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Member
Baran
Posts: 90
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DAQ Analog input and digital input

I want to acquire data using NI DAQ (USB 6009) and I have a pulse (the magnitude doesn't matter) and a sinusoidal signal which I want to do some analysis on the two signals (calculating the phase shift between the two,...)

 

So I put 2 DAQ assistants one for analog and one for digital input with N sampling, and it gives me error. If I change the digital one to "by demand" then I wont have the error, but I cannot do the analysis since I don't have the digital signal based on time.

 

Does anybody know what can I do to avoid the error, if there is any other way to do so?

 

(If I use analog input for the pulse signal everything works perfect, but I need the other analog input pins for other purposes) 

 

Thanks in advance.

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johnsold
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Re: DAQ Analog input and digital input

The only timed inputs on a USB-6009 are the analog inputs.  If you do not have enough analog channels for all the signals you want to measure, you will need a DAQ device with more capability.

 

Lynn

Member
Baran
Posts: 90
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Re: DAQ Analog input and digital input

Thanks. Where can I find such information? cuz I believe it doesn't say on the datasheet that the digital inputs are not timed.

 

Baran.

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Jeff·Þ·Bohrer
Posts: 8,285

Re: DAQ Analog input and digital input


Baran wrote:

Thanks. Where can I find such information? cuz I believe it doesn't say on the datasheet that the digital inputs are not timed.

 

Baran.


The 6009 spec clearly states the DIO supports software timing.  What is not clear is this means you can't hardware trigger the DIO.  the USB-625x seires will get you there. 

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Member
Baran
Posts: 90
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Re: DAQ Analog input and digital input

So if it has software timing, is it possible to synchronize it with the analog input? I mean the analog input has hardware timing, and if I can trigger the digital input and be able to synchronize it with analog one, then I should be able to compare the two signals.

 

Thanks.

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Jeff·Þ·Bohrer
Posts: 8,285

Re: DAQ Analog input and digital input


Baran wrote:

So if it has software timing, is it possible to synchronize it with the analog input? I mean the analog input has hardware timing, and if I can trigger the digital input and be able to synchronize it with analog one, then I should be able to compare the two signals.

 

Thanks.


NOPE, software timing means the channel takes a sample(s) on demand or when the program intiates a measurement- Now, if you ALSO wire your DI signal to PFI0, you can trigger your analog in task from the same source but, there is no timing relationship between the DI task and the Analog Task. outputs. 

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