45
ENG
mpxone +0300086EN rel. 2.2 - 13.11.2023
Functions
5.2 Control
Introduction
There are various modes for controlling air temperature for the preservation of foodstuff s in cold rooms and showcases. The fol-
lowing fi gure shows the position of the intake probe Sr and the outlet probe Sm. To control the temperature using the average
between outlet and intake, confi gure the virtual probe Sv that, based on the setting of parameter /4, will provide the value given
by the formula:
Code Description Def Min Max UOM User User terminal
/4 Virtual probe composition 0 = Outlet probe Sm 100 = Intake probe Sr 0 0 100 % S NO
For example, if /4=50, Sv=(Sm+Sr)/2 represents an estimated value of the air temperature around the refrigerated food.
Notice for HACCP: parameter /4 can be set to change the temperature used for control and for display. This operation may
be prohibited by HACCP procedures or require record keeping and authorisation.
Example: vertical showcase
DAY
Sm
Sv=(Sm+Sr)/2
Sr
300086_006_R01
Ref. Description
Sm Outlet probe
Sr Intake probe
Sv Virtual probe
Fig. 5.e
During the day, most of the load in a refrigerated showcase is due to warm air that enters from the outside and mixes with the
cold air inside. Control based on the intake probe, due to high temperature outside the showcase and the mixing of the air, may
not manage to reach the set point. Displaying the intake temperature would show a temperature that is too high. Setting a set
point that is too low for the intake probe Sr may cause the food to freeze. On the other hand, displaying the outlet temperature
would show a temperature that is too low. Consequently, the display of the control probe, set point or virtual probe can be
confi gured using parameters /t1 and /t2. ON/OFF control on the outlet probe is defi ned by:
• set point;
• diff erential
These values determine the control request and consequently, allowing for the protection times, disabling functions or activa-
tion/deactivation delays, the opening/closing of the solenoid valve.
Code Description Def Min Max UOM User User terminal
St Set point 50 r1 r2 °C/°F U YES
rd Diff erential 2 0.1 99.9 °C/°F U YES
rC Operating mode
0/1 = Direct/Reverse
001- UNO
Notice for HACCP: the set point and diff erential are critical parameters for food storage. Modifi cations to these settings may
be prohibited by HACCP procedures or require record keeping and authorisation.
300086_051_R01
Sreg
rd
St
ON
R
OFF
Ref. Description
St Set point
rd Diff erential
Sreg Control probe
R Control request
Fig. 5.f
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