In this post we are going to make a comparison between an Arduino Mega board and a PLC Arduino M-Duino 21+, to see the main differences and characteristics of each one. Although our PLCs for industrial automation are based on Arduino, there are many improvements that we have applied to turn the board into a proper industrial PLC resistant to industrial environments.
The first difference is that the power of the equipment is different as the Arduino Mega board works at 5V and instead the PLC controller is adapted for industrial applications with which it can be powered from 12V to 24V.
As for the I/Os, the digital pins of the Arduino board work at 5V and the analog pins have a voltage range that goes from 0V to 5V. Instead, the M-Duino 21+ is adapted to work with digital inputs and outputs ranging from 5V to 24V. On the other hand, we have the analog I / O's that go from 0V to 10V, but there is the possibility of working with 4-20mA analog inputs connecting the hardware that you can find in this link. To make sure that our programmable logic controllers are able to work in industrial environments, the Digital I/Os are optoisolated, so the voltage is isolated from the internal circuits.