ElPercha/PLsi — reverse-engineered prompt

Build me a low cost open source PLC with a built in touchscreen HMI for an ESP32, based on this repo. I want it to work as a DIY classroom and light industrial controller that can be programmed right on the device, without needing a laptop or phone once it is installed.

Please put together the firmware and whatever supporting docs or setup steps are needed so the unit can boot into a simple ladder logic editor on the 320x240 touch display, run and stop the PLC safely, and show a basic HMI with switches, buttons, value entry, indicators, and local I O status. It should support the digital model and the mixed digital plus analog model, with Wi Fi setup, firmware update from a web page, and storage for multiple PLC programs.

Keep it aligned with what the project already promises, including the relay outputs, isolated inputs, timers, counters, math, comparisons, and decent scan performance. If anything is missing or rough, finish it in the same style as the repo and leave clear build, flash, wiring, and usage instructions. Look up current docs online if you need to.