OSAKA
- USER MANUAL - B4U - v2 - PAG. 9
2 - Second control (Parameter P2). The second time foresees a delay
of the control relay, in order to ensure a minimum time between the
stop and the start of the relay parameter "P2" (delay after switching
off or minimum stop time).
3 - Third control (Parameter P3). The third time foresees not allowing
starts unless the time programmed in parameter “P3” between
consecutive starts has been exceeded (delay after consecutive
starts).
If the protection is operating, preventing the operation of the relay for
the programmed time, the LED of the relay output will be flashing.
Furthermore, by setting a time in the "od" parameter, it is possible to
set a delay and avoid the activation of all the outputs after supplying
voltage and turning on the B4U.
During this delay phase we will display od alternating to the normal
programmed display.
The “od” delay function is disabled by programming as = oF.
5.8 - DEFROST CONTROL
The defrost control mode acts on the output configured as "ot", "dF"
and "-d".
The parameters related to the defrost control functions are grouped
in the "-dF" folder.
The type of defrost that the B4U will carry out is programmed in the
"dt" parameter, which can be programmed as:
= EL -
WITH ELECTRIC HEATING (or also by compressor stop): with
this mode, during defrost, the "ot" output remains deactivated while
the "dF" output is activated. If the "dF" output is not used, a defrost
will be carried out by stopping the compressor.
= on -
WITH HOT GAS or CYCLE REVERSAL: with this mode,
during defrost, the "ot" and "dF" outputs are activated.
= no -
KEEPING THE REGULATION ON THE COMPRESSOR
OUTPUT: with this mode, during defrost, the "ot" output continues to
function as temperature regulation while the "dF" output is activated.
= Et -
WITH ELECTRIC HEATING AND THERMOSTAT: with this
mode, during defrost, the "ot" output is deactivated while the "dF"
output acts as a thermostatic temperature regulator of the defrost
evaporator.
With this selection, the end of the defrost is always the maximum
duration time programmed in parameter dE.
During defrost, the "dF" output acts as a temperature regulation
control in heating mode with Set = "tE", with a fixed hysteresis of 1 °
C and with cooling of the temperature measured by the probe
configured as evaporator probe ( EP).
In this mode, if the evaporator probe is not enabled or has an error,
the defrost acts as in the EL option (therefore, during the defrost, the
“dF” output will always remain active).
5.8.1 - START AUTOMATIC DEFROST
Automatic defrosts can occur:
- By time intervals (regular or dynamic);
- By evaporator temperature;
- By continuous running time of the compressor.
In order to avoid unnecessary defrosts, when the evaporator
temperature (EP probe) is higher than the one programmed in the
“tS” parameter, the defrosts will NOT be activated.
- Defrost at regular time intervals.
Through the parameter "dC" it is possible to set the counting mode
at defrost intervals as can be seen below:
= rt
- At real time intervals. The "di" interval counts the time since the
B4U was started.
This mode is the one currently used in refrigeration systems.
= ct
- At intervals of compressor operation time. Th
e interval “di” is
counted as the sum of the operating times of the output ot (output
on).
This mode is normally used in refrigeration systems with compressor
stop in defrost.
= cS
- Defrost cycle at each compressor stop. The regulator starts a
defrost cycle every time the ot output is deactivated, when the Set
Point is reached or at the end of the interval established with the “di”
parameter.
If
“di” =
oF, the defrost is only carried out when the compressor
stops.
This mode is only carried out in special machines that, after each cold
cycle, need to have the battery free of ice in conditions of maximum
efficiency in each cycle of the compressor.
To allow automatic defrost at intervals, after setting the "dC"
parameter in the desired way between rt, ct or cS, with the "dE"
parameter we will select the time interval between the end of defrost
and the beginning of the next one.
In these modes, it is possible to configure the first defrost at the start
of the B4U in the "Sd" parameter.
This allows the first defrost to be carried out at a time interval other
than "dE".
If you want to perform a defrost at each start-up of the B4U, program
the parameter "Sd" = oF. This will make a defrost immediately upon
start-up (provided that the conditions established with the "tE"
parameters are met).
This allows the evaporator to be permanently in defrost, even when
frequent power interruptions occur that could cause the cancellation
of several defrost cycles.
If, on the other hand, you want all the defrosts to take place at the
same time interval, set "Sd" = "di".
By setting "di" = oF, all defrosts are deactivated (including the first,
regardless of the time set in the "Sd" parameter).
- Defrosts by dynamic time intervals
Note: For this function it is necessary to use the evaporator probe
.
To activate the "Defrosts by Dynamic Intervals" function, we must
configure the "dC" parameter as desired between rt, ct or cS and the
"dd" parameter at any value.
In case of setting "dd" = 0, the defrost intervals are those established
by the user and the "Defrosts by Dynamic Intervals" system will be
deactivated.
This mode allows you to dynamically reduce the defrost interval time
("di" or "Sd" in the case of being the first defrost), anticipating if
necessary the execution of the defrost, all based on an algorithm that
detects a drop in the heat exchange performance of the refrigerator.
The algorithm estimates a reduction in heat exchange based on the
increase in the temperature difference between Pr1 (chamber
control) and the evaporator probe (probe configured as EP). The
result is stored by the B4U when the regulation temperature is close
to the Set point configuration.
The advantage of defrost by dynamic time intervals is that it allows
programming the defrost intervals longer than normal and working in
such a way that it is the system conditions that determine whether to
anticipate the execution of a defrost if necessary.
If the time entered is too short, it is possible that the “Dynamic Interval
Defrosts” do not give them time to act.
