[USB-205, digital sample rate]

Hi John,

Thanks for your prompt response! :-)

I take it then that the limit at 50 or 100 samples per sec is system dependent and a bit on the safe side from DAQami/TracerDAQ, so I might try upping it with custom software/script running on a dedicated & beefy computer?  Maybe this won't take me all the way to 10Ksamples/sec, less will also work for me - but 10Ksamples/sec really isn't that aggressive, it can even be achieved through an I2C GPIO expander (at least at 400kbits/s ;-).

I will update this post, e.g. with achievable performance numbers, if I ever get to it - but possibly I will just add a second USB-205 to my tool belt for the additional channels.

Again, thanks for your support, much appreciated.

Cheers, Martin

[USB-205, digital sample rate]

Hello MCCDAQ,

I just ordered and received a USB-205 device.  I intend to use it for validating a complex power sequence for an FPGA design, measuring approx 10 voltages at approx 10Ksamples/sec for approx 100ms - you could say that I want to use the USB-205 as a fairly slow oscilloscope with many, many channels...  Of course the USB-205 "only" has 8 analog inputs, but I intend to use a few of the digital inputs to get around this - some of the supply voltages I want to measure are 3.3V so are compatible with the digital inputs, and I am mainly interested in investigating timing, not specific voltage levels (I have other tests for that).  I intend to use whatever capture/logging software is available, possibly exporting data to e.g. Excel for presentation purposes if that makes sense eventually.

I do understand that the maximum analog sample rate of the USB-205 is 500Ksamples/sec, divided by the number of enabled analog inputs, so in my case 500K/8 inputs = 62.5Ksamples/sec - leaving reasonable headroom for my 10Ksamples/sec requirement (that could probably be relaxed if need be...).  But it seems that the digital sample rate is limited to 50-100 samples/sec - 50 samples/sec in DAQami, 100 samples/sec in TracerDAQ.  I had expected digital sample rate to be at least comparable to analog sample rate?!?

Is there a technical reason for the low digital sample rate - or in other words, might it be circumvented e.g. by accessing the USB-205 "bare-metal" through a script or custom software, instead of relying on the DAQami/TracerDAQ off-the-shelf software?

Cheers, Martin