cDAQ-9189 output voltage

[svazquez22]

This might be a redundant question addressed in the hardware's specifications, but I was wondering if the cDAQ-9189 is capable of outputting a TTL signal with any of the following modules: NI 9775 and NI 9401. I am simply trying to send out a TTL signal from the chassis to be read by another piece of hardware. Is this possible? Any help would be appreciated. Thank you.

[GerdW]

Hi svaz,

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@svazquez22 wrote:

This might be a redundant question addressed in the hardware's specifications, but I was wondering if the cDAQ-9189 is capable of outputting a TTL signal with any of the following modules: NI 9775 and NI 9401. I am simply trying to send out a TTL signal from the chassis to be read by another piece of hardware. Is this possible? Any help would be appreciated. Thank you.

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The NI9401 is a digital IO module with TTL compatible IOs…

[ZYOng]

NI-9775 -> No, it is an analog input digitizer.

NI-9401 -> Yes, it supports outputting 5V TTL.

[svazquez22]

How can I go about getting the 9401's TTL output function to work?

[ZYOng]

Use DAQmx Digital Output task. See shipping examples at Help >> Find Examples >> Hardware Input and Output >> DAQmx >> Digital Output.

[svazquez22]

I want to know if what I am trying to do is possible. I have an cDAQ-9189 chassis with 3 modules, 2 NI 9775 and one NI9401. I am trying to output a finite digital signal from the NI 9401 and convert it to an analog signal to be read by one of my NI 9775 modules. I am having a really hard time understanding just how the digital output works and I would greatly appreciate anyone's help on this. Thank you all.

[svazquez22]

I understand that, but I am sill unsure of how exactly to get it to work, the examples available do not really make it clear for me.

[GerdW]

Hi svazquez,

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@svazquez22 wrote:

 I am having a really hard time understanding just how the digital output works

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Generalized it's just a transistor switched on and off!

You output TRUE or FALSE and get the corresponding output voltage as described in the specs of the DIO module...

What background do you have in basic electronic circuits?

[svazquez22]

Here is what I have so far, I get an error that says:

Error -200294 occurred at DAQmx Start Task.vi:7220001

Possible reason(s):

Not enough samples were written to satisfy the initial data transfer request condition.
To successfully start a generation, increase the number of samples initially written to the buffer before starting. Alternatively, decrease the number of samples required to start by changing the data transfer request condition.

End of Data Sample Number: 0
Minimum Value: 0

Task Name: _unnamedTask<0>

[Kyle97330]

Well your input to "DAQmx write" is a zero-length array so you're giving it zero samples.  What happens when you put some numbers in the array?

Did you just want to turn it on or did you want to turn it off and on repeatedly?