Using Strings in Industrial Automation

I was wondering if you could explain some examples of why strings are used in industrial automation. What kind of information would be read and written in most common string applications. I know I used strings to communicate with a Cognex camera and ControlLogix , but it has been a while.

Could you maybe show me some links that explain string for beginners.

Thanks in advance , and have a great weekend.

I use them only if there is no other simpel way. Mostly i use them in barcode readers.

Rob,

You should define exactly what you mean by "strings". That word covers a lot of ground. My first impulse was to say that I used strings to hold my lunch box together after the latch broke.

I assume that your questions is really about ASCII character strings, as opposed to data words or PLC tag strings.

Character strings are often used where two different devices need to communicate, but do have a common communications protocol that can be used to read and write character strings of data.

I have used strings in order to defeat "default" formatting. I.E., I want a date to be displayed in a certain way, as one piece of data. Format it into a string and the job is done. If the data to be displayed is actually comprised of many smaller pieces, the string is actually efficient and simple (compared to alternatives).

Send alarm messages to mobile phones.

Strings can also be used to keep down the tag count on scada systems.
It is possible to combine many pieces of data into a string and use only 1 tag.
There is a bit more work to be done at the controller level in assembling and then disassembling at the other end.

Thanks , thats what I was somewhat looking for. Do you all have any sample ControlLogix code you can post?

Reason I am asking is, I had a interview , and there was some questions involving strings.

Thanks again,

Sorry, I do not use AB unless absolutely specified - have not had one that could not be changed for a long time to something else.