Remak VCS Installation And Operating Instructions Manual page 19

Control and Protection Functions
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, příp. 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.
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.)
Figure 16 – Constant pressure control
Control units VCS
Basic Information on VCS
Operating Modes
Operating states
There are three operating states defined for VCS control units
(Stop, Run, Auto):
Stop – The device is in standstill mode (fans stopped). Impor-
tant safety features like antifreeze protection and moderate
pre-heating of the water heater are retained.
Run – The device is started in accordance with the pre–set
temperature mode and fan speed.
Auto – Control is switched to the next operating mode with
a lower priority. The Auto operating state cannot be set in
the time schedule mode because it is a control type with the
lowest priority.
The operating mode determines which operating state will be
active according to priorities (see Operating Modes).
Operating Modes
The control unit's operating state (i.e. whether the air-handling
unit is in the Stop or Run state) is determined by one of the
operating modes (manual control, external control, HMI-SG
controller, BMS or time schedule modes). HMI-DM or HMI-TM
controllers affect control in the manual control mode. External
control is performed by single- or two-contact control. BMS
control enables control of the control unit by the higher level
control device (e.g. smart building control systems; Note:
pending). To control air handling systems, the HMI-SG control-
ler is connected to the control unit.
The operating mode which will determine the device's oper-
ating state (Run or Stop) is determined by the priority. Each
operating mode is assigned a priority, i.e. the first option to
control the control unit, to eliminate mutual interference. The
operating modes are prioritized as follows, from the lowest
to highest priority:
n Manual control
n External control
n
Local HMI-SG controller
n BMS (pending)
n Time schedule
n
Additional operating modes
The priorities and entire control system are shown in the
diagram on the following page.
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