Example of electric defrost with evaporator temperature control:
The defrost end after "d.dE" programmed time. During defrost the
“dF” output switch on/off to control evaporator temperature in
heating mode with set point “d.tE” and 1° differential (Hysteresis).
The active defrost is shown on the instrument display with the
lighting up of the DEFROST led
At the end of defrosting, it is possible to delay the new start up of
the compressor (output “ot”) at the time set in parameter
“d.td”
to
allow the evaporator to drain.
During this delay, the led Defrost flashes to indicate the draining
state.
4.8.4 - DEFROSTS IN EVENT OF EVAPORATOR PROBE
ERROR
In event of evaporator probe error the defrosts occur at intervals
"d.Ei"
and duration
"d.EE”.
In case an error occurs when the time remaining to the start or the
end of defrost it’s lower than that normally set the parameters
related to error conditions probe, the start or the end take place
with the shortest time.
The functions are provided because when the evaporator probe is
used the defrost endurance time is usually set longer than
necessary (the time “d.dE” is a security time-out) and in case is
used the "Dynamic Intervals Defrost System” the interval is usually
set more longer than what is normally programmed into
instruments that do not have the function.
4.8.5 - DEFROST DISPLAY LOCK
Through par.
“d.dL”
and
“A.dA”
it’s possible to define the display
behaviour during defrost.
The “d.dL” parameter pemits the display visualization lock on the
last Pr1 emperature reading (“d.dL” = on) during all the defrost
cycle until, at the end of defrost, the temperature has not reached
the lock value or the value [”SP” + “r.d”] or is elapsed the time
setted on par. "A.dA".
Or it permits only the visualization of label
“dEF”
(“d.dL” = Lb)
during the defrost cycle and, after the defrost, of label
“PdF”
until,
at the end of defrost, the Pr1 temperature has not reached the lock
value or the value [”SP” + “r.d”] or is elapsed the time setted on
par. "A.dA".
The display will otherwise (“d.dL”= oF) continue to visualize the
Pr1 temperature measured by the probe during the defrost cycle.
4.9 - EVAPORATOR FANS CONTROL
The control of the fans on the output configured as “Fn” depending
on determined control statuses of the instrument and the
temperature measured by the evaporator probe (EP).
In the case that the evaporator probe is not used or in error , the
output Fn is activated only depending on the parameters “F.tn”,
“F.tF” and “F.FE”.
The parameters
“F.tn”
e
“F.tF”
decides the funs functioning when
the output configured as “ot” (compressor) is off.
When output “ot” is off , it is possible to set the instrument so that
that the output “Fn”continues to work in cycles according to the
times programmed in the parameter
“F.tn”
(fan activation time)
and
“F.tF”
(fan deactivation time).
When output “ot” is switched off the instrument activates the output
“Fn for the time “F.tn”, then deactivates it for the time “F.tF” and so
on whilst the otuput “ot” remains off.
Programming “F.tn” = oF the output “Fn” in “ot” off condition will
remain switched off.
Programming instead “F.tn” to any value and “F.tF” = oF the output
“Fn” in “ot” off condition will remain switched on.
The parameter
“F.FE
” instead decides whether the fans must
always be switched on independently of the defrosting status
(“F.FE”=on) or switched off during defrosting (“F.FE”=oF).
In this later case, it is possible to delay the start up of the fans even
after the end of the defrosting of the time set in the parameter
“F.Fd”.
When this delay is active the led FAN flashing to signal the delay in
progress.
When the evaporator probe is used the fans, as well as being
conditioned by the parameters “F.tn”, “F.tF and “F.FE”, are also
conditioned by a temperature control.
It is possible to set the disablement of the fans when the
temperature measured by the evaporator probe is higher than the
one set in the parameter
“F.FL”
(temperature too hot) or when it is
lower than the one set in the parameter
“F.LF”
(temperature too
cold).
The relative differential that can be set in parameter
“F.dF”
is also
associated with these parameters
.
Remember that the fans functioning can be conditioned by the
“Door open” function by the digital input.
F.d F
F.d F
tim e
Fn
o ff
O N
F .LF
EP
T e m p .
F .FL
off
off
O N
Notes: It is necessary to pay attention to the correct use of this fans
temperature control functions because in the typical application of
refrigeration the stop of the fans evaporator stops thermal
exchange.
4.10 - ALARM FUNCTIONS
The alarm conditions of the instrument are:
- Probe errors :
“E1”, “-E1”, “E2”, “-E2”, “E3”, “-E3”,
- temperature alarms:
“Hi”
and
“Lo”
- External alarm:
“AL”
- Open door alarm:
“oP”
The alarm functions of the instrument work on the ALARM led, on
internal buzzer (if present and programmed by par. “o.bu”) and on
output desired, if configured by the parameters “o.o1”, “o.o2” or
“o.o3”, depending on what is set on the said parameters.
Any active alarm is shown on the instrument display with the
lighting up of the ALARM led, the silenced or memorized alarm
status is shown by the ALARM led flashing .
The buzzer (if “o.bu” = 1 or 3) is activated in alarm and can be
disabled (alarm silencing) manually by pressing any key of the
instrument.
The possible selections of output parameters for the alarm
signalling function are:
= At
- when one wants the output to be activated in alarm and can
be disabled (alarm silencing) manually by pressing any key of the
instrument (typical application for sound signal).
= AL
- when one wants the output to be activated in alarm status
but cannot be disabled manually and are therefore only disabled
when the alarm status ceases (typical application for a light signal).
= An
- when one wants the output to be activated in alarm status
and that they remain activated even when the alarm has ceased
(see par.4.10.4) Disablement (recognition of memorised alarm) can
only be carried out manually by pressing any key when the alarm
has ended (typical application for light signal).
= -t
- when one wants the function described as At but with an
inverse function (output activated in normal condition and disabled
in alarm status).
= -L
- when one wants the function described as AL but with
inverse logic (output activated in normal conditions and disabled in
alarm status).
= -n
- when one wants the function described as An but with
inverse working logic (output activated in normal conditions and
disabled in alarm status).
The instrument offers the possibility of arranging the alarm memory
function via the parameter
“A.tA”.
If "A.tA" = oF, the instrument cancels the alarm signal when the
alarm status ends, if instead it is programmed as "on" , the
instrument maintains the alarm signal when the alarm status ends.
To cancel the alarm memory signal, press any key.
It must be remembered that if an output function is desired with an
alarm memory (=An or =-An) it is necessary to set the parameter
“A.tA” = on.
ASCON TECNOLOGIC - Y33
- OPERATING INSTRUCTIONS - Vr. 01 - 04/16 - ISTR-MY33-ENG01 - PAG. 9