Specify different ADC timing modes for different TC modules in the same task

[Blokk]

Hello,

I guess based on the help, this is the way to specify different ADC timing modes for channels of a NI912 and a NI9213, inside a single DAQmx task? So I have to explicitly list the ActiveChannels for both property nodes:

My goal is to reach at least 1 Hz sampling for these 24 TC channels. If I use a single property node on the whole DAQmx task, and set all channels to "High speed" mode, I get what I want, but I think I could use the NI9212 module still in high resolution mode...I will give it a try, I did not test this code yet on my rig...

If I let everything default, the sampling is around ~1/2 Hz in total. By the way, is there any more detailed guide for the timing modes? I have only found this short doc: http://zone.ni.com/reference/en-XX/help/370469AH-01/daqmxprop/attr29f9/

[Chr15 · Accepted solution]

Hi,

I simulated your snipped and it worked for me. I created the NI-9212 and the NI-9213 virtual in NI MAX but I don’t think it makes any difference to the real HW.

I didn't find any further documentation to the timing modes either but I think its detailed enough. Do you have specific details in mind you want to know?

[Blokk]

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@Chr15 wrote:

Hi,

I simulated your snipped and it worked for me. I created the NI-9212 and the NI-9213 virtual in NI MAX but I don’t think it makes any difference to the real HW.

I didn't find any further documentation to the timing modes either but I think its detailed enough. Do you have specific details in mind you want to know?

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Yes, it worked. I decided just to use the high resolution setting for both modules, since it gives better signal. Also, I do not really look for temperature changes faster than 1-2 sec. With this setting, I acquire the 8+16 channels in ~1.5-2 seconds.

About the documentation: I do not think it is detailed enough, since the different modes are not compared to each others properly in any of the docs. At least I did not find such documentation. For example, how are the 50 and the 60 Hz "best rejection" modes compared to the high res and high speed modes, in terms of speed, accuracy, etc...? What is the difference between the 50/60 Hz rejection modes and the High res mode in terms of accuracy, noise, etc?

[Chr15 · Accepted solution]

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About the documentation: I do not think it is detailed enough, since the different modes are not compared to each others properly in any of the docs. At least I did not find such documentation. For example, how are the 50 and the 60 Hz "best rejection" modes compared to the high res and high speed modes, in terms of speed, accuracy, etc...? What is the difference between the 50/60 Hz rejection modes and the High res mode in terms of accuracy, noise, etc? 

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NI 9212 datasheet

NI 9213 datasheet

I found some documentation on the NI website about your modules. I hope this will help. The snippet is from the NI-9212.

On the datasheets on page 6 you will find sample rates and confersion times. if you scroll a bit down there are comprehansions about the noise input in defferent modes.