Siemens Synco 700 Series Basic Documentation page 136

Example:
Air handling plant
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Building Technologies
HVAC Products
The heat demand transformer converts the position heat request signals (in %) to heat
demand signals with a flow temperature setpoint.
The following example of an air handling plant shows this.
Air supply area
Central
air handling
T
DHW
precontrol
RMH760
Based on the valve position of the air handling plant(s), the heat demand transformers
calculate a flow temperature setpoint.
If an outside temperature signal is available on the primary controller, the flow tempera-
ture setpoint according to the heating curve is used as a start value. If there is no
outside temperature signal, the flow temperature at curvepoint 1 is used as the stat
value.
This flow temperature start value is matched to the actual heat demand in a way that
the heat consumer with the greatest heat demand has a valve position of 90%.
• If the valve position is >90%, the flow temperature is increased
• If the valve position is <90%, the flow temperature is decreased
The maximum flow temperature readjustment can be parameterized.
To ensure that minimum opening travel of the valve does not produce a demand for
heat, a switch-off threshold can be defined.
• Demand for heat is computed only if the valve positions exceed "Threshold on"
• If the valve positions of all consumers are below "Threshold off", the demand for heat
is suppressed again
Main menu > Commissioning > Settings > ... or
Main menu > Settings > Boiler sequence manager > Demand control
Main menu > Settings > Primary controller > Demand control
Operating line
[Curvepoint 1] outside temp
[Curvepoint 1] flow temp
[Curvepoint 2] outside temp
[Curvepoint 2] flow temp
Flow temp correction max
Control action
Request evaluation
Limit value request on
Limit value request off
Boiler Sequence Controller RMK770
8 Heat demand and heat requests
T
Room unit
(in reference room)
T
0...100 %
T
Chilled water
precontrol
RMH760
Range
–50...50 °C
0...140 °C
–50...50 °C
0...140 °C
0...100 K
Slow / Medium / Fast
Maximum / Average
(Threshold off)...100%
0...(threshold on)
Ventilation
RMU...
Refrigeration
Heat demand
demand
transformer
transformer
Precontrol
Precontrol
refrigeration
heating
Factory setting
–10 °C
70 °C
20 °C
70 °C
10 K
Medium
Maximum
10 %
5 %
CE1P3132en
23.04.2009