I'm trying to measure kWh with an Arduino that I have connected to a ESP8266 that communicates this value to a web server I have. And I've been trying to find the best and easiest way to go about this.

I'm thinking that I can hook a PMAC903 up to the Arduino using the interrupt pins and measuring the pulses, but I don't really know how I'm supposed to do that? Will it even work? Is this the way it's normally done? I can't really say I've found an easy solution to measure current.

You can find documentation for the PMAC903 here and I'm currently in possession of an Arduino Uno that I'm using.

  • 1
    You might get away with only the ESP8266, it's good enough to count pulses. The PMAC also seems to talk "Modbus-RTU protocol" RS485. I figure you're trying to measure consumption of a house and not something like the consumption/current of an LED?
    – aaa
    Commented Apr 26, 2016 at 10:00
  • Somewhat related project
    – Gerben
    Commented Apr 26, 2016 at 12:37

1 Answer 1


The state of this meter can be read in 3 ways:

  • Pulse, this is very easy to implement. But depending on the stability of the hardware u can miss pulses leading to inaccurate values. In this way u have to calculate the meter value yourself.

  • RS485, this is a communication bus not default on arduino. But given this link https://arduino-info.wikispaces.com/RS485-Modules i think it is doable but not easy. This will read the value from the meter.

  • M-Bus: There is special hardware needed to interact with it. This is the industry standard of doing it. It's not cheap. But u can link many meters together. This will read the value from the meter.

Depending on your time/knowledge/other requirements u have to make a chose what way your going to use.

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