Hybrid Car – More Fun with Less Gas

Hacking Xantrex/Trace SWCA( SW series inverters Communications Adapter)

register ::  Login Password  :: Lost Password?
Posted by j on January 2, 2005, 2:59 pm

Xantrex makes an SWCA (Sine Wave Communication Adapter) for hooking up a
computer to the SWxxxx model Inverters.

Does anyone here have one? Have you looked inside? Is it just a line
driver? (ala Max232)

Has anyone built there own?  These things sell for ~$50, which is a
little out of line, consider what we've already paid for the inverter.
I'd like to build my own SWCA, but wanted to find out what the rest of
you have learned already.

  - jim

Posted by Loren Amelang on January 2, 2005, 8:10 pm

I've never seen one. Like you I have been curious, but considered the
price outrageous for the limited capabilities.

You probably know the manual is online. One thing it reveals is that
the adapters are addressable, so you can have up to eight inverters on
a single phone cable bus connected to a single computer serial port. I
don't know any way to do that with just a serial driver chip - I
suspect there is a tiny microprocessor with a bit of Flash in there to
store its address. Once you have that for addressability, the
temptation would be to use it for other more complex conversions as
well - but I'm totally guessing.

Since it plugs in in place of the remote control panel, someone with
the remote control could use it to reverse engineer the required

I'm looking for an even simpler bit of information. I know you can
force the SW series to off by connecting pins 17 and 19 of the
stacking interface connector to pin 14. Is there a similar trick that
would force the inverter to on?


Posted by j on January 2, 2005, 9:34 pm
 Good point on the addressable nature of it. I did indeed notice that in
the manual. Agreed, some tiny little 8bit controller, would do it.

I'd sure love to build my own. I'm into Ham Radio APRS, if you know what
that is, so by hacking the SWCA, one would be able to put all the stats
up on the internet.

Good point on reverse engineering the remote. One might even be able to
reverse engineer quite a bit with just the SWCA software.

  - jim

Loren Amelang wrote:

Posted by Loren Amelang on January 3, 2005, 9:57 pm

On further thought, they say the capabilities emulate the buttons and
LEDs of the front panel. Eight buttons, eight LEDs, 25 connector
pins...  I wonder if there are just discrete TTL signals for those?
You still need characters coming back for the message display, though.
Wonder if it is serial or 8-bit parallel?

I doubt RS-485 is involved. The manual says the addressing capability
is a function of the adapter housing, not of the inverter itself.
Besides, the interface started out as a place to hook up an external
vcersion of the front panel, not an industrial computer. It is
probably as simple as possible, hence the unfriendly cost of making it
talk to a computer.


Posted by Morten on January 2, 2005, 11:04 pm
Hmmm that sounds like RS485 to me, a little more complex but still very easy
to interface up against. I once saw a IC that was made specifically for
interfacing between RS232 and RS485 that had provission for system address
via a couple of jumpers..

It may of course be much more complex, but if I was to make a serial
interface between some inverters and a controller I would use a industry
standard and go for RS485...


Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
Version: 6.0.825 / Virus Database: 563 - Release Date: 30/12/2004

This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread