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Input and output task synchronisation

Hello,

 

I need to generate finite digital and analog signals with the same rate and I want to measure analog inputs 10 times faster at the same time

Now it looks like that:

tests.png

 

Analog output clock is used to generate digital output at the same rate, I use analog output StartTriger to start Digital output and to start analog inputs.

is this synchronised correctly? What do I need to write in rate for digital output signal?

 

My another approach is to do finite acquisition:

tests2.png

 

Now I  am generating nalog output lets say at 10Hz, signal has 100 elements so it will take 10s to generate. In the same time I will acquire at 100Hz for 10s so I will get 1000 samples. I am thinking correctly? 

 

As far as I understand aoSample clock is created from 20MHz timebase. ant that is my 10Hz, so I can't acquire at faster rate using that clock? 

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Dear Pawel,

 

in DAQmx, there are fundamentally two ways of synchronizing tasks. One is to share a Sample Clock between each task, thereby ensurning that each sample is generated/read at the same time. This only works when the sample rae is the same for all tasks, so in your case DO and AO can be synced like this.

The other method is to share a Timebase and a Start Trigger between tasks. This allows for different speeds for each task, and thus is the suggested method for syncing AO and AI in your application.

The exact way of doing the synchronization depends on he device(s) you have. Let me know if you need any further help.

 

Regards:

Andrew Valko
National Instruments Hungary
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