S7-400 Uploading a station

[yxannes]

Hi guys, I am caught in a situation where I have no choice but to do a upload. This is what I get from the help file:

Restrictions when uploading:

1.Blocks do not contain any symbolic names for parameters, variables, and labels

I have the wiring diagram so I guess I can regenerate the symbol table. But what about the variables and variables tables?

2. Blocks do not contain any comments

That's ok.

3. The entire program is uploaded with all the system data, whereby the system can only continue to process the system data belonging to the "Configuring Hardware" application

Anyone wanna explain that?

4. The data for global data communication (GD) and configuring symbol-related messages cannot be processed further
Force jobs are not uploaded to the programming device with the other data. They must be saved separately as a variable table (VAT)

Anyone wanna explain that?

5. Comments in the module dialog boxes are not uploaded

Oh well...

6. The names of the modules are only displayed if this option has been selected during configuration (HW Config: the option "Save object names in the programmable logic controller" in the dialog box under Options > Customize)

Not that big a deal I reckon?

So if any of you guys did a upload w/o the source in s7 please share your experiences like was it a pain to get everything back,etc. Greatly appreciated.

 

[John Gaunt]

"Reverse Engineering" a S7 program.

You can upload the program from the CPU to Step7.

The uploaded program would have no comments or symbols.

The place to start is to use an I/O allocation list and begin to build your symbol table.

The next step is to try to identify what each block is about and give it a meaningful name.

You can then start to work out in detail what each block does adding comments as you go.
It is likely that you can defer doing this for most blocks until you need to make modifications.

Doing this "Reverse Engineering" is dependant on your expertise with Step7, your determination,
your detective abilities as well as the complexity of the programming and how well structured
the original program is.

Good luck with it.
Regards..................John Gaunt

 

[zrawi]

I have done similar reverse enginering without I/O allocation list. It was a pain for two weeks..

I'm curious about the GD comms. For example, if I upload a station A, whitch communicates with other station B(GD), to my Step7(new blank project) and make some HardWare changes, will it affect the Global Data between stations A and B?

p.s. I'm planning to add Ethernet CP and connect plc to pc..