Siemens S7 programming

The dude simpy wants some programming examples that incrementally break down the programming process/flow. There is no examples that clearly show how it is done. Basically the same thing that I am looking for.

It is good that some people have the decency to at least answer the question, explaining that Siemens Simatic is rather difficult and complex in comparison to other languages. It's interesting to find out that Step 7 is powerful but difficult. It seems comparitive to the power of C and the simplicity of Visual Basic.

Just because you understand it, doesn't mean that you are smarter than everyone else and everyone else is stupid. Your answer doesn't provide any guidance or a solution to the problem. Why can't people simply offer some examples and manuals? Why not just give me a map of Detroit, when I am in LA and tell me the reason that I am lost, is because I am not trying hard enough?

Please tell us where the resources are. If you are not gonna offer any assistance then just don't say anything at all. You're bogging down the forum with a stupid rant equivalent to why Mac is better than PC and it's not helping us make any progress.

In my experience, smart people who easily understand certain skills and concepts generally make terrible teachers. They look at you as if you are an idiot, when they lack the ability to convey and teach what they so easily understand. In reality, we are all capable of learning these concepts.
 
C
I would reply simply that the resources are there and what you look for, is an easy way to understand that which is not easy. Part of the problem with examples is that the complexity allows, some would say enforces, a variety of programming styles. There is no one way to break programs up or tie them together. And there aren't many small, easy to understand examples around. These PLCs tend to be used for large complex problems.

As far as manuals, the Siemens site has lots of them and they can be downloaded free. There is no "Step 7 for Dummies" type that I am aware of, but I haven't looked very hard. In a way, what you are saying is exactly what we have been trying to tell you, the product is not very approachable and has a rather daunting learning curve. The best help that I can provide is that some C and assembler programming experience is a great help in understanding the concepts they have exposed to the automation programmer.

This is not mean spirited or evasive, the simple fact is that you have to be familiar with some fairly low level, that is close to the hardware level, methods and concepts before what they are doing makes much sense. I'm sorry it's not easy, but that's the way it is.

Regards

cww
 
J

Jan Steen Nielsen, Denmark

>... They look at you as if you are an idiot, when they lack the ability to convey and teach what they so easily understand ...

Hello dear "Idiot"

I understand your anger, because I had the same feeling when I started to program PLC's, Siemens S5 and later on also S7. Here you have my e-mail for respond on your anger, so I can attach a zipped work of mine for Siemens S7, that really helps - no smart words, just solid help.

Kindly regards
Jan Steen Nielsen, Denmark
[email protected]2net.dk
 
J

Joakim Leijon

Hi there folks

To answer the original post; if you wrote your code in OB1 only using a S7-300 is most probably grossly shooting over the goal.
I write PLC-programs in whatever system the customer wants me to and Step7 is not an easy program to use if you are not already familiar with PLC-programming.

I disagree with a lot of the posts, all systems has it's pros and cons but Step7 is a fairly good system once you have learned it.
But as i mentioned earlier i don't think you need such a complex sytem. If you want to stick with Siemens you could probably do with a Logo! and that has an easy graphical programming language.
And there is a lot of other easy to use small system PLCs out there.

Regards
Jocke Leijon
Automation engineer
 
I tend to agree with Curt. I work mainly in maintenance mode, keeping the existing processes going and making incremental improvements. We buy our equipment and expect to maintain it ourselves. This means that troubleshooting and the modifications are done with a lot of reverse engineering. Any extra sophistication that would make a developer's life easier, almost always makes our efforts more difficult.

If you're an OEM and can afford to have well trained S7 experts, create libraries, take advantage of all the S7 languages, then great - go with Siemens.

If you are an end user with minimal maintenance staff and have the OEM service your gear, then go with your OEM's favorite brand.

If you are an end user and intend to maintain it yourself and have different age equipment, varying skill levels of maintenance staff (due to seniority, shift assignments etc.), various types of processes supported by this staff, then KISS.

In my opinion, S7 (the 300/400 kind, I haven't used the TI style) does not lend itself to troubleshooting on the floor - the clumsy interface impairs your ability to get all the information you need quickly. Every extra click and keystroke is frustrating and distracting when the plant manager is looking over your shoulder! The more toys you give a software guy, the more he's going to play, but doesn't mean he's trying to help >>you<< win.

-DD
 
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curt wuollet

Of course, there is nothing preventing Siemens from making decent pragmatic tools for these PLCs. They would certainly have enough examples to follow. It seems to be a target audience issue. There is a definite Siemens style of programming as well. You see it from large established EU firms that have a large programming and technical staff and on large complex projects. Perhaps it permits more code reuse, or it's easier to divide projects up among several groups. Or it provides justification for a large programming and technical staff :^) But these programs are almost impenetrable when a problem arises and you need to find it, right now. And talking someone through the maze on the phone simply sucks compared to something that takes you to the logic right now. If you only work on the one machine, it's probably OK once you know your way around. It's just not an Ad Hoc system.

Regards,
cww
 
In reply to curt wuollet:

I would say the Siemens Step-7 software is quite good (by the standards of the automation industry) in the sense of what it is trying to accomplish, but it isn't targeted at the casual user or maintenance person. It's targeted at someone who writes S7 programs day in and day out. The people who write S7 programs tend to like Step-7, the people who deal with it only casually tend to dislike it (although some maintenance people like it as well).

I don't know if you ever tried the Siemens Step-5 software (for the S5 PLCs). To anyone who has had to deal with Step-5, Step-7 was a welcome relief.

Siemens had a version of Microwin that would work with the S7-300. It was a good idea in theory, but the problem was that it would only work with basic I/O cards, and not with any of the intelligent modules (e.g servo modules). The result was that you would still have needed a copy of Step-7 anyway to handle the machines that had intelligent I/O cards. To add to the problem, the data file formats for the two programming packages were not compatible. Because of those problems I don't think they sold many copies.

I have to agree though that a lot of S7-300/400 (and S5) programs are often needlessly complex. The S7 PLC gives you more than enough rope to hang yourself. Good programmers will keep their programs simple. Bad programmers will try to use every possible feature in the S7 even for the simplest of tasks. The big problem is that a lot of the bad programmers think they are very clever, and that if other people can't understand their programs it's actually a sign of how smart they are. You see this less with simpler PLCs (including the Siemens S7-200) simply because those PLCs don't have the same degree of flexibility as an S7-300/400.

The S7-300/400 was an evolutionary development of the S5. Siemens was rather limited in how much they can change while still providing a straightforward migration path for their existing customer base. I think that for every feature in the S7-300/400 you'll find a big existing customer demanding that it be there.

To simplify the S7-300/400 much they would need to discard backwards compatibility (much like Koyo did with their new "Click"). They could try to do that by growing the S7-200 upwards, and that might be what they have in mind for the S7-1200. I don't know what plans they might have in mind though, or even if they think there is a problem at all.
 
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curt wuollet

Hi Michael

Yes, if I were reaching hard for nice things to say about step 7, I do concur that it is better than step 5, if only in the sense that drowning may be better than being burned to death. Step 5 issues were different, after navigating several levels of completely non-intuitive menus, it did present you with a working ladder diagram and you could troubleshoot with it. I've often wondered if you couldn't use TI or Koyo (automation direct) tools on some of the older Siemens stuff. Siemens also has the habit of using about 50 variations of programming cable gadgets that all look alike but are not interchangeable. It's a really hard system to like on an ad hoc basis, which sums up maintenance. I imagine in an all Siemens shop, where you could keep all that sorted out and you had nothing to compare it to, you might get comfortable with it. I do question if there is a good enough reason for all the complexity. It does seem that every other PLC vendor can accomplish _all_ the same things without it. Aren't PLCs supposed to be simpler to program than writing assembler or machine code? I prefer C to assembler for the same reason.

Regards,
cww
 
R
I am one of Luca's very happy customers. I *LOVE* picking his work apart just for the learning experience and simple direct elegance... he his correct to say what he has.

As for other PLC programming systems, each has their advantages and disadvantages. As for people, their are programmers and those who think they are programmers. A programmer does not care if it is Cobol, Fortran, C++, Lisp, Assembly, etc. He (or she) will program like the mountains the mountain climber climbs: Because they are there. The rest, the just complain.

R
 
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curt wuollet

Yes, but all those languages you mention can be done with the same tools. And you have a choice of many tools. And I'd rather program in any one of them rather than Step 7. No mountain climber will start with tangled, knotted, ropes and dull crampons. And I'd just as soon not have to climb a mountain just to program a PLC:^)

Regards,
cww
 
A
Mr Jan S.

Please can you send me some instructions for the Blokke.zip
really need help.

Thanks

Angel Scaggs

angel_scaggs [at] hotmail.com
 
looking for field support for S7 in our automation cell. we are using Motoman robots with Krass Mafii injection press tied thru PLC.
designed in Germany and looking for support in Ohio, north central near Bellefontaine.

[email protected]
 
E

ElecTroTechA

Re: question posted by Bapi (on April Fool’s Day! 2006)

It is now the day of the royal wedding (29/4/11) and as a beginner I have been pulling my hair out for days trying to find the same answer.

The answer was kindly provided by you on 15th April 2006.

As Siemens point out:
Engineers use LAD
Programmers use STL
Designers use FBD

Function Blocks belong to all but sometimes people like Bapi and myself can’t 'see the wood for the trees'.

Speaking as an agnostic, online forums such as this one sometimes are 'a God send'. :0)

Many thanks joeS7. "Live long and prosper".
 
P

powertech1970

To all those professional programmers who love to use Siemens, great, fine and dandy, wonderful.

But bear in mind, most of the time a professional programmer IS NOT the end user and maintaining equipment falls to a technician.

While on the subject of technicians, it is not the fault of the poor sap who was hired to be a technician who now has to put on the hat of a programmer. And usually, that hat is put on in the middle of a production run, out of the blue, without "years" to train or develop specific knowledge of a PLC language. He or she has OJT with management breathing down their neck and everyone commenting on his incompetency, while the "professional programmer" is sent to high cost training seminars to "learn".

Yes, in a perfect world, the hands on guys have full training, knowledge, and years of application experience.

In the real world, it is a guy who has very limited, if any, training, mechanical/electrical/instrumentation/machining knowledge on several hundred pieces of equipment, and years of fire fighting to rely on.

So, my question is, do you blame the guy who has been put in a position in which he can not be successful?
 
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Jan Steen Nielsen

How to get "Blokke.zip" file for
Siemens PLC S7-300/400 series, prepared for Siemens simulator and with lot of comments for every function.

You may download this useful program as follows:

1) Call "Controlwiki.com"
2) Call "PLC_Archive"
3) Call "PID_Controller"
4) Download "Blokke.zip" under the blue text.
5) Open "Blokke.zip" by "Retrieve" under "File"
with Siemens S7 PLC software, ver. 5.3 or later.

Hope this helps in your daily work with Siemens!
Regards
Jan Steen Nielsen
Denmark
 
> Ian Myers: "Siemens is probably the best and most versatile PLC and
> Programming Language ever used."
>
> I can't even express how much I disagree with that statement.

---- snip ----

This is not an issue of this is good/bad hardware. All of automation programming is moving away from the original concept: replace relay logic with a graphical representation that will allow those who understand and use relay logic to use a computer based control system.
The purpose of this was to facilitate the ability of technical people without a CS degree to be able to work with (but not necessarily design) PLC software. Siemens is not a PLC it is a industrial computer.

The people who are purchasing this equipment do not understand the difference and it is certainly not the people who use it that are buying in. The changes started when MB bought Mopar. Then MB bails after draining a couple of bil from Chrysler and all we got left with was S7. No stinking t-shirt or anything!

I saw the same type of problem mentioned above and I was not particularly enthusiastic about S7 afterward.

Perhaps the thought process for buying German technology is the same for buying German cars: it's German, it has to be better! Maybe, but at what cost? And when the Germans can't figure out how the S7 or the automobile work, that indicates that there may be better choices out there.

My thoughts for what they're worth...
 
>> Why did Microsoft beat out CP/M and Apple?
>> Why did VHS beat out Betamax?
>> Basically, Siemens is a safe choice.

> Siemens *has become* a safe choice.

---- sniped by moderator

> Over and over again, if you do not like Siemens and their STL, simply do not use Siemens products.

STL may be great for engineers, because you can program it so fast, but at 3am on a Sunday morning, when all the programmers are safely dreaming their sweet dreams, and a production machine is broken down, it will be an electrician who will be called to fix it. Someone who is also replacing blown lights, and adjusting sensors, and fixing the control room air conditioner for the precious operators who shut down when they sweat. Someone who an employer is never going to spend money on to learn STL, because they simply won't use it enough, and will forget it. So when the program is written in ladder, the hard working electrician/technician, has got some chance of seeing the conditions in order to determine where in the process the problem is. But if it's all written in STL, and the person in question doesn't have 10+ years experience on THAT process, and so already knows every permissive and quirk, then that machine isn't going again until the engineer can be roused from his bed (if he's even in the same country), and can tell someone what is going on. I can deal with ladder, I can deal with FBD (because we learn simple boolean algebra, and it's not a big leap), but if the program is written in STL, and I'm not going to be using it to fault find. Your STL may be fine on small machines and plants, but in a major production facility, it's a dog.
 
C
I can't agree more, I really won't use or recommend Siemens products to anyone I like. There are far too many good alternatives that don't require I do things their way. That is to say, I don't get their value proposition, all factors considered. I've used them a lot and they didn't grow on me. They are just harder and more expensive to use. That's a great selling point.

Regards
cww
 
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