Ascon tecnologic X34 User Manual

Ascon Tecnologic - X34 - OPERATING INSTRUCTIONS - PAG. 13
that detects a drop in the refrigerator thermal exchange perfor-
mance. In order to evaluate the thermal exchange efficiency,
near the first passage from the operating Set Point, the instru-
ment stores the temperature difference (DT0) between the Pr1
probe (cell temperature) and the EP probe (evaporator).
Subsequently, the dynamic defrost algorithm allows to
highlight the heat exchange reductions by evaluating the
current temperature difference between the 2 probes (Pr1
and EP) and the stored one.
The advantage of the Dynamic Defrost Interval is the possi-
bility to program a defrost interval time longer than normal.
In this way, when necessary, the instrument has the possibil-
ity to anticipate/posticipate the defrost cycle from the pro-
grammed time.
If the system results correctly set, it is possible to avoid
many unnecessary defrost cycles (and therefore obtain a
consistent energy saving) that may occur with normal opera-
tion when, to ensure more system efficiency, the defrosts
interval is programmed with a time that is often too short.
With parameter d.dd - Defrost interval percentage reduction
- is possible to establish the percentage of reduction of the
remaining time to start next defrost when the conditions for
the reduction happen.
If parameter d.dd = 100%, at first increasing (> 1°) of the DT
between cell (Pr1) and evaporator (EP) probes from the DT
stored value, the instrument starts immediately a defrost.
To function correctly the instrument needs a DT reference
value, but, as all variations (Active Set Point, r.d differential
or the execution of a defrost cycle) delete the DT reference
value, often no reduction can be made until a new reference
value has been acquired (at the end of the next defrost).
Phase
off off
ON
01 2 3
Temp.
d.di/d.Sd time to defrost Phases 0, 1
Defrost
off off
DT0
d.tE
d.tS
Cool
ot
Defrost
dF
SP + r.d
SP
Pr1
r.d
EP
1°
DT1 DT2 DT3
time to defrost Phase 2
time to defrost Phase 3
time
ON ON ON
E.g. “Dynamic defrost intervals system” with a reduction
d.dd = 40% and temperature defrost end.
Defrost by evaporator temperature
The instrument starts a defrost cycle when the evaporator
temperature (EP probe) falls below the d.tF programmed
temperature for d.St programmed time to ensure a defrost if
the evaporator reaches very low temperatures which, as a
rule, are symptomatic of a bad heat exchange compared to
normal operating conditions.
If d.tF = -99.9 the function is disable.
The function is active in all modes of defrost operation
(d.dC = cL, rt, ct, cS).
Defrost by continuous compressor running time
The instrument start a defrost cycle when the compressor is
turned continuously ON for the time d.cd.
This function is used because the continuous compressor
operation for an extended period is usually symptomatic of a
bad thermal exchange in comparison to the normal working
conditions.
If d.cd = oF the function is disabled.
The function is active in all modes of defrost operation
(d.dC = cL, rt, ct, cS).
5.8.2 Manual defrost
To manual start a defrost cycle, press the key / and keep
it pressed for about 5 s while the instrument is not in pro-
gramming mode. After the key pressure, if the conditions are
correct, the LED lights up and the instrument performs a
defrost cycle.
To stop a defrost cycle, press the key / and keep it
pressed for about 5 s during the defrost cycle execution.
5.8.3 Defrost ends
With 1 evaporator
The automatic defrost cycle can be ended by time or, if an
evaporator probe is used (EP probe), when the evaporator
reaches a particular temperature.
If the evaporator probe is not used the duration cycle is set
by the parameter d.dE.
If instead the evaporator probe is used, the defrost cycle
ends when the temperature measured by the evaporator
probe exceeds the temperature set at parameter d.tE.
If d.tE temperature is not reached, the defrost cycle is inter-
rupted when the time set at the parameter d.dE has elapsed.
If the temperature measured by the probe is higher than the
temperature set at parameter d.tS and d.tE the defrost is
inhibited.
d.tE
d.ts
Defrost
dF
offoffoffON ON
AB
Temp.
time
C
(NO defrost)
d.de
d.di
(Defrost)
d.di
d.di d.di
(Defrost)
EP
E.g.: Defrost A ends due to reaching of temperature d.tE,
defrosting B ends at the end of the d.dE time as the
temperature d.tE is not reached, defrosting C does not
take place as the temperature is higher than d.tS.
d.tE
d.ts
offoffoff off
d.di
ON ON ON
time
d.di
(Defrost)
d.de
1°
Defrost
dF
Temp.
EP
E.g.: Electric defrost with evaporator temperature control:
The defrost ends after the d.dE programmed time.
During defrost the dF output switches ON/OFF to con-
trol evaporator temperature in heating mode with d.tE
Set Point and 1° differential (Hysteresis).

Ascon tecnologic X34 Specifications

General

Brand	Ascon tecnologic
Model	X34
Category	Controller
Language	English