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Hi Paul. I have a similar setup to you, a 20kWp array with two meters, one generation and one import / export. I think you're far more savvy when it comes to setting up these monitors but I am trying to do something similar so I was interested to read of your experience. Have you made any progress? 

I have only just ordered my first emonPi and 2 sensors, one CT for private consumption and one optical to read my Landis & Gyr generation meter. I'm intrigued that you also have a generation meter as as far as I know they're not needed for FiTs so I wonder if you're in Northern Ireland like me?

Hi, yes I've got a workable system running now, but ended up just using the LED pulse output of the A1140 meter as unfortunately the IR interface is password protected by our utility company, so I can't access it. Not ideal, but it works. I haven't used the Open Energy Monitor system as I have a specific requirement here, I ended up using a networked Arduino Ethernet board with a custom built shield with interfaces for the meters and energy monitor we have here.

I'm in the UK, the generation meter is required as we have to post the readings up every month in order to get paid for the power we generate. It's also convenient for me as I like to dabble with these things :-)

If you want to contact me direct you're more than welcome to the details of my solution - I've sent you a private message with my email address.

Regards
PaulM

Thanks Paul. I am also in the UK the Irish bit - I take it you're in GB.

It definitely sounds as if what you've been doing is beyond my ken!

I have successfully set up a basic Emonpi system to record generation and domestic usage. One thing I would love to be able to do is use emoncms to show me a live power feed from my inverter, this would have to be done by counting the optical pulses over a fixed period of time to convert the kWh into kW, but I have been unable to figure out a way of configuring the feeds / visualisations to do this. Obviously it wouldn't be very accurate when the output is very low but I could live with that. I had to use the optical pulse sensor as the system is 3 phase so using CT clamps would have been problematic, but like you I conveniently have a 3 phase smart meter recording all generation. The inverter manufacturers (Delta) have quoted £110+VAT for a cable and a USB adapter to connect the RS485 interface on the inverter to my PC. This wouldn't allow me to integrate the data with emoncms or anything else as far as I can tell and is daylight robbery!

Hi, Yes sorry, I'm in Devon, England :-)

For USB to RS485 converters there are dozens on Amazon, from £1.40ea, take your pick ! Note I haven't tried any of them, I made my own using a MAX485 IC on my custom Arduino Ethernet shield. Alternatively have a look at these (http://www.ftdichip.com/Products/Cables/USBRS485.htm) available direct or from several UK suppliers like RS and Farnell. Again I've not used these but have used their RS232 USB cables and they work just fine.

Try measuring the period between pulses rather than counting pulses over a period of time, this will give you a faster indication of direct power measurement.

I have an Integra Ri3 energy monitor rather than a smart meter (http://www.crompton-instruments.com/integra.html) used to monitor the actual power we use on the farm. It uses CTs with no problem. Because we have a generator set I can't locate the monitor behind the incoming electricity meter and use it to measure both import and export power, hence have to use our electricity suppliers meter to do that. Unfortunately the problem I've now encountered is that the LED pulse on the A1140 meter pulses for import *AND* export power, so I can't separate the two, and can't read the meter directly due to the passwords, so have no way of reading the actual import power from the meter !!! The only solution I can see at present is to use a second energy monitor :-(

Regards
PaulM

Hi Paul.

I got one of those cheap USB converters but I've been frustrated in my attempts to connect it to the RS485 interface.

Delta's handbook gives one pin configuration, the board in the inverter gives another, and their "technical" help in the UK gave me another. I've given up trying.

I had hoped the Emonpi would solve the problem by allowing me to read the pulses from the generation meter to get an instantaneous power output. But as I said all it is giving me is the total energy generated. Plus this differs from the figure recorded by the inverter by about 1% for no obvious reason.

It should be simple enough to record my single phase consumption (this part of the Emonpi works), record my generation, and derive import and export arithmetically. I would like to be able to automatically upload live data to pvoutput.org which would do the calculations for me.

In practice it's unlikely you'll do any harm to the RS485 interface with wrong connections, so if you have an idea of the baud rate it can't do any harm just using a terminal emulator on the PC and finding the correct connections by trial and error. You usually find a simple Enter (carriage return) provides some recognisable response when you get the baud rate & connections correct, and garbage otherwise.

I can imagine how frustrating it can be when things don't work as expected. I get frustrated enough sometimes, and I'm fortunate to be able to design and build my own interfaces and write the software to manage them ! If you're up for it try writing your own software for the Emonpi, there appears to be plenty of info available here on the interfaces etc., plenty of knowledgable guys to answer questions and there's plenty of info on writing Python programs on the Raspberry Pi. There's some good tutorial stuff on the MagPi web site (https://www.raspberrypi.org/magpi/).

Good luck
PaulM