Danfoss AR05, Operation Instructions Manual, Page: 20 / 25

20 Reglermanual - VMGFF102
5.6 - Control point
The control point represents the water temperature that the
unit must produce. The heat exchanger entering water
temperature is controlled by default, but the heat exchanger
leaving water temperature can also be controlled (requires a
Service confi guration modifi cation).
Control point = active se reset
5.6.1 - Active setpoint
Two setpoints can be selected as active in cooling mode and
two in heating mode. Usually, the second setpoint is used for
unoccupied periods.
Depending on the current operating type, the active setpoint
can be selected:
•
by choosing the item in the GENUNIT menu,
• via the user’s volt-free contacts,
• via network commands
• via the setpoint timer program (schedule 2).
The following tables summarise the possible selections
depending on the control types (local, remote or network)
and the following parameters:
•
Setpoint select in local control: item LSP_SEL in the
GENUNIT menu permits selection of the active set-point,
if the unit is in local operating type.
• Heating/cooling operating mode.
• Setpoint selection contacts: setpoint selection contact
status.
• Schedule 2 status: schedule for setpoint selection.
LOCAL OPERATING MODE
PARAMETER STATUS
Heating/cooling
operating mode Local setpoint
selection Time schedule 2
status Active setpoint
Cooling sp 1 - Cooling setpoint 1
Cooling sp 2 - Cooling setpoint 2
Cooling auto occupied Cooling setpoint 1
Cooling auto unoccupied Cooling setpoint 2
Heating sp1 - Heating setpoint 1
Heating sp 2 - Heating setpoint 2
Heating auto occupied Heating setpoint 1
Heating auto unoccupied Heating setpoint 2
REMOTE OPERATING MODE
PARAMETER STATUS
Heating/cooling
operating mode Setpoint selection
contact Active setpoint
Cooling sp 1 (open) Cooling setpoint 1
Cooling sp 2 (closed) Cooling setpoint 2
Heating sp 1 (open) Heating setpoint 1
Heating sp 2 (closed) Heating setpoint 2
5.6.2 - Reset
Reset means that the active setpoint is modifi ed so that less
machine capacity is required (in cooling mode, the setpoint is
increased, in heating mode it is decreased). This modifi ca-tion
is in general a reaction to a drop in the load. For the Pro-
Dialog control system, the source of the reset can be
confi gured in the HCCONFIG confi guration: it can be
provided either by the outdoor temperature (that gives a
measure of the load trends for the building) or by the return
water temperature (heat exchanger delta T, gives an average
building load).
In response to a drop in the outdoor temperature or to a
drop in delta T, the cooling setpoint is normally reset
upwards in order to optimise unit performance:
In both cases the reset parameters, i.e. slope, source and
maximum value, are confi gurable in the RESETCFG menu (see
section 4.3.8). Reset is a linear function based on three
parameters.
•
A reference at which reset is zero (outdoor temperature or
delta T - no reset value).
• A reference at which reset is maximum (outdoor
temperature or delta T - full reset value).
• The maximum reset value.
Reset example in cooling mode based on the outside
temperature
Legend
A Maximum reset value
B OAT or delta T for no reset
C OAT or delta T for full reset
D Building Load
5.7 - Demand limit
The demand limit is used to restrict the unit power
consumption. The Pro-Dialog control system allows limitation
of the unit capacity, using user-controlled volt-free contacts.
The unit capacity can never exceed the limit setpoint
activated by these contacts. The limit setpoints can be
modifi ed in the SETPOINT menu.
5.8 - Night mode
The night period is defi ned (see GENUNIT confi guration) by a
start time and an end time that are the same for each day of
the week. During the night period, the number of fans
operating can be reduced, and the unit capacity may be
limited.
Reset value
Outdoor temperature (OAT)
Heat exchanger delta T
% Building load