IEC 61131 Siemens to Bradley

Hi,

Im investigating for my work if it is possible to transfer a simple program from Step7 to RSLogix5000. According to the site of siemens this must be possible. See this link http://support.automation.siemens.c...0&lang=en&content=skm/search.asp?&Query=61131. and on the rockwell site it is written that importing from other programs is possible with rslogix5000 through the import function when it is following the IEC 61131-3 standard.

I have read much about the standard iec 61131. especially that it's not applied in such kind a way that code can be copied and pasted in other enviroment. So now I wonder, is it possible to convert siemens step7 code to allen bradley logix 5000 code? Both vendors are certified in IEC 61131-3. see http://www.plcopen.org/pages/tc3_certification/certified_products/

Can anybody give me more information?

IEC 61131.3 as originally envisaged would have allowed you to easily move programmes from one PLC to another. Unluckily for end users, the voting structure at the IEC is sort of run by the manufacturers (witness the whole field bus debacle). It makes the Brussels EU stuff look positively efficient and cost effective.

The standard ended up being a joke and code is not easily ported from one PLC brand to another. Rockwell, ABB, Siemens, Bosch, whatever - all different.

This means that one manufacturers' interpretation of IEC 61131.3 is completely different than another. You don't even have to support all the languages to be compliant (a simple statement of compliance gets youy around that). Enough on that. So in a nutshell the certification is meaningless.

As far as conversion, you would have a lot of trouble. Rockwell for example don't do Instruction List. S7 ladder leaves a lot to be desired. SFCs in Rockwell are painful. The underlying OB structure for S7 is not used by Rockwell (Rockwell is easier to programme in that particular case). Etc.

Sometimes the OEM will give you a migration tool. More likely the code gets sent off shore to somewhere where the programmer charges $10/hr and the code is converted by hand.

I don't recall a Rockwell-Siemens tool - the last time I did a migraton was from S7 to ControlLogix and that was done by hand. It really did not take long. Ladder logic is the premier language in Logix and if I recall the S7 was mostly IL.

Ranjan Acharya
New Zealand

acharyar said:

The standard ended up being a joke and code is not easily ported from one PLC brand to another. Rockwell, ABB, Siemens, Bosch, whatever - all different.

Click to expand...

And that will remain so until The Microsoft decides to move in. Bill Gates, come and save us!

LadderLogic said:

And that will remain so until The Microsoft decides to move in. Bill Gates, come and save us!

Click to expand...

Give me a ballistic missile, I have to kill a mosquito .

Kind regards,

Hi RoRo,

I notice the Siemens link you gave leads to an article specifically relating to Structured Text. This is the one portion of the IEC standard where I think you would have greatest success between any two vendors. I'd definitely forget LAD (has anyone achieved PLCOpen certification on that yet?) and IL. Too many PLC manufacturers had vested interests in their own dialects of these languages before 61131-3 emerged.


Ken

On the Siemens side it is only "SCL" that conforms to IEC ST and "Graph" that conforms to IEC SFC.

I believe that Siemens SCL also only supports part of the possible IEC datatypes, but since you are porting from Siemens, then that is not a problem.
This means that you can actually copy and paste between STEP7 and RSLogix when porting SCL to ST code. Of course, the variables used in the code must be carefully setup to be the same or similar on both systems. I guess that you get 98% code that converts with no problem, and 2% must be manually touched up.

Graph code should be possible to convert one-to-one to SFC, but it must be done manually.

Siemens LAD does not conform to IEC LD.
However, the basic functionality is so similar that I guess 90% can be converted manually.
Problem spots are the S5 timers, and maybe also FB+IDB's.

Siemens STL is a problem. In particular S7 pointers dont have anything in common with AB indirect addressing.
There is no other way than to analyse what the S7 STL code does, and then recreate the functionality in RSLogix.

The code of the functions can be copied and pasted in the editors. The problem are the variables. Allen bradley doesnt declare variables in the (sub)routine but in the program tags(correct me If Im wrong. Im new to allen bradley). So I need to import the declarated variables from SCL to RSLogix 5000. Is there a way to import variables declared following the 61131-3 standard into logix5000?

Btw, Thanks for the answers.