Omega CN4321 Manual page 43

HYS Hysteresis: Hysteresis is that area around the main set-
point where the output does not change condition. That
area or deadband is intended to eliminate relay chatter
at setpoint for On/Off control applications. The wider the
Hysteresis, the longer it takes for the controller to
change output condition. The narrower the Hysteresis,
the less time it takes for the controller to change output
condition. When the Hysteresis is narrow, the On/Off
control is more accurate but the wear on the output relay
is increased. Enter a value which is small enough to meet
the control tolerance of the application but large enough
to eliminate relay chatter.
Setting range: 0 to 50% of FS, set in E.U., for output #1.
Hysteresis for On/Off action for dual outputs (heating and
cooling) is fixed at 0.5% of full scale.
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