Does PXI-5114 have seamless data logging capabilities at 125MHz?

[farin012]

I'm working to get a diagnostic up and running and I need a DAQ that can record a voltage signal that repeats on a 1MHz rep rate. (I am using a photodiode to measure the pulse-to-pulse integrated number of photons/energy). Since we would like to record several seconds of time history, we cannot use our oscilloscope for this - since it does not have seamless data logging capabilities. Does anyone know if this product has the ability to record voltage over time for a few seconds seamlessly (ie. without triggering)?

[jdel12]

Hello farin012,

I think you could use immediate triggering with the oscilloscope for this acquisition.

Regards

[farin012]

Thanks jdel12,

I am looking into this now. Really we just need something cheap that would record signals. Maybe there are cheaper options too, if anyone has had good luck with other DAQs for a similar purpose I would be interested.

[jdel12]

Hi farin012,

You mean that you want the device to have the data stored on an onboard buffer or what exactly do you mean by 'recording the data'? Because I think you should also consider the length of the 'recordings', the sample rate and the resolution of the measurements to avoid overflowing buffers in the devices. DAQ usually has an onboard buffer that stores the acquired values until the software tells it to send a portion or everything it has to the PC's RAM. You could also set multiple point acquisition in the 5114 and other oscilloscopes.

Regards.

[farin012]

Hi jdel12,

That's a very good point, I wasn't even thinking about buffers. Is there no way to continuously store data? (like stream it from an oscilloscope directly to a computer to log values over time at a high rate ~ 20MS/s?)

I found that this device has a buffer size of ~ 128Mbits, and a high speed (20MS/s) resolution of ~ 11bit. so I guess that means that the buffer size at this sampling rate would be ~ 0.58 sec or so.

This would probably be fine, but it might be better to just continuously log without gaps for several seconds, at this very high sample rate ~20MS/s. Is this possible with any oscilloscopes?