This is the machine that runs my maple syrup machine room. The PLC (the large grey box on the left in the second section from the top) runs a MEGA2560 Pro Mini with an ESP32 as a WiFi modem. There are more than 4,000 lines of BascomAVR running on the MEGA2560 and around 800 lines of Sketch on the ESP32.

The top section is power distribution. The middle section is supposed to be PLC only but my 24V power supply and distribution leaked into the right hand end opposite the PLC. The bottom three sections from left to right are analog input, digital input, and digital output.

This thing runs a vacuum pump (a MasterCool 90066A), a transfer pump (a small Iwaki), an RO pump, and two solenoid valves (to be replaced with motorized ball valves this summer.) It takes inputs from a bunch of float switches, two vacuum transducers, a pressure transducer, three high precision digital thermometers, and two last time of flight sensors. This thing runs the entire process from the trees through collection and storage through the RO into secondary storage and out a tap to be boiled in the evaporator.

The PLC uses a pair of custom boards that I designed to fit in the BUD case they’re installed in. I’ll post pictures of the inside shortly.