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sample at 2 two different rates on 2 devices

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Hi everyone,

 

I would like to synchronize the acquisition of the 2 following cards :

-4204 at 1kHz

-4353 at 70Hz

 

I have browsed through many examples (Multi-Device Synch-Analog Input-Finite Acq-Multi Rate-Trig Skew Correction) and discussions (http://forums.ni.com/t5/Multifunction-DAQ/pxi-multi-device-Synchronization/m-p/511540) but I can't get the cards to work together.

 

I have the 2 following errors :

-200452 when setting the reference clock source in common. I only have the 20Mz Timebase which is common.

-If I delete the reference clock (and trig skew correction), and only set the ai/start trigger, I have a delay of 20ms between the 2 devices.

 

Which clock do I have to share ?

 

Please Help! It's really getting painful

Christophe.A

 

 

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Re,

 

Please find attached the 2 codes I developed for that application (derived from the examples I found here).

 

No one of the clocks I have work or I have a big delay between the sampling.

 

Thanks for your answers!

Christophe

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Hi Christophe,

 

First, without setting the clock sources, you can try to use the 4353 (at 70Hz) as the master and 4204 (at 1kH) as the slave, this should reduce the delay since the slave have a higher rate.

 

Then it is better to set a common clock source for synchronization, error 200452 means the device doesn't support the property or the value for this property. Maybe the sample rate you need is not possible with the clock rate..  Could you post the entire error description ?

 

Regards,

 

Ludovic R.

 

 

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Hi,

 

Thanks for your suggestion, i'll try to set the 4353 as the master.

 

For the reference clock source, I have the following error : "-200452, Specified property is not supported by the device or is not applicable to the task".

I fisrt used PXI_Clock10 then PXIe_Clk100 which are available at the 4353 but not at the 4204. None of them work.

 

Thank you for your time,

Christophe.A

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