Siemens SIMATIC PCS 7 Operating Manual page 181

Using the "Compare with" drop-down list box, you can determine which programs you intend
to compare.
● If you have activated the "Program" option button, you will be able to select one of the
following programs here:
Reference
Last compilation
Online
Another project
● If you have activated the "Reference" option button, you will be presented with the
following selection options:
Current program
Last compilation
Online
Another project
Signature of the safety program
The program signature is used to identify a safety program. It changes each time a change is
made to the safety program. As a result, comparing the signature values of two safety
programs provides an initial indication of what changes have been made in the safety
program.
The signature of the current safety program in an AS can be found in the "Edit Safety
Program" window. To do this, in the SIMATIC Manager select the CPU that contains the
safety program and use the "Options > Edit Safety Program" menu command to open the
relevant dialog. There, you will see three signatures, each with a corresponding date:
● The most recent date on which the CFC charts with changes to the safety program were
compiled, and the signature formed for this.
● The date on which a safety program was saved as a reference, and which signature the
reference program has.
● The date of the last online change and the signature formed for this. Several online
changes may have been made since the last compilation.
Save the program you have checked as a reference using the "Reference" button in the "Edit
Safety Program" window; enter the password if requested to do so and answer "Yes" to the
query that appears following this.
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB
Last reference saved for this program
Last compilation of the program
Program in the state currently downloaded on the F-CPU
Any offline program, click ("Browse..." to select)
Current offline program
Last compilation of the program
Program in the state currently downloaded on the F-CPU
Any offline program, click ("Browse..." to select)
Changes, tracking changes, and acceptance
9.6 Tracking changes in the safety program
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