Carel IR32M Manual page 26

Ad: Temperature alarm delay
This indicates how many minutes of delay are requested before a registered deviation is signalled. If during
the delay Ad the temperature returns to permitted limits, the alarm will not be signalled. If there is a further
alarm state, the delay will begin again at zero.
Setting a delay in signalling temperature alarms can help to avoid false alarms due to interference with the
sensor or situations lasting only a limited time, such as briefly opening the door of a store-room. Alarm
delays do not affect two particular functions: defrosting and continuous cycle. To delay any temperature
alarms after these functions, parameters d8 for defrosting and c6 for continuous cycle must be adjusted.
Remember that temperature alarms are not generated during defrosting and continuous cycle operation.
Default: Ad=120 (120 minutes' delay in signalling temperature alarms). The default for equipment with serial
numbers below 5000 is Ad=0. See note at end of manual. Available on IR32S, IRDRSE/S0, IR32Y, IR32P,
IR32C and IRDRC. Parameter with direct access from remote control.
A4: Configuration of Multi-function digital input
This defines the effect of MULTIFUNCTION digital input.
MULTIFUNCTION digital input can have varying significance, according to the values given to this
parameter and as a function of the type of control employed. The various functions are described below:
Note: see the following chapter "Notes for the new release" to a more detailed description of this parameter
functionalities, effective for the instrument with serial number greater than 100,000)
A4=0: INPUT NOT ACTIVE: MULTIFUNCTION digital input is not used. This is the value set in the factory
for all versions except model IR32M.
A4=1 IMMEDIATE EXTERNAL ALARM: it is possible to connect to the digital input an external alarm which
will request immediate intervention (for example a high pressure or compressor temperature alarm). In
particular the alarm is registered when the contact is opened (normal operation being in the closed state).
Activation of the alarm produces a display signal (see alarm A1), sound the buzzer if so designed and
initiates the following actions:
compressor: functions according to values under parameter A6 (blocking compressor by external
alarm);
fans: continue to work according to fan parameters (F). If the external alarm is registered during
defrosting or a continuous cycle, control exits from the procedures.
When the alarm ceases the equipment resumes operation as follows:
Defrost: the opportunity to defrost is reinstated. The next defrosting is effected after the interval dI
(interval between defrosting) that has been set;
Compressor: If the compressor is operating at the moment when the alarm ceases, it remains operating
and follows the minimum on-time that has been set (parameter c2). If the compressor is
off, it is kept off for a minimum equivalent to that set under parameter c3.
Important note: it should be remembered that to guarantee the safety of the unit in case of serious alarms it
is necessary always to fit the unit itself with all the electro-mechanical safety devices needed to ensure correct operation.
A4=2 Delayed external alarm
The significance, connection and mode of operation are similar to those already indicated for the parameter
A4=1. However, when A4=2 it is possible to delay the alarm signal for a period in minutes equivalent to
value chosen for A7 (see below). This arrangement is particularly useful for controlling the low pressure
alarm. In fact it often happens that on first starting up, the unit registers a low pressure alarm due to ambient
conditions rather than to any malfunctioning of the equipment. By setting a delay on the alarm, false alarms
are avoided. In fact, by calculating the delay appropriately, if the low pressure is due to environmental
factors (low temperature), the alarm will be automatically re-instated before the delay set has elapsed. After
the set delay period, effects on the compressor, fans, defrosting and continuous cycle are the same as when
A4=1.
If A4 is set to equal 3, the effect varies according to the model of equipment in use:
Version IR32M:
A4=3: SENSOR SELECTION
Allows the digital input to be used to display the temperature registered by sensor 1 or sensor 2. When the
contact is open the reading on P1 is displayed, when contact is closed, P2. Default: A4=3 digital input for
sensor selection.
25 Cod. +030220151 - Rel. 2.1 - 04/09/98