I am building a pH probe interface. Cant decide whether I should go for HW calibration or SW calibration.
What would give the most accurate result? I guess SW based is more versatile.
Some compensation like temperature compensating I guess is easier done by SW, but how about offset errors etc.
somethings tells me that HW calibration might be more accurate... but maybe it is the feeling of turning a knob until I am getting the wanted result that fools an old HW hearth...
What is your experience?
* SW calibration needs no hardware effort
* SW calibration will not drift
* SW calibration can be done automatically
* SW calibration can have any resolution you like
* SW calibration is fast
* SW calibration can include many parameters like time, temperature, user name....
* SW calibration data can be archivated in a PC
What's the benefit of HW calibration?
As long as there is a microcontroller, I can't imagine a single benefit...
To add to Klaus list: Temperature stable, multiturn pots are expensive.
A 10 turn, 20k device costs US$29.35 at Digikey. Single quantities.
Prices drop down to US$3.03 for a 5 turn device.
And they still have a tempco of ±100ppm/°C.
EDIT: continued looking and found that 20 turn devices are far cheaper, who would have thought that? US$1.39 for ±100ppm/°C.
Wirewound ±50ppm/°C are about US$13.12
Sounds like going for SW cal is my very best option.
Saves me some board space too..
plus... less components gives less tolerances and strays to care for too
and better signal integrity...