Charts for heating control - Scaling problem for different values

Setup, Configuration and Use Items & Sitemaps
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1

Hello,
I`m quite new to openHAB - please be pationed.

Currently I wolk on homematic thermostats for my house. I have a little scaling problem when I whant to chart 3 values together: current and target temperature and current valve status. The temperatures will be around 15-25 °C but the valve status change between 0 and 100%. Charting them together I can’t see details for the temperatures:

Is there a quick and easy way to use an alternative scale for the valve opening value or to scale the valve valuses by 25% (or something like Y/10+15). Or should I better use a different chart provider and which should I use?

Thank you for your help.

Chris

2

I suggest you could use habmin. It auto-scales Y range and you can dynamically select which values to display.

3

Thank you for your quick response. I’m using habmin for detailed charts which provides different scales and min/max values and like it verry much. But I’m looking for a easy way to intgrate the chart in the UI and iOS App for a quick check if the valves are workling as expected (sorry UI is in German):

chart2.png580×712 72.5 KB

The peaks in this chart are results of testing and debugging my rules but it shows my problem verry visual.

4

There’s probably no easy way, see this.

You could add a persistent variable and a rule to compute it to <scaling factor> * (old variable) on every change, e.g. Ventiloeffnung_neu = Ventiloeffnung/10, then chart that new variable.

1 Like
5

Thank you, that worked for my purpose:

Extra Item for persistence:

Number Heating_GF_Office_VentilC “Ventilöffnung [%.1f%%]” (Heating,Chart_GF_Office)

Roule for scaling:

/* Ventilstellung für Charts skalieren */
rule “Valve Office state changed”
when
Item Heating_GF_Office_Ventil changed
then
var Number Valve = ((Heating_GF_Office_Ventil.state as DecimalType) / 10 ) + 15
logInfo(“Heating”, "Valve OFFICE changed! Value recalculated for Charts to " + Valve)
postUpdate(Heating_GF_Office_VentilC,Valve)
end

and here the result - much better! 100%=25 and 0%=15