Rami00972 said:
can i connect any aother ics to the plc in the future
like lm 358 "op amp"
adc
etc.....
You dont "connect other ICs" to a PLC.
PLCs can be a single unit with a defined number of inputs and outputs, or, they can be modular.
With a modular PLC, it is usual to have a backplane, a power supply and a processor module.
The power supply and the processor module are plugged into the backplane along with the required number of I/O modules needed for the particular application.
To control a machine in an industrial environment, use a PLC.
Yes it is more expensive than a micro controller, but for a very good reason, it is a fully engineered solution.
You dont have to build the I/O circuits, you dont have to code the program from scratch etc, etc.
You buy the hardware and the progamming software.
Wire up the hardware.
Write your use program (in a simple high level language)
Load the program into the processor
Run the machine (after debugging your program).
Replacement hardware is readily available, any someone who has to modify the machine in the future has an easily understandable program to edit.
Use a PLC.
If your existing PLC cant read an encoder, (if I understand your original post), FIX THE PROBLEM, dont redesign the control system.
JimB