PXI-6733 ... simultaneous ouputs?

[josborne]

So I have heard of simultaneous sampling.  And I know how it works.  But what about simultaneous output? 

For example, does the NI PXI-6733 output its 8 analog lines at the same time?  Or does it serially ouput them one-after-another?

[amezam]

Hello Josborne,

The NI PXI-6733 has a multiplexed DAC (NI 6733 Specifications). If you want to use multiple AO channels you can create a task with multiple channels. They will then share a sample clock, but there will be a very small delay because of the interval that takes the clock to change from channel to channel.

Have a good day! 

[josborne]

Thanks amezam!  I kind of suspected that was how it worked.

Could you tell me:  Is there a specification that quanitifies this tiny delay between sample outputs?  Maybe that is what what people call "slew rate" ?

[amezam]

Hello Josborne,

The slew rate is the maximum rate of change of voltage. Actually what you are asking is more related with the convert clock (KB Difference Between the Sample Clock and the Convert Clock). The devices use a sample clock that signal when to acquire or generate. If you have 4 channels that need to acquire or generate a value when this signal is fired, the convert clock is the one that specifies the rate at which the channels are scanned. Check the KB How is the Convert Clock Rate Determined in NI-DAQmx and Traditional NI-DAQ? for more reference on how to calculate this delay and overwrite it, if necessary.

Have a good day!