Strange rule calculation fluctuations

[Karol]

I have some rule that calculater power usage:

PV_KonsumpcjaDzisWoPC.postUpdate((PV_AutokonsumpcjaDzis.state as DecimalType) + (Ex9EMS_DayUsage.state as DecimalType) - (SDM_DayUsage.state as DecimalType))

Basing on that I have some notifications running when next tresholds are achieved (NORMAL, WARN, CRIT). Problem is that for first I’m getting info that level WARN is meet, and in few minutes that level goes back to normal - it’s not possible (same thing in case of WARN->CRIT->WARN).

I’ve mede some graph of values of above items, and strange is that fluctuations appers on “PV_KonsumpcjaDzisWoPC” item, but not on any other item on the basis of which the rule performs calculations. Any clue why?

Items definition:

Number PV_KonsumpcjaDzisWoPC “PV daily energy usage without Heat Pump [%s]”
Number PV_AutokonsumpcjaDzis “PV daily energy autoconsumption [%s]”
Number Ex9EMS_DayUsage “PV daily energy import [%s]”
Number SDM_DayUsage “Heat Pump daily usage [%s]”

[rossko57]

@Karol

Any clue why?

Not really. We cannot see any of your rules, any of your Items. We can’t see any of your data and we don’t know where it comes from.

@Karol

Basing on that I have some notifications running when next tresholds are achieved

Is this by a rule? Put some logging in your rule so that you can see what data it is dealing with.

@Karol

I’ve mede some graph of values of above items

I’m not sure what we are supposed to see as fluctuations here? Is it the little downward steps?

@Karol

PV_KonsumpcjaDzisWoPC.postUpdate((PV_AutokonsumpcjaDzis.state as DecimalType) + (Ex9EMS_DayUsage.state as DecimalType) - (SDM_DayUsage.state as DecimalType))

So X = A + B - C
What happens if you expect A,B,C to come as a set of readings, but then A gets updated first? In other words, when you calculate is rather important. (Rule trigger conditions)
X = new A + old B - old C
or any combination.
Maybe it will run again in a moment
X = new A + old B - new C
You’d get some odd results from that.

[Karol]

Thanks for the point. Problem solved. In this case the source was that values of those 3 item came from 2 different power meters, even from 2 separate bindings and data refreshing at the same time is not possible.

[rossko57]

@Karol

values of those 3 item came from 2 different power meters

mm, that is difficult to solve, how to “synchronize”.
What to take account of depends very much on what your readings and calculation mean.

This might be of use in your situation, or at least suggest ideas -

Asynchronous Events to Synchronous Event

Problem Statement At times we want to process events that happen asynchronously but only after we have recent data from a set of events. This can be difficult to implement without a lot of custom programming. As an example, MQTT does not guarantee the order of receiving messages. So if we need to process data from MQTT and we only want to do that when a recent set of MQTT messages has been received, we need to do a lot of work to track the timing of those messages. Concept Asynchronous to Sync…

or might all be as simple as just choosing the right rule trigger.

[Karol]

Synchronize could be more difficult because of:

• different power meters → different manufactures → different accurancy,
• multiple integration bindings (http/json, modbus) with different delays and not synced refresh intervals.

I managed problem differently on logical level of rule. Rule is blocking possibility of going back to previous state, so in sequence, NORM could only change to WARN, and WARN only to CRIT. After that going back from CRIT to NORM requires “PV_KonsumpcjaDzisWoPC” to have value near 0 (<3).