User manual

46
ENG
MPXPRO - + 0300055EN rel. 1.3 07/03/13
Duty setting with shared control status
For the description of shared control status, see paragraph 5.1. The
activation of the duty setting mode on the Master controller implies
that all the related Slaves observe the Master controller compressor
management times. This operating mode is highlighted on the Master
user interface by the compressor icon on steady; the Slave controllers
ignore the Master control mode and do not show the compressor icon
fl ashing when the compressor is off . If a Slave activates duty setting mode
due to lack of communication with the Master, the Slave manages the
display on the user interface as normal.
Continuous cycle (parameter cc)
Continuous cycle is a function used to keep the refrigeration cycle active
continuously for a settable duration, irrespective of the temperature
inside the unit. This may be useful when requiring a rapid decrease in
the temperature, even below the set point. The activation of the low
temperature alarm when exceeding the threshold AL or AL2 can be
delayed by setting parameter c6.
Par. Description Def Min Max UoM
cc Running time in continuous cycle
0 = disabled
1 0 15 hour
c6 Low temperature alarm bypass time after
continuous cycle
60 0 240 min
Tab. 6.v
The continuous cycle is activated by pressing UP and DOWN for more
than 5 s, from the supervisor or via digital input.
When the continuous cycle is running:
• the icon is displayed;
• the compressor/solenoid valve output and electronic valve control are
activated and the corresponding icon is shown on the display;
• the low temperature alarm with threshold AL is enabled relating to the
probe defi ned by parameter AA as well as the low temperature alarm
with threshold AL2 relating to the probe defi ned by parameter AA2.
Important: for the correct activation of the low temperature
alarms, set the parameters as follows:
• AA = outlet probe;
• AA2 = intake probe.
Note:
1. The continuous cycle cannot be activated if:
• the duration of the continuous cycle is set to 0 (cc=0);
• the measurements of the probes defi ned by AA and AA2 have
exceeded their respective thresholds AL, AL2.
• the device is OFF.
2. The continuous cycle remains in standby if:
• the compressor protection times are set (c1, c2, c3);
• the immediate or delayed alarm from external digital input delays
the activation of the compressor;
• defrost, dripping, post-dripping are running;
• the door is open. When door opens the continuous cycle is
stopped. It restarts for the remaining time when the door is closed.
3. The continuous cycle ends:
• by pressing of UP & DOWN for more than 5 seconds;
• when reaching the low temperature threshold (AL or AL2 in double
thermostat), whichever is reached fi rst;
• at the end of the time cc;
• when the controller is switched off from the supervisor (logical
OFF);
• from the supervisor.
Continuous cycle with shared control status
For the description of shared control status, see paragraph 5.1. The
activation of the continuous cycle on the Master controller implies
that all the related Slaves observe the Master controller compressor
management times (only parameter ‘cc’ on the Master has eff ect, while
the setting on the Slaves is ignored). This operating mode is highlighted
on the Master user interface by the corresponding icon on steady; the
Slave controllers ignore the Master control mode and manage the display
as normal (compressor icon on during the cooling request and off when
there is no request).
Defrost priority over continuous cycle
Par. Description Def Min Max UoM
c7 Defrost priority over continuous cycle
0 = no; 1 = yes
001-
Tab. 6.w
If c7=0 the defrost and continuous cycle are not mutually interruptible
(same priority): any defrost or continuous cycle request remains pending
if activated when running the other procedure. If c7=1 the defrost calls
activated when the continuous cycle is running terminate the latter and
activate the defrost.
Delay in closing suction valve during normal control
Par. Descrizione Def Min Max UoM
rSU
delay in closing suction valve during
normal control
0 = always open
0 0 999 sec
Tab. 6.x
If using suction valve for hot gas defrosts, the suction valve can also
be managed during normal control. If rSu is not 0, during normal
refrigeration control the suction valve will be closed rSu seconds after the
optional solenoid valve is closed. This allows the compressors to empty
the evaporator before completely closing the circuit.
6.6 Compressor
MPXPRO features the following compressor protection parameters.
Par. Description Def Min Max UoM
c0 Delay enable compressor and evaporator
fans on power-up
0 0 240 min
c1 Minimum time between successive starts 0 0 15 min
c2 Minimum OFF time 0 0 15 min
c3 Minimum ON time 0 0 15 min
d9 Defrost priority over compressor protection
times
0 = protection times observed;
1 = protection times not observed
101-
Tab. 6.y
• c0 is used to delay the start of control when the device is powered
up. This is useful in the event of power failures, so that the controllers
(in the network) don’t all start at the same time, avoiding potential
problems of electrical overload. In models with Carel electronic
expansion valve and ultracap technology, this parameter must be set
to a value greater than 2.
• c1 sets the minimum time between two successive starts of the
compressor, irrespective of the request. This parameter can be used to
limit the maximum number of starts per hour;
• c2 sets the minimum compressor off time. The compressor is not
started again until the minimum time set has elapsed;
• c3 sets the minimum compressor running time;
• d9 disables the compressor protection times when defrosting, useful
for hot gas defrosts:
– d9 = 0: the protection times are observed;
– d9 = 1: the protection times are not observed, the defrost has higher
priority.
c3 c2
c1
t
ON
CMP
OFF
Fig. 6.k
Key:
t time CMP compressor