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Log of gas count values

Posted: Sunday 25 September 2022 12:34
by GammaKappa
Setup:
Domoticz 2022.1 running on a RPi 3
I have a gas counter (Type General, Counter Incremental) that counts pulses from a hall sensor on the gas meter.

I noticed that sometimes the values in the log graphs are not consistent.

The values in Domoticz "per hour" graph match perfectly with the values received from my hall sensor.
However, if I add all the "per hour" values of a day from the first log graph, this total does not match with the "per day" value shown in the second graph.

The error is not compensated for the next day.

Can somebody help to explain and/or solve this problem ?
gascount.jpg
gascount.jpg (89.34 KiB) Viewed 230 times

Re: Log of gas count values

Posted: Sunday 25 September 2022 12:41
by psubiaco
This seems to be a rounding issue. If the displayed value by hour had 3 decimals instead of 2, maybe the daily value with 2 decimals will be perfect.
Obviously, the right value is the daily one, not the sum of hourly values.

Re: Log of gas count values

Posted: Sunday 25 September 2022 12:57
by GammaKappa
My hall sensor generates a pulse after every rotation of the last digit on my gas meter (i.e. one pulse per 0.01 m3)
So the logging is done with 2 decimals.
If I check the logged values, the 3rd decimal is always 0.