Digital Inputs; Analogue Outputs - Carel MPXPRO User Manual

ENG
Par. Description
/c4 Probe 4 calibration
/c5 Probe 5 calibration
/c6 Probe 6 calibration
/c7 Probe 7 calibration
/cE Saturated evaporation
temperature calibration
Important : the value read by the probe and already corrected
can only be displayed locally, and not using the virtual console
(display Slave controller status from Master terminal).

6.2 Digital inputs

Confi gure function of virtual digital input (par. A8)
Par. Description
A8 Confi g. function of virtual digital input
0= input not active
1= immediate external alarm
2= delayed external alarm
3= enable defrost
4= start defrost
5= door switch with compressor
and evaporator fans OFF
6= remote ON/OFF
7= curtain switch
8= start/stop continuous cycle
9= light sensor
As already mentioned, in a Master Slave network, using a virtual digital
input, MPXPRO can activate the same digital input on all controllers
without needing additional wiring. Likewise, the virtual digital input from
the supervisor can also be propagated. Parameter A8 is used to select the
function activated on each Slave. If needed, diff erent functions can be
confi gured on the Slaves, meaning a change in status of the contact on
the Master activates diff erent functions on the Slaves.
Select digital input propagated from Master to Slaves
(parameter A9)
This can be confi gured only on the Master controller, enabling the
propagation via tLAN of the status of one of the digital inputs on the
Master or sent by the supervisor to the Slaves. Based on the value
associated with the parameter, MPXPRO propagates only one of the
digital contacts across the LAN, according to the table on the side. The
Slaves receive the status of the virtual digital input and activate the
corresponding function, according to parameter A8.
Par. Description
A9 Select digital input propagated from Master
to Slaves (only on Master)
0 = from supervisor 3 = DI3
1 = DI1 4 = DI4
2 = DI2 5 = DI5
Example 1:
To propagate the curtain switch
function from Master to Slave,
activated by digital input 1 on
the Master.
Set:
Master Slave 1, 2, 3, 4, 5
A9=1 A8=7
A8=0
A4=7
MPXPRO - + 0300055EN rel. 1.0 30/08/10
Def Min Max UoM
0 -20 20 (°C/°F)
0 -20 20 (°C/°F)
0 -20 20 (°C/°F/barg/ RH%)
0 -20 20 (°C/°F/barg/ RH%)
0.0 -20.0 20.0 °C/°F
Tab. 6.a.g
Def Min Max UoM
0 0 8 -
Tab. 6.b.h
Def Min Max UoM
0 0 5 -
Tab. 6.b.i
Example 2:
To propagate the virtual digital
input from the supervisor and
activate the continuous cycle in the
Master Slave network.
Set:
Master Slave 1, 2, 3, 4, 5
A9=0 A8=8
A8=8
Light sensor threshold (parameter H12)
Digital inputs DI1, DI2, DI3, DI4 (not DI5) can be connected to the light
sensor (code PSOPZLHT00), setting one of the parameters A4, A5, A10,
A11 = 9. H12 represents the threshold for night/day switching. There is a
fi xed hysteresis Δ of around 10 lux for day/night switching.
Par. Description
H12 Light sensor threshold
day
night

6.3 Analogue outputs

As mentioned, the most complete version of MPXPRO features 2 PWM
outputs, used as the control signal to manage loads such as anti-sweat
heaters or modulating evaporator fans, for demisting the display cases.
Anti-sweat heater or fan modulation
The control of anti-sweat heaters is performed by comparing dewpoint
calculated based on the ambient temperature and humidity, and the
temperature of the display case glass, measured by a probe or estimated
using the outlet, intake and ambient temperature of the display case.
MPXPRO features two types of anti-sweat heater control:
• PI (proportional, integral);
• fi xed activation (manual control).
The conditions for the activation of the algorithms are as follows:
Algorithm
PI
fi xed activation (manual control)
If the temperature read by the glass temperature probe is only estimated,
PI control becomes proportional only. If both algorithms are activated,
the PI algorithm has priority over fi xed activation, which does not require
the ambient temperature and humidity probes. There are a series of
conditions whereby the PI algorithm stops operating and, if activated,
fi xed activation control takes over. In these cases, if MPXPRO is not OFF,
the signal AcE is shown on the display.
Condition Cause
• physical probe not confi gured or error;
• the estimate of the glass temperature probe cannot
Glass temperature probe
be used because the outlet probe or intake probe
not valid
is not confi gured or has an error or the ambient
probe is broken or missing (*)
• humidity probe and/or ambient probe are not
Dewpoint not valid confi gured and operating;
• the serial dewpoint value is not available
(*) If the intake probe is not confi gured or has an error, the outlet probe alone is used.
PI control
Inputs
The humidity (SU) and ambient temperature (SA) probes may be (see
parameters /FL, /FI):
• connected to the Master, which automatically shares them with the
Slaves;
• connected locally to each controller;
• sent from the supervisor via the serial probes.
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
42
Def Min Max
25 10 100
light (lux)
Δ~10
H12
Fig. 6.a
Activation condition
rHd > 0
rHd = 0; rHt >0
Tab. 6.c.a
Tab. 6.c.b
UoM
lux