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Inquiry -
10/15/2007
Hi,
I just saw your
website displaying your solar energy savings on-line.
I recently installed
a 10KW home system with three SunPower inverters.
Can you advise me
how I can get the inverter's info into my computer system as you have
done?
Thanks for the fascinating
website,
T.F.
Reply -
10/20/2007
Here's what you will need
in order to monitor your system:
Software:
GT-View (free from Xantrex --
http://www.xantrex.com )
(
Even though you and I both have the SunPower Inverters, that is just a
name-branding operation. I visited a neighbor a couple of doors
down
from me who also has solar and his inverters had "GE" plastered all
over them, but they were exactly the same as mine! So, what's in
a
name these days? Nothing. SunPower and GE were too lazy to
develop
their own devices. The Xantrex software will work with ANY of
them. )
Hardware:
* A PC (or laptop) with as many COM ports or USB
ports as you have
inverters. (Or if you're short on USB ports, you can get an USB
extender hub for more plug-in capability.)
(There
is an RS-232C connector in each inverter and the data that gets passed
out of that port is specific to that inverter. If you set up the
viewer with SYSTEM TOTALS showing and have the RJ-45 bus
interconnection in-place, then the sum of all the watt-hours generated
by all the inverters will be common data that will appear at each
RS-232C port. However, the DC volts, DC amps, AC volts,
Frequency, and
Output Watts (peak and cummulative) will still be reflective of that
specific inverter.)
* The same number of null-modem DB-9 cables (male at one
end, female
at other end) with sufficient length to go from each inverter to
your
PC / laptop,
-- or --
* USB-to-RS232C converter cables (Some come with
driver software, or
you may have to download a driver from a website. I had to do it
using website download. A source for these cables and driver is
http://www.goldxproducts.com/product/show-product.asp?pid=GXMU-1200 )
* (Number of Inverters) - 1 = number of RJ-45 interconnect
bus cables
so that you can gather SYSTEM TOTAL data across all your inverters.
Example: I have 3 inverters so I needed just 2 cables.
The inverters
each come with a bus terminator plug, so those are already available
and you won't need to buy any. (These cables can be purchased at
STAPLES, Office Depot, etc.)
At
this point, you have sufficient connectivity to view the performance
data from your PC monitor. If you want to make a webpage like I
did,
you need to read the next section.
Internet Connection:
* If you want to make your performance web page a 24/7
dynamic thing
like mine is, then it is suggested that you have a high-speed Internet
connection that is always "on" (such as DSL or cable modem). I
would
NOT recommend a dial-up arrangement because of the update frequency.
The GT-View software comes with an integrated FTP program that
will
upload your performance data screen(s) to your web server as often as
you choose (I do my updates every 150 seconds or so via FTP, but I do
the auto-refresh of the web page by browser command that is around
60
seconds.)
* The things being uploaded via FTP on a repeating basis
are the
*.png "screen captures" of the performance screens for each inverter.
These are snap-shot, static images. Whatever values were
displayed
are what is captured just prior to their being uploaded to the server.
(This explains why the arithmetic usually doesn't look right when
you
add the three inverters outputs to get the system total output!)
* Of course, if you don't have a web host service, you have
no place
to FTP a webpage with the performance data. That will be another
matter to resolve, not difficult by any means. If you know
someone who
has some available webspace, you might be able to use that space for
free or for a slight rental charge... Since you have a business
website, you could do like I did and create a separate directory to
which you point all your solar updates and in which you hold your
index.html (Solar Home page). Your link would look similar to
mine,
the difference being the domain name, of course:
http://www.h-and-m-analytical.com/solar/index.html
So,
basically, you're looking at a minimal dedicated PC, with high-speed
Internet connection, several cables to connect your inverters (which
cost me about $30 each as they were the USB-to-RS232C type), a couple
of Cat5 RJ-45 interconnect cables for the inverter-to-inverter data
gathering, and the FREE software from Xantrex, and possibly your serial
communications conversion driver which most likely would also be FREE.
I would say that you could do the whole thing for under $1,000.
That
is basically all there is to it. Once all the software and
drivers are
installed, it is just a matter of opening the Xantrex GT-View
application and setting up the application to output the information
that your inverters are making available. Oh, one other thing:
As you
have 3 inverters, there will need to be 3 "instances" of the GT-View
application running simultaneously. Each "instance" is tied to
one of
the COM ports for the particular inverter connected to that port.
That
is why you see 3 "meter panel" (performance data screen) images on my
website.
The
inverters' daily data will be logged to a file on your PC. The
logged
data is appended to the end of this file each successive day so you can
get a fairly substantial amount of information recorded that way.
On
the application set-up for the Xantrex GT-View, you set the time of day
when you want the logged data to be stored. I have chosen 10:00
PM for
mine. In the summertime, the systems will have shut-down and
stopped
producing power by then, in the winter it would happen sooner, but I
just set it and forget it.
I
hope that you will find this information useful and that you'll be able
to get your system information out to see it in the full light of day!
Have a nice weekend,
W.H.