RSLogix 5000 writing new program

It's your choice really.
However, you might benefit from creating a new program with its own routine(s) and locally scoped tags. That would keep your code isolated from the existing system.

Another benefit will be in the commissioning, since edits in your program can be tested and assembled without affecting any edits that may be in the existing program(s).

Think of a Program as a way of grouping related routines. You can put all of the routines related to a piece of equipment (or a step in a process) into the same program. When you go to another piece of equipment or the next step in the process then you can start a new program and put all of the related routines there.

Of course you could just have one Program with a whole bunch of routines too.

OG

Definitely provide a separate Program for the new equipment.

Having separate Program tags will make things simpler for you and for your customer. All the I/O tags are Controller-scope so that's all that matters for interfacing to his I/O.

Thanks. You guys are a godsend to the beginner. I am creating a new program for this and will tackle each hurdle as it comes while continuing to read the manuals. It was given to me to be used eventually in about three or four months but also for a learning process. Hopefully I don't go down in ball of flames. Most of the manuals and tutorials seem to just show creating a new program from scratch and not interfacing with existing equipment. I have yet to receive details on the CLX PLC and the I/O but I do know our equipment extensively. The customer has provided some ladder logic for another similar piece of equipment which I will need to use some of the same permissives such as "Line Run" "Line Slow" etc as XIC instructions. Since these are already created in their Main Program, do I need to create new tags in my program.

Hello Jim;

Depends: are these XIC tags related to any input signal in the field? If so, you will need to change the alias they point to (the input address on the module they are connected to). If they are internal tags (not connected to the field) you can use them in your logic.
Hope this helps,
Daniel Chartier

Word of caution
Your program tags will be limited to your program only. If you have to reference these tags to main routine or another program, use processor tags.

Thanks guys. These are internal tags in the customers main program. I'm not quite sure on how to create the processor tags. I've added a XIC on the ladder, right clicked, given the name and description same as the customer ie LINE_RUN, Line Run Mode but at an impasse here, so I'm back to the books.

The terms used in the Logix5k software are "Controller Scope", meaning global within that CPU, versus "Program Scope" meaning local to that program. It is possible to have two tags with identical names that are completely separate if they are "Program Scope" tags in two different programs. This makes it much easier to paste new programs into an existing project or to have many people work on the same project without having to use exclusive tag names. When you create a tag you can choose it's scope.

So if this is a globally used tag from the controller then I would create the tag as controller scoped and under the main program program tags since I don't have their program.

For Global Tags, you need to create under controller tags.
For local tags, create under Tasks: Your Program: Program Tags.

I just figured that one out. Forgot that, when the scroll bar was hiding the controller tags selector. School of hard Knocks here. Really appreciate the help. Time for a cup of coffee and regroup my thoughts. Thanks again!!