User manual

43
ENG
MPXPRO - + 0300055EN rel. 1.3 07/03/13
Alternatively, the supervisor can directly supply the dewpoint value
(Sdp) using the serial probes (see parameter /Fn). The glass temperature
probe (Svt) may be connected directly to each controller (see parameter
/FM), or estimated. The estimate of the glass temperature probe
reading is performed internally when: ambient temperature (SA), outlet
temperature (Sm) and intake temperature (Sr) are available, and depends
on parameters rHA, rHb and rHS. Parameters rHo, rHd and rHL determine
the modulating output.
Par. Description Def Min Max UoM
rHA
Coeffi cient A for glass temperature probe
estimate
2 -20 20 °C/°F
rHb
Coeffi cient B for glass temperature probe
estimate
22 0 100 -
rHS Virtual probe composition for glass tempe-
rature probe estimate
0 = outlet probe Sm
100 = intake probe Sr
20 0 100 %
rHo Off set for anti-sweat heater modulation 2.0 -20.0 20.0 °C/°F
rHd Diff erential for anti-sweat heater modula-
tion
0.0 0 20.0 °C/°F
rHL Type of PWM output load for anti-sweat
heater modulation
0 = resistive; 1 = inductive
001-
Tab. 6.l
If one of the probes is not available (SA or either Sm or Sr), only fi xed
activation control will be possible, based on parameters rHu and rHt.
Outputs
Confi gurable outputs (not
relays)
PWM1, PWM2
0 to 10V
The output used by default is output PWM2 (terminal 19), however this
can be changed to other analogue outputs using VPM. The actuator can
be selected between anti-sweat heaters or fan with inductive motor
using parameter rHL. If the load is resistive (rHL=0), the period is fi xed at
24 s and the ON time depends on the PI algorithm. The output is adapted
to control an SSR (solid state relay). If the load is inductive (rHL=1) there is
no period and the output is modulated continuously by the PI algorithm.
In this case, the output is adapted for the MCHRTF phase control modules
(see paragraph 2.7).
The percentage of activation (OUT) for anti-sweat heater control depends
on the diff erence between the dewpoint calculated and the value read
by the glass temperature probe, the value of parameter rHo (off set) and
the value of parameter rHd (diff erential), as shown in the following fi gure.
The CUTOFF is a constant equal to 5 °C and the hysteresis is 1 °C.
Svt
OUT
Sdp rHo rHd
1°C
CUTOFF
0%
Max
Min
Fig. 6.b
Key
SdP Dewpoint Svt Glass temperature probe
rHo
Off set for anti-sweat heater
modulation
Min Minimum fan speed
rHd
Diff erential for anti-sweat heater
modulation
Max Maximum fan speed
OUT Anti-sweat control
Min: minimum output fi xed at 10%; Max: maximum output fi xed at 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 used. 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
the propagation of the ambient temperature and humidity
values, MPXPRO 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 follow the trend
shown in the fi gure.
Par. Description Def Min Max UoM
rHu Manual anti-sweat heater activation
percentage (of period ‘rHt’)
0 = function disabled
70 0 100 %
rHt Manual anti-sweat heater activation period 5 0 180 min
Tab. 6.m
Confi gurable outputs
PWM1, PWM2
0 to 10V
AUX1, AUX2, AUX3
rHu
t
t
t
rHt
rHu
0
BA
C
10 Vdc
0
12 Vdc
OFF
ON
rHt
Fig. 6.c
Key:
A = PWM output B = 0 to 10V dc vutput C = Relay output
rHu = Manual anti-sweat heater activation percentage
rHt = Manual anti-sweat heater activation period t = Time
6.4 Digital outputs
Con gure compressor and fan output logic (parameters
H10, H11)
Parameters H10 and H11 are used to select the logic of the digital output:
0: with request active, the N.O. contact closes and N.C contact opens;
1: with request active, the N.O. contact opens and N.C contact closes.
Par. Description Def Min Max UoM
H10 Confi gure compressor digital output logic
0 = direct logic; 1 = reverse logic
001-
H11 Confi gure evaporator fan digital output
logic
0 = direct logic; 1 = reverse logic
001-
Tab. 6.n
Compressor output
NO NC C
L
N
435
H10 = 0, request active
NO NC C
H10 = 1, request active
NO NC C
Fan output
NO C
L
N
12 13
H11 = 0, request active
NO C
H11 = 1, request active
NO C