Kettles & Pumps
There are two main components of the software, which lives on the computer in the brewery. These are the server program and the webpage. Once I've loaded the webpage with my browser, it communicates with the server program, which communicates with the Control Panel hardware, and the other way around. These things are pretty chatty, they're talking to each other constantly, even when I'm not watching.
The server computer is just an old desktop system running Windows XP. The computer talks to the control panel via a serial port and cable. New computers don't have serial ports, but a $15 USB to serial converter is readily available if this one ever dies.
The software required hundreds and hundreds of hours to perfect. You probably noticed there are no PID controllers (Proportional, Integral, Derivative) in the Control Panel. I just wrote them in software - you can see part of the PID programming code above.