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USB server / USB device server & 32-bit or 64-bit?

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USB server / USB device server & 32-bit or 64-bit?

Postby dougxr » Thu Jan 18, 2018 1:01 pm

Hi,
I'm relatively new to using Pico products but have used a different USB 'scope in the past. Now I'm doing some work with a 3424 'scope and have run into an issue. It might be an issue of my own making but if anyone has any ideas they'd be appreciated.
I'm working on a project where the PicoScope will be in a fairly hazardous position so we'd like to operate it remotely. We will have access to a wired LAN type connection between the test area and the control area. One way we could do this would be to leave a laptop with the PicoScope and use Remote Desktop (or similar software) from another computer to operate the first laptop to drive the PicoScope.
Another option is to use a USB device server (sometimes called USB over LAN extender, or various other names). I bought one of these (a Rextron NCNU-H04) and tried it; it behaved a bit strangely but worked fine. However when I tried it on the laptops that we'll actually be using, it didn't work. The PicoScope comes up as USB Device 0CE9, which appears to be a reference to Pico Technology being the manufacturer. I can connect to it but when I start PicoScope 6 the computer crashes, blue screen.
The only difference I can find between the machines that work and those that don't is that the ones that work are 32-bit, all the 64-bit machines crash*. * - I did once get a 64-bit machine working, but don't know how; in that case it listed it as PicoScope 3000 from the very start, I could connect to it, run PicoScope 6, etc. without problems but when I tried moving machines (and back again) it failed again.
A 32-bit machine generally behaves oddly, listing the PicoScope as USB Device 0CE9. But when I start the software it disconnects from USB Device 0CE9 and then lists PicoScope 3000 as available. I connect to that and it works fine.
Is there a difference between the 32-bit and 64-bit drivers that could be causing this?
I've left out lots of details, because otherwise this would be a really long post! But if anyone has any questions I'll do my best to answer them and any suggestions would be appreciated.
Thanks for reading this,
dougxr
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Re: USB server / USB device server & 32-bit or 64-bit?

Postby dougxr » Thu Jan 18, 2018 5:45 pm

I've discovered that the problem appears to be related to the PicoScope 3424 hardware appearing to disconnect and then re-connect to the USB port of the computer / device server when the PicoScope 6 software is started. At this point the 64-bit machines crash but the 32-bit machines treat this as one device being removed and another becoming available (not connecting automatically though).
I think I read somewhere that PicoScope 6 does this in order to read the firmware from the PicoScope hardware? Is there any way of preventing this?
I have a very bad work around that I may not be able to use. This involves connecting (over network and device server) with a 32-bit machine, starting and stopping the PicoScope 6 software, then disconnecting the 32-bit machine and connecting the 64-bit machine that I want to use. If I do this without cycling the power of the device server or disconnecting the PicoScope 3424 hardware from the device server, then it seems to keep the port associated with a PicoScope 3000 device, rather than going back to Device 0CE9.
I don't think I can actually use this work-around, due to the nature of the project we may need to cycle power, which would mess this up.
Any suggestions?
dougxr
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Re: USB server / USB device server & 32-bit or 64-bit?

Postby dougxr » Thu Jan 18, 2018 6:29 pm

Hi, I tried posting a bit more information earlier but appear to have failed at that. But if it re-appears then please forgive me if I repeat myself.
Some of the problem appears to come form the way the PicoScope system disconnects the hardware from the USB (as far as the USB host is concerned) for a brief moment when the software starts for the first time after the hardware is connected. I think I read somewhere this is so that the firmware or settings can be read by the PC software?
I have found a sort of work-around to my issue. I don't think I'll be able to use it in our application but if I explain it then maybe someone will realise what is going on.
- Connect PicoScope 'scope to USB device server
- Using 32-bit PC connect to USB device server
- Using 32-bit PC connect to USB device 0CE9 on device server
- On 32-bit PC start PicoScope 6 software
- this causes the USB device 0CE9 to disappear
- PicoScope 3000 appears in list of devices on device server
- On 32-bit PC close PicoScope 6 software
DO NOT disconnect PicoScope 'scope from USB device or power down USB device server
- Using 64-bit PC connect to USB device server
- this now lists PicoScope 3000 as available
- 64-bit PC can now connect to PicoScope 3000 via USB device server and PicoScope software can be started, runs fine, etc..
I don't think I can use this because we will probably have to cycle power at times that we won't be able to access the necessary bits.

Does anyone know a way to stop or bypass the connect / disconnect behaviour?

Or if anyone knows how to stop the 64-bit PCs crashing when the 0CE9 device disappears then that would be a better solution. maybe.
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