I know there are tutorial on how to monitor home energy consumption with an arduino, but I already have (some) hardware that I would like to use.
On my electric panel, I have a MCI 45A energy counter that gives 0.5 Wh impulsions. I would like to connect it to my arduino due (3.3V) board, but I don't know how to proceed, and I am afraid to damage it and I am looking for guidance. In particular, the documentation of the energy counter is very light. It is made for experts and many informations (that are apparently obvious) are lacking.
Characteristics of the counter:
– 230 V ; 50 Hz ; 45 A
– Pulse emitter: 0.5 Wh ; 80 ms ; 27 Vcc max ; I max 27 mA
My questions:
Does the pulse emitter give some voltage, or is it like a relay (meaning no voltage, it juste acts like a switch)?
If it does emit voltage, I guess, I will need help connecting it.
If it acts like a relay, I will just need two resistors, and an interrupt pin (like pin 3) from the arduino.
Hard to tell without a link to it's datasheet. From what you posted it could mean that it's a simple internal open collect NPN transistor interface with the maximum voltage and current rating for the transistor as given.
If so that would be pretty easy to interface with an arduino digital input pin. However what isn't stated is if the device's ground pin (there needs to be a ground or common pin to complete the pulse-out signal) is isolated from the mains or not. If not then I would not proceed with this until you get more detailed information or help.
Thank you for your reply.
Sorry I didn't put the link to the data sheet. There are so few info in it. I believe I did put all that is relevant here. Plus, the data sheet only exists in french.
Below are the links to thew pdf files: Link 1 Link 2
What I can add is the the pulse emitter has a polarization: one line is written + the other -
My guess is that the + and - terminals are the collector and emitter connections of an optocoupler. If so, then you can connect the - terminal to Arduino ground, and the + terminal to an Arduino digital input, set to mode INPUT_PULLUP. But this is only a guess. Connecting 1K resistor in series with the ground connection and a 2.2K resistor in series with the other one will give some protection to the Arduino if it is an incorrect guess.
Thank you for your reply.
Perhaps I could test this hypothesis by using a 5V power supply and a 10 k? resistor. The diode should light up periodically for 80 ms. Is that right? How would you rate the probability of me damaging the $90 energy counter with this setup?
I think that's an excellent idea, with no risk of damaging the energy counter. Make sure the 5V supply is not grounded, i.e. use a 5V wall wart that has a 2-pin plug (no earth pin). 10K is rather a high value of series resistor for a LED and 5V, so you may need to darken the room to see it. Use a green LED rather than a red one, the eye is more sensitive to them.
It appears that this device is produced by a Dutch company called "inepro." The manufacturer intends for resellers to apply their own brand names to this product. Here's a link to a French version of what seems to be the datasheet: BIS-ELECTRIC | Distributeur de matériel électrique professionnel. I think that the pulse output, called, "Sortie d'impulsions," is on page 9. An online translation program says that the pulse output is electrically isolated from the rest of the device, that the external source voltage must not exceed 27V, and that the maximum current is 27 mA.
tmd3, that's a good find. It confirms my suspicion that it is an optocoupler output. From the English version of the manual:
The PRO1 series DIN rail energy meter is equipped with a pulse output which is optically isolated from the inside circuit. It generates pulses in proportion to the measured consumption for purpose of remote reading or accuracy testing . The pulse output is a polarity dependant, open - collector transistor output requiring an external voltage source for correct operation. For this external voltage source, the voltage (Ui) should be lower than 27V DC , and the maximum switching current (Iimax) is 27mA.
Thank you very much for your replies and sorry for the late follow up. I haven't had the chance to test everything yet, because I had to complete the refactoring of my home energy distribution circuitry. It prove to be most challenging, because of all the new regulation I wanted to comply with, and because of the crapiness of the former installation. I did my best.
Today, I managed to connect two different (not the same brand) energy counters to my arduino board. Thank you very much for your help.