Basic Documentation

175/332
Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Temperature controller (basic type A) 03.10.2011
11.8.4 Alternating control strategy
Room supply air temperature
cascade control
(Off for heating, summer) and
Supply air temperature control
(On for heating, winter)
Extract air/supply air temperature
cascade control
(Off for heating, summer) and
Supply air temperature control
(On for heating, winter)
N.X2
Y
SIGNAL Y
x
RT
N.X1
Y
SIGNAL Y
x
SAT
S3 S2 S1 S4 S5
yp yp yp yp yp
a
d
Controller 1
(Ventilation)
With supply air limitation
Cascade
Constant (supply air)
Cascade/const (alternating)
Seq. limit. Casc/Const

N.X1
Y
SIGNAL Y
x
EAT
N.X1
Y
SIGNAL Y
x
SAT
S3 S2 S1 S4 S5
yp yp yp yp yp
a
d
Controller 1
(Ventilation)
With supply air limitation
Cascade
Constant (supply air)
Cascade/const (alternating)
Seq. limit. Casc/Const

During the heating period (winter and intermediate season), room temperature
control is provided by the heating controller. This can be ensured with active room
influence or thermostatic radiator valves.
The ventilation controller controls the supply air temperature constantly to the
supply air temperature setpoint (see section 11.2.2).
Out
side the heating period (in summer), the ventilation controller assumes room
temperature control via room supply air cascade control (see section 11.6) or via
extract air
supply air cascade control (see section 11.6).
The ch
angeover heating period / no heating period occurs automatically based on
the heating limit switch at the heating controller. The heating controller sends its
signal via the bus to the ventilation controller which adapts its control mode
accordingly.
When cooling is called for while the heating plant is on, the heating system
immediately is switched off. It can be switched on again only after all cooling
sequences of the ventilation controller are shut down.
Operating principle