Micro-logix 1200 Program files

Could someone answer a pretty simple question for me.
Can you have more than 1 ladder in the program files for a micrologix 1200 program?

I wrote a program with 4 ladders in the pojects file tree.
The program verified and downloaded to the processor.
But now the pocessor won't scan anything but the Main Ladder (#2).

There are true rungs in the other files but the outputs aren't coming tue.

Thanks, Dave

Yes. You need to make sure you call (JSR) the other ladders from Ladder 2 and then make sure you have a Return (RET) at the end of each other ladder.

Thank you all for quick replys.

Appeciate it,
Dave

Old No. 7 said:

Yes. You need to make sure you call (JSR) the other ladders from Ladder 2 and then make sure you have a Return (RET) at the end of each other ladder.

Click to expand...

A "RET" is not necessary see pdf below

JD Micky posted a JSR pic on his other post for the same question. RET is only needed if you are doing funky things. If logic reaches the end it will return without the command.

Gotta act fast here.

Interesting. I guess I've been doing it wrong for a long time. I always thought you needed the return.

Old No. 7 said:

Interesting. I guess I've been doing it wrong for a long time. I always thought you needed the return.

Click to expand...

Its not a blanket statement ( not needed) there are reason to return before the end of a subroutine.You just don't need it at the end of a subroutine. Programmers choice.
And in the PLC5/?? world there are other reasons ( like passing parameters)

RET [Return from Subroutine]

Without a RET instruction, the END statement (always present in the subroutine) automatically returns program execution to the JSR instruction in your calling ladder program.

Click to expand...

For RSLogix500, I don't think it is a case where the RET is not needed, but a case of there being another instruction (END) that will fill in if the RET is missing.

For other languages, the RET or End-of-Routine is necessary. I once left it off of an old Unimate Robot program. Those programs were always recorded on top of older programs. If you left off the End-of-Program instruction, the the robot would just go to the next line of the previous obsolete program and keep on going - with bad results.

In my case, the arm oscillated rapidly out, up, and down, tore out a countertop, threw pieces of 2x4 and plywood all over, scattered process containers, caused two men to dive off stepladders, and upset the entire shop. No one was hurt, and I never forgot to include the END after that.

If you always put in the RET, you won't go wrong.

And in the case of Fishenguy, it's not that you have 4 programs, it's that you have one program with 4 sections. It may be that the logic to call those routines is mutually exclusive (only call one of them) to make it effectively 4 separate programs (depending on circumstances) but it's one project. The inputs are probably connected to the same thing and the outputs connected to the same thing, unless you got really wild and switched those also when switching which routines are called. Hmm, I never even though of trying that before and I think I'm going to permanently banish it from my brain.

In any case, know your processor and what is needed to process programs.