I search for a Solution for Power Consumption Fallback

General
1

Hi,

i search for a Solution to restore the Power Consumption if my Shelly get a powerloss and the Total Power Consumption falls back to 0

So far I've made it this far:

I have a MQTT IN with the actually results of the Shelly (optional for testing a Inject Node)
One goes into a Function Query for Influx DB to Read the latest Power Consumption stored in the Influx DB
Other goes after Rename the Payload into a Join Node
Both goes to this function Node:

var totalstarttime = msg.payload.TotalStartTime;
var totalkwh = msg.payload.Total;
var yesterdaykwh = msg.payload.Yesterday;
var todaykwh = msg.payload.Today;
var period = msg.payload.Period;
var watt = msg.payload.Power;
var voltage = msg.payload.Voltage;
var ampere = msg.payload.Current;
var factor = msg.payload.Factor;
var scheinleistung = msg.payload.ApparentPower;
var blindleistung = msg.payload.ReactivePower;

var totalDB = msg.payload.totalkwh;

if (ampere === 0 && watt === 0) {

    return [null, msg];

} else {

    if (totalDB > totalkwh) {

        msg.payload = {
            totalstarttime: totalstarttime,
            totalkwh: (totalDB + totalkwh).toFixed(3),
            yesterdaykwh: yesterdaykwh,
            todaykwh: todaykwh,
            period: period,
            watt: watt,
            voltage: voltage,
            ampere: ampere,
            factor: factor,
            scheinleistung: scheinleistung,
            blindleistung: blindleistung,

        }

        return msg;

    } else {


        msg.payload = {
            totalstarttime: totalstarttime,
            totalkwh: totalkwh,
            yesterdaykwh: yesterdaykwh,
            todaykwh: todaykwh,
            period: period,
            watt: watt,
            voltage: voltage,
            ampere: ampere,
            factor: factor,
            scheinleistung: scheinleistung,
            blindleistung: blindleistung,

        }

        return msg;


    }

}

The If Power and Current = 0 is for stopping Input to the Influx Database if Power and Current = 0

The other one is my problem:
if (totalDB > totalkwh)
If the actually Value from Shelly (totalkwh) smaller than the Database Value (totalDB)
Add the actually Value to the Database Value

But there is the Problem:
eg.: Database have 6.500 kwh
actuall Value is 0.100 kwh

i gettin 6.600kwh thats correct, but after that add this value is added to InfluxDB

Now i have 6.600kwh in Influx DB and a actually value from Shelly of 0.150kwh

After the Second pass i have then not 6.650kwh but the wrong 6.750kwh because it asks the InfluxDB a second Time for the latest value.

I hope I explained that a bit understandable

Unbenannt
Unbenannt1920Ă—1010 236 KB

2

I am still having problems with my routine for doing this - the overall maths is wrong.

However, here is the relevant part. I check the reading coming in from the consumption monitor (PZEM-004 in my case) and compare it with it's last reading AND the overall reading for today. This is a dirty routine, but I am still working on it...

//let elecPowerToday = msg.pzem.ENERGY.Today;  //Today Power from PZEM

let elecLastPowerToday = global.get("elec.LastPowerToday", 'storeInFile') || 0;  //Context PowerToday
let elecNewPower = msg.pzem.ENERGY.Today;  //Today Power from pzem
let elecOldPower = msg.payload[0].today;  //Today Power from last db pzem

//let negPower = elecOldPower - elecNewPower
//if PZEM has been reset recalc NewPower XCPT when @midnight!!
if ((elecNewPower < elecOldPower) && resetTimeFlag === 0 ) {
    elecNewPower = elecNewPower + elecOldPower;
}


let elecNewPowerToday = elecNewPower; //in case of pzem reset

It may help just a bit...

3

Hi,

thanks @mudwalker i try your code.

I have found another thread here in Nodered Forum with this code:

// Given current total energy from Shelly in msg.payload
let runningTotalEnergy = global.get("runningTotalEnergy", "storeInFile") || 0
let previousShellyValue = global.get("previousShellyValue", "storeInFile") || 0
// test whether the Shelly has reset since last input
if (msg.payload < previousShellyValue) {
    // yes it has, just add new value to the total
    runningTotalEnergy += msg.payload
} else {
    // no so add the difference between this and last to the running total
    runningTotalEnergy += msg.payload - previousShellyValue
}
global.set("previousShellyValue", msg.payload, "storeInFile")
global.set("runningTotalEnergy",runningTotalEnergy, "storeInFile")
msg.payload = runningTotalEnergy
return msg;

I'll try to combine the codes to get it running.

4

Thank you. I will be able to spend some time on it tomorrow.

My maths works, but I get the occasional 'glitch' which gives completely 'out of whack' results. I shall report back.

5

I have modified the Script from @Colin down here, that works for me.

Only i have a Question: Where do this Script store the Data ? and where is the File stored ? (I have Debian on Raspberry Pi)

// Given current total energy from Shelly in msg.payload
let runningTotalEnergy = global.get("runningTotalEnergy", "storeInFile") || 0
let previousShellyValue = global.get("previousShellyValue", "storeInFile") || 0
// test whether the Shelly has reset since last input
if (msg.payload < previousShellyValue) {
    // yes it has, just add new value to the total
    runningTotalEnergy += msg.payload
} else {
    // no so add the difference between this and last to the running total
    runningTotalEnergy += msg.payload - previousShellyValue
}
global.set("previousShellyValue", msg.payload, "storeInFile")
global.set("runningTotalEnergy",runningTotalEnergy, "storeInFile")
msg.payload = runningTotalEnergy
return msg;
6

EDIT: @Starfoxfs - wrote this as you replied.

I have modified the routine and think (hope) it will not give me the glitches the previous one gave...

//New routine************************************************************ */
//if PZEM has been reset or -ve anomalous reading recalc newPower XCPT when @midnight!!

//Fetch current and last stored readings  New should always be >> old (Don't check during daily reading reset)
if ((elecNewPower < elecOldPower) && resetTimeFlag === 0 ) {
    //Modify new reading if == 0 or < OldPower
    if (elecNewPower == 0){
        elecNewPower = elecOldPower;
    }
    
    //be careful- don't want to skew readings, so might be best to ignore
    /*
    //mitigate anomalous reading to ripple through routine
    else{
        elecNewPower = elecOldPower + elecNewPower;
    }
    */
}
//*********************************************************************** */

You will then be able to calculate the difference between the New Power and Old Power and get the power used between two valid readings.

HTH

7

The variables are stored as Context Data. 'storeInFile' is probably in memory and lost during reset.

See this thread here for more details.

1 Like
8

I have configured it out in Settings.json

Now it´s stored in

~/.node-red/context/global/global.json

9

Now modified my code to the less confusing version presented by @Colin. Thank you.

I have learnt some more about Javascript and dumped my routine where I was needlessly trying to trap completely unnecessary possibilities I had probably imagined! (Confused? So was I! :lol)

10

It is often a tricky balance to get the right amount of defensive code to guard against incorrect data.

11

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