Beckhoff First Scan Bit Patched May 2026

// 3. Request axes to home (if needed) fbAxis1.bHomeRequest := TRUE; END_IF

Caveat : This method is cycle-dependent. If your cycle time is 10ms, set PT to at least 1ms — but ensure it's longer than one cycle but shorter than two. With TwinCAT 3, Beckhoff introduced the Tc3_Standard library, which includes a dedicated function block: F_TRIG combined with a system flag is no longer needed. Instead, use: beckhoff first scan bit

PROGRAM MAIN VAR bFirstScan : BOOL; rst : BOOL; END_VAR // In your implementation section bFirstScan := NOT rst; rst := TRUE; With TwinCAT 3

: The official Tc3_Standard provides a clean helper: Beckhoff introduced the Tc3_Standard library

FUNCTION_BLOCK FB_DriveController VAR_INPUT bEnable : BOOL; END_VAR VAR_OUTPUT bReady : BOOL; END_VAR VAR fSpeed : REAL; END_VAR // This runs once when the FB is created (first scan of the FB) METHOD FB_Init : BOOL VAR_INPUT bInitRetains : BOOL; // TRUE if retain variables are restored bInCopyCode : BOOL; // TRUE if FB is copied END_VAR fSpeed := 0.0; // Initialize internal variable bReady := FALSE; END_METHOD