Let's Control It

i am trying to get actual power from my 3 strings of solar panels into domoticz
i installed espeasy on a nodemcu, and connected 3 s0 kwh meters to the nodemcu.

I am getting readings, but i have no idea what settings to use to get the correct current watts being generated in domoticz
My s0 meters have 1000 pulses

1000 pulses? per what? I assume your Meter gives 1000 pulses per kWh.

So one single pulse ist 1 Wh - unfortunately thats all information that a S0 Interface can deliver. If you want to know the actual Power in Watt, then you have to calculate the time out of the "Wh":
Measure the time between 2 pulses. Then just calulate: 1 Wh / time in hours = W

Thats why I always say "with an S0 Interface there is no Smartmeter possible". No actual reading of the real counter, no Watts, no Ampere, no Volt, no Hertz, only Wh!
Even more confusing when people are talking about a S0 Bus - because ITS NOT A BUS! It's just a potential free contact.

Anyway - hope I could help a little bit.

Dan

Another method is instead of timing between the pulses, just count how many pulses per set time period; I use 1 minute for "instant" data, and 10 minutes for more accurate averaged data for storing.

At 1000pulses per kW and 1min period, kWh is found by multiplying the count by 0.06; 5 pulses per minute is 0.3kWh (300Watts per hour), 80 pulses is 4.8kWh

For a 10min count, multiply by 0.006

If you are using NodeRed, here's a flow that can help with the timing/counting:
https://groups.google.com/forum/#!topic ... XYRCRtcDxE

Continuous measurement of time between pulses may be a a heavy demand on an ESP8266 firmware, and I doubt the accuracy ...........

It is not difficult to get Watts (W) if you have WattHours (Wh):
see https://www.rapidtables.com/convert/ele ... -watt.html

It only requires a certain mindset & accuracy to arrive at a practical solution, although always a compromise, as explained below.

Your energy-meter calculates the energy by multiplication of Power and Time => Wh
Your S0-interface (at 1000 pulses/kWh = 1 pulse/Wh) reports each passing Wh as a pulse.
If you count pulses for a certain time t, the result of the multiplication is the Energy E produced in that time t, with E expressed in amount of Wh.

Calculating backwards, then you can deduct the average Power (in W) produced during that time t, because P,avg = E/t.
For correct results, you have to be careful to have the 'magnitudes' correct: see the quoted URL!

The 'compromise' is caused by the following aspect:
- if you take time t long, then you usually have plenty of pulses within interval t, giving a stable calculation, but you miss the real, instantaneous actual power due to the averaging process.
- if you take time t very short, then you get closer to actual power, but the division E/t may produce strange results due to the small number of pulses divided by a short time-value.
Pragmatic, simple solution: take time t = 6 minutes.
Not too slow and also practical, because it is 10% of an hour, and therefore relatively easy to check whether your calculation is correct.

I should add that on my setup the ESP8266 only on-sends each pulse as an MQTT message, and all of the counting per time period and extrapolation is done on the RPi3, running openhabian with node-red. I "assume" a similar thing can be setup in domoticz

Why 'load' the LAN because of the MQTT-message/pulse?
At least the time-between-pulses in that way is (euphemistically) not very reliable information.
With some clever rules the ESP can do the job to calculate Power.
IMHO, if you want to divide the functionality, it is simpler to have the ESP8266 count the pulses and at intervals transmit the -interval-result to your server for the other 'clever functions'.

razimrj wrote: ↑18 Jun 2018, 16:12 Umm, I have no idea how to do it. and i also need solution for actual solar power to domoticz

Does your inverter have any sort of interface? Usually they come with an interface to report into the manufacturers website. Once you find that, with the make and model, it might be possible to "tap" into the data stream directly.

I own an Omnik inverter with WiFi module, which is meant to report data into the Omnik portal. There is a very good plugin that will also feed into Domoticz variables...

Perhaps interesting to have a look into this thread