Basic Documentation

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Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Sustained mode (basic type A) 03.10.2011
19.3 Examples of sustained mode
19.3.1 Sustained mode (Economy) for heating
The example refers to controller 1 with a main controlled variable for room
temperature. The example can be functionally applied to controller 2, controller 3,
and the IAQ controller.
At the end of occupancy, the plant switches off, i.e. the plant operating mode
changes from normal operation (Comfort) to sustained mode (Economy). The room
temperature falls or rises depending on the prevailing weather conditions and the
climatic conditions in the room.
If the room temperature drops below the Economy heating setpoint, sustained
mode heating results.
In sustained mode, heating is provided until the room temperature is 1 Kelvin
above the Economy heating setpoint. The plant is again switched off.
20
14
12
1 K
t
t
SpHEco
t
Smin
SpHCmf
22
18
20
14
12
SpHEco
SpHCmf
22
18
Comfort
Setpoint
Actual value
Setpoint
Economy setpoint
not reached
3140D35en
Actual value
End of
Comfort
Beginning of
Comfort
Comfort
Sustained mode
RT
[°C]
RT
[°C]
Economy
Plant component state
In Economy mode, the plant is switched on when the room temperature drops
below the set Economy heating setpoint (SpHEco). When the plant operates, the
set Comfort setpoints are maintained (fan speeds and setpoints of all control
loops).
Sustained mode can only be activated when there are no fault messages that
switch off the plant.
Function diagrams
Note