Ah, now I understand better.
That is correct.
It is there, but it is not interpreted correctly by emonCMS, because emonCMS has the wrong information. There is a mistake in the file emonhub.conf You can edit it via your web browser. Go down to the definition of Node 15:
[[15]]
nodename = emontx3cm15
[[[rx]]]
names = MSG, Vrms, P1, P2, P3, P4, E1, E2, E3, E4, T1, T2, T3, pulse
datacodes = L,h,h,h,h,h,L,L,L,L,h,h,h,L
scales = 1,0.01,1,1,1,1,1,1,1,1,0.01,0.01,0.01,1
units = n,V,W,W,W,W,Wh,Wh,Wh,Wh,C,C,C,p
whitening = 1
and change the line datacodes = … to
datacodes = L,h,h,h,h,h,l,l,l,l,h,h,h,L
Do the same for Node 16 - just in case you ever have another emonTx.
Then the Energy (‘E’) values should be correct.
The number -2882 comes from the rule to interpret a signed value:
x= ([byte 1] + ( [byte 2] * 2^8) + ( [byte 3] * 2^16) + ( [byte 4] * 2^24) )
if x > (2^31)
x = (x - (2^32))
return x
For you, x = 4294964413
x > 2^31, therefore x = 4294964413 - 2^32 = -2882
For item 8, x ≤ 2^31, therefore you see the correct value.
To us, “import” is power or energy that comes into your home, “export” is power or energy that leaves your home.
The power into your house should be positive at night when there is no sun. If that power is negative, turn the c.t. on the cable to face the other direction. The energy will follow the power.
Don’t worry, we were all beginners once.