hi guys i am new in this fantastic world of arduino, well i need make a PLC like the tittle say it, i dont known much how explain you but i let this link for more details
thank you so much, i hope that you help me
I need your help from scratch, I want the plc works level control relays, which would move the coils of contactors,
The Arduino is just a microcontroller, not a PLC (which entails lots of other stuff like rugged 24V signalling,
ladder logic programming, etc).
Yes, sequencing some contactors using relays is plausible. I'd start thinking along the lines of a small
opto-isolated relay board. Do you have an idea which contactors you will use? What voltage windings?
Opto-isolation is very wise in such an environment of high voltage switching, since the 5V Arduino
is prone to pick up interference much more than a 24V PLC.
yes, the contactors will use 220 volts to energize, now I just need a line, which could would have to go for the relays modules and the other line would be directly fed to the contactor, is simple only have to perform the sequence mentioned, the game the relays, with the arduinno,
would like to have 3 LEDs, to power the arduino might take LED1 and LED3 last 3 seconds off LED3, and turn the led2, mantenimiendo always lit LED1, I hope I understand.
So an opto-isolated relay board to switch the 220V to the contactors would be doable. A circuit
diagram would be much more useful at this point than words - I am worry by this in particular:
and the other line would be directly fed to the contactor
There should definitely be no direct connections anywhere between the Arduino and the mains side. It
would only drive the opto-isolated inputs on the relay board. You would still need to take pains
to reduce the chance of EMI getting back and upsetting the Arduino - a 3-phase motor contactor puts
out loads of interference, so shielded cables, star grounding and physical separation are all needed.
Also you'll need a power supply for the relays, which must not be shared with the Arduino as
that will just carry transients back to the Arduino.
Look, relays only serve as a bridge as you know, do not need to directly connect any line only, want to use the NC terminals and NO, but obviously use the Arduino to drive the coils of the optorelays.