isloators and status 286

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eric14
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isloators and status 286

Post by eric14 » Thu Mar 28, 2019 3:41 am

I've been using your 5244D scope with VB.net code that has been functioning fine. I had used the Advantech 4630 isolator previously and obtained usb 3 download speed. I am now trying the ALLDAQ usb 3 isolator and have some puzzling behavior. I can run the picoscope software and it just gives me a power source warning. I select use USB power and it starts fine (although I can't tell if its running at USB3 speed). In my own code, I now receive a status of 286 when I open the unit and blockmode doesn't function. Can you provide an insight on what is happening here? This seems to be a status associated with non-USB3, but my isolator is USB 3 and my code previously worked with the 5244B USB 2 model.

eric14
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Re: isloators and status 286

Post by eric14 » Thu Mar 28, 2019 3:15 pm

I need to diagnose this more. I just unplugged/replugged everything, perhaps in a different order than I had before, and both the picoscope software and my code work fine, running full USB 3 speed with the Alldaq isolator.

Gerry
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Re: isloators and status 286

Post by Gerry » Mon Apr 01, 2019 10:01 am

Hi Eric,

You need to ensure that the AllDaq Isolator PSU is connected. I did a lot of testing of that isolator, and it works well when powered. There is a small problem though when the device is connected to USB 2.00 devices when not powered as the connection can be dropped (I'm assuming due to insufficient power). Ordinarily, this wouldn't necessarily be too much of a problem because you can just reconnect (and AllDaq state in the accompanying data that the power supply should be connected so most people will use a PSU), but when this happens the device is locked out for a while which can be awkward because you don't know how long for (it was long enough for me to abandon testing and come back to it an hour later).

Regards,

Gerry
Gerry
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eric14
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Re: isloators and status 286

Post by eric14 » Wed Apr 03, 2019 2:11 am

Hi Gerry,
I am using external power, always do on isolators. I've found the problem to be my test machine. I have used 2 other test machines and everything works fine with the AllDaq including after the computer has gone to sleep, powered down, or restarted.

On my original test machine, I found I could generate the same behavior without the USB isolator, so this is USB/driver related, not isolator related. What I can repeat now is that after 'fresh starting' the test machine (this basically wipes it), and installing the picoscope software, I can plug the picoscope in (with or without isolator) and the picoscope software starts no problem. My custom software also works. After restarting the computer, instead of starting correctly, I get the 'use USB power or close' prompt from the picoscope (with or without isolator). This is also the same condition that gives the 286 status in my own code. I note that if I select 'use USB power' on the picoscope software, the software runs fine. That said, I don't know how to check if it is operating at USB3 transfer speed through the picoscope software.

If I uninstall the picoscope software, restart, then reinstall the picoscope software, the picoscope works (with or without isolator) again until I power cycle the computer.

This intermittent behavior made me think there was an isolator issue. I no longer believe this to be the case and have had excellent behavior with the AllDaq on 2 other machines. If there are any thoughts on the issue above I would appreciate them.

Gerry
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Re: isloators and status 286

Post by Gerry » Fri Apr 05, 2019 11:47 am

Hi Eric,

A way around this can be to perform a similar switch in your SDK code to what PicoScope 6 is doing, which you can do by looking using the status code returned from openDevice() (286), and switching it to being powered from the USB 3.0 port (see page 24 of the PicoScope 5000 series (A API) programmers guide here:https: //www.picotech.com/download/manuals/picos ... -guide.pdf). If this is working in PicoScope 6 then it should work in the SDK.

However, if the powering issue also appeared even when switching the software to running on USB power only then another solution would be to use a multiport USB 3.0 hub in between the AllDaq and the PicoScope, as it will have enough power to supply multiple USB 3.0 devices but will only be powering one.

If the PicoScope is connected via a correctly working USB cable then it should be using USB 3.00 for connection (it will enumerate to find what is connected using USB 2.0, then drop the connection and reconnect with USB 3.0 if it has found one USB 3.0 device, or if the user has chosen a USB 3.0 device). You can't really test the speed using transfers because the time taken to establish a USB connection overshadows the actual transfer time (I tested this by performing 200MS transfers on a 200ms Timebase at 1GS/s using a repeat Trigger and measurement with statistics showing the number of captures and then timed how long it took for 100 captures using a USB 3.0 cable connector, and a USB 2.0 cable connector, making sure to restart PicoScope 6 each time, and there was no noticeable difference). The only test that I can think of is to utilize as many resources in the software that you can while zooming in and out, as the zooming should be noticeably faster for USB 3.0

Regards,

Gerry
Gerry
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eric14
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Re: isloators and status 286

Post by eric14 » Tue Apr 09, 2019 1:56 am

Hi Gerry,
I believe this issue is related to my test machine/configuration, I have ordered a USB 3 card to further isolate the issue. I will update when I've tried it out.

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Re: isloators and status 286

Post by eric14 » Thu Apr 11, 2019 12:34 pm

Hi Gerry,
Installing a USB 3 PCIE card resolved this problem. I think there is nothing more to do here and whatever was going on had something to do with odd behavior of the onboard USB 3 controller in the PC.

I did not reinstall any software, just installed the USB card and plugged in and there are no longer any warnings from the picoscope software. Thanks for your help.

Gerry
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Re: isloators and status 286

Post by Gerry » Fri Apr 12, 2019 11:14 am

Hi Eric,

Thanks for giving us an update.

The start up procedure of our devices involves 2 stages of connection via USB which can sometimes cause issues with USB devices mediating between the PicoScope and USB port, and also USB ports if they don't correctly implement the switching.

Regards,

Gerry
Gerry
Technical Specialist

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