Hi So, *assuming* there is no other ADC on the board ….
DC performance of the STM8 ADC’s is somewhere in the 8 to 9 bit range as far as ENOB with significant averaging. For the sake of simplicity, let’s say they *do* make it to 10 bits. But … do we get the 10 bits? The range on the meter is 33V. The reference to the DAC is (likely) 5V. You just lost nearly 3 bits from that scale mismatch. At the 5V level, you would be running just over 7 of your (ideal) 10 bits. Net result is that you are trying to check a 16 bit gizmo with a not quite 8 bit device. Bob > On Sep 7, 2020, at 10:01 AM, DM <dgmin...@mediacombb.net> wrote: > > I must caution all who would buy the 5-digit panel meters, thinking that they > are actually capable of accuracy that you would normally expect from a > 5-digit meter. > The panel meters in question use a STM8S003F3 micro-controller, which > contains a single 10-bit A/D. Depending on which eBay or AliExpress listing > you look at, accuracy varies from 0.3% to 0.05%. > Make your own deductions from this info, just be aware that all is not what > you might expect of this cheap little meter. > > Cheers, > Dave M > > > From: "Perry Sandeen via time-nuts" <time-nuts@lists.febo.com> > To: time-nuts@lists.febo.com > Cc: "Perry Sandeen" <sandee...@yahoo.com> > Sent: Monday, September 7, 2020 12:20:12 AM > Subject: [time-nuts] 5 Digit Panel meters > > Learned List, > From the on and off list comments I've received I realize that I didn't > provide a fuller explanation of my proposed idea for this I apologize. > What I was proposing was to try and use the tiny panel meters fount on ebay > when you use the category listed as *Digital Panel Meters*. One listing > number is 203076543505. Measurement range: DC: 0.000-33.000V. for $3.83 plus > free shipping. This is just one of many listings for similar items. As I > stated in my original post, I have no idea if they are accurate, stable or > suitable to what I proposed. > Some of the replies mentioned temperature drift and other potential problems > which may make then unsuitable for my idea. This was to measure three > different voltages simultaneously and see if there was some useful > correlation in the readings. > This is an experimental concept idea which may or may not be > useful..Sometimes these ideas work or we learn to go to plan *B, C, or D* > Because of the low cost i felt that this might a useful idea. Others with > more experience of these voltages and how much they do or do not change may > judge my idea as impracticable. > That's fine. > > I learn from the list comments and I'd rather hear that it's not a good idea > from the members before spending the money and effort. > I do have a Fluke/Phillips 6.5 for making precise reading when needed. > > Regards, > Perrier > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
