Retrieve FC after over written

Ranjith · Mar 5, 2015

Hi Gents
I did a terrible mistake.
Copied 2 FC's from a different project to the existing one.
Accidentally press the over write button and I lost at least couple of weeks work in 2 seconds. Is there a way to retrieve the old FC? Haven't done a backup or never downloaded the program to a cpu since this code is for a new machine.
This must have happened to someone before and hope there is a way to retrieve it. Any help is much appreciated.
SIEMENS STEP 7 V5.5

jstolaruk · Mar 5, 2015

Not that I know of, I've done the same in Step 7. Now, for any s/w, I have a backup for everyday I work on code; delete stuff older than a week every couple of days.

L D[AR2P#0.0] · Mar 6, 2015

Can you post the archived project?

Ranjith · Mar 6, 2015

Please check your PM.
Sent you a link to the archived file on drop box.
FC's in question are FC102 and FC103 in PLC7301 Control.
Copied FC101,102 and 103 from another project.
There was no FC101 in the current project, so it copied OK.
Then FC102 and 103 replaced the existing ones.
Is there a way to retrieve the old FC102 and FC103.
Thanks for your help again.

boneless · Mar 6, 2015

Have you by any chance installed some software recently? You might be lucky and Windows made a restore point that might (or might not) include your old code.

L D[AR2P#0.0] · Mar 6, 2015

The code for your FC's prior to overwriting them is stored in the data files within the S7 project. I have seen multiple copies of code/interfaces/comments when digging around S7 files with a Hex editor. Here's an example that shows that the code is present. I created two libraries both with an FC1 containing a single line of code. Library X loads DW#16#22222222 and library Y loads DW#16#11111111

Here's the Hex editors view of the code shown for X

L D[AR2P#0.0] · Mar 6, 2015

..and here is the Hex editors view of Y:

L D[AR2P#0.0] · Mar 6, 2015

I copied FC1 from Library Y to Library X, ovewriting the FC.
The HexEditor reveals that both copies of the FC are present, the original at offset 600 and the new at offset 2400:

L D[AR2P#0.0] · Mar 6, 2015

The interface and comments for both versions are also located in the DBT file.
So.... it looks like it would be possible to wade through your SUBBLK.DBT file and by a process of elimination find the code the corresponds to the overwritten versions of your FC's (by coping each FC individually to another empty project and inspecting the DBT file to show the code).
Wether you want to take this on rather than re-writing is your choice, I'd go for the re-write myself.

Ranjith · Mar 6, 2015

Thanks L D[AR2,P#0.0]
I can see your point.
In S7Proj there are 9 folders (00001-00009) in Offline folder.
Each folder has a subblk.dbt file.
But only one dbt file has yesterday's date stamp in folder 00002.
I have zipped the whole folder and attached here.
I have not open it with hex editor yet.
I will keep you updated.
Thanks again for your help.

Ranjith · Mar 6, 2015

This FC was copied multiple times from project to project and I can see the tag names and network comments in the hex editor right hand side column.
Most importantly I can see the logic I needed to retrieve as well.
Now It's just a matter of moving the stuff I need into the right area in the hex editor. I am trying to workout a pattern,

As per your test offset 2400 is the current logic and 600 is the old logic.
So if you move the numbers in 600 to 2400 then it should represent the old logic.

Ranjith · Mar 6, 2015

boneless said:
Have you by any chance installed some software recently? You might be lucky and Windows made a restore point that might (or might not) include your old code.

I haven't installed any software since then.
I think the restore will only modify the system files.
I have few restore points prior to disaster.
Is it worth trying?

L D[AR2P#0.0] · Mar 7, 2015

A data base editor looks more promising. I have found what appears to be the previous versions of blocks using DBF Viewer 2000.

Ranjith · Mar 7, 2015

Not quite sure what you see in DBF viewer.

L D[AR2P#0.0] · Mar 7, 2015

If the original FC102 looked like this...

Retrieve FC after over written

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