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Idea

Kevin Windrem suggested Jul 17, '21

Increase temperature sensor resolution

The temperature sensors appear to report temperature on dBus in degrees Centigrade as in integer. (VRM is reporting to the nearest 0.5 degrees!)

For us in the US that use the Fahrenheit scale, this results in a 2 degree jump in displayed value.

I would like to see dBus temperature values published to at least the nearest 0.5 degrees C. to 0.1 degrees C would be better.

Also, I'd like to see a Centigrade/Fahrenheit setting for all displayed temperatures.

Yes, I know, the US should just change to the Centigrade scale like the rest of the world, but ...

Temperature Sensor

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Mike Dorsett commented Jul 17, '21

I'd like to see 0.1 degree resolution for this. Whilst most analogue Temperature sensors use an approximation to convert the dc voltage back to temperature, sometimes resulting in an error of 1-2C, having the additional resolution would look better, and certainly suit the digital temperature sensors that are becoming more common.

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mike4nl commented Mar 22, '22

#Cerbo GX
I have tested the Temp.-Sensors (LM335Z) and the original one on a ESP32 and a STM32.
It is very simple to show 0.1 deg. C or F values bevacuse default it is 10mV / per Kelvin.
It is only a little part in the software (analog input) and the calcultaion from Celsius to Fahrenheit and back.

I could help out Victron if they have an issue with that. ;-).

I hope we get a answer from you guys from Victron.

This is for the Celsius redaing.Fahrenheit converstion is easy as simple
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// get temperature in tenths Kelvin

int k_temp = analogRead ( A5 ) * 4 ; // 4 = 4096/1024

// calculate temperature in tenths °C

int c_temp = k_temp - 2732 ;

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gone-sailing commented Mar 22, '22

I don't think this is a limitation of dbus or VRM, my sensors show up in VRM with one decimal place.

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mike4nl commented · Mar 24, 2022 at 02:33 PM

You are right.

But this is an issue with the OS for the Cerbo GX in my case. It shows always a ZERO (e.g. 24.0) after the decimal point.

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Kevin Windrem commented Mar 25, '22

My GuiMods package makes use of the temp sensor's raw data and calculates temperature from that and the offest/scale numbers. GuiMods displays temps to 1/10 degree.

GuiMods also provides a C/F selection for temp display in the flow and mobile overviews.

https://github.com/kwindrem/GuiMods