Carel plug-in User Manual page 23

C2: minimum compressor off time
Sets the minimum time, in minutes, that the compressor stays off. The compressor is not re-started until the minimum time selected
(c2) has passed since the last shut-down. This parameter is useful in ensuring pressure equalisation after the shut-down, in the case of
systems with hermetic and scroll compressors.
c3: minimum compressor on time
Sets the minimum time the compressor stays on. The compressor is not shut-down unless it has been on for the minimum time
selected.
c4: duty setting or safety probe
In the event of the control probe fault alarm (that is the ambient probe is short-circuited or disconnected) this parameter ensures
the operation of the compressor until the fault is resolved. In practice, the compressor, not being able to be activated according to
temperature (due to the probe fault), works cyclically with an ON time equal to the value assigned to parameter c4 (in minutes) and
a fixed OFF time of 15 minutes. There are two values for c4 which create special conditions.
If c4 = 0, in the event of an ambient probe fault, the compressor will be always off;
if c4 = 100, the compressor will remain always on; and the 15 minute off time is not considered.
 For other values of C4, at the moment a probe error (E0) is detected, the duty setting cycle starts from the current status of the
compressor:
1. if ON, it remains ON for the set time (C4), considering the time it has already been ON;
2. if OFF, it remains OFF for the OFF time, again considering the time it has already been OFF.
The time settings for compressor C1, C2, C3 are in any case always respected.
 If the control probe error occurs when the control is defrost mode or continuous cycle, the control instantly exits this status and
activates duty setting. To re-activate the defrost or continuous cycle operation, the ambient probe must be reset. Remember that
in the event of ambient probe errors, manual defrosts can not be performed.
If the probe error is no longer present, the machine returns to normal operation. The compressor again takes on the logic of the
control, respecting the times C1, C2, C3.
cc: continuous cycle duration
This is the time in hours that the compressor stays continuously on in order to lower the temperature to the set point. This function
is used when rapid product temperature drops are required, for example, after loading the store; in this phase the temperature can
fall below the set point by the value set using parameter AH. If cc=0, continuous cycle is not enabled. The control exits the
continuous cycle procedure after the time set for the parameter cc or when the minimum temperature has been reached (see
minimum temperature alarm, parameter AL).
Def.: 4 (hours). Available on all models .
c6: alarm bypass after continuous cycle
This is the time, in hours, that the temperature alarm is disabled after a continuous cycle. In practice, if the temperature of the
refrigeration unit, after the continuous cycle, falls due to inertia below the minimum temperature level (set point - AL) the
activation of the low temperature alarm is delayed for a time equal to c6. Remember that at the minimum temperature (set point -
AL) the continuous cycle is forced off.
Def.: 2 (hours). Available on all models.
Cod. +030221881 rel. 1.5 - 26/10/10
Def.: c2=0 (no minimum OFF delay time).
Available on all models.
t
Fig. 4.6.3
Def.: c3=0 (no minimum operation).
Available on all models.
t
Fig. 4.6.4
Def.: 0 (compressor always OFF in the event of ambient probe
fault).
Available on all models.
t
Fig. 4.6.5
23
plug-in