xyphro
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @05:11AM (#46383453)
Linux gpib also supports my adapter natively with a special linux gpib firmware you can download from the page above. It also supports multiple instruments connected to one adapter then.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @04:00AM (#46383160)
Works even well on Mac and Raspberry PI btw :-)
Actually world would need an open source visa stack. Right now you find many applications doing their own thing, but then not supporting vxi11, hislip or usbtmc. Visa is something which solved that problem for years already but the most standard package NI Visa is overloaded and scaring people away. For that reason I propagate the usefulness of R&S Visa a lot. Lean and mean, supporting all OS and procotocols as it is supposed to be.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:55AM (#46383128)
As I have a CMU200 myself I was majorly interested in getting it to work too :-)
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:53AM (#46383110)
I know that very well. Ethernet=security concern. Connecting your shiny new scope to company network=no way. Hard to discuss arround it in company environments or push for split network topologies.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:51AM (#46383099)
Yes, those cables are often called "garden hose cables". The only benefit of that bus infrastructure under a nowadays view is that it gives the ability to synchronously trigger multple instruments which is very rarely used or required.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:49AM (#46383091)
The step to go to ARM or risc v based controllers is easy. That's what I did with V3. Gives a tremendous performance boost and costs 1/2 of that old AVR.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:47AM (#46383081)
Yes, it is easier to fall into the trap of getting a clone, even if you think you buy an original one.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Thursday December 25, 2025 @03:46AM (#46383073)
A good way around application overloaded applocation stacks is R&S Visa which is lean and mean while still exposing full visa to applocations like labview. Or going with something like python usbtmc.
If you also have other instruments to control e.g. with usb or ethernet you'll likely anyway look into a visa.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Wednesday December 24, 2025 @05:18AM (#46374261)
For a situation where the instrument is directly connected to the adapter like here there is no difficulty in fast T1 timing on a MCU.
V3 will have btw. fully compliant GPIB electrical specs without 74 series buffers.
48mA drivers are not required for a direct connection scenario as V2 supports. VIH is a bit violated, though not practically meaningful. So far I heard of no device not working after over 6 years and those who did not in early stages I managed to get running with sw updates.
This is not a one shot plain textbook GPIB simple thing implementation, it's years of iterations, debug, improvement.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Wednesday December 24, 2025 @04:36AM (#46374056)
The upcoming V3 adapter reaches even more than 1 MByte/s with my fastest instruments. Unless you connect long GPIB cables to it, because capacitive load slows down GPIB as it self regulates speed down in the way GPIB is designed.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Wednesday December 24, 2025 @04:34AM (#46374035)
If you buy used equipment which doesn't have Ethernet or your company wants you to ise the stuff that is in the Lab since 10+ years there's simply no other choice. Or companies that see Ethernet as a potential security attack vector.
It's indeed not that GPIB is better than Ethernet. In tiny aspects that's argueable, but as general statement true.
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Wednesday December 24, 2025 @04:05AM (#46373866)
Here a comparison from a user:
https://github.com/xyphro/UsbGpib/discussions/47
Re:Open source USB to GPIB converter (for Test and Measurement instrum...
on Wednesday December 24, 2025 @04:03AM (#46373859)
You are correct. UsbTmc exposes no multi device capability. Also when I made first versions many years ago I had no "garden hose" GPIB cables and saw they were more expensive as the whole adapter.
V3 which will come early next year supports GPIB daisy chaining/multi device support via Ethernet VXI11 & HiSlip.
The V2 adapter shown here supports trigger, SRQ, serial poll, trigger, clear, local lockout, goto lockal, pulse indicator, all features though.
If you absolutely need common synchronous trigger to a chain of GPIB instruments which is quite seldomly absolutely required, you'll have it in next version V3.