Help in understanding Ladder Logic

I am still trying to understand some things. The one thing I am haveing the most problem is the numbers. For example


00027 |---] [----------------------------------------------[FUN 13]
|--03203---------------------------------------------[ DIFU]
|----------------------------------------------------[ 03210]


I had to put in so many dashed to get the numbers to stay where I wanted them.

I know that 00027 is the Current program line number. 03203 is the number that stores the True/False Value. Are these just any number you want, within the data storage locations? And how would you go about setting them to 1 or 0? Sorry for this newbie question, but I just cant seem to understand it after reading a Some student guides and some books. Let me know if this doesnt make sense and I will try to explain more if I can. Thanks

If you use the Ladder button in the edit menu, it will come out like this:

00027 |---] [---------------------------------------[FUN13]

         03203                                      [DIFU ]

                                                    [3210 ]

When you go to the electronic store and pick up a terminal strip, typically it is numbered sequentially from 1 to how many terminals there are. Omron uses third party manufacturers for their terminal strips and the manufacturer of the terminal strip has the numbers already embossed into the strip. Here is a typical wiring layout for a input and output module. Watch for the COM terminal per eight points.

If you need more information , here's a link to Omron manuals:
Omron Technical Manuals

It would help if you identified the brand and model of PLC you're talking about. The numbers attached to the ladder logic elements are memory addresses. They are where the PLC's operating system keeps track of the ON/OFF status of the inputs and outputs. Every brand has its own addressing scheme, so the numbers aren't random, and you have to follow the rules established for the particular model you're using.

A hint for posting ladder logic: Enclose the text 'ladder' (without the quotation marks) inside square brackets to define the start of ladder logic. That's a custom html tag that Phil has defined. It renders the text as a fixed-width font and forces your browser to print every character, including spaces at the same width. When you finish posting the ladder logic, enclose the text '/ladder' inside square brackets to return to the standard font.

Chris,

You may want to repost your ladder. This time type

 a line above the beginning of the ladder and 

a line after the ladder, or you can just click on the ladder icon and type it in there. This should give it a neater appearance. Please state the plc brand and model if you know them. This will help everyone better understand your situation and make better replies.

Jay and Steve,

You guys are quick. I don't even know why I tried.

Chris, your first post before you edited it was a question regarding wiring. Now you have rephrased it as to what terminal corresponds to what address. Hope this helps:

PLC 101

Chris:

Have you looked at the tutorial on this site? Phil has a lesson specifically about the DIFU instruction HERE.

To answer your basic question - it depends.
In many models of PLCs, there are memory registers (or addresses) dedicated for use by the programmer to store, as you put it, TRUE or FALSE indications. In other models of PLCs, there is only one big memory space for both real-world inputs AND internal flags, so you have to be careful to know how a particular address is being used/configured.

As to how to control the value of a particular register, that is going to depend on the instruction set of the PLC you are using. Most of the instructions are designed to change the value of a register in some fashion. The most common is the 'coil' instruction: -( )-. This sets the referenced bit to "TRUE" if the rung conditions leading up to it solve as TRUE, otherwise it sets the bit to FALSE.

But go through the tutorial (and order Phil's book). Links to both can be found at the top of the page (Tutorial: LEARN PLCs ; Book: GET THE BOOK .