Order No. 2104 ..
Figure 21: 2-point feedback control for the single "Cooling" operating mode
An additional 2-point feedback control heating or cooling level works exactly the same as the
2-point feedback control of the basic level. The difference is that the setpoint and the hysteresis
values will shift by taking into account the configured level offset.
"Heating and cooling" mixed operating mode:
In mixed operation, a distinction is made whether the change-over between heating and cooling
is to be effected automatically or in a controlled way through the object.
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With automatic operating mode change-over, in the heating mode the controller will turn on
the heating when the room temperature has fallen below the preset hysteresis limit. In this
case, as soon as the room temperature exceeds the setpoint of the current operating
mode, the feedback control will turn off the heating in the heating mode. Similarly, in
cooling mode, the controller will turn on the cooling system when the room temperature has
exceeded the preset hysteresis limit. As soon as the room temperature falls below the
setpoint of the current operating mode, the feedback control will turn off the cooling system
in the cooling mode. Thus, in mixed operation, there is no upper hysteresis limit for heating
or no lower one for cooling, respectively, for these values would be in the deadband. Within
the deadband, neither heating nor cooling will take place.
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With operating mode change-over via the object, in the heating mode, the controller will
turn on the heating when the room temperature has fallen below the preset hysteresis limit.
The feedback control will only turn off the heating in the heating mode if the preset upper
hysteresis limit has been exceeded. Similarly, in cooling mode, the controller will turn on
the cooling system when the room temperature has exceeded the preset hysteresis limit.
The feedback control will only turn off the cooling system in the cooling mode if the
temperature has fallen below the preset lower hysteresis limit. As with the individual modes
of heating or cooling, there are two hysteresis limits per operating mode. Although there is
a deadband for the calculation of the temperature setpoints for cooling, it has no influence
of the calculation of the two-point control value, as the operating mode is switched over
"manually" through the corresponding object. Within the hysteresis spans, it thus will be
possible to request heating or cooling energy for temperature values that are located within
the deadband.
i
Also with an automatic operating mode switch, an upper hysteresis limit for heating and a
lower hysteresis limit for cooling can be configured in the ETS for 2-point feedback control,
although they have no function.
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Software "KNX CO2 sensor"
Functional description
