difference in hardware and software timing

[Xiang00]

Hi, everyone.

I have some questions on hardware timing and software timing.

1. What is the difference between hardware timing and software timing?

2. What does the hardware mean? PC or DAQ such as usb 6211?

3. When I use "DAQmx timing", does this mean I use hardware timing?

Thanks for your help!

[SteveChandler]

Software timing is done using the OS timer which is not deterministic. You get jitter. Hardware timing is done using a dedicated timer. DAQmx I believe uses a dedicated timer. Unless you are on a real time OS you might still get jitter but I am unsure.

[Dennis_Knutson]

DAQmx uses whatever timer you specify - either hardware or software. Most DAQ cards have a clock that is used to time the acquisition. The time between samples is very precise and repeatable. That is hardware timing.

[Y.Minami · Accepted solution]

Hi Xiang00,

>>1. What is the difference between hardware timing and software timing?

Hardware timing is more acurate since it uses the onboard clock. Software timing is less accurate since it depends on the PC performance.

>>2. What does the hardware mean? PC or DAQ such as usb 6211?

"Hardware" means the DAQ device such as USB-6211.

>.3. When I use "DAQmx timing", does this mean I use hardware timing?

Yes. You may find more information at KnowledgeBase DAQmx Timing and Sample Rates.

Best regards,

Yusuke Minami

Applications Engineer, NI Japan