Ref.
Description
Sm
outlet probe (air off)
Sr
intake probe (air on)
T
temperature
Ref.
Description
Sv
Virtual probe
t
time
Daytime status: Sm = -21 to -23°C, St = -22°C
Night-time status: Sm = -19 to -21°C, St = -22°C
Sr = - 12 to -14°C, St = -16°C
Sr = - 17 to -15°C, St = -16°C
Fig.5.m
Fig.5.n
Ref.
Description
Sm
outlet probe (air off)
Sr
intake probe (air on)
Note:
l
if one of the probes has an error or is missing, it is considered as signalling the request;
l
if both probes are faulty or missing, the controller switches to duty setting mode.
Important:
if the double thermostat function is activated, the setting of the following parameters has
no effect:
l
r6 (night-time control probe);
l
r4 (automatic night-time set point variation).
Control offset with probe error (parameter ro)
Code
Description
Def
Min
Max
UOM
User
User
terminal
ro
Control offset with probe error
0
0
20
°C/°F
S
NO
MPXone in standard mode uses the virtual probe Sv for control, that is, the weighted average of the
outlet and intake probe (see parameter /4). If one of the two probes making up the virtual probe is
broken or has an error, parameter ro is used to continue normal control in controlled conditions, without
the need for immediate intervention by maintenance personnel. The recommended value of ro is the
temperature difference between the outlet probe and intake probe reading in steady operating
conditions of the refrigeration unit:
The following cases may occur:
l
outlet probe (air off) Sm error: MPXone starts control based on the intake probe Sr alone, considering
a new set point (St*) determined by the formula:
ENG
0300086EN rel. 1.0 – 04.09.2018
5. Functions |
57
