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For integrated parallel compression (single compressor), when the
parallel compressor is active, the reference for calculating the delta will
no longer be more the medium temperature line compressor suction
pressure, but rather the (liquid) receiver pressure, which coincides with
the parallel compressor suction pressure
The changeover in reference from suction to receiver pressure is
automatic, and does not need to be enabled.
For parallel compression enabled via pLAN, the same I/Os (oil receiver
pressure probe and solenoid valve digital output) and the same settings
(delta and diff erential) can be used as seen above, or new I/Os and new
parameters can be set on the parallel compressor board (always on
screen Eaab25)
6.17 Settings
6.17.1 Clock
pRack PR300T features an internal clock with backup battery that keeps
the time and date for all related functions (see Chapter 2 for details
relating to the hardware).
The date on pRack PR300T can be set as follows:
•
day, month, year (dd/mm/yy)
•
month, day, year (mm/dd/yy)
•
year, month, day (yy/mm/dd)
The current date and time can be set, the day of the week corresponding
to set date displayed, plus changeover to daylight saving can be enabled
by setting the changeover date and the deviation.
The related parameters can be set during start-up or in main menu
branch F.a.
Note: the date and time are managed on pRack boards with
addresses 1 and 2; on power-up and whenever the pLAN network
is reconnected, the software on pRack synchronises the settings on board
2, sending the date and time set on board 1.
If the clock card is not operating, an alarm is generated and the functions
relating to the time bands described in the following paragraph are not
available.
6.17.2 Time bands
pRack PR300T allows the operating seasons, the closing periods and
weekends to only be set once, and consequently these are common to
all the system functions.
As well as these settings, each function can be associated with a weekly
scheduler, setting up to 4 diff erent daily activation bands for each day
of the week. For each time band, the start and end time can be set and
settings made can be copied to the others days of the week.
The priority of the schedulers, from lowest to highest, is:
•
weekly scheduler
•
closing periods
•
special days
Copyright HPL March 2021
pRack PR300T +0300018EN rel. 1.5 - 02.05.2017
For example, if the weekly scheduler requires activation of a function,
yet a closing period is in progress, and requires deactivation of the same
function, then the function is deactivated.
The following functions allow the setting of time bands:
•
Split-condenser: the function is active only based on the operating
seasons, and consequently special days, closing periods and daily time
bands are ignored.
•
Silencer: the function is only active with daily time bands, there is no
link to operating seasons, special days and closing periods
•
Heat recovery: the function is active with daily time bands, special
days and closing periods, no link to operating seasons. The link to the
general scheduler can be disabilitato, considering the time bands only.
•
Set point compensation: active with operating seasons, special days,
closing periods and daily time bands (two diff erent off sets).
•
Generic functions: the generic scheduling function is active with the
operating seasons, special days, closing periods and daily time bands.
Operation of the generic functions can be separated from the generic
scheduler, considering the daily time bands only.
For details on the functions that use time bands, see the corresponding
paragraphs.
6.18 Managing the default values
pRack PR300T can manage two diff erent sets of default values:
•
user defaults
•
Carel defaults
The two functions can be activated in main menu branch I.d.
Important: after having reset the default values, the pRack PR300T
board need to be switched off and on again.
6.18.1 Saving and resetting the user default values
pRack PR300T can save the exact confi guration set by the user inside the
instrument, allowing it to be recalled at any time.
All the set values are saved, therefore loading user defaults restores the
exact same conditions that the pRack PR300T controller was in when the
data were saved.
Note: only one user default confi guration can be saved, therefore
when the data is next saved, this overwrites the previous data.
Important:
•
the Carel default reset procedure totally deletes the pRack PR300T
permanent memory, and consequently is an irreversible operation;
•
the user values cannot be reset after updating the software on the
pRack PR300T (see Chapter 10).
6.18.2 Resetting the Carel default values
The Carel default values are shown in the Parameters table.
The values pre-set by Carel can be installed at any time, restoring the
pRack PR300T default settings, and requiring the startup procedure
described in Chapter 4 to be repeated.
Important: the Carel default reset procedure totally deletes the
pRack PR300T permanent memory, and consequently is an
irreversible operation; nonetheless, the user settings can still be restored
if these have already been saved. Given that pRack PR300T, following the
installation of the Carel default values requires the startup procedure to
be repeated, select the fi rst pre-confi guration and then restore the user
defaults.
Note: to complete a new confi guration procedure (reff er to Chapter
4), fi rst restore the Carel default values.
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P4114S Rev 03
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