ENG
Code Description
Def Min Max UOM User
User
terminal
rHS
Virtual probe composition for glass temp. probe estimate
0 = Air off probe Sm
100 = Air on probe Sr
20
0
100
%
S
NO
rHA
Coeff. A for glass temp. probe estimate
2
-20 20 °C/°F
S
NO
rHb
Coeff. B for glass temp. probe estimate
22
0
100
-
S
NO
rHo
Offset for anti-sweat modulation
2
-20 20 °C/°F
S
NO
rHd
Differential for anti-sweat heater modulation
0
0
20 °C/°F
S
NO
If one of the probes is not available (SA or either Sm or Sr), only fixed activation control will be possible,
according to parameters rHu and rHt.
Outputs
The percentage of activation (OUT) for anti-sweat heater control depends on the difference between the
dew point calculated and the value read by the glass temperature probe, the value of parameter rHo
(offset) and the value of parameter rHd (differential), as shown in the following figure. The CUTOFF is a
constant of 5°C and the hysteresis is 1°C.
Fig.5.y
Ref.
Description
SdP
Dew point
rHo
Offset for anti-sweat modulation
rHd
Diff. for anti-sweat modulation
OUT
Anti-sweat control
Ref.
Description
Svt
Glass temperature probe
Min
Minimum fan speed
Max
Maximum fan speed
Min: fixed minimum output of 10%; Max: fixed maximum output of 100%.
The action is proportional only if the estimate of the glass temperature is used, and proportional and
integral (Tint=240 s, constant) if the actual glass temperature probe is us. The aim of the integral action is
to bring the glass temperature towards the set point (Sdp+rHo).
Important:
if the serial probes from the supervisor are used for sending the ambient temperature and
humidity values, MPXone has four auxiliary variables that save the last useful value available for 30
minutes. This may be useful in the event of a supervisor power failure.
Alarms due to probes without updated values are therefore normally shown on start-up, when these
variables have not yet been initialised.
Fixed activation control (manual control)
Control depends only on parameters rHu and rHt and follows the trend shown in the figure.
Code Description
Def Min Max UOM User
User
terminal
rHu
Manual anti-sweat heater activation percentage (of period ‘rHt’)
0 = function disabled
70
0 100
%
S
NO
rHt
Manual anti-sweat heater activation period
0 = function disabled
5
0 180 min
S
NO
72
| 5. Functions
0300086EN rel. 1.0 – 04.09.2018
