USB Device Not Recognized -5244D - USB3

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BSI
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USB Device Not Recognized -5244D - USB3

Post by BSI »

Hi,
Are there some issues with some of the USB 3.0 cables shipping with 5244D scopes please ? I am seeing a few of these issues in the forum that are not unlike what I am facing.

I have a 5244D scope that is not being recognized (see image).
The computer runs Win7 Pro , SDK 32_10.6.13.97 . The computer's USB is Intel(R) USB 3.0 eXtensible Host Controller.

Another behavior during testing was that the driver seems to load and the device being recognized, then 1 sec later it would drop and says it is not recognized, then again recognized... This is the original computer, and original cable. It looks like there is something electrically faulty.

If I connect the same scope, with the same cable to 2 other computers with the same SDK, it is fine. If I twist this USB cable near each of the end connectors, still fine.

The original computer detects a 5244A fine (different cable).

Once I use a different USB cable the scope is now recognized on the original computer.

So it looks like the one cable is faulty, despite it working with 2 others computers...
Any insights :shock: as to why a cable can be ok on some machine and not all? Thx

L.
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Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by Gerry »

Hi BSI,

These sort of issues can be associated with powering the device over USB. So, let's first of all establish what we know (correct me if I'm wrong):
The issue has a marginal aspect, because you can get temporary connections to Windows (via the Driver).
The Blue Pico cable works for the PS5244D on 2 other computers without any issues, and the mechanical connections appear fine (as you twisted the ends).
Using a non Pico cable you can get a connection long enough for PicoScope 6 to work, on the original computer.

This doesn't necessarily suggest that the Pico cable is faulty, because it works on the other 2 computers. What it does suggest is that your original computer is not capable of supplying enough current through the Pico cable for your PicoScope.
The 5000 series PicoScopes can push the limits of the USB 3 spec on powering, so they need to run from a computer that has not been designed with marginal USB 3 ports (to save on costs). Good quality, reliable computers are able to easily supply the requirement for USB 3 (which would seem to be the case for the other 2 computers you tried).

The fact that a non Pico cable worked on your original computer is probably because it has a slightly lower resistance (doesn't necessarily mean that it is better, i.e. the Pico USB 3 cable meets the USB 3 specification for its ability to supply sufficient current) and so the non Pico cable would then able to supply slightly more current.

So, could you tell me the following:
Was the USB cable that worked on your original computer shorter than the Pico USB cable?
Is the original computer a Laptop, and what make/model is it?
Have you tried the Pico cable on all of the USB ports of the original computer?
Did you have anything attached to a USB port when attempting to connect the PicoScope (and if so, could you try without anything attached)?

Regards,

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by BSI »

Hi Gerry,
thx for your detailed answer. Comment and responses below:

These sort of issues can be associated with powering the device over USB
that is my suspicion as well.

The issue has a marginal aspect, because you can get temporary connections to Windows (via the Driver).
yes, most time though the driver does not load and the scope is not recognized, but it has had this intermittent recognition/fail cycle (1-2 sec).

The Blue Pico cable works for the PS5244D on 2 other computers without any issues, and the mechanical connections appear fine (as you twisted the ends).
yes

Using a non Pico cable you can get a connection long enough for PicoScope 6 to work, on the original computer.
There is only the SDK,on this touchscreen computer, but yes I could acquire signals for a few seconds without issue. I did not run for minutes.

The 5000 series PicoScopes can push the limits of the USB 3 spec on powering, so they need to run from a computer that has not been designed with marginal USB 3 ports (to save on costs).
Do you have some figures on current draw on this? that depends on the sampling rate I realize... but are 2 channels acquiring going to create a problem?

So, could you tell me the following:
Was the USB cable that worked on your original computer shorter than the Pico USB cable?

shorter, half the length or so

Is the original computer a Laptop, and what make/model is it?
no, it is an industrial computer: USB 3.0, as per specs, no details other than it is a Celeron J1900 Sytem-on-Chip. I need to find out from the manufacturer...

Have you tried the Pico cable on all of the USB ports of the original computer?
yes, same behavior. USB pins inside connector and plug look ok.

Did you have anything attached to a USB port when attempting to connect the PicoScope (and if so, could you try without anything attached)?
no.

L.

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by Gerry »

Hi BSI,

I forgot to ask if you could point out where you saw these issues elsewhere on the Forum, so that we can look at a collective solution to this.

Also, the fact that the "working" cable is shorter, seems to suggest that the issue is the USB current capability. Depending upon what you're doing with the key functions, their settings and the waveforms being captured, the current drawn can push 900mA, even with 2 channels.

Regards,

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by BSI »

Last edited by BSI on Sat Mar 20, 2021 12:48 am, edited 1 time in total.

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Re: USB Device Not Recognized -5244D - USB3

Post by BSI »

Gerry,
The USB 3.0 controller on the computer that had trouble with the long cable is a VIA Labs VL812.
https://via-labs.com/product_show.php?id=41

USB 3.0 Rev.1 compliant, so the max 900mA as per standard. I can't see anything in the specs about whether it can produce a little bit more for short period of time...

But would the digitizer require close to 900mA - and supposedly max out the USB controller - just at plug-in?? That sounds surprising.
L.

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by Gerry »

Hi BSI,

Thanks,

Your references to similar issues experienced by other Forum members show that they aren't 5000 series PicoScope related, and we do have similar USB issues with other series of PicoScopes from time to time (there a number of factors involved in the start-up process).

However, I didn't check what software you were running, which opens up other possibilities. So:
What OS are you running the app on and what version do you have installed (is it fully up-to-date)?
Are you running the same app successfully on the other 2 computers, with the same version of OS?

I agree that it would seem to be unlikely that you would be pushing the current limits on start-up (but we can't be absolutely sure that it doesn't have a factor in this, without looking into the intimate details of the hardware/firmware/driver start-up process), but let's look at alternatives and rule it out for now. So, there is another potential factor that is plausible in this situation, and that could be a timing issue (which could explain the cable difference).

Also, if the app is running OK on the other computers, and all of the software on your original computer is correct and up-to-date (and the same for the other computers) then we have to question the original computer hardware/firmware/driver and/or the VL812 USB controller, and a quick search on the internet does reveal some issues with the USB controller (I couldn't search for the computer). Unfortunately, this is not really our area of expertise, so in this case I would encourage you to search for any similar issues that may be relevant with the computer and controller, and then look into these with either with the manufacturer or supplier of the Computer, or Via Labs.

Regards,

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by BSI »

Hi Gerry,

So: The industrial computer runs Win7 Pro , and I use pico SDK 32_10.6.13.97 . The computer's USB is Intel(R) USB 3.0 eXtensible Host Controller which should have the updated driver.

The problem occurs before the application runs. When the scope is recognized then the app does not create problems. It was on Win 7 Pro, Win 7 Home (one of the tests) and WES7, Win10 in this instance. In the past an older version of the app ran on XP, Win7. No issues at this level, and it was with USB2. I ran 4227, 5244A with 2 port power fine.

I agree with you , timing or current, and has to do with either the driver assignment (software issue?) or with the USB controller (that would be where my bet is). But I wonder if there is a chance the initial handshake between the digitizer and USB controller could be the cause (I know nothing about how USB devices work at the low level like here)

I can try an experiment : I have an identical industrial computer, and an image of the OS that is present on the original computer I described the issue. If I can successfully run this I can test cable and digitizer again. Monday, I expect to have another 5244D on hand as well.

Can you share the link about the issues you mentioned with regards to the VL812 please ? thx

L.

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by Gerry »

H iBSI,

Here's the search results: https://www.google.com/search?q=VL812+u ... e&ie=UTF-8

I didn't follow these up because I'm not able to do anything with the information, and I didn't go into detail regarding their relevance, just wanted to see if others were experiencing problems with the controller, using a quick search. So, for a more relevant search, adding "Windows 10" to the search gives this result:

https://www.google.com/search?q=VL812+u ... CA0&uact=5

Regards,

Gerry
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Re: USB Device Not Recognized -5244D - USB3

Post by BSI »

Hi Gerry:

a new 5244D was received:
With either cable (presumably "bad one" long pico cable; "good one": good quality 3ft USB 3 cable : no issue recognizing scope.

Same test as above with previous 5244D... no issue this time. :roll:

I will test with other industrial computer as soon as I can.

L.

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