Compare Input¶

The Compare Input block evaluates a selectable system signal against a user-defined threshold using flexible comparison logic. It supports hysteresis, optional filtering, and timing control for stable and precise event detection.

1. Input Source¶

The user can select a signal from available system variables (e.g., coolant temperature, pressure, RPM) to use as the input for comparison.

2. Comparison Modes¶

Specifies how the input is evaluated relative to a defined Value.

• Equal¶

  • Output is true only when the input equals the specified Value.
  • Deviation is forced to 0 in this mode — no hysteresis or tolerance is applied.
  • Ideal for detecting exact matches.

• Window Compare¶

  • Output is true when the input is within the range:

    Value - Deviation ≤ Input ≤ Value + Deviation
    

  • Output is false when the input is outside this range.
  • Useful for checking valid or safe operating windows.

• LessThan¶

  • Output turns true when:

    Input < Value - Deviation
    

  • Output turns false when:

    Input > Value + Deviation
    

• GreaterThan¶

  • Output turns true when:

    Input > Value + Deviation
    

  • Output turns false when:

    Input < Value - Deviation
    

  These hysteresis thresholds prevent output toggling due to small signal oscillations.

3. Value¶

The central threshold used in all comparison modes.

4. Deviation¶

Defines the hysteresis band or tolerance around the Value.

• Used in Window Compare, LessThan, and GreaterThan modes.
• Helps filter out signal noise or rapid transitions.
• Not used in Equal mode (automatically set to 0).

5. Filter Enable¶

Controls how the input signal is processed and whether timing constraints are applied.

• Filter Disabled¶

  • Compare Input operates in level-based mode.
  • Output reacts immediately to input crossing thresholds.
  • Delay and Cooldown are ignored.

• Filter Enabled¶

  • Compare Input operates in event-based mode.
  • Output is triggered on rising/falling transitions of the condition.
  • Delay and Cooldown become active:
    • Delay: suppresses short glitches.
    • Cooldown: prevents rapid retriggering.

6. Delay¶

• Only evaluated when Filter is enabled.
• The input condition must remain valid continuously for the full Delay time before the output is activated.

7. Cooldown¶

• Only evaluated when Filter is enabled.
• Defines the minimum time after the end of the trigger condition during which new events are ignored.
• Prevents repeated or bouncing events immediately after a trigger ends.

Example Configuration¶

Input:          Coolant Temperature
Mode:           LessThan
Value:          80
Deviation:      3
Filter:         Enabled
Delay:          50 ms
Cooldown:       200 ms

Behavior¶

• Output turns on when the input drops below 77°C and stays there for at least 50 ms.
• Output turns off when the input rises above 83°C.
• After turning off, the system waits 200 ms before allowing another trigger.