Operating and Maintenance Instructions
210-OMI13277_Iss1.doc
ORIGINAL INSTRUCTIONS
Page 5 of 15
© ebm-papst UK Ltd, 2012
Chelmsford Business Park Chelmsford Essex CM2 5EZ
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CN1090
Proportional Band Control, Operation
The controller varies the fan speed to the level required, based on the sensor measurement (“airflow demand”),
as shown in the Proportional Band Control Profile drawings below.
If two sensors are in use the fan speed will be set to the higher of the two fan speed demand levels.
Select inputs can be used to force the Fan Speed to Minimum, Maximum, or set to the Proportional Band
Demand Speed.
The Variable Resistors and rotary DIP switches configure the operation as shown below:
Example Proportional Band Control Profile, Sensor 1
0 1 2 3 4 5 6 7 8 9 10V
Example Proportional Band Control Profile, Sensor 2
0 1 2 3 4 5 6 7 8 9 10V
Max speed,
Rotary Switch
S3
Sensor 1 Voltage
Min Speed,
Rotary Switch
S2
Top of
Control band 1
R2
Sensor 1
Reading
Max speed,
Rotary Switch
S3
Sensor 2 Voltage
Min Speed,
Rotary Switch
S2
Top of
Control band 2
R4
Bottom of
Control Band 2
R3
Demand
Fan
Speed
Bottom of
Control Band 1
R1
Demand
Fan
Speed
Sensor 2
Reading
10V
9
8
7
6
5
4
3
2
1
0
10V
9
8
7
6
5
4
3
2
1
0
