3 phase + 1 phase measurement at the same time

Juraj_Hotovy · 2017-04-28T01:31:07.273Z

If I buy 1x emonPi, 1x emonTxV3, 4xCTs
will I be able to derive information about
total consumption (all 3 phases)
& consumption on each individual phase separately
from the same measurement period?
(and possibly 1 phase PV generation as well).

(I understand the slight inaccuracy due to single-phase voltage measurement.)
Thank you.

Robert.Wall · 2017-04-28T12:23:11.449Z

You cannot synchronise the emonPi and the emonTx. Though both should sample at the same rate, the exact 200 ms period over which the measurement is made will drift over time, due to small inaccuracies, temperature changes, etc.

But, unless there is something else you have not mentioned, why do you want to do that? You will get the consumption of each phase (assuming a 4-wire system) plus the 4th C.T. from the emonTx, so adding the three phases together, either in the emonTx or in emoncms, will give you the 5 quantities you want: 4 × 1 phase + total across 3 phases, all derived from the same 200 ms sample.

The emonPi will give you two more, single phase currents/power/energies. If you do not need those, a cheaper solution would be an emonBase instead of the emonPi.

Juraj_Hotovy · 2017-05-19T15:22:28.860Z

Thank you very much for your quick answer.
My question was not precise, but I found the answer from one of your comments here: 3 Phase Summary Power Feed - how to configure kWh in emonCMS?

Thank you again for your effort