6025E & 6259M sync'd, Is 10kS/s all she's got?

[super-neuron]

Hi friends,

I have a 6025 E series sharing its master timebase w/ a 6259 M series for synchronization.   The 6025E produces a square wave to power an LED, while the 6259M produces uniform white noise to speaker.   The max sample rate for AO on the 6025E is 10k, and as the master pushes the slave 6259M at 10k also.   10k is perfectly adequate to power LEDs, but is extremely poor in the world of auditory signal generation.  I would very much prefer to run 40k on the 6259M if at all possible.   Right now I basically have a perfectly synchronized VI that runs at a very slow 10k.   Is there any way to do one of the following:

1. Export the E series master timebase and multiply up to the M series

2. Export the M series master timebase and divide down to the E series

3. Other suggestions... ???

I've attached my current working VI below for reference.

If anyone is wondering why I chose this construct, please see the tutorial M Series Synchronization with LabVIEW and NI-DAQmx, under the section titled 'Special case: E Series and M Series Synchronization.'

Thank you,

Zach

[S_Hong]

Hi super-neuron,

The different timebases on your boards are mainly used to derive the AI and AO sample clocks. These timebases can be derived from one of two sources: either the onboard oscillator or an external signal by using the external reference clock. If you decide to use an external reference clock, the derived timebase will be phase-locked through a PLL. So to have synchronized acquisition/generation between boards, you can export the master timebase of the E Series device and use it as the reference clock to your M Series. Your M series board will then use this reference clock to derive its sample clocks so that the sample clocks on both boards will be derived from a synchronized timebase. Please refer to chapter 9 of the M-Series manual for information on clock routing.

Now although the timebases are used to generate the sample clocks, they do not determine the maximum operating speeds as these are often set by hardware limitations. Therefore, although you may not be able to generate both outputs at 40 kS/s, you will be able to output the 6025E at 10 kS/s and the 6259 at 40 kS/s. To do this you can refer to the E Series and M Series Synchronization on our Developer Zone article as you pointed out. The example shows exactly what to do to to synchronize your E & M Series boards.

I noticed that in your example, you did not take into account the difference in sample clock delay between the E & M Series cards. Since with the E Series, the default delay is 2 ticks of the master timebase and with the M Series, this delay is set to 3 ticks, you will have to configure their delays to match in order to ensure proper synchronization. This is done through the use of property nodes as shown in the article. Once your devices have their timebases synchronized and delays adjusted, you will be able to simply set different sampling rates for each board and the output will remain synchronized.

I hope this helps,

[super-neuron]

Hello S_Hong,

Thank you for responding to my post.   I have two followup questions regarding your comments:

1. If I understand correctly, are you recommending I just keep the construct I currently have and set the 6025E sampling rate to 10k and the 6259M sampling rate to 40k?   How does this not impact the master time base?

2. You mention the sample clock delay between the E & M Series cards.   I thought that this only applied to AI ADC, and not the DAC AO.   Would you please expound on this delay and how I can substract it out?

I sincerely appreciate your help to me and the community!

Thank you,

Zach

[S_Hong · Accepted solution]

Hi super-neuron,

It is important to note that the different update rates on your two boards does not affect the master timebase since this is what is being used to derive your update clocks. Now although each board will have its own timebase from which the update clocks will be derived, by essentially exporting the timebase from your E-Series to your M-Series, you are using the E-Series' master timebase as your reference clock to derive your M-Series' timebase. This will allow you to have two different timebases on two different boards to be synchronized with each other. So to answer your first question, you need only to have two different controls to set your sampling rate on each board.

And you are absolutely right that there is no need to set the delay from the sampling clock as this is only applicable for acquisitions.

Please let me know if you still have any questions.