Calculation involving time series and time based constants


I managed to setup live data from industrial equipments using grafana as a time series monitoring tool plugged into an elastic database fed every 10s with new values.

I would like to be able to display calculated graphs based on the time series values from elastic and some constants specific to the equipment monitored (stored in an XML file). These constants would be valid for a specific time range which is the runlife of the equipment.

When the equipment is replaced, by design the upstream configuration won’t change and the time series data will continue to “flow” but the calculated data will have to get the new values for the equipment just commissioned.

Is it possible to do it with grafana? How would you proceed?

I imagine how I could use the option of the metric to apply a formula with a variable declared in grafana. But how could I link it to my xml files uploaded regularly and relate it to time.

In case I was not very clear, let’s say I have a sinus wave displaying in grafana over a year, each point separated by 10s. Let’s say I have a XML file that says:
01/01/2019 - 01/04/2019 : const1= 10
02/04/2019 - 01/08/2019 : const2= 20
02/08/2019 - 31/12/2019 : const3= 30
Is there a way to display my sinus value over the year with the following formula sinus value * constx where constx corresponds to the constant at this time.

Thank you very much for your guidance,