sync among four devices and DO problem.

[labmaster]

I have to use AI(two ch), AO(two ch), AWG, and DO(one line in port0).
DO is intended to use in trigger signal in AWG and the digital version of ch1 in AO.
DO include two digital steps to change the freqeuncy in AWG on the fly.

At least, AI, AO and DO should be synchronized in starting.

Although I reviewed typical examples,
I didn't understand fully its mechanism among multi-devices.

My questions are..
1) is it possible to make a pulse train (up to 2 kHz) in DO continously?
when I select port1 or port2, I received some errors, not supported operation.

2) AO and DO should be synchronized before starting AI.
Do I have to omit "the start trigger" DO part?

3) I used pre-defined waveforms as a timing in AO and DO.
But, Labview asked me what is the external sample clock.
How can I setup the external sample clock?

4) Maybe, AO, DO, and AWG should be started in synchronous prior to start AI.
How can I garantee this thing? can you find some error in sequence?

This is my first experience in timing program.
You can see some depicted waveforms in subVI.
Please explain and help me to complete this project.

labmaster.

Message Edited by labmaster on 05-20-2009 03:16 PM

[Burban]

labmaster,

Could you please post what hardware you are using in this application for each of the tasks?

Regards,

[F._Schubert]

Just some basics:

* with PXI, you sync the sampling clock of the channels via using the 10MHz PXI (select that one for all channels, I wouldn't use the DAQ-traditional way) clock from the backbone.

* You set the start trigger of all slave channels to the start trigger of the master channel and start the task of each slave channel (they don't recieve any trigger until the master channel start trigger is shot); now you say start to the master task, the trigger starts all the slave tasks in sync.

Can't help you more, have no Daqmx in here for some reason, don't know what 'AWG' is, and don't have your hardware.

Felix

[labmaster]

Oh, forgive my mistakes as a beginner in singal sync work.

I did misunderstand there should a general solution for my sync problems.

AWG is PXI-5421 for function generator in script mode.

DAQmx is PXIe-6125 and BNC-2110 for AI/AO/DO.

Thank you.

Labmaster.

[Burban]

labmaster,

Are you certain that you have a PCIe-6125?  I cannot find the product page for that particular card.  61xx would be a S Series card, but the nearest I can find is a PXIe-6124.

With that in mind, I will attempt to answer your questions based on the PXIe-6124.

1.  You can only use Port0 for correlated (clocked) DIO.  Ports 1 and 2 only support static DIO.

2.  There is no way to directly trigger DIO.  Instead, you should trigger your digital sample clock and thus indirectly trigger the DIO.

3.  Use a DAQmx Timing VI to configure a sample clock on a PFI line.

4.  All signals can be started on the same trigger, so it's possible to synchonously start AI, AO, DIO, and AWG.  Please note that AI and AO use the same sample clock, so it is not possible to trigger the sample clock of these two functions independently.

Regards,