this is the data logger that comes with the solar control I showed in another post. Plug it into a USB port and slip the SD card into it. Now you can program the control parameters. Then take the card to the control, plug it in and it transfer the set up data. The control does come pre-programed with 5 or so arrangements. You cannot build new arr. but you can change setting within them. Then the card records the system data as it runs. Here are a couple screen shots of the set up screen and the view screen. When you put the cursor over any point on any line it reads the temperature and time of day. This control also accepts input from the Grundfos flow and temperature sensors. I know the manufacturer of this control and have been testing a few versions for them. They are looking for dealers or distributors. I suspect street price could be under $300 depending on dealer markup.