Hello folks,

I am a newbie on plc programmer and I need learn more about FBD language. I started from ladder but when circuit or logic programmer began a begin more complex I started difficult handle this issues through ladder. My teacher talk with me about FBD.

Normally I draw a grafcet and after this I build a logic on ladder. But I can't understand how can I convert my grafcet logic to FBD language.

I am search about book or article where explain what paradigms we have on FBD language. For example, I learned which ladder language I should use memory to steps and this memory will be activate output. The output should be alone on respective FB - Function Block. Because I never repeat output's.

But how should think when I use FBD language. After see some examples on FBD I must agree which FBD its more simply and friendly when programmer it is more complex. But I can't handle with change of thinking.

Thanks

[UPDATE1]

I pick up some examples about books which I read to learn about this issue, on this forum:

• https://support.industry.siemens.com/tf/ww/en/postattachments/download/?attachmentId=4176
• http://www.brilliant-training.com/step-7-made-easy

But I am searching some more resume to started. Also I read this book: https://cache.industry.siemens.com/dl/files/487/45522487/att_61497/v1/s7fup__b.pdf

Ok, this pdf/book it is useful to started and learn how use different features but how should I think when I need start build the logic code about my programmer in FBD? From grafcet?

[UPDATE2]

Maybe I don't need grafcet to programmer on FBD. Maybe I only need this tool to help me think how should I structure the code on ladder. I don't know :(

FBD is not much better than LAD. Its graphic representation is more compact, but in general that's all.

The main difference between them is the way the logic operations are ... coded.

In case of LAD "electrics" philosophy was adopted with all contacts and coils - like in relays.

FBD is successor of "electronics" philosophy with all logic gates - like in integrated circuits.

Then both of them adopted arithmetics blocks, because building adders, multipliers and so on out of basic logic elements was very time consuming

Finally grafcet... It's completelly different thing. It's purpose is not to depict logic operations but to depict finite state machines with their states and transitions.

Can grafcet be "translated" to FBD (or LAD, which is almost the same)? Yes. But what for if you have grafcet already?

Other story is that things like finite state machines can be directly coded in LAD or FBD.

There must be some misunderstanding between you and your teacher.

What do you mean by grafcet?

Are you talking about GRAPH Siemens package? Have I guessed?

As concerned FBD, if you feel yourself quite familiar with LAD language, anyway you should understand 2/3 of FBD at least. Because there are not so much difference between them.

Moreover, both languages you can easily convert. Those things that you don't understand on the  FBD language, you can see on the LAD language. There is nothing special there. It's usual self-study process.

However, you should have at least base knowledge on digtal electronics. It's, so to speak, the base for LAD & FBD languages.

Cheers,

Msorich

Ok, I understand all what you say but how can I should I think when I will create a logic.

For example, to the basic logic programmer present in the following image (basic_grafcet.png) I create two programmer. One of them through grafcet and another without recourse to grafcet.

How can you see the difference are in size and needs of networks. One this example I prefer the solutions without grafecet. Because through only network I can handle the all logic on my programmer. Whereas through grafcet I will need memory and more networks. But if the logic of programmer it is more complex and bigger I will need create the logic programmer through grafcet and I will need to respect all stages and create memory for each of the steps of the grafcet.

I am thinking write? Can you share with me some example where I can see how should I think ans structure/organize my thought to programmer my programs through FBD?

See images as attached

Thanks

Note: Sorry about my English. If exist any part where you can't understand please tell me. I will try fixed this.

Ok, this means that there are several ways to build a logic program? Both in Ladder as FBD? Depends on the imagination each one? Or exist any philosophy or method of programmer solutions to PLC?

For example, on language C I can build a program through procedure logic,  with recourse to function or (the best solution) through objects!

Thanks