Hi For a variety of reasons, if you go the MCU ADC route, put an op amp in between the thermistor bridge and the ADC. It takes care of a whole lot of issues.
Bob > On Jun 6, 2017, at 12:13 PM, Adrian Godwin <artgod...@gmail.com> wrote: > > The specs for the ADC are pretty vague : most of the errors are around 2 > LSB but all are quoted with vref at 4V. If you reduce vref (there's an > internal option of 1.1V) you'll increase gain but some of those errors are > going to stay physically the same. In general, I'd tend expect to get more > precision but also more noise. Averaging may help a bit. > > > On Tue, Jun 6, 2017 at 3:00 PM, Riley, Ian C CTR NSWC Philadelphia, 515 < > ian.riley....@navy.mil> wrote: > >> Chris, >> >>> The trick with using a uP and it's built-in A/D converters is scale. You >>> want the limited 10-bits of revolution to fall over the operating range >>> which is very narrow, like 1C. Anything outside of that is either 0000 >> or >>> 1111 and only seen at start-up., So at start up the the controller is on >>> "bang-bang" mode then later you have milli-degree resolution over your 1C >>> range. Basically you are measuring noise. but your $2 uP can take >> 100,000 >>> measurments per second and putt tour a digital filter. >> >> I have seen but not used the AREF pins on Arduino and similar uPs; as you >> lower AREF, do you lose any sort of accuracy? Is there a practical minimum >> for what voltage you can feed into AREF? >> >> -Ian R. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
