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Emoncms import_kwh with 2 tariffs

Hi all,
Well, I’ve modified my system because the import data received from the EnvoyS are quite wrong (like -/+ 15% !!). So now I get the import directly from my official meter.
But… I’ve 2 tariffs, so, my meter increments an index from 7am to 11pm and another index from 11pm till 7am on the next day.
I’ve created 2 feeds for importxx_kwh and importxx_kwhd for each tariff. How can I define 2 “merge” feeds import_kwh and import_kwhd which will “combine” both tariff?
Thx in advance for the help
Fred

Hello @FredM67, am I following correctly that you are reading these kWh values digitally from the meter? and that you now have two inputs in emoncms for each kWh tariff? to which you have logged both to feeds? Can you just add them together to give total import_kwh?

You could then use the time of use app to apply the pricing… or could you apply the unit cost at the input processing stage to create a import_kwh_cost feed?

Perhaps a screenshot of what your current input processing looks like would help to see what you have in place already?

Hi Trystan,
The digital meter in France have a feature called “Tele-information”. The meter sends continuously frames through a serial output, each frame contains a lot of line with data like SN of the meter, index of ON-Peak tariff, index of OFF-Peak tariff, active power, real power, current for each phase and so on.
Both index are in Wh. The OFF-Peak (idxHC) index increments during off-peak period, the ON-Peak (idxHP) during on-peak period.
I can add both indexes, that’s not a problem, but the resulting value will have no sense at all. I understand that only the delta and how quick the sum increments is important.


The node 90 comes from my Envoy-S through a python script, the 91 through Modbus TCP through a python script too, and the 92 from an esp-01 programmed by my own and reading the serial output of the meter.
Thx
Fred

Here what I’ve tried:

BTW, does it matter on which input I “base” this calculation steps?
How can I specify that the start index is not 0 for both, so I get the proper kwh per day?
Fred

So, this way doesn’t work properly. Since I’ve based all this stuff on one specific input, as long as this input doesn’t get a new value, the process list isn’t run.
What about a virtual feed? It seems to be updated properly. On the picture, both values marked in the red circle should be the same.


So one other way would be to send all the time both indexes. I can do that, but what about the space needs? If I send between 7am and 11pm all the time the same value for idxHC, how does the system write “redundant” data?

Hi all, hi @TrystanLea,
So after a couple of tries and deeper investigation, it seems the only way to get it work properly is to send all the time both indexes.
This way, the sum of both indexes is always up-to-date and other calculations too.
The other point is also to send both indexes all the time, even both indexes aren’t incrementing (PV-Production) and define the feeds as “phpfina”. If I send the index only on changes, and define the feed as “phptimeseries”, I get a “bad” quality in the stats. That’s somehow strange because “PHPTimeseries is for data posted at a non regular interval such as on state change.” The periods between 2 updates of the index should not be considered as “missing data”.

Fred