AB Micrologix 1100 on Multiple Machines

A deep thinker engineering question that I pose to you. I have 6+ machines with basically the same PLC program (Micro 1100 with 4 cards). My question is: Best programming method so that if I make a change on one PLC program and I want to implement the change to all other PLC programs, I want ease and to save time.

Solution A) Make one program with each particular machine counts in their own separate sub routine.
Problem: each time I make a change to program I would have to manually enter counts that machine is at after download new (changed) program (could be 15+ different counts I would have to keep track of and enter). Program would get large with each sub routine count.

Solution B) Every time I change program on Mach. 1, I can upload from Mach. 2, make changes (copy and paste, etc.) and re-download.
Problem: time consuming.

From my own experience with revision control on "almost identical" machines, I very strongly recommend the brute force method of copy-pasting logic changes to each machine individually.

I also always reserve an integer data table address for the program revision, which is then displayed on the HMI. When I do my ladder changes, I also increment that value so that I can see at a glance which units I've updated.

Because you have MicroLogix 1100 controllers you can do the changes online during runtime.

In practice, attempts to write a universal program always end up resulting in individualized versions.

Are these machines' PLCs on the same network? If so, then you really cannot have identical PLC code because their IP addresses, or node numbers will be unique.

In my experience, when you attempt to use the exact same code on multiple machines, you end up jumping through at least a couple of hoops to deal with differences. FACT: there is not any such thing as identical machines. If they have moving parts, they are not identical.

I would advise that you have a unique program for each machine. When making edits, there are design ideas that can make it relatively easy to port the changes from machine to machine, the most basic of which is to segregate the code into logical sections. This way, you make a change to the "Input_Cnv - Entry Transfer Conveyor" LAD routine of the code (for example), you can open multiple instances of RSLogix and drag and drop that new code into the others.

This is just my opinion. I have supported operations with up to 72 "identical" machine sections and there were ALWAYS differences in things like timer values and so forth that would create problems if I tried to have a "master" program that I dumped into all of them.

I agree with separate programs for each machine. I figured this is the best method, but I didn't want to eliminate any dumb ideas at first. These PLC's are going to be connected to a network in the near future.

I guess brute-force method it is. Perhaps someone will program/invent some way to easily change multiple AB programs. Until then, god bless the hourly paid engineer.

jwalz2014 said:

I guess brute-force method it is. Perhaps someone will program/invent some way to easily change multiple AB programs. Until then, god bless the hourly paid engineer.

Click to expand...

They already did... When RSLogix came out. Try out using multiple instances and using drag and drop. You can do this with ladders files or just sections of selected ladder logic. You can do it with data tables too (with some caveats)...

You can still call it brute force, but I think it is pretty sweet compared to the DOS based days.