Insulation alarm threshold hysteresis
A hysteresis is applied to limit the error in the insulation
alarm due to fluctuations in the measurement when approaching threshold
value.
A hysteresis principle is applied:
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When the insulation value measured decreases and falls below the setting threshold, the insulation alarm is triggered or the countdown is started if an insulation alarm time delay has been set.
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When the insulation value measured increases and exceeds 1.2 times the set threshold (i.e. the setting threshold +20%), the insulation alarm is deactivated.
The following diagrams show the behaviors:
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Without hysteresis:
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With hysteresis: