What is the sampling rate error in my NI-6220?

[bogiasac]

Hi all,

I have a 5 year old PCI NI-6220 card (uncalibrated for 4 years).

I would like to know the approximate sampling rate error, if I am sampling two channels at 20kHz each.

From the cards Specification document I read it is 50ppm. Would I thus expect the sampling rate to be off my +/-1Hz?

Could you also provide me with some approximate 'agging per year' value for the sampling rate.

A slightly unrelated question is whether the DAQ card has an onboard quartz crystal or not? Typical 'agging per year' values for quarz crystals are +/-5ppm.

Thanks and regards

Alex

[John_P1]

Hi Alex,

The accuracy of the on-board clock is indeed 50 ppm.  Therefore it's true that if you're using the on-board oscillator to generate a 20 kHz clock signal it could be off by as much as ±1 Hz.  The 6220 is also capable of accepting external clock signals, so you do have the option to use a more accurate clock source if you have one available.

I don't have aging information for the on-board oscillator, but it does use a quartz crystal.  The datasheet for it can be found here (SM7745DSV80.0M)

Best Regards,