digital signal on an analog input

[BOGIE01]

Is there any way to pass a digital signal to the output of the DAQ without changing the signal in any way?The card is a 4431 and does not have digital input capability so I would have to use the analog input.

[K C]

Just measure the voltage of the digital line. If it is a 5V digital signal, everything above 2V is a '1' and below 0.8V is a '0'. Between 0.8 and 2V is undefined

[BOGIE01]

I was thinking along the same line but then somebody told me that is not possible.I will try it anyway.Thanks 

[NIthan]

Hey BOGIE01,

When you say "pass a digital signal to the output of the DAQ" do you mean you would like to pass a digital signal (0V-5V) to the analog output of the your 4431 card? If so, you may be able to do this by outputting an equivalent analog square wave on the output line, but be aware that the output limit of the card is ±3.5V. Assuming you want a full swing of 0 to 5 volts, you may need to create a square wave from -1.5V to 3.5V and then offset the ground (or negative terminal) of your input by 1.5V.  For more info on your card's capabilities refer to the specifications: http://www.ni.com/pdf/manuals/372485e.pdf.

If you want to convert an analog input into a digital signal, you can use the 'Analog to Digital.vi' which will convert your analog signal to a digital signal in software. Note that you can set the resolution to 1-bit if you just want to convert an analog square wave to a single digital signal.

-Nathan H