following the thread "Precision Weigh scale Issues".....
I want to make a comparison between a weighing scale that we have operating with exceptional behavior (AD7195), and a new one that we are designing with the
1- I do not understand why the AD7195 behaves better than the AD7172-2 over the temperature range, in addition to all the improvements that I am supposed to
have made in the design with the AD7172-2.
2- I attached comparative tables of the 2 devices, and the AD7195 does not need temperature compensation in the entire range, even in no chop mode (VDC
excitation of load cell). With the AD7195 we do an internal zero and full scale calibration when turning on the equipment (only once), while with the AD7172-2 we
do the internal zero calibration when turning on the equipment (only once). Then we apply the equation of the line, with the points recorded with empty scale and
scale with known weight.
NOTES: The load cell is 30kg, the 2 in bipolar mode, load cell excitation in AD7195 is + 7.5V and in AD7172-2 is + 5V.
I was quite disappointed by the AD7172-2 regarding its temperature deviations, and I still have no idea how I can make that compensation in the microprocessor.
Even so, I will try the AD7175-2, which is pin-to-pin compatible, to see if it works better, although it is more expensive.
[edited by: JValeriani at 4:40 PM (GMT 0) on 3 Oct 2019]