how to get the samples of the ni-9263 and ni-9201 in the same time?

[Yun_Zhu]

I got the data from ni-9263 and ni-9201 in my vi.I found them started to acquire data in diffrent time.How can I control them start to acquire in the same time.

[Dennis_Knutson]

You are only acquiring a single channel with the 9201. You can add the output of the 9263.

[Yun_Zhu]

Really?Do you see the same vi?I think I acquire the data in 9263 as well.Maybe I misunderstand your meaning.

[Dennis_Knutson]

Do you really think you are aquiring with a DAQmx write with that board? Do you know what an aquisition is? The 9263 does not even have to be there in order to display the signal in the graph.

[Yun_Zhu]

I didn't express my idea clearly.9263 is a board for output.9201 is the board for aquisition.Now,I want to see the response of 9201 when 9263 changed,I display them in the same wavegraph and write them to  files.But,I discovered that I couldn't compare them because they are not synchronization want them start at the same time(acquisition of 9201 and output of 9263)Do you understand what I mean this time?

By the way,Is it the same way if I want to acquire the data in 3 channel with 9201?

[Yun_Zhu]

I didn't express my idea clearly.9263 is a board for output.9201 is the board for aquisition.Now,I want to see the response of 9201 when 9263 changed,I display them in the same wavegraph and write them to  files.But,I discovered that I couldn't compare them because they are not synchronization want them start at the same time(acquisition of 9201 and output of 9263)Do you understand what I mean this time?

[Yun_Zhu]

By the way,Is it the same way if I want to acquire the data in 3 channel with 9201?

[Dennis_Knutson]

Then I think you should look at the example called Multi-Function-Synch AI-AO.

[Yun_Zhu]

I try to use the trigger like the example.But,I still get the different time record in two files.Could you tell me what's wrong with my vi?

Thanks

[MichaelAE]

Hi Yun_Zhu,

The AI channel is handling the triggering, so you want to start the AO channel before so that it’s ready for the AO trigger.

You’ve got the sharing clock and sharing trigger. What you need to do is make sure that your trigger doesn’t start on your AI channel before your AO channel is ready to accept that trigger.

If you look at the example that Dennis mentions, you can see the error clusters being merged together before the start of the AI channel. This merging is on purpose to control the data flow and force the AO channel to be ready to catch the start trigger before the AI channel can trigger the start trigger.

Regards,

Michael M

NI Americas | AE

NI.com/support | 1866-275-6964

[Dennis_Knutson]

Your expectations are wrong. You are generating a waveform in software that has some start time and x number of samples and then at some random time later, you are acquiring a signal with it's own timestamp and a different number of samples. The triggering in the example will assure that the generation will occur at the same time as the acquisition. Your code only does one read. In any case, the synchronization has nothing at all to do with your time records. If synching the output with the input is your true goal, run the example and see if that is happening. If it is, either ignore the start timestamps, modify one to match the other, or actually acquire the output signal instead of just reading it from the array you create.

[Yun_Zhu]

Thank you Dennis and Michael,

I changed my vi.The results are:the started time of them are exactly same and the wavegraph seems like synchronization.But,why the data recorded in file are not nearly same?

You told me"In any case, the synchronization has nothing at all to do with your time records".You mean the data in record were not the data when trigger took place?