05-31-2018 04:57 PM
I'd like to make the above connections to a PCI 6115 DAQ Card. I've had success powering it through a USB port on the PC, but something went wrong when I tried to use the +5V pin. I'm not sure what, but I lost one AI channel and had to perform a self-calibration for fix a second one.
Has anyone had success with this type of configuration? Which GND would be the most suitable for the +5V output and is it safe to connect the negative input directly to this GND pin?
06-01-2018 04:52 AM
What is the circuit's output voltage? Make sure that does not go above 10V or you will damage your DAQ.
06-01-2018 07:21 AM
At 15V supply, the output swing measured after the capacitor was about +/-6V. At first I was getting sort of a loading effect on the output signal - ie. a sinusoid looking like a low ac coupled square wave when power was supplied from the +5V bus. A test with the USB power showed the amp was fine but when I plugged the +5V back and powered it on, something went wrong and I lost the AI channel.
I can continue troubleshooting but I want to be sure that I'm connecting it correctly. Can you think of any other issues besides over-voltage that I should be concerned with?