Technical data

The individual switching points for ON of each fan stage can be adjusted via
control parameters P55…P57. The fan speed switch off point is 20% below the
switch on point. The diagrams below show fan speed control for modulating PI
control.
Heating / Cooling
1- or 3-speed fan
w Room temperature setpoint
Q Fan speed
Y
H
Control demand "Heating"
Y
C
Control demand "Cooling"
XpH Proportional band "Heating" (P30)
XpC Proportional band "Cooling" (P31)
X
dz
Dead zone (P33)
Fan speed switching point high (P55)
Fan speed switching point med (P56)
Fan speed switching point low (P57)
The diagram only shows the PI control's proportional part.
On applications with 2-position control:
1) The switching point for low fan speed is synchronized to the heating / cooling
output. Parameter "Switching point fan speed low" P57 is not relevant.
2) The maximum switching range of the fan (XpH
Fan
/ XpC
Fan
) is defined by the
switching differential (SDH/SDC) via a look-up table.
Heating / Cooling
1- or 3-speed fan
ECM fan
T [°C] Room temperature
w Room temperature setpoint
Q Fan speed
Y Control command "Valve"
SDH Switching differential "Heating" (P30)
SDC Switching differential "Cooling" (P31)
Xdz Dead zone (P33)
XpH
Fan
Switching range for fan "Heating" (Table)
XpC
Fan
Switching range for fan "Cooling" (Table)
Fan 3-speed switching point high (P55)
Fan 3-speed switching point med (P56)
Fan_max Max. ECM fan speed (P55)
Fan_min Min. ECM fan speed (P56)
SDH/SDC [K]
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
>4.5
XpH
Fan
/XpC
Fan
[K]
2
3
4
5
6
7
8
9
10
Y
Q3
Q2
Q1
Off
Y
Q3
Q2
Q1
3
-speed fan control
with modulating
heating
/ cooling
control
(PWM
, 3-pos or
DC 0...10 V)
Note:
3-speed / ECM fan
control with
On/Off
heating
/ cooling
control
Look
-up table with
On/Off control
54 / 102
Siemens RDG100KN, RDG160KN Basic documentation CE1P3191en
Building Technologies Functions 2014-05-23