IF bFirstScan THEN // Perform Initialization Tasks here iTargetVelocity := 1500; bMachineReady := FALSE; END_IF // All other machine logic goes here... // The very last line of the program: bFirstScan := FALSE; Use code with caution. 2. Using FB_GetCurTaskIndex (The Pro Method)
Never make your First Scan bit a RETAIN or PERSISTENT variable. It needs to reset every time the PLC power cycles. beckhoff first scan bit
Ensuring your sequences (SFC) start at "Step 0." IF bFirstScan THEN // Perform Initialization Tasks here
Establishing a "heartbeat" or initial connection status with HMIs or third-party devices. How to Implement "First Scan" in TwinCAT 3 There are two primary ways to handle this in Beckhoff. 1. The Manual Method (Most Common) bMachineReady := FALSE