Technichal Manual Heating Actuators AKH
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4.4.2 Limitation of the control value
The control value can be limited as well as at the heating as at the cooling in both directions
(minimum and maximum):
Figure 20: Limitation of the control value
Die Einstellmöglichkeiten für diesen Parameter sind in der nachfolgenden Tabelle dargestellt:
Sub function
Dynamic range
[default value]
comment
Minimum limit of control
value at heating
0%, 5%, 10%
,…,
50%
[0%]
Adjustment of the minimum limit of the
control value at heating
Maximum limit of control
value at heating
100%, 95%, 90%
,…,
50%
[100%]
Adjustment of the maximum limit of
the control value at heating
Minimum limit of control
value at cooling
0%, 5%, 10%
,…,
50%
[0%]
Adjustment of the minimum limit of the
control value at cooling
Maximum limit of control
value at cooling
100%, 95%, 90%
,…,
50%
[100%]
Adjustment of the maximum limit of
the control value at cooling
Table 32: Limitation of the control value
The limitation of the control value limits the height of the control value, which is transmitted to
create a PWM-signal. The limitation is activated, when a value is chosen which is smaller/higher than
the possible value for the control value, so minimum larger than 0 or maximum smaller than 1.If an
input signal is out of the adjusted limitation, it will be decreased or increased. The PWM signal is
calculated from the new input signal.
Example:
At the heating mode, the maximum limit is chosen as 70% and the
minimum limit is chosen as 10%. The PWM cycletime is adjusted as 10min. If a
control value is sent as 100% for the input, the channel takes the maximum limit of
70% and calculates from this value the on-pulse as 7min. A control value in the
limitations works normal, so a control value of 50% creates an on-pulse of 5min
The limitation can be parameterized individually as well for the heating as for the cooling.
Here the minimum limit is done in the way, so that a control value of 0% also causes a control value
of 0%. Every control value above 0% but below the minimum limit is set to the adjusted minimum
limit. This behavior is reasonable because of energy saving issues, because otherwise the
electrothermic valve drives would consume, even if they are not used, the minimum limit of the
nominal power consumption.
