GitHub - DanielMartensson/STM32-PLC: STM32 microcontroller with lots of periferials such as ADC, differential ADC, Input Capture, PWM, USB, Encoder, DAC, Digital Input, RTC, CAN-bus + Alarm etc.
Honeywell 14500152-004 Module PLC PCB Board 14500152004 (TK5066-2) - River City Industrial
PLCDuino - EasyEDA open source hardware lab
Small Open Source PLC Components and Source Files
PLC Industrial Control Board, High Speed Built in Timing Circuit PCB Programmable Logic Controller DC24V Analog for Program : Amazon.in: Industrial & Scientific