Beckhoff First Scan Bit !free! Online

The First Scan Bit is a that is TRUE only for a single PLC cycle immediately after the runtime system starts executing the application. On the second cycle, it becomes FALSE and remains FALSE until the next controller reboot or program download.

For official documentation on these system variables, you can refer to the Beckhoff Information System Are you looking to initialize specific variables or are you migrating logic from another PLC platform RSLogix 5000 First Scan Bit (S:FS) Programming Guide beckhoff first scan bit

What the first scan bit is