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Control and Protection Functions
Figure 14 – Constant Airflow Control
Example: K-factor = 308, Maximum sensor range Pmax =
2000 Pa, Vmax = 13774 m
as the maximum range of the sensor in the VCS using HMI.
Note: In AC, the "Max. Air Flow Rate" is stated for the fan as-
semblies. Attention! This is not the maximum range of the air
flow sensor to be entered in the VCS control unit.
n
Number of fans (for twins = 2). The air flow rate of one fan
is measured and is then multiplied by the number of fans.
n
Required values (separately for the inlet and outlet fans)
5 required values are available for selection.
Constant pressure control
Fan speed is controlled depending on the desired air pressure
(Pa). The air pressure is measured by a sensor; the control
system evaluates this value and compares it with the required
value. The resulting fan speed is controlled so that the required
air pressure will be reached at the point of measurement.
It is necessary to set the following air flow sensor param-
eters (see the Sensor Operating Manual):
n
Mode (for CPG = Mode 4.00)
n
Measuring range: As needed (200 Pa, resp. 1000 Pa)
It is necessary to set the following parameters of the VCS
control Unit (see List of HMI Data Points):
n
Air pressure sensor measuring range – (maximum value
from the CPG air pressure sensor in Pa)
n
Required values (separately for the inlet and out-
let fans). 5 required values are available for selection.
Constant Air Flow + Overpressure in the Room Control
The inlet branch (fan) is adjusted to the constant air flow so
that the required air volume is delivered to the room. The outlet
branch is adjusted to the required difference in overpressure in
the room. Thus, the outlet fan is adjusted to the required pres-
sure (overpressure) depending on the pressure sensor location.
Application: Preventing dirt from entering the room.
Constant Air Flow + Underpressure in the Room Control
The outlet branch (fan) is adjusted to the constant air flow.
The inlet branch (fan) is adjusted to the difference in under-
pressure in the room. Thus, the inlet fan is adjusted to the
required pressure (underpressure) depending on the pressure
sensor location.
18
/h. This value is then entered
3
Figure 15 – Constant pressure control
Application: Preventing dirty air from entering the adjacent
rooms
Note: When commissioning the system, it is necessary to
perform the settings and regulation of the device (PID con-
stants, FI ramp, etc.)
Frequency Inverters
For five-stage control devices, the request for the inlet and outlet
fan speed is set in common. However, for frequency inverters,
the request for the inlet and outlet fan output (0-100%) can
be set separately for each stage (1 to 5) (see the Data Point
Settings – Fans).
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