Fan Control - Siemens DF301 Basic Documentation

Note:
Fan command value
Enable fan command
value
Fan operation
Fan stage 1-2-3
Fan output
3-speed fan control
with modulating
heating / cooling
control
Note:
3-speed fan control
with ON/OFF heating /
cooling control
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Siemens...........................RDF301, RDF301.50..., RDF600KN, RDF600KN/VB, RDF600KN/S
Smart Infrastructure
3.8

Fan control

The fan operates in automatic mode or at the selected speed with manual mode.
In automatic mode, the fan speed depends on the setpoint and the current room
temperature. When the room temperature reaches the setpoint, the control valve
closes and the fan switches off or stays at fan speed 1 according to the setting of
1)
parameters P15 (fan stage in dead zone Comfort on RDF600KN, RDF600KN/VB)
and P60 (fan kick).
Factory setting for "Fan in the dead zone":
· RDF600KN, RDF600KN/VB:
· RDF301...:
Fan speed 1 (P60 = 0)
1) P15 is not implemented into RDF600KN, RDF600KN/VB SW version <
V1.8.
2) On RDF301 and RDF301.50, it is recommended that the fan is running in
deadzone, i.e. P60=0, or using a return air- or external temperature
sensor.
The fan speed and mode can be changed via bus.
For this purpose, the fan command value needs to be enabled.
The fan speed and mode can be monitored via bus.
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.
Q
Q3
Q2
Q1
100 0
w
x
Y [%] XpH
H dz
The diagram only shows the PI thermostat's proportional part.
On applications with 2-position control:
1) The switching point for low fan speed (Q1) 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
switching differential (SDH/SDC) via a look-up table.
Y
x
1
0
SDH
Q
Q3
Fan speed OFF: (P15 = 0, P60 = OFF)
2)
0 100
Y [%]
XpC
C
dz
w
T[癈 ]
SDC
Cool
w Room temperature setpoint
Q Fan speed
Y Control demand "Heating"
H
Y Control demand "Cooling"
C
XpH Proportional band "Heating"
XpC Proportional band "Cooling"
X Dead zone
dz
/ XpC ) is defined by the
Fan Fan
T[°C] Room temperature
w Room temperature setpoint
Q Fan speed
Y Control command "Valve"
SDH Switching differential "Heating"
SDC Switching differential "Cooling"
X Dead zone
dz
Basic Documentation CE1P3171en
2020-02-21