Newbie Student - Please Help.

[psychotic_monkey]

Hey, Im very new to plc's, and unfortunatley due to lack of numbers the course im on has been merged with another and i have now found myself faced with these machines.

Anyway, i have an assignment on plc's and im struggling to find some information ans was wondering if anyone can help. This question is probably really simple and i'll sound like a right muppet.

I need to describe the resolution and relationship between analogue inputs, and outputs and word length. [this doesn't even seem worded right]

So i think i need to know what the analogue inputs/outputs are that can be used on plcs and what word length is.

As i say, this is probably really easy but plcs aren't my thing and i haven't got the first idea.

Please help,

Many thanks,

Si

 

[glaverty]

Nobody here is going to give you an answer outright but we are willing to lead you in the right direction.

To learn about what a word is check out this page.

http://www.learn-c.com/data_lines.htm

Here is a hint, I found that link by typing "bit, bytes, words" into google.

Come back with more questions after you have read that and found out what a word is. Before you ask again try to figure out how these may relate to the inputs and outputs on the PLC be them either Discrete or Analog.

 

[Kim Gold]

I'm not sure what PLC you are using, but you can find lots of information on the Allen Bradley website. Here is a link to their I/O library, where you can download manuals for various analog cards.

Allen Bradley I/O library

 

[Tom Jenkins]

Requst for Info from our Brittish Friends

In the UK, don't they assign or reccomend a text for each class? And doesn't the text have at least basic information related to the course material? I keep asking myself why all of these students come here for answers to questions that I really think ought to be covered in some kind of assigned reading!

Am I totally off base, or is the system so totally different over there? I know European universities tend to be less structured, relying more on written and oral final examinations to determine passing of a course, but do they not use text books?

 

[PLucas]

Tom

What you described was the way it worked when I was at college.

Paul

 

[rsdoran]

I will offer some reading material that may help:
http://www.patchn.com/plc_analog.pdf