[EC8010]

That's a beer you owe me.

 

[FastEddy]

http://www.sparkfun.com/commerce/product_info.php?products_id=549 ... US$149 instead of US$499 ... same, same = Agelent chip but also WinPC and Apple Mac compatible.

The old HPIB / GPIB / IEEE488 interface is still viable. The interface to USB2.0 is a plus, but not much as it is rare for the GPIB buss to exceed the 12 mbps performance of USB1.x.

(Mercenary announcement: I have not tested these but intend to have these Prologix gadgets in our own catalogs shortly = USBStuff.com, USB-Shop.com, IndustrialComponent.com etc.)

 

[Schaef]

Another alternative that includes information needed to DIY it:

USB to GPIB interface

I know nothing beyond this yet, as I only just found it the other day and marked it as a later read.

 

[Conrad Hoffman]

Fasteddy- that looks just great! Because I use a $20K LCR meter at work, and fast interfaces, I sometimes forget that something lesser might just possibly be acceptable for home use. I have only limited time to build anything, so I'd rather work directly on what I want, rather than interfaces that are only a stepping stone.

I just went down to the lab and felt around back of various things to see what had GPIB. Unfortunately the HP3581A does not, which is too bad. Naturally one can do the datalog trick, but full control would be really cool. I have an HP8903B audio analyzer, and that can be made to do far more tricks with GPIB than can easily be accomplished via the front panel. Nice as it is, my Bob Cordell THD analyzer built many years ago can still blow it out of the water when it comes to noise and distortion floor. I also have various DVMs with GPIB- the big and cheap HP3455A will hold within a few PPM for years, and is good to near 100kHz. The rest of my stuff is quite primitive. The GR bridges are completely passive and need separate oscillators and tuned null detectors. They use the "full manual" interface

Any opinions on buying a laptop with Vista? I'd really like XP instead, but it's getting harder to do that. I think Dell will still supply XP if you ask. Anybody got Vista and tried using it in a programming and instrument control setting?

Regards,
Conrad

 

[FastEddy]

One of the neat things about GPIB / HPIB / '488 is that you can daisy chain up to 7 devices off of a single USB adapter, just like older SCSI. I believe it will be about 30 days before we have the adapter available, so you might get it from that other source (above).

IMOP, for any serious pro-audio work, get a Mac laptop ... I did = . It is quite easy to build a complete multi-track recording studio w/multichannel 24 bit/192K I/O, around a single Mac computer. (http://www.apple.com/macbook/macbook.html ... includes FireWire & USB ports, lots of great audio software, [don't sell Garage Band or iTunes short], multimedia oriented, etc. "Pro" ADC/DAC examples: http://3dotaudio.com/maudio/mobilerecording.html ) Almost every working professional recording studio has an Apple computer with OSX somewhere in their mixing / mastering circuits, doing all of the heavy lifting ...

When it comes to lab / engineering work, the windows world is better equipped, software wise, alas. I usually recommend Windows 2K (almost bullet proof) ... XP is a resource pig and Vista is not bug free, yet.

For the biz, I buy monitors, I/O gear we don't carry, etc. from the Dell "close out" catalog or our suppliers.

 

[Conrad Hoffman]

Well, I ordered the interface this morning and now see the email that they shipped it, so will have to study the manual for the unit and have a look at the drivers. Now I need a more portable computer- I'm thinking maybe one of the very tiny desktop boxes would be cheap and do what I want- more bang for the buck compared to a laptop. I also have an HP network analyzer out in the garage waiting for a rebuild/tuneup. It has the earliest version of the GPIB, without even a standard connector- hey, I love a challange!

 

[FastEddy]

" ... maybe one of the very tiny desktop boxes would be cheap and do what I want- more bang for the buck compared to a laptop. ..."

Same, same = Apple Mac Mini, Apple MacBook laptop = 1.6 GHtz CPU, 1/2 Gig RAM ... I have two Minis at work for the web graphics, email, SqueezeBox driver, etc. and a MacBook at home for this report & home media server. (I gave our older Apple Cube to my niece with the M-Audio FireWire 24bit/96K I/O for her recording studio. She has hundreds of songs in the can waiting for release on optical media ... and I'm real proud of her work. )

I have personally built more than 3000 "clones" since 1982 , all but a few are WinPC types, but I love my Macs.

Of passing interest: http://www.appleinsider.com/article..._firewire_audio_interface_for_garageband.html

 

[jackinnj]

Any opinions on buying a laptop with Vista? I'd really like XP instead, but it's getting harder to do that. I think Dell will still supply XP if you ask. Anybody got Vista and tried using it in a programming and instrument control setting?

Regards,
Conrad

I think that the first versions of Labview under vista are just coming out now.

I am still on VB.NET 2003 -- never migrated to 2005.

 

[Conrad Hoffman]

Just an update- I got the Prologix USB-GPIB interface a while back, and picked up a new computer. I didn't really want a laptop, but wanted something reasonably powerful I could move around easily. Got an Acer L310, which is about the size of a medium Webster's dictionary (8"x10"x2.5"), with Vista Home Premium.

The whole mess works great- no problems with Vista at all, other than the well known issue of not working with old style help files unless you download the support program. Even with that, you have to load the helps separately, and they aren't context sensitive. No problems with drivers, no problems with speed, no operational problems. Still have to test my Emu audio driver, but the on-board sound is working ok, so the Emu should too. I didn't want to like Vista, but I'm very pleased so far.

I've got GPIB communication with my HP audio analyzer using the low level driver dll, and am presently designing test routines to attach to the buttons on my screen layout. When that's done, I want to automate a capacitor dielectric absorption test, because when I do it by hand it's hardly consistent. Man, I can think of all sorts of things this will make easier, and tests that aren't practical to do manually at all.

Regards,
Conrad

 

[jackinnj]

I want to automate a capacitor dielectric absorption test, because when I do it by hand it's hardly consistent. Man, I can think of all sorts of things this will make easier, and tests that aren't practical to do manually at all.

Regards,
Conrad

Conrad -- the GenRad patents for DA analyzers can be found at the USPTO website -- they are also cited in the Digibridge manuals (if I had time to find it.)

 

[Conrad Hoffman]

I collect GR stuff, and didn't even know they did DA tests! BTW, I email now and then with Henry Hall, who oversees the GR museum. He worked at GR and did a lot of work on the traditional bridges, then developed the first Digibridge. A year or three ago he did a very extensive paper on the history of impedance measurement. Covered every piece of measurement equipment known to man. I think it was for the IEEE, but not sure. One very fine engineer. Thanks!

 

[jackinnj]

Henry Hall is the named inventor of the Digibridge under U.S. patent 4,196,475 -- he must've written the manual for my GR 1658 -- a tool which is in use every day.

I collect Hallicrafters and Krohn-Hite.

 

[Conrad Hoffman]

Hey, it works! Vista has been a pleasure- no problems at all with the low level drivers or anything else. I've written a nice little interface program for my HP audio analyzer that works a treat. Let me emphasize that I *don't* think gross response and THD are the end all word in audio design, but this setup makes it pretty painless to get the numbers. Thanks for the hint on the little Prologix converter. Screen shot attached.