I'm using a flex rio system with a 5782 module ( the DC coupled version)
We have some trouble with the analog inputs AI0 and AI1, we measure a DC voltage of 250 mV on both inputs.
The module has been returned for repair but no problems were found.
I wander if other modules have the same "problem" so is there anyone out there that can do this simple test:
Disconnect your cable from AI0 or AI1 and measure the voltage on the bare input terminal with a simple multimeter.
If other modules also have this Dc offset then it's probably the "nature of the beast"
Thanks in advance for any reply's.
Solved! Go to Solution.
I measured +250 mV DC offset on the AI0 and AI1 inputs of my DC-coupled NI 5782 also. NI should have included that in their spec sheet.
This indeed confirms that all DC coupled NI5782 modules have got this DC offset.
This was also the conclusion of the NI service engineers that helped me, and I must admit that I forgot to post this conclusion.
Meanwhile we changed our hardware connected to the inputs and created a work around for the offset.
So my problem is "solved" but I agree that NI should have mentionned this in the specs.
Hello, i have been going through same issue and i finally stumbled upon this. I thought there was a problem with the impedance mismatch, but it seems it starts to make sense if there is a DC offset internally in the input. See attached picture, when i plug in the AI of the 5782, there is a shift on the original sine wave input.
My second question is what did you do for the workaround?