Setting On/Off Control Hysteresis - Automationdirect.com prosense PPC5 Series User Manual

Chapter 8: Output Setting Functions
8.7

Setting ON/OFF Control Hysteresis

Description
In ON/OFF control, since the only two possible output states are ON and OFF, the control
output cycles are as shown in the figure below. ON/OFF becomes quite narrow, so that if
relay output is used, chattering occurs. In this case, the hysteresis should be set wider to
prevent relay chattering and for the service life of the relay.
One Point of Hysteresis
Set one point of hysteresis.
Hysteresis
ON
Output
OFF
SP
PV
Hysteresis
SP
Temperature
ON ON ON
OFF OFF
Output
(Example of reverse action)
Two Points of Hysteresis
Set two points of hysteresis (upper-side hysteresis and lower-side hysteresis).
Lower-side Upper-side
hysteresis hysteresis
ON
Output
OFF
SP
PV
Upper-side hysteresis
SP
Temperature
ON ON ON
OFF OFF
Output
(Example of reverse action)
Lower-side hysteresis
8-9
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