Archived Forum

Check that you have installed the CTs correctly, that they were plugged in to the V3 before you powered it (or that you have reset it since powering it) and that the plugs are fully inserted, that you actually do have a sensible current in the primary winding of the CT (namely the cable it is clipped onto), that the CT halves are correctly clipped together.

The usual fault is the CT has been clipped onto a 2- or 3-core cable, when of course it will read zero since there is no nett primary current.

Thank you for those checks.I tried the multiple times but unfortunately no change.

Only when I plug out and in to I see life on a change jump up to say 700 then decay 2-3 steps to zero. Once at zero it is solidly at zero. The Voltage appears to be logging fine at all times.

Are there amy other tests you can suggest pls?

What happens if you try swapping CT4 with another at the emonTx only? This will establish if the issue is internal ( emontx/sketch) or external (CT/mains circuit) depending on whether the issue remains on CT4 or moves to CT?

Paul

The fact that you see a value when you connect and disconnect the CT shows that the emonTx itself appears to be working. What you are seeing is the step change in the input from 0 V (it is grounded inside the socket when the plug is out) to 1.65 V dc which is the normal quiescent working condition, as it goes through the software high-pass filter. You need to check your CTs.
If you have the YHDC SCT-013-000 from the shop, then with a multimeter, you should read about 90 Ω between tip and sleeve of the plug. There's no connection to the ring. If that is OK, put your multimeter on mA, again connected between tip and sleeve, and then clip the CT on its cable. You should read 50 mA per 100 A of current, so 4 mA with a 2 kW load.

The system works now.

I checked the CT as suggested and it had the 90-100 Ohm and the expected current reading on the plug.

I connected the system to the fridge that was running at 900mA.

emoncms registered 220 W which checks with the reading an in-line commercial meter which registered 210 W.

Now for an admission, my mistake was that my initial testing was monitoring the power consumption in the AC-AC transformer itself. The TxV3, it appears, uses only 0.9 W and this is just too low to register on the system with that model CT. I think what fooled me is that the initial reading on the input interface of the cms is "0.00", suggesting that the system will read to two decimal places - I guess it would but with a different model CT.

Thanks for your help in sorting this out!

Sorted it out (see other reply), but you are quite right,the key was understanding if the components themselves where operating correctly.

Thanks Paul.