If you use the manual variable method, ensure the line bFirstScan := FALSE; is at the very bottom of your MAIN task. If you put it in a sub-function, other parts of your program might miss the "True" state.
Setting default temperatures, speeds, or timers. beckhoff first scan bit
Without a initialization bit, your PLC logic simply resumes from its last state or starts with default values that might not be appropriate for a running machine. Common use cases include: If you use the manual variable method, ensure
Wiping the slate clean on startup so old errors don't prevent a start. ensure the line bFirstScan := FALSE
TwinCAT provides internal system information via the Tc2_System library. You can check if the current cycle is the very first one by looking at the system task info.