Hey Y'all,
I figured I'd bug the community to get some additional input. I am also going to apologize in advance, because this is going to be a jumbled rambling with no code attached.
Background:
I'm a test engineer in a lab that mostly plays with network analyzers and switches. Occasionally we have our DAQ's, DMM's, MUX's, and other goodies but our bread and butter are those network analyzers. We speak mostly GPIB (VISA) to them.
I've also inherited quite a bit of legacy code. Some started development in LV6. Most of the executables that we have to modify are coming from LV2014 though. When a program crashes and requires the exe to be modified, we're upgrading them to LV2017 in the process.
In the past, the lab mostly used Agilent Technologies 82357B USB/GPIB Interface. We started noticing that when upgrading to LV2017 for the exe's, the network analyzers would no longer communicate with them. It was a squirrely timeout issue where in the end we just decided "white = bad, blue = good" and swapped to NI GPIB-USB-HS on all of our "critical stations."
Then for kicks and giggles, I got my managers to purchase me a new toy of the GPIB-ENET/1000 for the places where we had a really long separation between equipment and computer. I also have a few GPIB-ENET/100 that we plan on re-purposing for a few test stations as well.
Oh, I should also mention half of our computers are Windows 7, the other half are Windows 10.
tl;dr: Our lab is hodgepodge'd together with whatever I can scavenge in order to speak GPIB.
Current Frustration:
On a Windows 7 computer, I keep having my VISA instruments drop out unexpectedly. Ideally, I would like to have all eight of my GOM-804s and my single GOM-802 on a single GPIB bus.
(Sidenote: I'm using NI Max to sleuth my GPIB instruments. This is code independent, but it is verified by when I run my code and it tells me the instruments don't exist)
Here are the rules I've found: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P8slSAC
And I feel like I'm following them:
- I am under the requirement for 15 instruments (9 + 1 board < 15)
- I am under the requirement for total cable length ( 10 m cables < 20 m)
- I have tried multiple GPIB interfaces
- The Agilent crapped out on me with any more than four devices
- The NI GPIB-USB-HS seemed to work with 6 devices, but upping it to 9 caused all instruments to not work.
- The GPIB/ENET 1000 appeared most stable. But then during a power cycle, all instruments dropped out. They have yet to return.
My current solution is to just have the single GOM-802 running on what I've dubbed "evil PC" and I plan on bringing up an entirely different computer for my eight other GOM-804's.
Question for Y'all:
Have any of y'all ever run into these limitations?
What's the max number of GPIB instruments that you've been reliably able to keep on a single bus?
I seem to remember at my previous job I was able to link up 12 DMM's on a single bus with no issue. I don't know if this is an issue with "evil PC," my GOM's, or how I'm hooking them up.
