Mitsubishi - Gettting Started/Advantages/Disadvantages

[Paullys50]

All - Our company recently got a request for a small automation system, however they spec'd Mitsubishi. Our typical clients request AB (ControlLogix/CompactLogix), as such we pretty much have all of our standard software on AB taking advatages of things like AOIs, UDTs, Import/Export features. How difficult is it to transition to using a Mitsubishi? I'm starting to look into the product line and software, for the people who have used both whats the biggest differences? Advatages/disadvantages? Part of the project process is to evaluate risk, so of course a new platform is a risk, just trying to quantify it. Thanks! Edited January 16, 2015 by Paullys50

[gleblanc]

I like the Mitsubishi programming software pretty well, though I mostly hire other people to do programming these days. Actually, for maintenance personnel who only use the software every few months, I think that GX works is actually easier to use than RSLogix 500 or 5000. And as with anything else, ladder logic is pretty much ladder logic, and things work about the same. All that said, I think that RSLogix 5000 is much more powerful, if you use it's advanced features, which it sounds like you're doing. I'm not entirely sure if Mitsubishi has something akin to AOIs, etc. There are some things that the Q series does that make large programs easier to re-use than on AB. With the Q PLCs, your I/O numbering is fixed, even if cards are missing. So I can put a Q02U on my bench in a small chassis, and load up the program from the Q03(mumble) on my plant floor that is in the biggest chassis, and the program will load up without much complaint that it can't find things. I'm sure that one of the gurus here can explain that much better than I can.

[panic mode]

that was asked before, you may want to check: http://forums.mrplc.com/index.php?showtopic=1104 it covers transition from AB to Mitsubishi Personally I like Mitsubishi a lot, (GX Developer). If there is something I would like different - it would be to have more characters to comment devices

[Paullys50]

Thanks, I came across that but since that thread is 10+ old years I figured I'd ask again ;)

[JRoss]

Definitely worth re-visiting. The new GX Works software now allows you to build function blocks and define data types, which wasn't true in previous versions (the European IEC version being the exception, I think.) There were/are other ways to skin the cat, but it wasn't as easy. The big thing to be aware of is that tags used fixed memory locations that you have to set. This is unlike RS Logix 5000 which doesn't have fixed memory at all, but lets you create whatever tags and data types you want. This isn't such a big deal, except that in Mitsubishi there are essentially only two memory types, bits and 16-bit words. You have all the normal data types (INT, DINT, REAL, STRING), but they are all using the same range of memory, and the software uses the type of instruction to know how to interpret the data. This can lead to weird "errors" if you aren't familiar with it. Or even if you are... Mostly you have to be careful not to overlap the data. Also, unlike AB, memory isn't necessary retained through a power cycle. You set up ranges of memory that are "latched", and then you have to make sure that important tags are in that range. I think that's the biggest difference to be aware of. Obviously, there's a learning curve with the software, the hardware setups are different, and so forth. But those items won't surprise you! Ask any other questions you want. I've done plenty of programming in both environments, including conversions in both directions. And there are others on the forum with experience in both platforms.

[Paullys50]

Thanksf or the feedback JRoss, I think the biggest challenge will be to replicate our AOI/UDT functionality that we have created in RSLogix5000 into equivalent code. Coming from an AB world, seems I will need to fall back to my SLC/PLC5 experience when it comes to memory allocations and tagging. Then go back to our "pre-AOI" world of calling routines for device control and indexing through it.

[Crossbow]

Keep in mind JRoss that assigning addresses for variable names is OPTIONAL. If left blank, the compiler will assign its own. That makes it more like other IEC vendors.