1. Buy the RS485 converter.

These are readily available from ebay. If your computer or server has a serial port, the RS232 type is recommended. Otherwise you can buy a USB version.

The PHP script and serproxy has not been tested with a USB adapter. Your results may vary if a USB adapter is used. Please let us know if you have success with a USB adapter.

2. Buy the connectors and cable

For the internal connection to the inverter's LCD board, I used Altronics' P2652, a 2-way pluggable terminal block. This terminal block is almost an exact fit to the socket on the LCD board.

For the external connection, I used Altronics' P9463, an IP67 3-Pin 5-amp Chassis locking socket. For the plug, the corresponding 3-pin P9483 was used (image shows the 5-pin version).

2 or 3 pin? The reason why the 3-pin version was chosen is because the RS485 standard includes provision for a shield (ground) to prevent interference.

If needed, replace the unshielded pair with a shielded twisted pair cable, and connect the third pin to the shield. The third pin on the inverter socket should be internally connected to the chassis. If earthing is done, don't do it on the computer end. Shielded balanced / twisted pair connections should only earthed at one end.

For most domestic installations, a 2-pin unshielded connection should suffice.

Note: if your inverter already has a socket fitted, do not purchase the plug and socket pictured. Instead, you need to purchase a Buccaneer 400 Series 3-pin plug, part number PX0410/03P/4045 (green with 4.5mm cable entry) or PX0410/03P/5560 (Blue with 6.0mm cable entry). Then skip to step 4.

3. Make the connections inside the inverter

Unplug power. Remove all power (PV and Mains) connections to the inverter. Wait several minutes for the PV capacitors to discharge.

Open Inverter lid. Open the lid of the inverter by unscrewing the 4 bolts using hex screwdriver bits. Carefully lift the lid. It may be stuck tight due to the airtight foam seal - just pry it carefully and eventually the lid will pop open. There is a ribbon cable and earth wire connected to the bottom of the lid - don't open the lid too quickly or you may snap/break the cables. You may disconnect these cables to make the next few steps easier.

Remove the bung. Note that even though the bung has a slot for a flat-blade screwdriver, DO NOT attempt to remove it this way. It is inserted into a keyed hole and you will not be able to unscrew it from the front. Instead, you need to unscrew the retaining nut from the inside.

Make the internal cable. Make a short 20 or 30cm piece of twisted pair wire. Strip one end and attach it to the 2-way terminal block. Solder the other end to Pins 1 and 2 of the IP67 socket. Take note of polarity; pin 1 on the socket should be T+/R+ and pin 2 should be T-/R-.

Attach the connectors. Once the internal cable is completed, screw the IP67 connector to the chassis, connect the terminal block to the LCD board (JP405).

Close the inverter lid. After double-clecking your connections, carefully close the inverter, ensuring none of the RS485 wires get pinched under the lip of the enclosure and lid. If you disconnected the ribbon cable from the LCD board and earth wire from the lid, remember to re-connect them first!

4. Make the connection to the computer

Use a twisted pair cable. Cat5 is readily available and cheap for this purpose - just use one of the 4 twisted pairs. The RS485 specification allows for a distance of up to 1.2km, so if your computer is located more than the length of a box of cat5 (usually 305m), the wires can be joined.

On one end, strip one pair of wires and solder them to the back of the plug. If a 3-pin plug is being used, solder the wires to pin 1 and 2. Then assemble the cable glands.

On the other end, strip the corresponding pair and terminate them onto the terminal block supplied with the RS485 converter. Use only the T/R+ and T/R- terminals. Ignore the GND and VCC terminals.

Once the ends of the twisted pair cable have been terminated, plug the IP67 connector into the inverter, and the RS485 converter to your PC's serial port.

Inverter Com port note: The inverter's communications port is electrically isolated from the PV input and AC grid. It is essentially floating, and can be directly connected to a computer without fear of earth loops or dangerous voltages.

Pictures note: The pictures show a different type of cable. Cat5 was not used at the time. However it is still twisted along its length.

5. Set up the com port

Under Device Manager, open the Properties of the com port to be used. Go to the Port Settings tab and ensure the defaults are set (Bits per second=9600, Data bits=8 , Parity=none, Stop bits=1, Flow control=none.

6. Configure Serproxy

Download serproxy and extract it to a suitable location. You should have at least a serproxy.exe and a serproxy.cfg file. It is recommeded that you create a serproxy folder in c:Program Files to sore these files.

Open the serproxy.cfg file in notepad.

Under comm_ports, remove all except for 1 (if you're using com1. Pick another port if com1 is already in use).

Leave the default settings as they are:

comm_baud=9600
comm_databits=8
comm_stopbits=1
comm_parity=none

Set the idle timeout to 3 seconds. If the inverter doesn't respond (e.g. gone to sleep overnight), it won't delay the PHP script excessively.

Under port settings, leave only port 1. Delete all the others, leaving:

# Port 1 settings (ttyS0)
net_port1=5331

Once you're done, save and close the file. Run serproxy.exe and leave the window open.

Downloads

Serproxy 0.1.1 win32

7. Set up the PHP scripts

Open the aerosharp_php.zip file and extract the aerosharp.php script to your webserver's folder where web documents are served.

By default, the script is set up to use localhost and port 5331 to access serproxy. If your configuration is different, change the corresponding settings under the get_aerosharp_status_from_port() function.

8. Test your configuration.

Test SerProxy by telnetting into it (i.e. telnet localhost 5331). If activity appears in the serproxy window, it has been set up correctly.

At this point, ensure your inverter is running.

Next, execute the PHP script by loading it in your browser (e.g. http://localhost/aerosharp.php).

The URL depends on how your web server is set up and where you saved the script to.

If all is well, you should see the inverter stats listed in a table.

If no data is received, or the data looks wrong, try reversing the polarity of the RS485 wiring on one end of  the cable. Check the continuity of your wiring. If you're using a 3-pin connector, make sure you have used the correct pins.

9. Use or improve it.

If you're happy to just be able to view the inverter status on your computer, you can stop here.

If you have your router and port forwarding set up for your web server, you can view the inverter status page on your smart phone or tablet from anywhere in the world.

If you're a PHP and MySQL developer, you may want to expand upon this simple script, adding logging and graphing capabilities.

The inverter's data is updated internally every two seconds. A script could be set up so that the inverter's return string is stored in a database every couple of seconds for analysis or graphing later.

The com port computer running serproxy doesn't necessarily need to be the one running the web server as well. You can put the PHP script on another web server, and change the IP address or hostname in the script so it connects to a remote computer running serproxy (the one connected to the inverter's RS485 port).