A quick and dirty interface that allows an Arduino to act as an industrial PLC input.
##Design Notes The first stage is a simple RC network to covert the Arduino 490 Hz PWM output to analog. That's followed by a voltage doubler to buffer and scale the 0-5V output to a standard 0-10V PLC signal.
The LM2904 is a dual op amp and there was space on the board so I added a second channel.
There's also a DC-DC buck converter to power to the Arduino from 24VDC.
##Build Notes
The terminal block were a little larger in life than in Fritzig so I had to move a couple things around.
##Credits I haven't worked with analog designs since college. Thanks to Mike over at Adafruit for his helpful reminders. Adafruit Forum: 0/4-20ma current loop output