Using

network diagrams

as appropriate to illustrate your answers

describe

:

a$.$

Star and bus

topologies that can be

applied to a modern programmable controller

system.

b$.$

A

commercial PLC

network

protocol

that could be using to connect

PLCs to field

devices

$.$

c$.$

I

nclud

e

its international standard and

how

th

is

communication protocol

links to the OSI $7$

layer standard