GPIB cables, newbie questions about ATE - Page 1
Forum section: electronics / testgear

author: petieken
author_rank: Contributor
timestamp: September 25, 2014, 02:58:25 pm
content: Hello everyone,I bought an Agilent PCI-GPIB card recently because I want to fiddle around a bit with automated measurements. Please note I am a complete newbie in this territory.My first question, I need a GPIB cable to connect my equipment. I found some cheap cables on ebay with free shipping to my countryeBay auction: #221295759917. Does anyone have any experience with these no-name cables? Or should I stick to the brand name cables (HP, NI,...)?Second; to start out I just want to take some series of measurements and program my 3456A DVM. I chose the Agilent 82350B card because of the VISA support. I also have excel which has VBA so I figured I should learn Visual Basic to control the 3456A and log some numbers in an excel worksheet.Does anyone have a recommendation for a tutorial or a good book to learn VB/VBA, if possible oriented towards controlling test equipment?Thanks in advance

author: alex.forencich
author_rank: Frequent Contributor
timestamp: September 25, 2014, 06:20:37 pm
content: I have some no-name cable similar to those. They work just fine. They're actually nice and flexible, in contrast with the incredibly stiff HP cables. The connectors are plastic with metal plating, so they are not the most sturdy devices ever built, but they get the job done. GPIB is not a very high-performance bus.I personally would not recommend VBA for instrument control. It's very easy to write some sort of logging interface in some other programming language (e.g. Python, C, etc.) and dump a csv file that you can open in excel for analysis. But, whatever floats your boat.

author: KJDS
author_rank: Super Contributor
timestamp: September 25, 2014, 07:29:44 pm
content: I've run into problems when there have been a lot of instruments on a bus and cheap cables. I suspect that it's unlikely to be a problem for hobby use.

author: petieken
author_rank: Contributor
timestamp: September 25, 2014, 07:40:13 pm
content: I'm not dead set on VBA, I just thought about the combination because I have excel and it has VBA built in. I have no real programming experience, except for some GW-BASIC and Q-BASIC back in the DOS days.Maybe C will be the better language to learn, because it's also more useful for other stuff like microcontrollers. Now I only need a good tutorial or book.

author: MarkPalmer
author_rank: Regular Contributor
timestamp: September 25, 2014, 07:53:42 pm
content: I have 10 pieces of equipment and peripherals on my HPIB network using the off-name cables and haven't had any trouble with them. After a certain length of cable, (I forget the figure, might be 15 meters) you are supposed to use an HPIB extender.I just use good old HP Advanced Basic with my hobby-shop system, it's easy to imbed the mnemonic codes in to it and no Windows drivers to bother with, etc.-Mark-

author: alex.forencich
author_rank: Frequent Contributor
timestamp: September 25, 2014, 08:09:47 pm
content: Quote from: MarkPalmer on September 25, 2014, 07:53:42 pmWhat do you run the HP flavor of BASIC on? Did you get an old HP-UX system? Or will it run on something more modern?

author: MarkL
author_rank: Unknown
timestamp: September 25, 2014, 08:10:06 pm
content: The maximum total cable length is 2m * the number of devices, or 20m, whichever is less. And you can have any combination of linear or star.I like the old HP 10833 series cables because they're almost indestructible. It's true, they're stiff, but with a 3456 to weigh it down it's not going to be a problem.There's tons of them on ebay at the same price as new, no-name cables. Some even less. Make sure you see a picture of the connector ends, though, before you buy.

author: MarkPalmer
author_rank: Regular Contributor
timestamp: September 25, 2014, 08:27:35 pm
content: Quote from: alex.forencich on September 25, 2014, 08:09:47 pmAs vintage computers are another hobby of mine I run the network on a HP 85 computer with a 9121D 3.5” diskette drive.Antiquated, but 100% functional and on par with the 1980's vintage HP test equipment I use. I don’t want to get in to the expense of a Windows based system and all the software, drivers, upgrades, obsolescence, etc.-Mark-

author: alex.forencich
author_rank: Frequent Contributor
timestamp: September 25, 2014, 08:37:07 pm
content: Quote from: MarkPalmer on September 25, 2014, 08:27:35 pmNice! I don't want to deal with the drivers, incompatibilities, and obsolescence stuff either, so I control all of my stuff either via LAN directly or via VXI-11 to GPIB bridge boxes and pure Python. It gets the job done, and I can control all of my equipment over the wi-fi network.

author: KJDS
author_rank: Super Contributor
timestamp: September 25, 2014, 08:40:59 pm
content: Quote from: MarkPalmer on September 25, 2014, 08:27:35 pmThe last time I did any serious GPIB programming was on a HP-85. These days I get someone else to do it.

author: MarkPalmer
author_rank: Regular Contributor
timestamp: September 25, 2014, 08:55:54 pm
content: I have a lot of fun with it as I still remember BASIC programming from classes in high school in the mid 80's. I had the HP 85 sitting around and decided to get what I needed to make it to work with HPIB, which was a learning fiasco. It was a moment of glory when I got the first handshake with a piece of test equipment, I think it was my 3325A function generator at the time.-Mark-

author: macboy
author_rank: Super Contributor
timestamp: September 26, 2014, 01:39:52 pm
content: You can also make your own cables inexpensively using 24-conductor ribbon cable (IDC) and matching connectors. The magic connectors to buy are a 24-way "Amp Champ" or "Amphenol" or "Centronics" or "Miniature Ribbon". The following may help:http://www.adam-tech.com/catalog/2012/page_117-121.pdfhttp://www.te.com/catalog/menu/en/19336?BML=19337http://www.ebay.com/sch/i.html?_nkw=%28champ%2Ccentronics%2Cminiature+ribbon%29+24+connector&LH_PrefLoc=2If you make your own this way, you can put multiple drops along a single length of ribbon cable, reducing clutter behind your instruments. You can secure the connectors to the insturments with a M3.5 x 0.6 screw of appropriate length.p.s. If you are interested in doing some kind of GUI application (as opposed to a command line script) then you might also consider HTA, HTML Application. This is essentially an html page that runs on your computer with application-level permissions (web pages are severly restricted). Agilent has an ActiveX control ("3494A") that scripting languages in that HTA can access. It works reasonably well, and your development environment is just your favorite text editor (for better or for worse).

author: petieken
author_rank: Contributor
timestamp: September 26, 2014, 02:10:55 pm
content: Thanks for the replies!Because I have no real programming knowledge, I'm looking for something easy to program. My current goal is only to take a bunch of readings, activate some math functions and program the registers of my 3456A. Then put those values in an excel file and make some graphs.