Debugging Not Possible - Program Mismatch

What does The program has changed! mean?

Debugging on the safety CPU is not possible even though the "Enable debug" parameter was set to "ON" and correctly loaded. This indicates that the safety project on your PC is not identical to the one currently loaded in the safety CPU, leading to a program mismatch.

• A project download was performed to the safety CPU from a different engineering station or an older/newer version of the project file.
• Changes were made to the local project on the PC without being downloaded to the CPU, creating a mismatch.
• The CPU's operating system or firmware was updated, causing a change in its internal structure that the debugger doesn't recognize with the current project.
• Data corruption of the project file on the engineering station or within the CPU's memory, leading to a perceived mismatch.

Click steps to track your progress.

1. 1

   Perform a "compare online/offline" operation in the PLC programming software to identify exact differences between the PC project and the CPU project.

2. 2

   Download the identical project version from the engineering station to the safety CPU, ensuring all changes are synchronized.

3. 3

   If multiple engineers work on the project, ensure proper version control (e.g., using a VCS) and that the correct project version is being used.

4. 4

   Power cycle the safety CPU (remove and re-apply 24VDC) after confirming the "Enable debug" parameter is set to "ON" and a fresh download.