50
ENG
mpxone +0300086EN rel. 2.2 - 13.11.2023
Functions
If the fault is on Sr, the new control probe will be Sm with:
St*= -4-8 •50/100=-8.
ON time for duty setting operation (par. c4)
Duty setting is used to maintain control in emergency situations with errors involving the temperature control probes, until
service is performed. In the event of a temperature probe error, MPXone uses the other probe available and adjusts the set point
according to the setting of parameter ro. In the event of errors on both probes, MPXone switches to a special mode called “duty
setting”. The controller is activated at regular intervals, operating for a time equal to the value set for the duty setting parameter
c4, and off for a fi xed time of 15 minutes.
Code Description Def Min Max UOM User User terminal
c4 ON time for duty setting operation (Toff = 15 minutes, fi xed value)
0 = compressor/valve always OFF
100 = compressor/valve always ON
0 0 100 min M NO
300086_065_R01
c4 15 min
t
ON
R
OFF
Ref. Description
R Control
c4 ON time
t Time
Fig. 5.o
With duty setting active, during the ON time the solenoid/compressor icon remains on, while it fl ashes during the OFF time.
The table below describes the possible fault situations relating to the control probes and the function that is activated.
Type of system
Control probe fault
Control Parameter
Sm Sr
1 probe
z
Duty setting c4
z
Duty setting c4
2 probes
z
control on Sr ro(*)
z
control on Sm ro(*)
zz
Duty setting c4
Tab. 5.i
* ro must be > 0.
Duty setting with shared control status
Activation of the duty setting mode is signalled on the main user interface with the solenoid/compressor icon on steady; the
secondary controllers ignore the main control mode. On the other hand, if a secondary device activates duty setting mode due
to lack of communication with the main, the secondary manages the display on the user interface as standard.
Notice:
• activation of duty setting mode on the main controller implies that all the related secondary devices observe the main con-
troller compressor management times.
• in duty setting mode, the compressor protection times are ignored.
Notice:
• if a second ON/OFF compressor is managed with an activation delay, both compressors will start based on the set times.
Parameter c4 must be set correctly in relation to the activation delay c11.
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.
Activation of the low temperature alarm when exceeding the threshold AL or AL2 can be delayed by setting parameter c6.
Caution: The time defi ned by parameter cc is in hours, the alarm delay c6 is in minutes.
Code Description Def Min Max UOM User User terminal
cc Continuous cycle running time, 0 = Disabled 0 0 15 hours M NO
c6 Low temperature alarm bypass time after continuous cycle 60 0 240 min M NO
The continuous cycle can be activated using the direct continuous cycle function on the user terminal (see “Direct functions”),
from the supervisor or via digital input. When the continuous cycle is running:
• the
+ icons are displayed.
• the solenoid/compressor valve output (with icon) and electronic valve control are activated;
• 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.
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