Newbie - new install

Hi all,

I would like to get this up and running. But before I buy, a few questions ;). I have a server on all the time that I can run the software and post to over Wi-Fi. I believe I will require emonTx, with Wi-Fi card and power via usb.

Can someone confirm and advise what cables I should clamp for best results

Thanks in advance!


The one marked LL will give you your import from the grid. I cannot see any solar so that should be it.


Welcome, @mooneym17 to the OEM forum.

What are the Henley Blocks bottom right? One pair of cables goes to the consumer unit we can see, another pair goes upwards. There’s something else going on out of the picture.

One goes to consumer board inside the house, the other to export meter outside

Is that what we call a Generation Meter? Does that imply you have P.V. and an inverter?

If yes, do you want to use an optical pulse detector on the generation meter (if it has a flashing LED), do you want to measure current directly, or do you want/can you get its readings in some other way? The difference is, the LED gives you generated energy accurately, but it’s ‘historic’ - you only know the energy, and can infer average power, after the event, whereas measuring power with a c.t. is less accurate, but the data from both c.t’s is essentially synchronised, so doing maths on both (e.g. deriving a sum or a difference, and accumulating power to give energy) is easy.

I planned on using both ct’s , just not sure where to place them.

Hhmmm … seems everything is out of stock on the online shop ;(

What do you want to measure? Remember, all we know about your installation is what appears in this Topic.

I would like to measure pv generation and overall consumer power / pull from grid.

That is simple - as John wrote, it’s the right-most cable coming out of your main meter. Or if it’s easier, the brown cable going into the bottom of the Henley Block.

Is the SDM 120A your generation meter? If it is, then the cable for the second c.t. is the cable from the ‘Line’ Henley Block (the left-hand one) that goes from there into that consumer unit - the one containing the generation meter.

If it’s easier, you can of course put the c.t. on the equivalent Neutral cable. If you do, it must face in the opposite direction.

Having put your c.t’s on those cables, you will have, in OEM terms, a “Type 2” installation. CT1 is the one below the Henley Block, CT2 is the one above it.

Like many suppliers, OEM has been hit by the global semiconductor problems. Keep an eye on the topic AVR-DB: emonTx V4, new hardware in progress - #156 by TrystanLea pinned at the top of the ‘Latest’ page for any news.

Great. Thanks so much guys! I will keep an eye on that topic :wink: