Please help me out regarding plc programming as soon as possible.

I have working in a cold rooling mill and its under construction. We are using PLC siemens S7-300 In Bell Annealer Facility. The seller is giving us PLC program in Statement list but I wanted it in Ladder language.ALL I wanted to know that weather IS there any thing in a PLC programming software that can convert Statement list in a ladder language and if it can then I can change statement list program in a Ladder language without facing any problem /it can convert the whole program in ladder language.
Kindly send me your answers as soon as possible.

mohsin.khan said:

I have working in a cold rooling mill and its under construction. We are using PLC siemens S7-300 In Bell Annealer Facility. The seller is giving us PLC program in Statement list but I wanted it in Ladder language.ALL I wanted to know that weather IS there any thing in a PLC programming software that can convert Statement list in a ladder language and if it can then I can change statement list program in a Ladder language without facing any problem /it can convert the whole program in ladder language.
Kindly send me your answers as soon as possible.

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If the S7300 is programmed originally in STL, it cannot be automatically converted. This is because it has to be added brackets, jumps and help flags to the code so that the compiler can interpret and draw the ladder diagram. A STL code is normally much more compact and uses less CPU power.


Kalle

A STL code is normally much more compact and uses less CPU power.

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And impossible for the average guy in the field to understand. OK for all the boffin types but absoultely useless to the average maintenance guy.
Many consultants in Australia are now banning STL and even FB because of this.
It is great for programmers, useless for electricians and maintenence guys.

Hi BobB!
Looks that you're sharing mohsins' wiew on STL.

But that Australian consultans are banning FB's, must be caused by lack of knowledge. FBs can, like FCs and OBs, be written in LAD.

Kalle

BobB said:

Many consultants in Australia are now banning STL and even FB because of this.

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KalleOlsen said:

Hi BobB!
But that Australian consultans are banning FB's, must be caused by lack of knowledge.

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I'm guessing he meant FBD (Function Block Diagram) rather than FB's themselves??

(but may be wrong)

I imagine it would be difficult to 'ban' STL as there would be no way of doing things like indirect addressing etc..?

However, I'm a staunch advocate of using ladder wherever possible. I think it just makes it easier all round.

Hi Kalle
Of course they can be written in ladder but that only print an FB - the ladder is not exposed until online and open the FB up.
I write a lot of sophisticated software for controlling power stations, complex switching systems etcetera, including high voltage.
The reason they are writing 'ladder only' into specifications is for the above reason.
May I add that I have no problem with ST, except it is hard to debug. Great for complex maths though.
FBs are an absolute pain - if you want to change one and download to the PLC due tyo a contact coming in the other way, you have to stop the PLC, download, start the PLC again.
I gave FBs away about a year or so ago and went back to ladder exclusively, except for complex maths.
At least when a customer rings with a problem I can help get them online with the PLC and explain the code in a way that they understand with ladder. Makes it easier for me to trouble shoot as well as they can view and tell me what is going on.
Some of my customers insist on all programming in FBs - I then quote them an extra amount to write the software in FBs as I know it is going to take me longer to wriote the software and commission it! They usually take the ladder option and finish up agreeing with me at the end of the day when I explain to them why I generally use ladder. Cost them less too.
The secret to writing good, efficient and fast ladder and very fast comissionig is a very large and useful function set. Not many PLCs have that these days and insist of heading in the direction of FBs.
Many will probably disagree with me but when I can write and commission a full generator control system in a couple of days, for example, and commission it in a day, they do like the cost savings over the guy that was there before and took a week.
By the way, indirect addressing in ladder is easy with my favourite brand of PLC - do not need STL at all for almost everything.

BobB said:

By the way, indirect addressing in ladder is easy with my favourite brand of PLC - do not need STL at all for almost everything.

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Hi Bob,

I mistakenly assumed you were talking about Siemens (don't know why - probably because its the brand I'm most familiar with).

Ofcourse with Siemens you can download FB's, FC's etc without switching the PLC into stop. You only need to change to stop mode in order to download a change to the hardware config.

As for indirect addressing in ladder, I've seen this done in Allen Bradley but not in any other brand.

Which is your "favourite" brand out of interest?

With Siemens you only need to be careful with FB's when you change the interface or STAT areas, that is why in the case of STAT's I build them with UDT's with built in spares.

An FB in Siemens is different than FB's with outher products, I remember using Concept in Modicon and having to download when the PLC was stopped.... yuk...

To the OP, learn STL language, as somne have mentioned even in programs where the developers maintain a ladder first phylosophy, they still have to program some parts in STL.

The secret with good STL programming is good comments that explain what is being done for those so well converse.

uptown47 said:

Hi Bob,

....
Which is your "favourite" brand out of interest?

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In danger of revealing a secret, I guess it starts with OM and ends with RON.

Kalle

KalleOlsen said:

In danger of revealing a secret, I guess it starts with OM and ends with RON.

Kalle

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Hmmm... I think I've got it...

Ot?

Ad STL programmers and maintenance personal. Molly Hatchet has made this song "One man's pleasure(is another man's pain)".
Play it while you're STL'ing.
http://www.youtube.com/watch?v=nKn-QB_RViw

Kalle

Correct. I do use Siemens from time to time, and other brands, and really struggle with Siemens.
I find trying to remember 'byte' based a pain as everything else is 'word' based.
Price is a major issue, as is software development time. It just takes too long.
Software prices are exhorbitant too.
Online programming is also 'tedious' to me.
I had a 'major' supplier trying to get me to change brands and they sent me one of their programmers to help me get my head around their software. I set some programming tasks up and we had a race. I was finished in 10 minutes and it took him 25 minutes to accomplish the same task. Obviously that is where I can make or lose a lot of money quite frankly.
I find the cost of complete software packages outrageous after Omron and I also find that not having a useful combined simulator that works with a simulated PLC and a simulated screen an absolute pain. Omron simulators do work together amking the development and testing of screens offsite really easy. That is why I no longer consider using Red Lion screens unless I need an outdoor screen or a protocl translator. Although external translators are now cheap enough anyway.

The secret with good STL programming is good comments that explain what is being done for those so well converse.

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Believe me the maintenance people still do not understand. Even having them open up an FB with ladder inside while on the phone is painfull.

mohsin.khan said:

I have working in a cold rooling mill and its under construction. We are using PLC siemens S7-300 In Bell Annealer Facility. The seller is giving us PLC program in Statement list but I wanted it in Ladder language.ALL I wanted to know that weather IS there any thing in a PLC programming software that can convert Statement list in a ladder language and if it can then I can change statement list program in a Ladder language without facing any problem /it can convert the whole program in ladder language.
Kindly send me your answers as soon as possible.

Click to expand...

Using Simatic manager, create a library, insert an S7 program into the library and copy the blocks (or a selection thereof) from your project blocks folder to the library blocks folder. Archive the library, then post on here for an assessment.

KalleOlsen said:

Ad STL programmers and maintenance personal. Molly Hatchet has made this song "One man's pleasure(is another man's pain)".
Play it while you're STL'ing.
http://www.youtube.com/watch?v=nKn-QB_RViw

Kalle

Click to expand...

Molly Hatchet... jeepers that takes me back

Hi again, BobB!

BobB said:

...
Believe me the maintenance people still do not understand. Even having them open up an FB with ladder inside while on the phone is painfull.

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Don't you normally use (tested and error-free) object FBs for AI and Motor and Valve control?

Just curious.

Kalle