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Siemens Building Technologies
HVAC Products
12
Function block Space heating
12.1
Operating lines
Line
Function, parameter
61
Heating limit (ECO)
62
Building time constant
70
Effect of the room temperature (gain factor)
71
Parallel displacement of the heating curve
72
Pump overrun time heating circuit pump
73
Maximum limitation of room temperature
74
Optimization with / without room temperature sensor
75
Maximum heating up time
76
Maximum early shutdown
77
Maximum rate of flow temperature increase
78
Quick setback
12.2
Compensating variables
12.2.1 Outside temperature
The RVD240 makes use of 3 types of outside temperatures:
• The actual outside temperature (T
• The composite outside temperature (T
side temperature by the building time constant. The proportion of the actual outside
temperature is 50 %.
The composite outside temperature suppresses unnecessary reactions of the control
system if the outside temperature changes for short periods of time.
In the case of the weather-compensated control (without or with room influence), the
RVD240 uses the composite outside temperature.
The building time constant is a measure of the type of building construction and indi-
cates how quickly the room temperature would change if the outside temperature
suddenly changed. The building time constant is adjustable and applies to both heat-
ing circuits:
Type of building construction
Light
Medium
Heavy
• The attenuated outside temperature (T
outside temperature by the building time constant. This means that, compared with
the actual outside temperature, the attenuated outside temperature is considerably
dampened. This ensures that no heating will take place in the summer when, under
normal circumstances, the heating would be switched on because the outside tem-
perature drops for a few days
If operating line 25 is selected (display of the actual room temperature) and the two
buttons
and
are pressed simultaneously for about 3 seconds, the attenuated and
the composite outside temperature will generate the current measured value; the gen-
eration of these two variables will then start anew (outside temperature reset).
Basic documentation RVD240
12 Function block Space heating
Unit
K
h
K
min
K
h
h
°C/h
)
A
). It is generated by filtering the actual out-
AM
Recommended building time constant
10 h
20 h
50 h
). It is generated by filtering twice the actual
AD
Factory
Range
setting
–3
--- / –10...+10
20
0...50
10
0...20
0.0
–15.0...+15.0
4
0...40
---
--- / 0.5...4
0
0 / 1
0:00
0:00...42:00
0:00
0:00...6:00
---
--- / 1...600
1
0 / 1
CE1P2384en
27.05.2004
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