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Operating Modes
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 (Figure 16 ).
Additional Operating Modes
If no operating mode is applied and the time schedule mode
is in the Stop state, the air-handling unit can be started from
additional operating modes. The user can use the following
additional operating modes to start the air-handling unit:
n
Night chilling
n
Temperature start-up
n
Optimized start
Additional operating modes can be activated by the HMI-SG
controller in the List of Data Points in the section Settings
– Additional Operating Modes, Functions.
Control Application Starting Algorithm
Air-handling system operation safety is assessed first (fire
detection and operational safety of the air-handling de-
Control units VCS
vices). Then the operating modes and their priorities are assessed
(Manual, External, HMI-SG controller, BMS and time modes). If no
control mode is currently used, the air-handling unit can, but may
not, be put into one of the additional operating modes depending
on the user's option. All the operating modes and their correlation
are shown in the figure # 10 - "Operating modes".
The current operating mode can be monitored through the HMI
controller in the List of Data Points in the section Monitor –
Current Modes.
Obrázek 16 – Operating modes
Yes
Alarm A
Ne
Stop,Co1,EC1,...
l
Manua
HMI-SG (p. 125)
HMI TM, DM
Auto
External
control
Auto
HMI-SG
controller
Auto
BMS
Auto
Co1,EC1,Co2, ...
Time
modes
Stop
Optimized
start
Passive
Active
Temperature
start-up
Passive
Active
Night
chilling
Passive
Night
Active
turning
Passive
When the fans run and the air-handling unit is in operation, two
basic groups of parameters are used to control operation:
n
Temperature mode or humidity mode
n
Fan output (speed)
The fan output or speed can be set directly at levels corresponding
to the air-handling system configuration:
Co1,EC1,Co2, ...
RUN
State
Fans
Stop
(stage 1-5)
Comfort/
Economy
Optimized
start
Temperature
start-up
Night
chilling
Night
turning
STOP
19
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