today I finshed a serial port expander for my online energy meter. It lets the software I've written on the PDA talk to both the Pentametric power meter and the Outback charge controller and inverter. The problem was that the PDA has only 1 serial port. The expander acts as a 10 position switch that lets the PDA decide which of 10 devices will be connected to the PDA. Support for only 2 devices is complete. Number 3 will be an AVR butterfly microcontroller. The PDA will then be able to tell the microcontroller to turn things off. There are a variety of loads around the house and shop that are not always needed or only needed in conjunction with certain loads. One example is the 220 volt transformer. It's only needed when the well pump is running or 220 volt machine tools are being used. That transformer takes 13 watts 24 hours/day. I will also be setting the PDA to allow internet remote control of loads.
The energy server web page now sports some new data that this upgrade made possible.
Under "links" click on "real time power meter" to check it out or browse cobblies.blogdns.net