Internal FB Error

What does 7FFF hex mean?

This diagnostic code (represented by value 16#7FFF) indicates a severe internal error within a PLCopen Safety function block. This implies a malfunction in the block's internal logic or execution, preventing it from performing its intended safety function correctly and potentially leading to a safe state.

• Internal firmware fault within the PLCopen Safety function block (FB_SafeBool, FB_SafeInt, etc.) due to a rare execution state.
• Memory corruption affecting the safety function block's internal variables or program counter.
• Incorrect or incompatible safety PLC firmware version loaded, leading to function block instability.
• Hardware malfunction on the safety CPU itself, impacting the integrity of safety logic execution.

Click steps to track your progress.

1. 1

   1. Check the safety PLC's diagnostic buffer for specific error sub-codes related to the function block.

2. 2

   2. Save the PLC project, then perform a complete power cycle of the safety PLC and re-test.

3. 3

   3. Update the safety PLC's firmware to the latest compatible version as recommended by the manufacturer.

4. 4

   4. Review the safety program logic for any complex or unusual conditions that might trigger internal FB states.

5. 5

   5. If the error persists, replace the safety CPU module and then download the project.