I have been thinking of a project for a while.
I wanted to create a testing equipment for basic I/O tests for industrial panels. This is to make sure that the wiring is accordingly to the drawing and that the external equipment connected to the terminals wich usually end up in a PLC.
So in the beginning i was just thinking about digital signals how they could be handled. Normally simulating them with a switch or a relay on the terminals to make sure the Inputs to the PLC changes state or that the output sets the connected terminal high or low.
This was too simple so i thought i could use a Switch/relaybox and the problem was solved? What abut the analog signals? Well i have a few common signals i use 0-10V, ADC 0-10V, DAC 4-20mA, ADC 4-20mA, DAC
This could be solved with a PLC
And also we have the analog temp sensors, these i can simulate with std components depending on what type of sensor will be connected to the terminals of the panel.
So should i use a PLC for the project? To interface with the equipment i wanted to use mostly program selectors and wired switches for testing and an HMI to watch progress and change scaling of the analog I/Os. Sure enough i could use the HMI to store testresults aswell in a database.
But what about Arduino? The size would be smaller, i could have a screen to print on. Sure it would be more fun to write the code instead of using ladder especially when handling analog scaling and calculations. I also could use a ETH module on the arduino where i could access the testresults or even run the interface on a webserver. Usually i would be connected to the PLC anyways to check the I/Os and see if the addresses are OK when tested.
The PLC would be of of the box and if something is missing i could just expand and setup the hardware configuration. It is compatible with 24Vdc standard industrial voltage for most sensors.
But still, it would be more fun to get it running on an Arduino. So how can i get the most out of an Arduino. I want to interface all possible sensortypes and wiring methods? Small shields for ADC, DAC and temperature sensors?