(2) Sequential Defrosting
The Master enables defrosting for the
various devices in the network. When
each device has completed defrosting
(and not dripping) it begins thermostat-
ing.
Finally, using the parameters dty, defrost
type. (and and dCt, defrost
Countingtype thedefrosting modes are
defined.
LIGHT-DOOR SWITCH
• button enabled
If you press the “LIGHT” button the auxil-
iary relay/light is activated (if it was off,
otherwise if it was on it is deactivated
(see par. H34, for IWK WIDE and 6-but-
ton keyboards only ).
• digital input enabled
The digital input can be configured as
auxiliary/light (parameter H11=3/4): in
this case, a digital output can be config-
ured as light/AUX (parameters
H21…24=5).
As stated, this function can be used to
activate the light relay if it was de-ener-
gized or energize it if this was not the
case.
When the digital input (D.I.) is activated
the light relay is enabled (if par. dSd=y)
and the light relay is disabled when the
D.I. is disabled.
The status is stored so that it functions
correctly in the event of a black-out; the
light button and the light enable function
can also be activated is the unit is in
STAND-BY (see par. H06). The light but-
ton always disables the light relay if par.
OFL=y
STAND BY/ON-OFF
Note: The STAND BY/ON-OFF function
can be rapidly selected by pressing
the dedicated on/off button for at
least 2 seconds.
Once the STAND-BY/ON-OFF function
has been enabled, the display goes out,
the controls are blocked including the
alarms and the cycle times are reset.
OFF will also be displayed.
The status is stored so that when power
is restored after a black-out the device
can resume operation in the same way as
before the power failure. After start-up,
the temperature alarm is excluded for
the period of time set by parameter PAO.
%%RRHH FFUUNNCCTTIIOONN
Press one of the programmable buttons
to activate the %RH function (enabling
the humidity reduction control) if the
parameter H31…33=9 has been set.
The %RH function can also be D.I.-
enabled if par. H11=9.
If this control is enabled, the fans oper-
ate continuously (always on). During
defrosting the fans are controlled by the
defrosting parameters and during the
dripping cycle they will be turned off
even if RH% is active.
NOTE: RH% status has priority over all
other parameters.
If there is a power failure or the machine
has been turned off, the RH% status will
be restored as soon as the mains power
supply returns or the machine is turned
on.
NIGHT & DAY CONTROL
The Night & Day control algorithm can
be used to set events and cycles at pre-
defined times of the week. You can set
an event start time and duration, as well
as functions and defrostings (daily or fes-
tive) to be enabled for each day of the
week. By pressing the “set” button when
the “nad” label appears, the label d0 (day
1) is displayed in the “Programming”
menu. Tip: consider d0 = Sunday). Use
the “UP” and “DOWN” buttons to set
other days (d1 (day 2 = Monday)…d6
(day 7 = Saturday)) and Every Day. By
pressing “set” the first parameter E00 is
displayed; use the “UP” and “DOWN”
buttons to scroll through other parame-
ters E01…03.
If you do not use the keyboard for over
15 seconds (time-out), or if you press the
“fnc” button once, the last value shown
on the display is confirmed and you
return to the previous screen mask.
The different functions are set using the
appropriate parameters (see the parame-
ter table for the folder with the “nad”
label)
GENERAL PRESSURE SWITCH CONTROL
The Pressure switch algorithm can be
used to effect a diagnostic role on a digi-
tal input (see par. H11-H14 =11).
Every time the pressure switch is trig-
gered, the compressor is deactivated, the
alarm LED is turned on and the displayed
in the alarm folder of a subfolder called
nPA. The number of times the pressure
switch has been activated is stored in this
folder: once the number set by the para-
meter PEn has been reached this folder is
replaced by the PA (pressure alarm)
Label. When the pressure switch input is
reset, control restarts automatically and
any timings and protections are
observed.
If the number of activations in the inter-
val established by parameter PEI (pres-
sure switch error count interval) exceeds
the number established by parameter
PEn (number of errors allowed per pres-
sure switch input) the control activates
an alarm condition. This condition con-
sists in 1. Deactivation of the compressor
outputs, fans and defrosting;
2. Display of the PA label in the alarm
folder;
3. Switching on of the alarm LED and
alarm relay if configured.
Once the device is in alarm mode, it
must be switched off and on again or
reset using the rAP (pressure switch
alarm reset) in the Fnc functions menu
(see).
During the pressure switch intervention
time, counting of the defrosting time
proceeds normally.
If parameter PEn = 0 the function is
excluded, the alarms are excluded and
the counts deleted and disabled.
MAXIMUM AND MINIMUM PRESSURE
SWITCH CONTROL
As above with the digital input set cor-
rectly (see par. H11-H14 =9, Minimum
pressure switch input; H11-H14 =10,
Maximum pressure switch input). In this
case the labels displayed will be LPA
(minimum) or HPA (maximum).
PREHEATING CONTROL (THERMAL
PROTECTION)
As above with the digital input set cor-
rectly (see par. H11-H14 =12). In this case
the label displayed in the Alarm folder
will be Prr and the compressor LED will
blink.
DIAGNOSTICS
The alarm condition is always signalled
by a buzzer (if present) and the alarm
icon LED. The alarm signals from the
faulty thermostat control probe (probe
1), the faulty evaporator probe (probe 2),
and the faulty display probe (probe 3)
appear on the instrument display as E1,
E2, and E3 respectively.
An error condition in probe 1 (thermo-
stat control) causes the following:
• E1 code appears on display
• compressor is activated as indicated by
“Ont” and “Oft” parameters if these are
programmed for duty cycle or:
The error condition for probe 2 (evapo-
rator) causes the following:
• E2 code appears on display
• end of defrost caused by time-out. The
error condition for probe 3 (display)
causes the following:
• E3 code appears on display. Other
IWP 740 (LX) 4/20
DISPLAY
E1 E2
E3
If simultaneous, they will be showed on the display
alternatively every 2 seconds
If E1 or E2 appears on the Master (see LINK net-
work) and the display is shared, the slaves will
always show the Master display: to understand
which unit is faulty, refer to the alarm LED for
each instrument.
FAULT
Faulty probe 1 (thermostat control)
Faulty probe 2 (evaporator) Faulty
probe 3 (display)
Probe errors table
Ont
0
0
>0
>0
Oft
0
>0
0
>0
Compressor output
OFF
OFF
ON
dc
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