A piece of hardware to control Multiple ADC (like 9239) at the same time

[otehrani]

I need to computer 16 ADC lines simultaneously. 9239 is great except when I use 4 of them, each start with a random delay. Also after about minutes, they start drifting and the phase shift is very obvious.

My signals have to be isolated from each other and the USB port.  It would be ideal to have them connected through a second port or the DB9 which already exist so that they share the same synch signal and clock. Once one of them starts, it kick start the rest.

Thanks,

Omid

[Brad_K]

Hi Omid,

Are the modules in the same location? If so, the cDAQ-9174 will do exactly what you want. Creating a single DAQmx task that uses multiple modules in the same CompactDAQ chassis will automatically synchronize them.

Brad

[otehrani]

Hi Brad,

Thanks for your posting.  This is what I really need.  I have one more question.  The maximum sample rate of 9239 is 50K Samples/s.  Can all 4 channels sample 50K Samples/s at the same time? Or are they mutiplexed and the maximum rate is 50K/4=12500 Samples/s?

Thanks,

Omid

[Brad_K]

Hi Omid,

The NI 9239 can acquire from all four channels simultaneously at 50 kS/s. It has a separate ADC for each channel.

Brad