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Author	Topic: IEC61131
Dan Sexton Member	posted 08-15-2007 01:52 PM I am in the process of selecting a replacement PLC. Our standard, the Modicon Compact 984 has been discontinued. Direct Logic meets most requirements and at a much reduced cost but I'm very concerned about some posts in this forum which seem to indicate that your third party software provider is moving as fast as possible toward IEC61131 which I wish to avoid, almost at any cost. So, it gives me pause. Any assurances, comments?
Steve Bailey Member	posted 08-15-2007 02:00 PM Dan, I think it would be helpful if you clarified your understanding of what IEC61131 is and why you think that "your third party software provider is moving as fast as possible toward [it]". Is your concern that Automation Direct is going to abandon relay ladder logic? IEC61131 defines multiple programming languages for industrial automation controllers. Relay ladder logic is one of them.
Dan Sexton Member	posted 08-15-2007 02:33 PM Yes, that's exactly the concern. My indications are comprised of inquiries on this forum about availability of structured text and function block programming and the response has been -not yet, but we're working on it. Looking at implemetation of IEC61131 by major manufacturers, I don't see it the same way you apparently see it (i.e. benign). For example, not only are these packages huge (301 Mb for Phoenix Contact) but there are casualties which must be ferreted out one by one and package by package(run time edit, anyone?). At least one manufacturer (Schneider (Unity)) is eliminating ladder logic from the programming group altogether.
franji1 Member	posted 08-15-2007 03:10 PM The current controller CPUs will ALWAYS support the traditional ladder logic programmed by DirectSOFT.
Steve Bailey Member	posted 08-15-2007 03:12 PM [sarcasm] I have been hearing predictions about the imminent demise of the PLC in favor of PC-based controllers for over a decade. Furthermore, the overwhelming popularity of Steeplechase flow charting software proves that RLL was effectively killed off several years ago. [/sarcasm]
Dan Sexton Member	posted 08-15-2007 03:35 PM Well Steve, I appreciate your sarcasm. But this packs more of a wallop than Steeplechase. If it wasn't for the fact most PLC manufacturers are now in European hands, and if it wasn't for the fact that most American firms wish to bow before International standards in favor of established US standards, I wouldn't be concerned at all. I kinda like standards that accrue acceptance over time because a popular manufacturer made the standard ubiquitous. A perfect example - Modbus. A standard that is de facto imposed like IEC61131 thwarts creativity. In my view, that's the intent, anyway.
Steve Bailey Member	posted 08-15-2007 03:59 PM Dan, I guess I just don't share your concern. I think the Microsoft vs. Apple example is valid here. Despite Microsoft's dominance of the PC operating system market, Apple manages to maintain a solid and profitable niche. Even if Siemens et al manage to displace RLL as the most common IEC61131 language, I believe there will continue to be a robust market for controllers that use RLL. As long as there is a market there will be a company willing to provide produsct to that market. If that company isn't Automation Direct, then it will be someone else. However, don't forget that it was savvy people at Koyo who first recognized that the number of people who could specify and program a PLC without the need for a local distributor rep holding their hands had reached "critical mass". With that realization, they formed PLC Direct, which became Automation Direct. Granted, past performance is not a predictor of future results, but if anybody is going to stick with RLL, I'd put my money on AD. Look at how long they've stuck with the 305 line. Furthermore, AD seems to be among the best at listening to and responding to their customers' desires.
Dan Sexton Member	posted 08-15-2007 04:13 PM Steve, Those are all excellent points. I'm just trying to look into all corners to make the best decision I can. For instance, my Idec sales rep claims Idec's policy is to not embrace IEC61131. I would love to hear the smae from DL. I mean, we're talking RLL as it is NOW at DL, not just as it might be available as a piece of IEC61131. This is my last post on the topic.
a agnone Member	posted 08-15-2007 04:23 PM Dan, I was wondering about the same issues. At our plant we have both programming. I do not see the Ladder going away anytime soon. The IEC61131 comes at a price, it isn't cheap. It requires at the least a CPU running Windows CE. The only attraction it has is the "box you can create which contains ladder" simular to the ibox. You can cut and paste these boxes into simular software. You still need to understand programming. I think people think this will make programming easier. What ever that means. For low cost machines, it is not cost effective. I love the Stage programming using ladder that AD offers. And of course there is the Think and Do using the WinPLC. Actually the i-box is easier to use, since you just fill out a form like box. Bottom line, do not loose any sleep over it.
franji1 Member	posted 08-15-2007 05:13 PM Please realize, that ADC and all Federation members (e.g. Host Engineering, Facts Engineering) are always looking to improve the existing product line. Note that this does NOT mean "replace". For example, when Host came out with the Ethernet based products like ECOMs, ADC did NOT eliminate DCMs (as a matter of fact, they came out with a slick D0-DCM for the 05/06). ADC's catalog GROWS. RLL is here to stay, it will never die (sounds like that old Rock-N-Roll song). If Host came out with a Java-based processor (we're not, but I'm using this as an example), that would NOT mean RLL is going away. It WOULD mean that people out there who want to program their control solutions in Java would buy this processor. We're always looking for better ways to help YOU solve YOUR control issues. Be it a WinPLC, a CTRIO module, an Ethernet Co-processor, or ???. Trust me, RLL (and DirectSOFT ) is here to stay.
krak Member	posted 08-16-2007 09:42 AM Steve, please note that Bill Gates owns 51 percent of Apple. he uses the company to test some of his ideas that he believes his hardcore windows people would not approve of. hence the Que and the Iphone are very close to being the same, but you'll hear no complaints from either company. just some food for thought.
marksji Member	posted 08-16-2007 03:41 PM Dan, just in case you didn't catch it Franji works for Host and they write DirectSoft. If he says RLL and DS are not going anywhere you can take it to the bank.
marksji Member	posted 08-16-2007 03:43 PM Oh, and Krak, where in the world do you get something like Gates owns 51% of Apple? That put me on the floor laughing until I realized you might actually have been serious...
krak Member	posted 08-16-2007 07:44 PM i was being serious. it is a figure i heard a few months ago. i'll do some research on it. maybe it was an april fools thing that i heard in passing. i'll let you know what i find
Steve Bailey Member	posted 08-16-2007 08:33 PM Googling "Bill Gates owns 51% of Apple" turned up this: http://forums.macrumors.com/archive/index.php/t-30188.html
franji1 Member	posted 08-16-2007 09:19 PM fwiw, even if Bill Gates owned 51% of Apple, RLL is here to stay
krak Member	posted 08-17-2007 09:49 AM i was mistaken, microsoft did own a good portion of non voting shares. they bought 150 milliom in 1997 when apple stock was at it's lowest. the sale of those shares back to apple had completed in 2003. with court rulings and contracts in place each side creates programs for the other. and yes rll is here to stay. after all it's still just 1's and 0's
Bent Member	posted 08-28-2007 09:20 AM As a big fan of structured programming languages, I would be very excited to see IEE61131 or any other structured language available. I use DL PLCs mostly for dumb remotes and almost never in a situation where any significant programming is required. The reason is that ladder logic is awkward to program and difficult to support (try running WinMerge on a ladder program!) For simple applications, ladder logic is great but when you need to do anything significant, it quickly gets out of hand. For example, I have to create adaptive polling algorithms that can poll multiple remotes, determine what interface they support, and then queue up the proper polls. Oh yeah, and prioritize polls based on a couple of different factors including whether the remote has been responding recently. I've done some of this in ladder as an exercise and it was a nightmare. Doing it in structured text is not difficult. Plus I've got ready to use tools like WinMerge and Subversion for support and archiving. Also, to correct one statement in this thread, IEEE61131 does not require a WinCE PLC. 61131 is a specification for programming only, not for implementation as far as I know. The two PLCs that I use for serious work both use 61131 and neither has WinCE running. I'm not sure of the exact sequence, but the 61131 may be interpreted to C code which is then linked and compiled with a native C library to generate the program. All of this is transparent to the user as they just have to Build the program (kind of like clicking Accept in the DL.) So, no surprise, I'm in the other camp. I would REALLY like to see a structured programming solution. And, while they were joking about it, yes, a JAVA based processor would be a real plus for serious work and would get my first vote. 61131 would be second. If I couldn't get anything else, I'd go for C or embedded C++ (C tends to be dangerous to program...too easy to get lost in pointer dereferencing hell.)
marty_J Member	posted 09-06-2007 08:35 PM Hi All , This is my first post. In response to Java programming, Yokogawa have a platform you can program in Java, Stardom. i think its a kind of a hybrid PLC/PAC, and thats about as much as i know about it.
ees76230 Member	posted 09-10-2007 12:11 AM Dan I feel your pain. I have several customers with Modicon 984’s and we just love them. And don’t you just love that “Run Time Edit”. It made my life of trouble shooting and quick bypasses so easy. I use my ProWorx Software all the time and can not imagine this PLC world without it. Although it sounds like we may have to face that grim possibility. I began using AD PLC’s about 4 years ago as an alternative to the high cost of others and have found them to be very acceptable for the projects I am involved with. It took some practice to get use to the programming and I am still learning new tricks almost daily. I think you will be happy with the product and their customer support. They have helped me several times without any cost. Sadly the Modicon guys have to send a bill when it gets past a level 1 support tech unless things have changed over the past couple of years. I’m not familiar with the IEC61131 but if RLL does go away, we’ll get on that new bike and learn how to ride it just like we did when we were young. It may not be the easiest thing to do but we simply have to keep up with the changing world in which we work in. Keep in mind that there are several places to get replacement controllers and cards for the Modicon and even some deals on those internet bidding sites. They may be used equipment but I have installed several with dependable results. Good Luck Fellow Compact Programmer
RHanrahan Member	posted 09-24-2007 03:28 PM Here is a link describing the various parts to 61131 http://www.61131.com/languages.htm
wildalan Member	posted 10-18-2007 09:13 PM Look at how many older units are still out there I mean old stuff like the symax unit I found on a mac nut hulling machine last week talking about a blast from the past had to get out the suit case they called an HHP for that one the point is as long as it works well the industries using them will not replace them so I believe RLL is here to stay for a while!!!
franji1 Member	posted 10-19-2007 11:03 AM quote: Originally posted by wildalan: so I believe RLL is here to stay for a while!!! Amen! Preach it, Brother!
wildalan Member	posted 10-19-2007 08:28 PM just today some one called me to trouble shoot a square d norpack system remember these you program them with jumber wires

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