Current value (watts) every 5 seconds. Help to create Daily, Weekly, Monthly usage.

heiko1988

Good day,

I have a variable which always shows me the current consumption every 5 seconds in x watt

Example:
$aktuell-bezug.value 600W
This variable is updated every 5 seconds.

My concern is from the info

Hourly use
Daily use
Weekly use
Monthly use
Annual use

to calculate.

Can someone help me?)

What I have found so far.
is from a total electricity meter reading or via pulses.

Thank you

mwittig

One way of doing this: First you need to calculate the Watt hours (or Kilowatt Hours) per time interval. As you say, the variable is updated every 5 seconds. The consumption in the given time interval is $aktuell-bezug.value * 5 / 3600. The result of this needs to be added to a “register” variable, let’s call it hourlyUse.

I have drafted a boiler plate you can use which consists of two Rules and a Variable to count hourlyUse. Moreover, I have added a VariablesDevice, which is only used to display values on the device pages. That’s just the starting point, but it should be relatively simple to add more “register variables”. What might be trickier is to create the logic to reset the registers (daily, monthly, yearlier). I think one needs to use pimatic-cron for this purpose. I’ll have a look at it later.

Variable

   {
      "name": "hourlyUse",
      "value": 0
   }

Rules

    {
      "id": "measure-interval",
      "name": "measure-Interval",
      "rule": "when $aktuell-bezug.value changes then set $hourlyUse to $hourlyUse + ($aktuell-bezug.value * 5 / 3600)",
      "active": true,
      "logging": true
    },
    {
      "id": "reset-hourlyuse-counter",
      "name": "reset-hourlyUse-counter",
      "rule": "when its 0:00 then set $hourlyUse to 0",
      "active": true,
      "logging": true
    }

VariablesDevice

     {
      "variables": [
        {
          "name": "hourlyUse",
          "expression": "$hourlyUse",
          "type": "number",
          "unit": "Wh"
        }
      ],
      "xAttributeOptions": [],
      "id": "energy-meter",
      "name": "energy-meter",
      "class": "VariablesDevice"
   }

EDIT: Here is little of explanation about the calculation and theory behind. The accuracy of the simple set-point accumulation should be accurate enough if the current consumption does not fluctuate a lot faster than the measurement interval (see Nyquist-Shannon Sampling Theorem). Given the short interval you have, it should be fine for typical household appliances. For a PV generator, however, this may be different. As PV generation is fluctuating all the time, you may expect a significant inaccuracy.
https://electronics.stackexchange.com/questions/237025/converting-watt-values-over-time-to-kwh

heiko1988

Hi,

hi, thanks for the detailed answer.

At the rule

"rule": "when $aktuell-bezug.value changes then set $hourlyUse to $hourlyUse + ($aktuell-bezug.input * 5/3600)",

I changed the variable from $aktuell-bezug.input to $aktuell-bezug.value

Does the variable always last only one hour?

What I do not quite understand, why do I have to reset at 0.00 hours?

and for daily usage is creat a Variable and the Rule.

"rule": "when $aktuell-bezug.value changes then set $dayUse to $dayUse + ($aktuell-bezug.value * 5/86400)",

is this correct?

and
For my PV generator, i have a direct api and can read this.

Tanks

mwittig

@heiko1988 said in Current value (watts) every 5 seconds. Help to create Daily, Weekly, Monthly usage.:

I changed the variable from $aktuell-bezug.input to $aktuell-bezug.value

That’s right. I used a different type of device setup for testing, and did change the attribute names properly. I have edit my post to correct this.

Does the variable always last only one hour?

I think this should work like data logger where you calculate usage per hours of the day, day of the month.

What I do not quite understand, why do I have to reset at 0.00 hours?

Sorry my fault. That’s complete nonsense. To make it work as intended you need to reset the value very hour. Possibly a job for pimatic cron.

and for daily usage … create a Variable and the Rule. … is this correct?

Yes

mwittig

Here is corrected rule for reset-hourlyuse-counter. In the rule editor you need to switch to “text mode” to be able to enter the every predicate. You can create another rule for resetting the daily usage counter according, i.e every 1d

    {
      "id": "reset-hourlyuse-counter",
      "name": "reset-hourlyUse-counter",
      "rule": "when every 1h then set $hourlyUse to 0",
      "active": true,
      "logging": true
    }

heiko1988

Hi,

Thank you.

have everything set up and works so far quite well.

Is there no function that always calculates an average value from x packets.

because that’s how he starts every hour from 0.

heiko1988

Thanks for your thoughts.

that has brought me to another idea.

I use the filter plugin.
Since I can enter x packages from which he again and again the sum erchenent, have the update interval set to 1

Here’s a picture for hourly
config:

Here is a picture for Daily Last 24H
config

Finished

The Variable i push in the Front end with the Variable device.

it will fill up slowly and then you will see it exactly, will upload a picture tonight / tomorrow again.

it can be that easy without rules

Without your thoughts I would not have come to that.

Thank you