Emon Pi2 on Three Phase supply and Solar, one solar reading incorrect

[CampdenLad (Alastair Wheatcroft)]

I’ve installed an EmonPi2 with 12 Ct’s to monitor Supply, Load 1, Solar generation, and Load 2.

I reinstalled the 3phase 12 CT sketch from within the Admin menu

The Voltages on the 3 phases all seem ok.
All the phases are in the same order as the supply - L1 first!
All the CT’s except P12 have readings to be expected.
CT’s P10, P11, P12 are on inverter cables, P10 and P11 are roughly a third of the generation as on the inverter, but P12 reads nowhere near.

Just wondering if Ive messed something up in setup.
Ive swapped out the CT with another one, and the one previously working did the same thing on P12.
The jack seems to seated home properly.

Any ideas?

Thankyou

[Robert.Wall]

Welcome, Alastair, to the OEM forum.

1. Have you got anything connected to the analogue input of your emonPi2? (Because CT12 and the analogue input on the green connector share the same input on the processor.)
2. Is it paired with the correct voltage (presumably 3)?
3. Is the entry in emonhub.conf correct? (Compare it with this taken from the front-end sketch. Is there a weird number in the ‘scales = …’ line?)

[[29]]
   nodename = emonDB_29
   [[[rx]]]
       names = MSG, Vrms2, Vrms3, P7, P8, P9, P10, P11, P12, E7, E8, E9, E10, E11, E12, digPulse, anaPulse
       datacodes = L, h, h, h, h, h, h, h, h, l, l, l, l, l, l, L, L
       scales = 1.0, 0.01, 0.01, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
       units = n, V, V, W, W, W, W, W, W, Wh, Wh, Wh, Wh, Wh, Wh, p, p

4. Is there anything different in the processing of P12 on the Inputs page of emonCMS, compared to P10 & P11? (Though I can’t see any processing there at all!)

@CampdenLad

Ive swapped out the CT with another one, and the one previously working did the same thing on P12.

5. Can you do this the other way round – plug the c.t. presently on L3 into CT11? It should read approx -75 there, if the current is the same on all 3 lines.

[CampdenLad (Alastair Wheatcroft)]

Thankyou for the welcome!

@Robert.Wall

Have you got anything connected to the analogue input of your emonPi2? (Because CT12 and the analogue input on the green connector share the same input on the processor.)

No, not knowingly!

@Robert.Wall

Is it paired with the correct voltage (presumably 3)?

Yes, All inputs are configured L1(brown) L2 (black) L3 (grey) on emonVS, to p1(brown) p2 (black) p3 (grey), p4( brown ) p5 (black) etc

@Robert.Wall

Is the entry in emonhub.conf correct? (Compare it with this taken from the front-end sketch. Is there a weird number in the ‘scales = …’ line?)

It looks like autoconf is enabled so the list doesnt appear? There is no difference in the node setup.

@Robert.Wall

4. Is there anything different in the processing of P12 on the Inputs page of emonCMS, compared to P10 & P11? (Though I can’t see any processing there at all!)

No processing yet…

@Robert.Wall

Can you do this the other way round – plug the c.t. presently on L3 into CT11? It should read approx -75 there, if the current is the same on all 3 lines.

Swapped ct12 with ct11, with this result.

Interestingly the solar ct’s are not reading a third of what the inverter is saying this morning (the sun is making an appearance so higher values!) Generating 11kW and the ct’s are only showing 1.5kW a phase.

Thankyou for helping.

[Robert.Wall]

Which c.t’s (rated current) have you got and what are inputs CT10-12 set up for?

This might or might not explain CT12 being so far wrong, but CT11 reading -733 on Line 3 is what I’d expect if CT10 is correct. It’s also what I’d expect from CT12 on Line 2. If the CT12 input is set for the same current as the rating of the c.t., it looks very much like a faulty input on your Pi or the connection between the expansion card and the main OEM board in the emonPi2. (The swap ruled out the c.t. itself.) If the input is set up correctly, from what I can see I don’t think you’ve done anything wrong and an email to ‘The Shop’ referring to this thread is called for.

[CampdenLad (Alastair Wheatcroft)]

@Robert.Wall

Which c.t’s (rated current) have you got and what are inputs CT10-12 set up for?

50A CT’s, I could probably have used 20’s for the Solar, but the rest needed 50A CT’s. they are all set as 50A CT’s.

Thankyou for your help, I’ll contact the shop.

[TrystanLea]

Thanks @CampdenLad I’ve responded to your email.

It would be great to see what you see in the Serial Config window and it might be worth resetting the unit with ‘restore to default values’ and then reapplying the CT calibrations.

It might also be worth reuploading the firmware, I tested the 3phase 12CT firmware yesterday and checked CT12 again at it worked correctly here but it might be worth re-uploading the firmware just in case we shipped an earlier version with the analog input enabled on CT12. This isn’t a known issue but it’s an easy mistake that we may have made during firmware compilation.

If neither of these sort it then I think the best thing will be for us to send you a replacement.