Hello.

At collegue there are new Siemens Learning modules, more specific a PCS 7 DCS module with the PCS 7 v8,1 sp1 software for programming and  a S7 400 cpu 410 5h as a core, the cpu has its CP's (a 443-1 and a 443-5 ext). I've been trying to learn about it by doing the examples of the documentation in the web but I have a lot of questions and a I hope you can help me with them. (I have automation background, I know programming languages like ladder and scl, I've do some projects using PLC, etc. so please be as precise as you need).

- is there a way to program the CPU in ladder logic or SCL, if there is so, could you tell me how please? or where to find the documentation about it. I did some research but with no luck

- why Is CFC in almost all the examples? is there advantages using this languages over ladder? my level of programming in LADDER is good so it's really necesary to do this transition of doing CFC instead of ladder?

- In the exaples I made all the CFC programming was loaded in OB35 why is the reason for that? why I can not program over OB1?

- I want to do some MODBUS coms so I can communicate a third party PLC to this CPU, there are no MODBUS librarys on the CFC editor, where can I download this libraries. againg I did some research but with no luck on this too (i know there are libraries for this but i jave not luck find them).

I know there are plenty of questions here but fell free to answer the ones you know about. thanks a lot for the help.

regards.

Oreca

Hello ANTONIO7765,

Welcome to the community!

ANTONIO7765

Hello.

At collegue there are new Siemens Learning modules, more specific a PCS 7 DCS module with the PCS 7 v8,1 sp1 software for programming and  a S7 400 cpu 410 5h as a core, the cpu has its CP's (a 443-1 and a 443-5 ext). I've been trying to learn about it by doing the examples of the documentation in the web but I have a lot of questions and a I hope you can help me with them. (I have automation background, I know programming languages like ladder and scl, I've do some projects using PLC, etc. so please be as precise as you need).

- is there a way to program the CPU in ladder logic or SCL, if there is so, could you tell me how please? or where to find the documentation about it. I did some research but with no luck

In PCS7 the main programming language is CFC. You can however use STL/LAD/FBD or SCL. Especially SCL is used for programming your own blocks. When using SCL, you create a source, compile it so it becomes a block and then you insert the block in CFC where you can connect it's inputs and outputs. Another possibility is to create a programming logic in CFC language and compile it as block type. I suggest you focus on SCL for creating your own blocks. See below for manuals.

Manual SCL (for creating SCL sources)

Programming blocks (Manual about creating your own blocks for PCS7. This manual is based on the old style library, you can use this manual as reference though. The newest concept and library is the APL library see below)

APL Library Styleguide (This manual explains APL functionality to create your own custom blocks according to APL library. You need to know how to use SCL first)

- why Is CFC in almost all the examples? is there advantages using this languages over ladder? my level of programming in LADDER is good so it's really necesary to do this transition of doing CFC instead of ladder?

PCS7 is mainly used for big installations, you will notice that using CFC is highly recommended for visibility and clear programming. You can program in LAD, but I suggest you will not do so...

- In the exaples I made all the CFC programming was loaded in OB35 why is the reason for that? why I can not program over OB1?

All blocks in the PCS7 library are created using interrupt OB's. An interrupt OB like 1 second, will always be executed in 1 sec. If you use OB1, you don't know what the cycle time is, because when the CPU has high load, it can be that OB1 cycle time increases (up to 6sec). If you program blocks in OB1, it may be that some logic is not executed correctly. 

- I want to do some MODBUS coms so I can communicate a third party PLC to this CPU, there are no MODBUS librarys on the CFC editor, where can I download this libraries. againg I did some research but with no luck on this too (i know there are libraries for this but i jave not luck find them).

See below manuals for more information. Is this helpful?

Modbus PtP

Modbus TCP

I know there are plenty of questions here but fell free to answer the ones you know about. thanks a lot for the help.

I cannot explain PCS7 in a few steps, you may want to look at the following manuals in order to start with PCS7. You can also check my topic for more information about manuals/updates and FAQs. 

First steps

Getting started part 1

Getting started part 2

Topic: PCS7 Complete Overview

Good luck!!!

regards.

 

Dear Oreca.

thank you so much for your time and help, that was pretty helpful. today I'll try your advices on the lab, I hope I can let you know how it goes so we can help other people who are in the same situation like me

Regards