Handbuch-KnxSmartmeter-85A-en-3.odt, 2018-10-04
Seite 18 von 69
This is realized by the hysteresis function.
With the following parametrization this concept can be implemented. The limit value for the
three-phase active power is set to “-20” (=-2%). This corresponds to the following power:
35A
⋅−
2
%
⋅
3
⋅
230V
=−
483W
The value 35A corresponds to the parametrized reference current. The term
3
⋅
230V
is required
to convert the reference current in a three-phase reference power. The value for the hysteresis
is set to “-40” (=-4%). This corresponds to the following power:
35A
⋅−
4
%
⋅
3
⋅
230V
=−
966W
With the limit values and the hysteresis the following thresholds arise:
•
Under threshold:
−
483W
−
1
2
⋅−
966W
=
0W
•
Upper threshold:
−
483W
1
2
⋅−
966W
=−
966W
If the three-phase active power reaches the upper threshold of -966W, the value 1 is transmitted
to the group object “Active power limit message” (ID:66). In contrast, if the three-phase active
power reaches the lower threshold of 0W, the value 0 is transmitted to the group object “Active
power limit message” (ID:66). Exactly these values of the group object “Active power limit
message” (ID:66).are needed for switching on/off a consumer load. So the “switching”-group
object of the switching actuator of a consumer load has to be linked to the group object “Active
power limit message” (ID:66) of the Smartmeter.
However, the connected consumer load has also be suitable for this automatic enabling or
disabling. Possibly suitable consumer loads are for example electric heatings, heat pumps,
boiler, cooling aggregates or charging devices.
A much less critical method than the automatic switching of consumer loads is just to have the
energy excess displayed. Thus the residents are signaled by a green signal lamp at which time
the current is cheap (green signal lamp on) or at which time the current is expensive (green
signal lamp off). For this purpose the group object “Active power limit message” has to be linked
to the group object of the switching actuator of the signal lamp.
For parametrization of the load management the following values have to be selected in the tab
“Measurement- three-phase”:
Figure 15: Settings „Measurement - three-phase“ Example 2
In the next tab “Energy counter/Tariff cost counter” in Figure 16 the applied counter are
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