Operation Manual

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Siemens Basic Documentation RVP340, RVP350, RVP351 CE1P2545en
Building Technologies 13 Function block: District heat 15.03.2011
13 Function block: District heat
Together with function block "Actuator heating circuit", this function block provides
control of the flow temperature in plants with an indirect (heat exchanger) or direct
district heat connection.
It acts as a flow temperature controller for weather-compensated control of space
heating with a district heat connection (plant type 2 - 0).
If the settings of this function block have been locked (on operating line 248; refer
to the respective section), the display shows
when and .
13.1 Operating lines
Line Function, parameter Factory setting (range) Unit
112 Slope, maximum limitation return temperature 0.7 (0.0...4.0)
113 Start of compensation (point of inflection), maximum limita-
tion return temperature
10 (50...50) °C
114 Integral action time, maximum limitation return temperature 30 (0...60) min
13.2 Limitations
13.2.1 Maximum limitation of primary return temperature
For the primary return temperature, maximum limitation is available to …
 prevent too hot water from being fed back to the district heat network,
 minimize piping losses of the district heat utility,
 comply with the regulations of the utility.
T
PR
T
A
s
90
80
70
60
50
40
30
20
20
10 0
-10
30
T
L constant
T
L start
2381D03
s Slope of limitation (operating line 112)
T
A
Outside temperature
T
L constant
Constant value of limitation (operating line 101)
T
L start
Start of shifting limitation (operating line 113)
T
PR
Primary return temperature
The maximum limit value is generated from the following variables:
 Constant value (setting on operating line 101)
 Slope (setting on operating line 112)
 Start of compensation (setting on operating line 113)
Purpose
Generation of maxi-
mum limit value