Cycle Time Error

What does E2-37 mean?

The Safety PLC's program execution time has exceeded the configured watchdog time (cycle time). This can lead to safety function violations, system halts, and an inability to maintain real-time control, compromising safety.

• Program execution time exceeding the configured watchdog time (e.g., Parameter P1-33 Scan_Time).
• Excessive communication load on the Safety PLC's CPU from connected safety devices or network traffic.
• Poorly optimized safety logic with complex calculations or large data processing within a single scan cycle.
• Integration of too many safety I/O or function blocks, saturating the CPU's processing capability.
• Hardware malfunction on the CPU causing delays in program execution.

Click steps to track your progress.

1. 1

   1. Review the Safety PLC's program scan time reported in the engineering software diagnostics (e.g., 'Cycle Time' or 'Scan Time').

2. 2

   2. Increase the watchdog timer setting (e.g., Parameter P-WATCHDOG_TIME) in the Safety PLC configuration, if permissible by safety requirements.

3. 3

   3. Optimize complex safety logic blocks or reduce the number of calculations performed within a single scan cycle.

4. 4

   4. Verify communication settings (e.g., bus cycle time, update rates) for connected safety devices (e.g., F-I/O) to ensure no excessive network load.

5. 5

   5. Disable non-essential diagnostic or logging functions temporarily to reduce CPU overhead.

6. 6

   6. Consider upgrading to a Safety PLC with higher processing power if the current application consistently exceeds cycle time limits.