fpga

[dan_u]

Of course, the code will work in the full range -10V..10V. It's really simple math.

The value will fluctuate, that's just in the nature of measurements. If you think there is an offset then you can correct for it.

Look at the DMA examples for how to transfer values to the host system.

[crossrulz]

I would just like to say that it is best to do as much calculations and processing using the raw value as possible.  This will use less gates (very important in FPGA) and be more accurate.  Once you transfer the data to the host, let the host convert into a double.  This will give you the best accuracy.

[gaks]

hey i am not able to correct it for 2.50....what is the maths behind dis can you please explain it once

[dan_u]

You shouldn't correct a value just because you expect it to be 2.5V. It's possible that the analog inputs have an offset, but that's usually below a mV for that FPGA card.

How do you know the value is actually 2.50V?

[gaks]

actually i measured it via multimeter ...it shows 2.5 v....

[dan_u]

How precise is your multimeter? What's the resolution, 12bits?

If you think your reading is off by -0.01V then add 0.01V to it.

You might also want to think about averaging several readings from the FPGA analog input if you're interested in the DC value. Or use a low-pass filter.