These values determine the control request and consequently, allowing for the protection times,
disabling functions or activation/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 Differential 2 0.1 20 °C/°F U YES
Note: HACCP: the set point and differential are critical parameters for food storage. Modifications to
these settings may be prohibited by HACCP procedures or require record keeping and authorisation.
Fig.5.f
Ref. Description
St Set point
rd Differential
Ref. Description
Sreg Control probe
R Control request
ON/OFF control depends on the capacity of the produce to absorb and release heat, as well as on the
evaporator cooling time. The temperature therefore fluctuates above and below the set point, and this
may cause a decline in the quality of food preservation. Decreasing the differential to make control more
precise increases the frequency of solenoid valve opening/closing cycles. Precision of the measurement is
in any case limited by the tolerance of both the controller and the probe.
Minimum and maximum set point values (parameters r1 and r2)
The minimum and maximum value of the set point can be set by parameter.
Code Description Def Min Max UOM User
User
terminal
r1 Minimum set point -50 -50 r2 °C/°F M NO
r2 Maximum set point 50 r1 50 °C/°F M NO
Night-time operation
During night-time operation the curtain on the display case is closed and consequently less cold inside
air is mixed with warm outside air. The thermal load decreases. The temperature of the air that cools the
produce is near the outlet temperature, and therefore to avoid excessively low temperatures and reduce
energy consumption, the set point needs to be increased at night, by setting parameter r4. Parameter r6
can then be used to possible the virtual probe Sv or intake probe (air on) Sr as the control probe.
Naturally, the change to night-time operation must be signalled externally. This is usually done using the
curtain switch, set with parameter DIG, signalling that the curtain has been lowered, or by setting the
time bands (parameters tS1 to tS8 and tE1 to tE8), from the supervisor, or from the Master controller via
the Master/Slave network. To set the time bands, see the paragraph "Setting the day/night time bands".
Code Description Def Min Max UOM User
User
terminal
r4 Automatic night set point variation 0 -50 50 °C/°F S NO
r6
Probe for night-time control
0/1 = virtual probe Sv/air on probe Sr
0 0 1 - S NO
tS1..8-d Start time band 1 to 8 day: day - see (td1...8-d) 0 0 11 day S NO
52|5. Functions
MPXone +0300086EN rel. 1.0– 04.09.2018
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