Temp.
off
ON
SP
time
r.d
off
off
off
ON
ON
Pr1
Out
(ot)
Second control (par.
“P.P2”
) foresees an inhibition to the
activation of the output by a time delay that starts when the output
is turning off (delay after switching-off).
ON
off
P.P2
P.P2
P.P2
SP
Temp.
time
r.d
ON
ON
off
off
Pr1
Out
(ot)
Third control (par.
“P.P3”
) foresees an inhibition to the activation
of the output by a time delay that starts when the output was
turning on last time (delay between switching-on).
P.P3
off
SP
ON
Temp.
P.P3
P.P3
time
r.d
off
off
ON
ON
Pr1
(ot)
Out
During the output inhibition the led OUT (Cool o Heat) blinking.
It is also possible to prevent activation of the output after the
instrument is turned on, for the time set in the parameter
“P.od”
.
During the power on delay phase, the display shows the indication
od,
alternating with the normal visualisation.
All the functions are disabled by relative parameters = oF.
4.8 - DEFROST CONTROL
The defrosting control acts on the outputs configured as “ot” and
“dF”
.
The type of defrosting that the instrument must carry out is set by
the parameter
“d.dt”
that can be programmed:
= EL
- WITH ELECTRICAL HEATING (or BY STOPPING
COMPRESSOR): during defrosting, the output “ot” is deactivated
while the output “dF” is enabled.
The defrost will be by Stopping compressor if not using the “dF”
output
= in
- WITH HOT GAS or INVERSION OF CYCLE:
during defrosting the outputs “ot” and “dF” are enabled
= no
- WITHOUT COMPRESSOR OUTPUT CONDITIONING:
during defrosting, the output “ot” continuous to operate in order to
temperature controller while the output “dF” is enabled.
= Et
- WITH ELECTRICAL HEATING AND DEFROSTING
TEMPERATURE CONTROL: during defrosting, the output “ot” is
deactivated while the output “dF” operate as evaporator
temperature control. In this mode the defrost lenght is by time-out
(time "d.dE"). During the defrost "dF" output it behaves as an
heating mode temperature control with Set = "d.tE" and fixed
differential at 1°C and operate in order to evaporator probe (EP).
4.8.1 - AUTOMATIC DEFROST
STARTS
The automatic control of defrost occours by interval times.
The automatic defrost function is activate when at the parameter
“d.di”
is set the defrost interval time.
The first defrost after swiching on can be set by par.
“d.Sd”
This allows to perform the first defrost to a different interval from
"d.di." time.
If it is desired that to every instrument power on a defrost cycle is
realized (as long as the conditions set in the parameters “d.tS” and
"d.tE" apply) program the par. "d.Sd" = oF.
This allows the evaporator to be permanently defrosted, even when
frequent interruptions to power supply occur that may cause the
cancellation of the various defrosting cycles.
Instead
if is desired all defrost to the same interval program "d.Sd"
= "d.di."
Automatic defrost function is disable when “d.di” = oF.
Counting mode interval and automatic defrost starts is set through
the parameter
"d.dC"
that can be programmed:
= rt
- intervals with counts the total function time (instrument on)
This mode results that currently used in the refrigerators systems.
= ct
- intervals with counts only the compressor function time
(output “ot” switched on)
Mode typically used in the positive temperature refrigerators
system with defrost by stopping compressor.
= cS
- the instrument carries out a defrosting cycle at each
compressor stop (i.e. at each deactivation of the output “ot”) or
however at defrost interval end with counts the total function time
(instrument on).
If "d.di" = oF the defrost happens only to the compressor stop.
This mode is used only on particular refrigerator system in which is
desired to always have the evaporator to the maximum efficiency
conditions every compressor cycle.
= St
- Defrost for evaporator temperature. The instrument starts a
defrost cycle when the temperature evaporator (“EP” probe) goes
below the “d.tS” programmed temperature or however at defrost
interval end with counts the total function time (instrument on).
If "d.di" = oF the defrost happens only when the evaporator
temperature goes below“d.tS” temperature.
This system can be used in heat pump defrost system (in this case
the defrosting intervals are usually disabled) or to guarantee a
defrost if the evaporator reaches very low temperatures that
normally result symptomatic of a bad thermal exchange in
comparison to the normal working conditions.
= dd
- "DYNAMIC DEFROST INTERVALS SYSTEM". This mode
allows to dynamically reduce in progress the defrost interval
counting ("d.di" or "d.Sd" if is the first defrost), anticipating so the
execution of a defrost when it was necessary, in order to an
algorithm that allows to notice a decrease performances of
refrigerator thermal exchange.
Besides it maintains activates the mode "St" that it allows a further
possibility of control of the defrost in order to notice a decrease
performances of refrigerator thermal exchange.
The algorithm allows to esteem a reduction of thermal exchange in
base to the increase of the difference of temperature between Pr1
(controlled temperature) and evaporator (“EP” probe) that is memo-
rized by the instrument in proximity of the Set Point.
The advantage of the “Dynamic Defrost Interval” is the possibility to
program a defrost interval time more longer than normal.
The instrument will have the possibility to anticipate the defrost if
necessary or to start the cycle after the programmed time.
If the system results set correctly is possible to to avoid many non
necessary defrosting cycles (and therefore to obtain an energy sa-
ving) that could instead happens in the normal operation when, to
guarantee with greater certainty the system efficency , the defrost
interval is programmed at a too low time.
In addition to normal defrost parameters the “Dynamic Defrost
Intervals System”, it foresees the parameter:
“d.dd”
- DEFROST INTERVAL PERCENTAGE REDUCTION. It
allows to establish the percentage of reduction of the remaining
time to start defrost when the conditions for the reduction happen.
If par. "d.dd" = 100% at the first increase of the memorized diffe-
rence of temperature between cell (Pr1) and evaporator (> 1 °) a
defrost start immediately
ASCON TECNOLOGIC - Z31Y
- OPERATING INSTRUCTIONS - Vr. 02 - 04/12 - ISTR-MZ31YENG02 - PAG. 6
