Beckhoff First Scan Bit Jun 2026

Another method, often considered more accurate for truly catching the first PLC tick after the system is fully booted and ready, involves using the TwinCAT system library functions if needed, but the method above is generally robust for most applications.

: Essential for setting default values for retentive memory variables. beckhoff first scan bit

Initialization block with handshake:

⚠️ Caution : This resets on warm start. For cold start retention, use VAR RETAIN . Another method, often considered more accurate for truly

PROGRAM Example VAR FirstScan : BOOL; END_VAR For cold start retention, use VAR RETAIN

// Also override certain retained values if needed IF NOT bRetainValid THEN // Force defaults END_IF

To use the First Scan Bit in a Beckhoff PLC, you need to access the PLC's system variables. The First Scan Bit is typically represented by a specific system variable, such as FirstScan or InitDone .