PLC2 to PLC500 Ladder

[Guest Luis Ferrigno]

I'm rewritting the ladder logic from a plc 2 to a plc 504. I am trying to decide what is best the logic, if jump a subrutine to a different place in the logic with a Label instruction or Jump to a diferent file with JUMP instruction? Please give me a sugestion. Lui Ferrigno lrferrigno@mailcity.com luis.ferrigno@sonoco.com Edited 23 Feb 2005 by Luis Ferrigno

[mgvol 0]

If you want to jump within a program file, use JMP. In Program file 2, you must use JSR's to call the other program files, or they will not be executed.

[Guest technogumbo]

Are you needing to move to subroutines to run logic based on situations, or do you want to seperate the PLC-2 logic into separate subroutines to clean things up? If you just want to separate the logic, typical A-B programmers put block read/write logic and JSR logic in the File 2-Main program file. Another thing to consider is the I/O addressing. PLC-2 processors used 2-slot, or double-slot, addressing (i.e., each card is a member of a rack/group/slot). With double-slot addressing, there was also rules in-place for the first slot of a group to be an input card and the 2nd slot to be an output card. So if you are re-writing the logic and re-wiring the racks, what I have done is to build up an Excel spreadsheet with the old and new I/O addresses with descriptions.