How to implement PLC using Atmega 8535

[umang]

hello fellow members,
this is my second try, and again i am posting my question!!!!!!!!!!! anybody of u can please help me out to implement PLC using microcontroller??? I have done research and have finalized ATMEGA 8535 microconroller to use. so anybody of u can suggest some of the circuit ideas for this project. the application r to be simple for this plc i.e measuring between two of the given tempreture measures or u can say simply turn off or on dc motor or such simple industrial applications.

thanks!!!!!!!!!!!!!!!!!

 

[soundar]

plc help!!!!!!!!

1. Use Optical Isolator between your Microcontroller and External Environment. ( This will protect your Controller )
2. Use Relay of proper rating to switch ON Switch OFF external Device. (This will avoid overloading Optical Isolator)
3. For input, if isolators can with stand the rating use directly or use a level converter.
4. Scan the input based on the logic and drive the output isolator.

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