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the delayed external alarm is thus signal-only.
• both the immediate and delayed external alarm have automatic reset;
• if more than one digital input is confi gured as the delayed alarm, the alarm will be generated when at least one of the inputs is open;
• if control with two compressor steps is selected (with or without rotation, H1, H5 = 12 or 13) the delayed external alarm acts
on both steps.
A4 =3 The meaning varies according to the model used
Version ir33M = probe selection
This is used to exploit the digital input in order to show, on the display, the probe selected by parameter /tI or the fi rst enabled
probe (see parameters /A2, /A3, /A4, /A5). In practice, if the contact is open, the probe selected by parameter /tl is shown,
whereas, if the contact is closed, the fi rst enabled probe is shown.
For all other models = Defrost enabling
An external contact can be connected to the multifunction input to enable or inhibit the defrost.
• Contact open: the defrost is inhibited. Contact closed: the defrost is enabled.
• Contact closed without request from the controller: the defrost is not performed.
• Contact closed and defrost in progress: when the digital input is opened, the defrost is immediately stopped and the unit
restarts normal operation (without performing the dripping or post-dripping phases). The LED starts fl ashing to indicate that
the defrost request is pending, awaiting the next enabling signal (closing of the contact), when the defrost will be performed
completely.
Suggestion: this function is useful in the following situations, for example:
- multiplexed showcases with hot gas defrost. In these systems, defrosts must be performed by "islands", and therefore, at any one
time, some islands are enabled to be defrosted, while others are disabled;
- to prevent defrosts on the units accessible by the public during opening times. Any defrost request arriving when the contact is
open will remain pending until the contact closes.
A4 = 4 Start defrost from external contact
This function used to start the defrost from an external contact.
If dI=0 and no defrost enabling signal related to the clock is set, the defrost can only be performed on start-up, from the digital
input, by the supervisor and from the keypad. This function is useful to run real time defrosts. To perform the defrosts, connect a
cyclical, mechanical or electronic timer to the digital input: When the contact on the timer closes, the defrost request is sent.
As seen in the description of parameter d5, a series of units can be connected to the same timer.
Important warning for versions operating on 12Vac and 12-24Vac
When connecting a series of units to the same timer, the best solution is to insulate all the contacts galvanically, inserting an inter-
mediate relay for each contact. Setting a diff erent value for d5 on each unit will avoid simultaneous defrosts.
Note:
if more than one digital input is confi gured to enable the defrost, the defrost will be disabled when at least one of the
inputs is closed.
A4 = 5 Door switch with compressor and fan stop
Setting A4=5 manages the cold room door switch. The behaviour of the door switch depends on whether the door is opened
with the light OFF or light ON. The need to diff erentiate the two operating modes is mainly designed for controlling display cases
and cold rooms.
Case 1 - door opened with light
OFF:
If the door is opened with the light OFF:
• the compressor and evaporator fans are switched off (to stop the fans only, set parameter A4=9);
• in the models fi tted with an auxiliary relay programmed as the light output, the light is switched on;
• the reading displayed and the icon fl ash;
• the temperature alarms are disabled.
If the door remains open for longer than time d8, the controller restarts normal operation:
• compressor and fan ON, if requested;
• light ON (the auxiliary relay is selected as the light);
• the buzzer and the alarm relay are activated;
• the temperature alarms are enabled;
• the reading fl ashes.
To stop the reading from fl ashing, close the door. When the door is closed, the controller returns to normal operation, switching off
the light and enabling the temperature alarm after the delay time d8. The compressor is re-started observing any protection times
selected (see the C parameters).
Case 2: door opened with light
ON:
SAssuming the user enters the cold room, turning on the light before entering, closing the door behind him, and then exits the room,
closing the door a second time. When the door is opened:
• the compressor the evaporator fans are switched off (to stop the fans only, set parameter A4=9);
• the light stays on (only in the models fi tted with an auxiliary relay programmed as the light output);
• the reading displayed and the icon fl ash;
• the temperature alarms are disabled
When the door is closed the fi rst time, the controller maintains the previous situation. When the door is closed the second time,
the controller returns to normal operation, switching off the light and enabling the temperature alarm after the delay time d8.
The compressor is re-started, observing any protection times selected (see the C parameters).
If the door remains open for a time longer than d8, the controller returns to normal operation:
• compressor and fan ON, if requested;
• light OFF;
• the reading fl ashes;
• the buzzer and the alarm relay are activated;
• the temperature alarms are enabled;
• when the door closes the temperature alarm delay d8 is not set.
If, after being closed for the fi rst time, the door remains closed for longer than time d8, or if the light is switched off manually, the
controller restarts normal operation:
• compressor and fan ON, if requested;
From ser. no.:
Page:26
Ed.1" 08-2014
t
defrost
dP (1)
defrost
d5 (2)
dP (2)
d5 (3)
defrost
dP (3)
defrost request
Fig. 7.l
Key:
t=
impulse from the timer to start the defrost:
the minimum duration must be 0.5 s.
dP (1)= maximum defrost duration on unit 1.
dP(2)= defrost delay from external contact for unit 2,
higher than dP(1) to prevent overlapping defrosts.
Same for d5(3) and dP(3).
560001 EG
Doc. No.:
timer
unit 1
unit 2
unit 3
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