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Why didn't my recurring form trigger? (Continuous vs. Cumulative Time)

The Issue

You have a form set to repeat every 120 minutes based on a Machine State (e.g., Running). However, the form does not trigger even though the machine has been "Running" for a total of 3 hours over the course of the morning.

The Explanation

OFS-Flow triggers evaluate uninterrupted spans of a state. They do not "buffer" or accumulate time across different events.

  • How it works: When the machine enters the target state (Running), a timer starts. If the machine stays in that state for the full duration defined in your trigger (e.g., 2 hours), the form fires.

  • The "Gap" Problem: If the machine state changes—even for a single minute—the timer for that specific span is destroyed. When the machine returns to "Running," the timer starts from zero.

Example Scenario:

  • 08:00: Machine starts Running (Timer starts).

  • 08:20: Unplanned Downtime for 5 minutes (Timer is killed).

  • 08:25: Machine starts Running again (Timer starts at 0).

  • 10:05: Machine is still Running.

  • Result: No form triggers. Even though the machine ran for 120+ minutes total, it only ran for a maximum continuous span of 1 hour and 40 minutes.

Key Caveats

  1. State Sensitivity: Any state not explicitly selected in your trigger will break the chain. If your trigger is set only for "Running," then "Run Slow" will reset your timer.

  2. The "Start" Toggle: If you have the "Start" toggle ON, the form will fire immediately when the state begins (or after the offset). The 2-hour "Repeat" timer then begins after that first alert is generated.

  3. Shift Changes: Depending on your configuration, a shift change or a job change can also conclude a state span, effectively resetting your frequency timer.

Best Practice Recommendation

If your production environment is prone to micro-stops or frequent short downtimes, a 2-hour Machine State repeat may be too "fragile."

The Alternative: Use a Shift-based Trigger with a repeat interval. Shift triggers look at the wall-clock time of the shift rather than the machine's heartbeat, ensuring the form pops up every 2 hours regardless of technical interruptions. Here is an article on setting up count based triggers.