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6.7 - Night mode
Night mode allows users to configure the unit to operate
with specific parameters in a specific time period. During
the night period, the unit capacity is limited and the number
of operating fans is reduced.
The night period is defined by a start time and an end time
that are the same for each day of the week. The Night mode
settings or the maximum capacity value can be configured
via the Configuration menu (GEN_CONF – General
Configuration). Only logged-in users can modify night mode
settings (see also section 4.4).
6.8 - Head pressure control
The condensing pressure of each circuit is controlled by 10
fans maximum. Up to 5 fans can be controlled by a speed
variator. The fan speed is independently controlled in each
circuit based on the outdoor air temperature, water
exchanger fluid temperature and circuit capacity.
6.9 - Circuit lead/lag selection
This function determines the lead circuit and lag circuit on
dual-circuit units. It controls the start/stop sequence of the
refrigeration circuits called circuit A and circuit B.
The circuit authorised to start first is the lead circuit. Lead
circuit is used first for capacity increases and at the same
time should be decreased first when decreasing capacity.
The lead/lag circuits can be selected manually or
automatically according to the unit configuration (GEN_
CONF – General Configuration).
•
Automatic lead/lag circuit determination:
The control
system determines the lead circuit to equalise the
operating time of each circuit (value weighted by the
number of start-ups of each circuit). As a result, the
circuit with the lowest number of operating hours
always starts first.
•
Manual lead/lag circuit determination:
Circuit A or
circuit B selected as the lead circuit. The selected
circuit is always the leader.
6.10 - Time schedule function
The Touch Pilot system control includes two time schedules.
The first schedule (schedule 1, OCCPC01S) allows for the
automatic changeover of the unit from occupied to
unoccupied mode: the unit is started during occupied
periods.
The second schedule (schedule 2, OCCPC02S) allows for
the automatic change of the active setpoint from occupied
to unoccupied setpoint, provided that the Auto mode has
been selected (RESETCFG – Reset Configuration).
6.10.1 - Occupied/unoccupied periods
Each schedule consists of eight user-configurable periods.
Each period can be validated as active or inactive for each
day of the week as well as for a given holiday period.
The day begins at 00:00 and ends at 23:59.
Cooling setpoint 1 is active during occupied periods.
Cooling setpoint 2 is active during unoccupied periods.
The schedule is in unoccupied mode unless a time period is
active. If two periods coincide or they are active on the same
day, priority is given to the occupied period. Time schedule
can be modified by the user in the Configuration menu
(see also section 4.6.2).
6.10.2 - Holidays
This function is used to define 16 holiday periods. Each
period is defined by three parameters: the month, the start
day and the duration of the holiday period.
During the holiday periods the controller will be in
occupied or unoccupied mode, depending on the periods
validated as holidays. Each holiday period can be modified
by the user (see also section 5.4).
6.11 - Master/slave assembly (option 58)
The Touch Pilot control system allows for master/slave
control of two units linked by the CCN network.
The master unit can be controlled locally, remotely or by
network commands (CCN), while the slave unit remains in
Network mode.
All control commands to the master/slave assembly (start/
stop, setpoint selection, load shedding, etc.) are handled by
the unit which is configured as the master. The commands
are transmitted automatically to the slave unit.
If the master chiller is turned off while the master/slave
function is active, then the slave chiller will be stopped.
Under certain circumstances, the slave unit may be started
first to balance the run times of the two units.
In the event of a communication failure between the two
units, each unit will return to an autonomous operating
mode until the fault is cleared. If the master unit is stopped
due to an alarm, the slave unit is authorised to start.
NOTE: Master/slave assembly can be configured only by
Carrier service.
