1) I am using ADS1248 to measure RTD signal. I checked the INTERNAL REFERENCE LONG TERM DRIFT graph in datasheet. So as per graph, it is seen that there is no long term stability for internal reference. So i decide to go with external reference voltage +2.5V.
My question is, if I use external voltage reference, then will this affect the input signal measuring time?
Pl. suggest which option will be better internal or external voltage reference? Suggest best external voltage reference +2.5V for long term stability.
2) Also in datasheet, they have mentioned that there is 4 differential / 7 single ended inputs for ADS1248. But as per pin description, there are 8 analog input AIN0 to AIN7 (8 nos.). For my application, I have to use 4 channel for 2 nos. of RTD and rest 4 channel for 4 single ended inputs. So can I use rest 4 channel for single ended input? Wiil it work?
3) Also let me know can I use same external voltage reference for 4 nos. of single ended inputs? If not then on which pin shall I connect external reference voltage for single ended inputs?
4) How to calculate accuracy through the temperature range -10 deg C to +30 deg C for the 4-20mA input for ADS1248?