RS Logix5000 ST to ladder program

[zai_jnr]

[FONT=Söhne]Hello everyone,[/FONT]
[FONT=Söhne]I'm currently using RS Logix5000 software for machine programming with this Rockwell PLC using the Structured Text method.[/FONT]
[FONT=Söhne]The client has requested that I convert all Structured Text programs to Ladder diagram programs. Are there any tools or software available that can automatically convert this program from ST to Ladder?[/FONT]
[FONT=Söhne]Any ideas?[/FONT]

 

[cardosocea]

You'll have to re-write everything... This is also a very stupid request of a customer that specifies a brand of controllers that doesn't allow all instructions to be used in Ladder.

I hope that you have loops in your program so that his request is actually counterproductive. Also, sprinkle some MCR's while you're at it to make things fun for their people.

 

[joseph_e2]

Stupid request? I've been the customer requesting no code other than Ladder. Because I'm stupid? No...because I don't want to be the one on call 24/7 to support the thing. "Just hire qualified technicians"...because they're just swarming the streets in packs looking for jobs?

Be careful where you blindly fling "stupid". There are many reasons someone might not want "advanced" languages in their PLC and being stupid is almost certainly NOT it.

 

[plvlce]

Also if the customer has 'Standard' license(s) for their techs they may not want pay to for another license to support just one machine.

But no, I don't know of any method for automatic conversion.

 

[JasonWade]

If this MUST be done, I'd be looking for a concession to pack up some of the code into ST AOIs and call them in ladder. Some parts of ST can be tortuous to write (and to read/understand) in ladder, loops being to obvious example.

 

[Slwagner73]

If you want to be the guy answering the phone at all hours, or worse yet, ignoring the customer, then just ignore the request.

 

[dwoodlock]

If this MUST be done, I'd be looking for a concession to pack up some of the code into ST AOIs and call them in ladder. Some parts of ST can be tortuous to write (and to read/understand) in ladder, loops being to obvious example.

This is the way…..if they’ll agree to it?

I do this as standard. Main routine is always ladder, sequences in ST with text output indicating what’s happening on what step in case an issue occurs.

 

[Cheeseface]

You might be able to find a yacc parser for structured text, then modify it to emit ladder.

You'll have trouble with certain things like loops and things like TONR, but it depends on how much code you're dealing with.

If it's just a couple of files just bite the bullet. If it's 20 or 30 you might try to automate it, but you'll still wind up verifying it by hand.

 

[cardosocea]

Stupid request? I've been the customer requesting no code other than Ladder. Because I'm stupid? No...because I don't want to be the one on call 24/7 to support the thing. "Just hire qualified technicians"...because they're just swarming the streets in packs looking for jobs?

All absolutes are stupid, I stand by it and feel sorry you're like that because in a way it shows your lack of experience with Rockwell stuff and possible applications with those controllers.

Also, because Rockwell doesn't allow certain instructions in Ladder, doing so increases the likelihood of issues being brought in or code that technicians that you drag off the street won't understand in a million years either...

If you instead told me that you want the majority of your code to be ladder and provide examples of where other languages are to be used provided they're encapsulated and tested independently, I'd say that we're pretty much alike.

Be careful where you blindly fling "stupid".

Be careful where you blindly throw absolutes...

There are many reasons someone might not want "advanced" languages in their PLC and being stupid is almost certainly NOT it.

And those reasons are generally absolute ******** from neckbeards who are affraid of change... there are indeed reasons to stick to Ladder and I support them in pretty much all platforms. But there are also a magnitude of problems where ladder is definitely the worst possible language to use which make the code more obscure when it would be simpler in ST or even FBD.

And this is coming from someone that won't accept most SFC sequences because of the risk of resetting them at the wrong place... but Ladder isn't the right language for a fair few things in automation.

But hey, if screwing in nails has worked for you, keep at it.



P.S.: Sorry if I'm being blunt, but being a fundamentalist irks me to an extreme.

 

[I_Automation]

A big Gotcha to be aware of, and a good idea to let the customer know, is there are things done in ST that can not be done in ladder logic.

Even with S5K programs in mostly ladder there are frequently subroutines or AOIs in ST of FB.

 

[cardosocea]

A big Gotcha to be aware of, and a good idea to let the customer know, is there are things done in ST that can not be done in ladder logic.

Indirect bit addressing being one. It's a pretty powerful ability to be able to do it.

 

[joseph_e2]

All absolutes are stupid...

P.S.: Sorry if I'm being blunt, but being a fundamentalist irks me to an extreme.

Then quit being fundamentalist and understand that different folks have different situations that need different solutions. And that I'm not stupid for having a different situation than you.


With our local labor base and wage structure (that I can't fix, btw), I can't have techs on staff who understand ST. Period. It's not ideal and I agree that it would be nice to be able to use it...but I'm not superman who can be here 24/7 to keep the machines running. I'm not stupid for asking my machine builders and integrators to work around the limitations that I'm already having to work around. All I'm asking is for the common courtesy of not being called stupid

 

[drbitboy]

Indirect bit addressing being one. It's a pretty powerful ability to be able to do it.

btw, some vendor's ladder syntax does allow for this (.[index] in A-B). It is not some magical concept originated in ST.

 

[parky]

As DR posted, loops are not limited to ST, most PLC's can doo loops even if it uses jumps & compares of the index, the real power of ST is the ability to nest many maths functions like in other programming languages like basic, C++ etc.
Traditionally, some functions in ladder need to be kept seperate for example special maths functions like COS only takes one parameter & returns one, in ST & ladder this requires individual calls to the function as the return parameter is within the brackets so has to be stored in some temporary memory. so no real advantage in using ST. Some PLC's may have the more complex maths functions that can use them directly.
certainly, the usual maths like +-* / etc can be used directly, traditional ladder means these functiond are out instructions so need storing in variables before being used again, in FBD these functions can be used directly.

 

[JaxGTO]

For me it's the Buba Effect. I don't want that 2am call when Buba cant find an output to see why it's not coming on.


That's also why I try to never even use indirect addressing. If the PLC has the memory and the scan time, I'd rather use it up and keep it easy for Buba.