Help please

[daisyfgw]

Hello, i am new to this forum and im sorry if ive posted in the wrong place.

The subject in question is:
'Give a well documented account of a complex P.L.C system of your choice, including an explanation of the program'

I have no idea what to even look for and what ive tryed to look for on the internet makes no sense

any help is much appreciated.
Thank you.

 

[Steve Bailey]

Is this for the HNC course? If so, it's about time they changed the homework assignments. People here have been ranting about some the inane homework questions for more than a decade. I especially hope they got rid of the question about unitary, modular, and rack mounted PLCs.

Does the reading matter for your course suggest places to look for information about a "complex PLC system"? What is your definition of complex?

You are more likely to find information about a specific control system that incorporates PLCs by contacting a facility where one is installed. That could be just about any manufacturing facility. Contact one in your area. Ask to speak to the engineering manager or maintanance manager. Politely request a few minutes of his/her time and explain what you're after. Remember that every facility you contact is a potential employer once you have completed your coursework.

 

[daisyfgw]

Hello,
No this is for the BTEC national diploma in mechanical engineering but i have recently done the one on rack, modular and unitary PLCs it was horribe haha.

Honestly that question i have written is the only thing i have to help with it, all the books at college have nothing on a complex PLC system. My deffinition of a complex PLC system would be a larger more complicated system compared to say a simple traffic light on a simple junction.

I was thinking about doing that but wasnt sure on whether they would discuss this with me but i shall try thank you for the advice.

 

[bernie_carlton]

I think they will realise that you are not trying to steal their system.

A description would include the PLC components inluding local and remote I/O, any communication methods between the central CPU and remote I/O, displays (HMI) and their methods of communication and any SCADA networks which may be involved. Inlude specialised sensors, like barcode readers. Detailed diagrams of the various processes and networks would show a good understanding of the layout.

Be sure to ask about any difficulties or extra planning they had to do in laying out the system. Nothing ever goes exactly right at the start.

Good luck.

 

[Lancie1]

Daisy,

I think a description of a comples PLC system would include the following:

Brand and model of PLC microprocessor
List of Input modules, number and type of each input
List of Output modules, numer and type of each output
List of the Inputs and Outputs actually used by the process (often called an "I/O List").
A brief summary of what the program does, how it is organized into parts, subroutines, or pages.

I may have an example that I can post later.

 

[Goody]

Another fine example of our brilliant education system where the teachers nor the pupils have a single clue as to what constitutes a 'control system'

including an explanation of the program'

What does that mean? Individual bits, inputs outputs or the machines process - way too vague.

a complex P.L.C system

Complex might mean distributed I/O and signals over hundreds of miles or a massive factory. Or it might mean a single process that has PID's and lots of analouge signals.
Complex to one, is simple to another

 

[iant]

I would suggest take on a factory setup
like Petro Chem. - It is a Multiple Process control system.
This may be too vast but it is an Idea.
A Plc can control a single machine
then An additional PLC can control how that machine is fed.
these can communicate to a main Computer control setup

As 'Goody' has stated how complex is complex.

see how you go.

 

[daisyfgw]

Hello,
Thank you all so much for your replies they have helped me alot, i shall have a go at the assignment and let you all know how i get on

 

[harryting]

I wonder what you would get if you answer with:

" this is a stupid question that shows the lack of understanding of the subject and is a waste of my time"

 

[Lancie1]

I can tell it has been awhile since a bunch of us have been in a classroom setting. These are the kinds of questions that students get asked.

Never mind that it is vague and poorly worded. The intent is to get the student to think about the subject, to put her own intrepretation on what a complex PLC means. Yes, it could be any type of PLC, and this question is not meant to have a definite one-size answer, but to encourage the student to do some research and come up with a valid answer.