Basic Documentation

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Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Temperature controller (basic type A) 03.10.2011
11.7 Cascade / constant control with changeover
via casc/const changeover input
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)
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
SAT
N.X2
Y
SIGNAL Y
x
RT
N.X2
Y
SIGNAL Y
x
dig

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
SAT
N.X2
Y
SIGNAL Y
x
dig
N.X1
Y
SIGNAL Y
x
EAT

This control mode is sensible if room heating is controlled e.g. via thermostat
valves and a ventilation controller is used to cool the same room in summer.
11.7.1 Operating principle
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).
Cha
ngeover occurs via digital signal at the casc/const changeover input.
Contact closed: Supply air temperature control
Contact open: Cascade control