Basic PLc

Hi ,

Can someone explain modus and profibus here ? and PLc networking techniques ?

I believe this is the most important thing if one wants to build up a PLC network (small / large).

That is a very large topic, and can't be covered in a forum like this. Suffice it to say that Modbus and Profibus are two "protocols", that is they are two forms of creating data string enquiries and responses. Protocols include headers, checksums, commands, adresses, and data and are PLC platform specific.

You also have to have the communications parameters - baud rate, error checking, parity, number of data and stop bits - defined for a network.

Finally, there are various communcations configurations available. RS232 is a short distance serial link, RS485 is a long distance serial link, ethernet is both a data packet standard and a hardware configuration (but NOT a protocol). You can use copper wire or optical fiber for the transmission.