Guest Mandible4 Posted April 2, 2004 Report Posted April 2, 2004 Hi, I've been working in automation and SCADA for many years. I've just been doing a trawl of the major PLC players looking for comparative data on the latest and greatest products and was struck by the fact that fundamentally, there seems to be be nothing really to distinguish one from another in either functionality or even in general appearance. Does this mean the the PLC is now totally a commodity or am I completely wrong! What exciting new features are to be had? I welcome your expert views! Regards Mandible4 Quote
Guest Guest_Dave Posted April 2, 2004 Report Posted April 2, 2004 Hello, From an operation perspective (i.e. what can a PLC control), I would have to agree that not a great deal has changed. But if you look at things like communications and flexibility in programming, certain PLCs have "raised the bar" considerably. The ControlLogix is a good example. Simply looking at brochures does not do this platform justice - you have to program one (or two or three) to really understand how powerful/flexible the latest AB platform really is. Quote
Chris Elston Posted April 3, 2004 Report Posted April 3, 2004 I tend to agree. I really like what GE Fanuc has done with Simplity Machine Edition software. They have put the HMI and PLC combine into ONE SOFTWARE package. Sometimes I wish Allen Bradley would do this with there SLC family. But Control Logix has done a good job of combining Servo/Motion control and PLC into one software program so you have to give AB some credit here. However I hope that everyone will follow GE's lead and design some a SINGLE software packge that I can do my PLC, some scripting, my HMI, my motion control, and whatever else they can give me into ONE SOFTWARE package... I hope that is where the cutting edge leads us. Quote
KinK Posted April 16, 2004 Report Posted April 16, 2004 I agree with chakorules. I think that it would be better if all PLC makers, build there software as a complete unit that way as an intergrater you can walk into a plant and be able to trouble shoot anything with that system. Quote
Macgyver BR Posted April 24, 2004 Report Posted April 24, 2004 What is news? Relative.. It accommodate, do not I see need and motive. Exists, in my count 72 manufacturers of PLC, do an estimate to read the pages of manuals. The present advancement:: previous Comments, technologies news adaptation The revolution within the reach of: 01) What promises revolutionize the PLC would be the processing by EPLD, chips ALTERS and similar. These Chips: Saint capable units of processing of will be programmed like a representation físíc of logic. In structures logic (AND,OR,XOR), logical blocks (ADD, MUL, DIV,SHIFT...) program the chip, and at present we insert to logic it to be processing. Turned out not , SCAN-TIME microsegundes 02)New technologies you will help of control, as nets neural; coming it produce refined algorithms of control. The software revolution: Multi-plataformas: Only I know CADEPA from the Famic, a dream, only interface and program varied manufacturers, and conversion between plataforms. ..another but disappeared the web site. A group of programmers existed, that initiated development of software of this style, closed. S differences between PLCs exists, sufficiency classify the given important things to be able to mount a table of judgment. Difference that myself: PLC LG, capable of measure the width of the wrist (hardware circuit) of its entrances... exists another??? Happiness presenters and future Quote
Pierre Posted April 25, 2004 Report Posted April 25, 2004 But just one thing. I hope that if AB goes that way they outsource the job to somebody else. If they do the same thing as when they combined there com softwares to end up with RSLinx it will be a nightmare. Quote
Rebuke Posted April 26, 2004 Report Posted April 26, 2004 In regards to Farming out AB, look what happened the last time they did that, e.g. MicroLogix being designed in England. Sure, it's an inexpensive platform that shares existing programming software, but did leaving out the capibilty to online edit really keep the pricing down, or was it sheer oversight? As anyone who's tried to modify a SLC 502 or lower (i.e. replacing a burnt input) while it's running production knows, Online Editing can be a huge asset, used wisely of course. Even though having AB in the blood right from college and my apprenticeship, as a designer now if I'm specing out a low end machine my preference is either OMRON or SIEMANS, as they are the same price as MICROLOGIX (If not cheaper) and I could care less whether the machine builder knows the PLC langauge or not, they'll learn it if they want the contract. (Although this seems to be less of an issue as the market changes) It's important to take into account the entire life of the machine you've designed and programmed, not just getting it out the door to the customer. Things like ONLINE-EDITING are what the Troubleshooter on the lines thanks you for, and curses you soundly for if you don't spec it. Quote
Pierre Posted April 26, 2004 Report Posted April 26, 2004 When you outsource you set the specifications and this cannot have been just something they forgot. AB deciced and they have to live with it. The first time I connected to a Micrologix I was looking for the ONLINE edit. Could not find it but kept on looking. When I was told by a partner that you could not I told him "No way! Its impossible." Well it was. One of the problem with softwares having been included in there own "profit center" is that you have to pay for a bunch of programmers which yearly wages have to be justified. They need to come up with new stuff every years so they can proove that they at least do some work. RS softwares are not bad, they have many very nice features, I just dont like to upgrade so often. Not to talk 'bout the price they charge for this. One of the thing I really like is when yoou COMPARE two versions and you have two windos with the unequal rungs in red color showing which rungs don't match. You can then Copy&Paste between the versions. That's nice. Quote
RichWargo Posted April 27, 2004 Report Posted April 27, 2004 What would I like to see? An integrated development environment. I like the direction that CimplicityME has gone, integrating logic development and HMI development. Only wish it didn't have so many bugs and weird features. Support for ALL the IEC 61131-3 languages. Clean up the communications mess. Too many different cables and connectors. Ethernet is good, but by definition distance-limited. RS-422 is good for long distance communication. Anything else is a waste of time. Support for online monitoring/debugging. Yep, I know, potentially risky, but if you don't know what you are doing, then please have enough smarts to stay away from that feature. For those of us that are experienced, i.e., been bitten a few times and hence evolved caution, we should have the option of working online. Don't presume to think for us. Error Analysis and Optimization. I can't believe how many times I've looked at someone else's code and seen so many redundancies and errors. It's not rocket science, guys. Better analysis and optimization exists for much more complex computer languages. Hire some real software engineers and develop a useful compiler ferchrissake. All computer languages (and PLC languages ARE computer languages nowadays) do is tell the compiler what the developer wants to accomplish. Let the compiler figure out the best way, oh and tell the developer when he/she screws up. BUT, NO USE of speculative, out-of-order processors! These are NOT desktop computers, SAFETY should be first in mind. Get together and figure out ONE way of doing I/O wiring. I read Jim Rowell's article, http://www.mrplc.com/kb/index.php?page=ind...x_v2&id=44&c=38, and he is RIGHT on the mark. Figure out the ONE way of doing things SAFE, SAFE , SAFE! None of this "we'll give the customers what they want" crap. Most of your customers are ignorant of the safety aspects. Take a leadership role and push safety. As for me, I have better things to waste my time on than figuring out yet another wiring scheme. More use of modular connectors and cabling. Embedded OPC servers. Tired of tying up a computer to do OPC. Embed the dang server in the PLC. Do it as an add-on module if you need to. Store the annotation on the PLC with the code. Should all be ONE unit, indivisible with liberty... yah, I think you get the drift. Tired to sucking up OLD logic and having to figure out what everything is for. Oh, and make annotation MANDATORY for used contacts, coils, registers, etc. and require every rung to have a comment line. Again, I am so tired of trying to visualize what some lazy bast**d had in mind from naked unannotated code. Don't tell me you don't have the time to document. But then, I'm not above glaring at a client and telling him to wait the extra ten seconds. Amazing how many of them ask me back... (all of them.) dang, this is getting long.... but in retrospect, this is a great time to be working in the industry. I enjoy what I'm doing and hope the good times continue. Quote
RichWargo Posted April 27, 2004 Report Posted April 27, 2004 Oh yeah... HMIs.... Okay, now IMHO, the only logic the controller should be doing, (PLC or otherwise) should be concerned with the process ONLY. There should be no logic to support HMI features. The HMI should include time-based behaviours, such as "display this animation starting two seconds after this bit is set, and continue for five seconds or until the bit turns off, whichever comes first." The need to burden the PLC with extra logic and communication to support HMI features is nonsense. The PLC should do process logic ONLY, the HMI should do all logic relating to display elements. Better documentation of PLC-HMI linkages. I want a cross-reference facility that tells me all the uses of a particular contact, say, in an HMI project. Global search and replace. Use of master screens, a screen that has dummy linkages along with sets of lists associating the dummy links with real references. An example, a reactor screen for a facility that has 5 similar reactors. One master screen. and five lists, one for each reactor. Call up the screen for a reactor and poof, the master screen with the particular references for the specific reactor. Easier to keep current. Vendor-supplied diagnostic screens for all troubleshootable elements, CPUs, modules, I/O, etc. Tired of doing my own every time. Make the dang HMI generate automatically and keep current. Also tables of HMI screens. (directory). BTW, I don't use the pretty, fancy, USELESS graphic symbols. My clients want clear, concise screens, not those that look like they are out of "Factory Beautiful" and are inversely useful. 256 colors is more than enough. Unless you are integrating color video. Believe it or not, I am NOT gonna disparage using Microsoft Windows. As far as development goes, it is a very rich and powerful environment. Nobody else has come close. Linux is still too techish and fragmented. Too many different ways to do the same basic things; how many GUIs are there anyway? And all are inferior to Windows in terms of ease of development. I don't care how proud you are of your code. I have real problems to solve. Quote
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