good morning youtube so we're here on the home automation controller screen
and i wanted to talk a bit about this home energy monitor generation five so this is from aotech and
i've had a number of these over the years these home energy monitors all look pretty much the same
they haven't changed the external appearance but they've changed the way they work inside
i started out with the generation one device back in 2013 i believe i think it has an
option for battery power or there's a little five volt dc wall supply you can plug in at least in
the us version has two current transformers that you put in your breaker panel and monitor line one
and line two yeah so one of the quirks with the generation one device is that you actually have
to enter the voltage so for the us you enter 120 volts because this device doesn't measure
the voltage it only measures the current and then because of that it doesn't know anything about
like power factor all it sees is the ac current through the current transformers and it then
multiplies that current by 120 volts to get watts it also has no idea which way the power is flowing
that device was pretty primitive so a few years later i picked up the generation 2 device and that
one has a built-in ac power supply you put the two current transformers on so here's my breaker panel
and i have the two current transformers inside the home energy monitor just hangs down here on the
wall and there's a power cord that runs over and plugs into an outlet and show you what the current
transformers look like i have line one on this wire coming in and then i used to have the line
two transformer over here but i had to move it up here and i'll talk about that in a little bit
but that's the way you install these you just clip these two current transformers around the incoming
wires in your breaker panel you run those wires outside and you put the unit outside and plug in
the power down here so with this unit if we look at the device options you no longer had to tell
it what the voltage was because it knew what the voltage was i think it was a little more accurate
number one they could actually measure the actual voltage instead of just a constant number
and then they likely also could measure power factor and adjust for the power factor but one of
the problems with this meter is it didn't measure the direction of power flow it just assumed power
was coming into the panel that meter didn't know if power was going in or out with this diversion
load project one of the things i did was i upgraded to this generation five home energy meter
because it was supposed to have the capability of measuring positive and negative power flow
so that's one of the reasons i had to move this current transformer up here from down here because
you have to get the correction of current flow proper way so these transformers are marked within
and outside so i put these little arrows on there to say the power is coming in from the grid it
comes down here and then into the breakers and in order to get the line two transformer oriented the
right way i had to actually put it up here above the main breaker instead of down here because if
it was down here it was going to be backwards and measuring the power flowing out here's
the installation manual you can see here they have the clamps mark k and l for the direction
of current flow and you have to make sure line one is coming in and then the line two is going
out because on the us power connection you've got essentially the neutral is in the middle
line one is off to one side and 180 degrees out of phase is line two so you've gotta actually flip
the line two transformer relative to the line one so that they're both in phase and then the meter
is running off of a line one circuit and i hooked all that up and paired the unit with my controller
and i got positive power so what the previous home energy meters did was they just did absolute value
of the power so the power was always positive no matter which way it was flowing
and i looked into the user's manual or the the technical manual and there's this parameter two
so this is the parameter number definitions the parameter number
the description the value and the size yeah if we scroll down here there's this new parameter number
two which says an hour in energy detection mode so zero which is the default is report
power and energy absolute value and that's what the previous meters did then there's this mode one
which says positive negative power and algebraic sum of energy and then there's these two other
modes two and three one is port positive negative power but only report positive or imported energy
and mode three is only report exported energy but both of them say positive negative power
of course when you plug the meter in you get this mode zero i'm pretty sure i tried mode one
but i must have either not got it configured right or didn't test it right so then i decided to try
mode two which i thought would actually be the same thing report positive negative power because
that's what i want to do with the diversion load is i don't want to export any energy i want to use
it all internally so anyway like i said i had switched over to mode two again i don't know
if i was not testing it right or something was amiss you know after i had that problem about a
month ago june 17th i posted on the eslo community forum they're the ones that acquired vera i always
see 0.000 watts when there's negative power flowing and then i see positive numbers when
power's flowing in but i made a support request on the eslo site and it told them same problem
number one they came back and said why would anybody be interested in negative power that's the
craziest thing they'd ever heard of and they said well we're not supporting the bureau of firmware
anymore or we're not updating it so no chance that it ever works but you will give you a discounted
price on a new controller and so i asked them you know would the new controller support negative
power readings and they came back and said nope it won't do it either but you can request that we add
that feature but then the funny thing was out of the blue i get a report from this guy tin man on
the eslo forum and he said he plugged one in two years ago and probably found the same thing i did
was he was getting negative power because one of his current transformers was backwards and then he
he basically turned the ct around and was getting only the positive reading but that gave me a clue
that oh it is possible and i asked the guy what mode he was using he said he hadn't changed any
modes but i bet he did and he gave me his port flags or bit fields here anyway what i did was
i thought you know what this description in the manual might not be correct or the device is not
working like the manual says so i'm not sure if it's a documentation problem or a firmware problem
but if you read this only report energy positive part and if you apply that to power here it's
power energy absolute value here positive negative power and algebraic sum of energy and then here
i'm guessing they really meant only report positive power and energy only report negative
power and energy i went and tried mode one and i had some trouble getting that to take i had to
enter mode 1 several times show you where that is it's under device options and that's this right
here to energy detection mode i was running two i would enter one save changes and i kept getting
errors error setting user configuration when you would do that after like 15 20 minutes i would
come back to this screen and it was still two so i'd enter one again save changes go away for half
an hour i'd come back it was still two so i kept changing it to one saving the changes and then all
of a sudden it took and it was like okay now i've got mode one running and as soon as i did that
i started seeing negative numbers here and so i think that was the problem i just probably didn't
wait long enough here for this mode 1 to take effect so yeah let's see if we can get negative
power showing up here gradually increasing it usually has to get up a little over 900 watts
before it starts generating you can see we're pulling a little bit of power from the utility
that's the proof that it does work so you do get the negative readings there the other reason
i wanted to make this video was to explain why i've gone through several iterations of this code
it looks like right now i've still got a bit of a problem we're stuck here at one percent
and i'm not sure exactly why but my original code from several years ago was written based
on the generation two meter that only reported absolute value power so it was always positive
and so that code i had to be very careful never to go negative so i would always check did i go below
25 watts and if i did i better do something to prevent it from going below zero so i always
tried to keep the power between 25 and then 50 watts and i had the meter set up to report 25 watt
changes if the power changed by more than 25 watts it would send out a report so i had everything
based on that i figured if it went below 25 i was getting close to zero and if it went above 50
i was getting away from 0 and then i went to the generation 5 meter and originally i had it working
to where like this number would actually read out 0.00 when i was in mode 2 which is only report
imported energy so then i modified the code to work off of 0.000 i assumed the power was negative
and then i would step up the diversion load by like five percent increments and i would keep
incrementing the load until this number went positive and then i would stop but
now with the true negative numbers i can take this negative 48 and i could say divide this by six and
come up with an actual number to put in here so yeah if i go to like eight percent and i i went
to nine 54 watts now you can see this should go close to zero because i added 54 watts of load
let's see what this does well we went to 33 so i have to go up another five so let's go to 14.
now let's see so this is basically the way the diversion code works so we're still
minus nine so let's add another percent maybe add two percent try to get ahead of it here see if we
can get up to plus yup you can see the the power is still building so we have to go up another
one let's go up two percent and we'll see what that comes out to there yeah now we're finally
positive so you can see i can get positive numbers and negative numbers just by adjusting this slider
to use up any negative power here so yeah if you have any questions on setting that up if
you need any more details post up in the comment section below and as always thanks for watching