Function Block Translate / Transfer

[b.bartel]

Greetings All,

I am hoping for some guidance on if there is a quick and easy way to translate or transfer Function Block logic into ladder logic.

I have a program that almost solely uses FB programming and it is very difficult for me to monitor the process or see where to make changes to sequence, timing or alarm triggers.

I am using RSLogix 5000.

I have little experience with FB programming and am not sure how to go about making changes to improve our process with the current logic.

Any assistance will be greatly appreciated and if you can point me in the right direction of some good source or literature on the topic I will try to read my way to a solution.

Thank you.

 

[rdrast]

That depends on what instructions the FB uses.

Some have ladder equivalents, some don't.

They shouldn't be all that hard to read or troubleshoot though, FBD's are scanned pretty much like ladder elements, Top to bottom, Left to Right.

And before making changes, are you certain that problems exist in the existing logic?

 

[AutoMax]

Hate to be a know-it-all, but FBD in ControlLogix doesn't necessarily scan top to bottom, left to right. That's why there's a "show/hide execution order" feature...

 

[dmargineau]

Some of Rockwell's FBs are not "translatable" in Ladder...There are Logix functional reasons for this and it's not much the user could do about it...

It is a bit extreme to write a Logix program exclusively in FBD since each language has specific functionality designations; LAD I/O processing will return the best performance; process logic will benefit from FBD and raw data handling ST is usually the norm.

You will have to go through each FBD routine and find out (using Instruction Help) which of the FBD blocks have LAD equivalencies and then try to replicate the FBD logic in LAD while being very careful when defining the new LAD logic Tasks timing; throwing FBD-to-LAD logic in a Continuous Task will probably significantly alter the system functionality and/or performance.