First Scan Bit !!top!! | Beckhoff

During an Online Change, the PLC continues execution, and the first cycle flag remains FALSE . Summary Table of Methods _TaskInfo.FirstCycle Production Systems Native, accurate for runtime starts. Requires GETCURTASKINDEX . Initialized BOOL Simple Logic Easy to read, portable. Can be manually reset by accident. System Event Complex Init Clean separation of startup code. Harder to debug for beginners.

To utilize the Beckhoff First Scan Bit, programmers can use the TwinCAT 3 programming environment to create a simple ladder logic (LD) or function block diagram (FBD) program. The First Scan Bit can be accessed using a special system variable, typically called "FirstScan." beckhoff first scan bit