Products > Test Equipment

SainSmart DDS120 & DDS140 USB Oscilloscope

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mozart5474:
i have got the same problem as gambit 58 on my win7 64bit. device not be found error. any help how i might get it running? i have tryed it on a 32 bit machine and had no troubles but at this machine it is not going anywhere. tryed installing reinstalling over and underinstalling sideinstalling screaming and crying at it, begging snobbing and of course the good old delete it and make it anew from the root to the top but no luck. "Device not be found." anyone?

psynapse:
Mozart5474,

Sadly I am not a windows expert, far from it.  The generic answers are likely to be
1) the device does not work (though not in this case)
2) that it is not plugged in (although it might appear so.  Note in particular the high current needs of the device, machines differ in their USB current delivering capacity)
3) that the driver is not installed (does it appear correctly in what I continue to call "control panel")
4) access permissions, the device might function, be connected, have a driver installed but not be accessible to you as a user.

mmark:
Update:

timebase setting, y-scaling and switching between AC and DC coupling works for me now at least somewhat for my DDS120. I didn't do any real calibration yet (traveling right now and only have the DDS120 with me). And still no triggering, but at least it starts to get somewhat useful...

There seems to be a problem with sample sized > 2048 bytes. If I try to read more then 2048 bytes, then there is always a jump in time at sample 1024 (e.g. at 2048 bytes). You can see that if you set the sample size to large (which is 32768 for now...) and select a time base of 1ms or longer. I tried sending 0x33 cmd before reading the data with various delays, but the discontinuity stays there no matter what. The data after this point seems to be continuous again... I am wondering if the OEM software discards the first 2048 bytes for buffer sizes > 2048...

Also, my 5 year old mac book is somewhat struggling keeping up with redrawing the screen if the small buffer (2048) is selected. I added a 10 ms delay to the end of getSamples() to relief this a bit, but the GUI still get sluggish after a few seconds. Either switch to the large buffer or start/stop the sampling only for short times. And there is a display error in the lower right part of the DSO widget, but this goes away after toggling the zoom mode once (I have only seens that on my mac and not on linux) .

Anyhow, the updated code is attached.

here is a complied binary for ubuntu 14.04 (in fact it is compiled under xubuntu 14.04)
https://drive.google.com/file/d/0B4k4TyIzvHKANXdlSTQ4bDZaaHc/view?usp=sharing

and here a dmg for those with a mac:
https://drive.google.com/file/d/0B4k4TyIzvHKATW1rb1VpOXVpbzQ/view?usp=sharing

To compile und linux/ubuntu, you need to have libqt4-dev (or libqt5-dev) and fftw3-dev installed. To access the device as a user, add this to /etc/udev/rules.d/50-sainsmart.rules:

--- Code: ---#add SainSmart DDS120 and DDS140 to group plugdev
#DDS120
SUBSYSTEM=="usb", ATTR{idVendor}=="8102", ATTR{idProduct}=="8102", GROUP="plugdev"
#DDS140
SUBSYSTEM=="usb", ATTR{idVendor}=="8312", ATTR{idProduct}=="8312", GROUP="plugdev"

--- End code ---

and make sure that your user is member of the plugdev group.

jimon:
Hi guys,

When playing around with it, I connected signal, that is suppose to be square with freq around 4.8 mhz, to both channels.
Probe connection is made to exact same points (both signal and ground connections).

And I got what on screenshot.

First I thought that it's a probe compensation difference, but then I switched probes on oscilloscope side (so just swaped bnc's).
And guess what, I got same result - more sin-ish on second channel, and more square-ish on first channel.

What it could be ?

PS. siqnal source is an attiny13a that I playing with now, it runs this simple program http://pastebin.com/HH1sscZN and fuses are set to 7A FF

doctormord:
Well, at 50Msps, you'll get 10 datapoints per periods (at 5MHz signal). - that's what you see. Additional errors are from the non compensated AFE (analog frontend).

The shifting, timewhise, might be a result of the increased propagation delay on one channel due to the bigger pcb-loop.

To interpret correctly, the signal waveform, generated by the attiny, should be checked with a proper scope. (rise-/fall-times)

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