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Cant get voltage reading from analog input channels in test pannel?

I have my DAQ software installed and i have a powersupply hooked up to analog channel 0 positive to pin 1 and negative to pin 3. I have a DAQ PAD 6015. Everytime i bring up the test pannel i see the value maxed! 10 volts. I dont have my power supply turned on and if i remove the positive wire from pin 1 the reading will drop back down to around .2 volts. Once i plug in that pin 1 my reading goes back up to 10 volts? My DAQ is communicating with my computer, but i am confused why without power my reading goes straight to 10 volts? Is there jumpers that i need to install? Is my configuration incorrect? What am i missing?
 
Thanks,
 
Christian Maestas
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Message 1 of 3
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Hi Christian,

I see that you are just getting started with using your DAQPad-6015 and needed a few pointers about why your measurements appear to go to near the maximum voltage when you connect your power supply.

Since the DAQPad-6015 is only connected to the computer through a USB port, the only input configurations for the device are Differential and NRSE.  If you take a look at the tutorial Field Wiring and Noise Considerations for Analog Signals you can see a really useful table showing how to properly connect your signals (see below).



Since you are measuring a power supply, that will be a grounded supply, so you will use the connection diagram in the bottom right-hand corner of the table.  That means that you actually need to connect your positive line to aiX (ai0 = Pin 1) and the negative line to ai sense (Pin 13).  Also keep in mind that when viewing the device via MAX or when using the device in your application you will need to properly define the device as being in NRSE mode.

If you wanted to use differential mode, then you would connect the positive to aiX (ai0 = Pin 1) and the negative to aiX+8 (ai8 = Pin 2).

I hope this gets you pointed in the right direction, let us know if you need any more help.

Regards,
Message 2 of 3
(2,701 Views)

Otis/Christian

Just a word of caution- not all power supplies have an output that is referenced to ground.

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"It’s the questions that drive us.”
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Message 3 of 3
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