Know Apples but want to learn about Oranges

Hi all,

Am fairly fluent in Omroneese in terms of memory areas, numeric ranges for IO and instruction set etc. Have completed mostly small projects IO wise, but some quite high speed and reasonably complicated projects, some servo work etc. But am quite sheltered. Pretty much exclusively Omron except where I have reverse engineered something to make minor changes in Siemens and RS500.
I have programmed both using CXProg and Sysmac. Although Sysmac was different I found it quite intuitive and loved using peripherals over EtherCAT. Motion was a cinch.

I have the opportunity to do a logical but quite fun series of machines, some will be Omron, but some will be AB due to customers requests.
CPUs will be CompactLogix and I guess will be using latest RSStudio 5000. Am hoping to use EthernetIP to interface with VFDs and Servo Drives if only to reduce wiring.

I will be reading the programming manual but that may be challenging as I tend to fall asleep reading dry material. Apparently me eyes are to blame as I come into my 40s but I'm not so sure. I generally learn best by practise and indirect comparison rather than focussed learning.

To get a jump start and any info would be appreciated, and quoting any relevant Omron jargon;
- what are fundamental differences between Omron and AB in your opinion
- Is AB more like Omron than say Siemens which is just plain not intuitive.
- Is there a document that directly references Omron areas, numbers, ladder, keyboard shortcuts and translates it into AB?
- any hints/tricks that can catch Omron users out? (big obvious ones, not normal everyday ones)

Thanks,
Stew

http://plccompare.com/
The above is a good overview comparison of several controllers.

The differences between Omron and AB really depends on each system and the instructions that you need to use.
I would start out by looking at the numbering systems of the AB PLC. Addressing and indirect addressing is slightly different.
AB has allot of examples on their website for communication of the VFD's using EthernetIP.

http://forums.mrplc.com/index.php?/topic/2907-rslogix5000-fast-ladder-editing-possiblejavascrip/
Here is a link to a thread that you might find helpful.

Regards,

I haven't worked with Omron much, so I'm not 100% sure how the IO scans work in those, but the Logix series processors are asynchronous. That means the IO is updated during the scan, and the PLC accesses the most recent value. This means an input could be off for the first half of the scan, and on for the other half, which can have frustrating consequences in the logic.

It is generally considered a best practice to manually buffer most/all the IO tags, mapping inputs to somewhere at the beginning of the scan, and then mapping something to each output at the end of the scan.

In Omron (CJ series, for example) you can have multiple programs per processor. Within those programs then there are "sub-sections" (don't have software on this PC so can't find proper term) which organize the code but are basically splitting up the main lad (if you look at the rung numbers...)

In AB you also can have multiple programs and within those sub-routines. One thing that catch many out is that, you have to call those sub-routines (from the main routine in each program) using the JSR command. There are 3 operands to the JSR, but the 2nd and 3rd are generally not needed and can be removed by right clicking and selecting "remove instruction paramater". If you do not JSR you're sub routines it will look like they are being scanned but values inside will not update etc.

Perfect replies, regarding addressing and indirect addressing, subroutines and the asynchrony of AB - I am trying to get my hands on a v20 program of a machine I am familiar with to compare with Omron directly.
Hopefully all going well I will be able to build the panel and get everything talking and the basic lay of the land sorted before I ship it and myself to site.
Right now I am sitting on the fence - the voice inside me that I knew well in my 20s is telling me to go for it, but the sensible side of me is warning me of that burning feeling when people are looking at you during commissioning and wondering what is taking so long.
I will start with trying to compile a basic list of direct translations with memory areas and IO. I have a good friend and system integrator for AB that should be able to kick start my software familiarity and help me get the bones of the first system ready to get stuck into ladder.

Thanks again!
Stew