Digital Inputs - Carel MPXPRO User Manual

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5.2 Digital inputs

Introduction
MPXPRO manages up to 5 physical digital inputs and one virtual digital
input. Of these, as already mentioned, DI1, DI2, DI3, DI4 are analogue/
digital inputs, confi gured as digital inputs by their respective parameters
A4, A5, A10, A11, while DI5 is only a digital input and can be confi gured
using parameter A12.
See the general connection diagram in paragraph 2.8.
The virtual digital input is a function whereby the status of a digital input
is propagated via tLAN from Master to Slave. This is useful, for example,
for a curtain switch, allowing switching from day to night status and vice-
versa without having to connect additional wiring from the Master to
the Slaves. The virtual digital input can be confi gured from the supervisor
or the Master, based on the setting of parameter A9 (only settable on
the Master). A physical input on the Master can be associated with the
virtual digital input on the Master, to be propagated to the Slaves. This
is some using a parameter, either A4, A5, A10, A11 or A12 (based on the
setting of A9) set on the Master, and parameter A8 set on the Slave. See
the advanced parameters explained in paragraph 6.2.
Note: if needed, parameter A8 can have diff erent settings on the
Slaves, so as to activate diff erent functions.
The table below lists the various functions that can be activated by digital
input, when closing or opening the corresponding contact.
Digital inputs
S4/DI1
Parameter
Functions of the digital inputs (Parameters A4, A5, A10, A11, A12)
Selection
0 = input not active
1 = immediate external alarm
2 = delayed external alarm
3 = enable defrost
4 = defrost call
5 = door switch
6 = remote ON/OFF
7 = curtain switch/light
8 = start/stop continuous cycle
9 = light sensor
1 = Immediate external alarm
Activation of the alarm causes:
• message 'IA' shown on the display and alarm icon (triangle) fl ashing;
• activation of the buzzer (to confi gure this function, see parameter H4);
• activation of the alarm relay (if confi gured, see parameters H1, H5, H7);
• deactivation of the compressor/solenoid output (to confi gure this
function, see parameter A6).
Note: activation of the external alarm shuts down the evaporator
fans only if these follow the status of the compressor output, as set
for parameter F2. When the compressor is shut down due to an external
alarm the compressor ON time is ignored (parameter c3).
MPXPRO - + 0300055EN rel. 1.0 30/08/10
S5/DI2 S6/DI3 S7/DI4
A4 A5 A10 A11
Contact
open closed
-
active not active
active not active
not enabled enabled
not active active
door open door closed
OFF
day status night status
not active active
-
2 = Delayed external alarm
The operation of this alarm depends on the setting of parameter A7
(delay time for delayed external alarm):
• A7=0: signal only alarm on the display, normal operation of the
controller is not aff ected (default);
• A7≠0: alarm similar to the immediate external alarm, activation is
delayed by the time set for A7.
3 = Enable defrost
Used to disable any defrost calls. When the contact is open, all defrost
calls are ignored. Parameter d5 can be used to delay activation.
Note:
• if the contact is open while a defrost is in progress, this is immediately
stopped, the defrost icon fl ashes on the display indicating the defrost
call is active (this starts again when the contact closes);
• this function may be useful to prevent defrosts on controllers exposed
to the public during store opening hours, and to be able to perform
special hot gas defrosts.
4 = Defrost call
The closing of the digital contact starts the defrost, if enabled. In the
event of Master Slave network connection, if the controller is the Master,
the defrost will be a network defrost, while if it is a Slave, it will only be a
local defrost. The defrost digital input can be used eff ectively to perform
DI5 real time defrosts. Simply connect a timer to the multifunction digital
A12
input on the Master and use d5 to delay the defrosts on the various Slaves
and thus avoid current overloads.
Note: if the defrost is inhibited by another digital input confi gured
as "enable defrost", the defrost calls are ignored.
-
5 = Door switch
Door open:
• stop control (shutdown compressor/solenoid and evaporator fans);
• switch light on (if confi gured, see parameters H1, H5, H7);
• alarm icon (triangle) fl ashing on the display;
ON
• disable temperature alarm.
Door closed:
-
• resume control;
Tab. 5.f
• switch light off (if confi gured, see parameters H1, H5, H7);
• triangle icon stops fl ashing on the display;
• enable temperature alarm after bypass time defi ned by parameter d8.
32
MPXPRO
Fig. 5.c