Incorrect readings for Analog input

[SSepulveda]

I am using your test panel to find the voltage at the analog inputs 0 and 1. The test panel shows the correct voltage placed on the inputs, when your AIonePoint example is run, as well as my program to find the inputs of two channels in Visual C++ I recive a value greater than the input voltage as an output. The offset is around .7 to .8 volts. I am using two sensors where a change in the voltage gives me a bad reading. I would like to know what I can do to get an accurate reading, my range is between 2.1V and 0.1V. I am using AI_VRead as the funtion to grab the voltage at a certain sampling rate. I have scale set to 1.
Thank you

[JaredA]

If you are seeing the correct voltage when using Test Panels and not when using the actual C++ code, then the problem is not with the DAQ card itself, but rather with the code that you are using. The problem could be related to using an incorrect input mode. If you look into the AI_Configure function you will notice the parameter inputMode which can be set to Differential, Reference Single-Ended, and Nonreferenced Single-Ended. Depending on how you are trying to transmit the signal will determine which of the input modes you should be using.

You may also consider performing a self-calibration on the device to make sure for optimal settings in the current environment your application is running.

The final think you should check is whether you get the bad readings when measuring a single channel in your code. You mentioned that you are trying to read from AI 0 and 1. The offset that you are seeing could be caused by some residual voltage that is left because you are trying to read the channels at too fast of a rate.

Good luck.

Jared A