Doc: 70-00-0792B V1.3, 20220830 © Vector Controls GmbH, Switzerland Page 24-34
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5.8.2 Proportional control (proportional band or switching differential)
The proportional control function calculates the output based on the difference between temperature set point and measured
room temperature. The proportional band (P-band) defines the difference between temperature set point and input required
to produce a 100% output. For example: a heating control sequence and a 2.0 °C P-band value will produce a 100% output
when the input temperature is 2.0 °C below temperature set point.
Proportional band (P-band) is the inverted proportional gain. Small P-band values lead to a fast reacting controller
(susceptible for oscillation). Large P-band values lead to a slow reacting controller.
5.8.3 Integral control (integral time)
The integral time is the time required to obtain the same manipulated variable as for the proportional action when using
only an integral action. The shorter the integral time, the stronger the correction is of the integral action.
The integral time can be set between 10 and 1200 seconds (20 minutes). The default value is 300 seconds (5 minutes).
For room temperature control the integral time should be chosen above 120 seconds (2 minutes), since the temperature
change needs in minimum several minutes to take place after heating or cooling valve was changed.
5.8.4 on/off control
The diagrams show the on/off control sequence for all applications except 4-pipe heating and cooling (P200 = 4) which is
explained below.
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