Digital Outputs - Carel MPXPRO User Manual

/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
Coeffi cient A for glass temperature probe
rHA
estimate
Coeffi cient B for glass temperature probe
rHb
estimate
rHS Virtual probe composition for glass
temperature probe estimate
0 = outlet probe Sm
100 = intake probe Sr
rHo Off set for anti-sweat heater modulation
rHd Diff erential for anti-sweat heater
modulation
rHL Type of PWM output load for anti-sweat
heater modulation
0 = resistive; 1 = inductive
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 PWM1, PWM2
relays)
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.
OUT
Max
Min
0%
Sdp rHo
Fig. 6.b
Key
SdP Dewpoint
Off set for anti-sweat heater
rHo
modulation
Diff erential for anti-sweat heater
rHd
modulation
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.
Def Min Max UoM
2 -20 20 °C/°F
22 0 100
20 0 100
2.0 -20.0 20.0 °C/°F
0.0 0 20.0 °C/°F
0 0 1
Tab. 6.c.c
0 to 10V
1°C
Svt
rHd CUTOFF
Svt Glass temperature probe
Min Minimum fan speed
Max Maximum fan speed
Fixed activation control (manual control)
Control depends only on parameters rHu and rHt and follow the trend
shown in the fi gure.
Par. Description
rHu Manual anti-sweat heater activation
percentage (of period 'rHt')
0 = function disabled
rHt Manual anti-sweat heater activation period
-
%
Confi gurable outputs
12 Vdc
A
-
0
ON
C
OFF
rHu
Key:
A = PWM output
rHu = Manual anti-sweat heater activation percentage
rHt = Manual anti-sweat heater activation period

6.4 Digital outputs

Confi 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
H10 Confi gure compressor digital output logic
0 = direct logic; 1 = reverse logic
H11 Confi gure evaporator fan digital output
logic
0 = direct logic; 1 = reverse logic
Compressor output
3 4
NO NC C
Fan output
12 13
NO C
43
Def Min
70
5
PWM1, PWM2
0 to 10V
AUX1, AUX2, AUX3
10 Vdc
B
0
t
rHu
rHt
t
rHt
Fig. 6.c
B = 0 to 10V dc vutput
Def Min
0
0
H10 = 0, request active
N
L
NO NC C
5
H10 = 1, request active
NO NC C
H11 = 0, request active
N
L
H11 = 1, request active
MPXPRO - + 0300055EN rel. 1.1 30/08/10
ENG
Max UoM
0 100 %
0 180 min
Tab. 6.c.d
t
C = Relay output
t = Time
Max UoM
0 1 -
0 1 -
Tab. 6.d.a
NO C
NO C