ON-OFF DIGITAL CONTROLLER FOR QUICKCOOLER/FREEZER MANAGEMENT
EK 825A
GENERAL CHARACTERISTICS
* Frontal size: 72 x 144 mm (2.83 x 5.66 ").
* Power supply: 230 Vca.
* Six easy selectable cycles of functioning: quick-cooling, cold-stor-
ing, quick-cooling and cold-storing, quick-freezing, very cold-storing, quick-freezing and very cold-storing.
* Adapt to manage quick-cooling/freezing for temperature or time.
* Alarm buzzer included.
* One 3-digit 12.5 mm (0.49 ") high red LED display showing the
temperature read by the needle/cabinet probe.
* One 3-digit 12.5 mm (0.49 ") high red LED display showing the
remaining time at the end of a cycle/phase of quick-cooling/freezing.
* Adapt to manage electrical, hot gas and air defrost (automatic and
manual).
* Three measure inputs (cabinet, evaporator and needle probe) for
PTC probe.
* One configurable door-switch digital input.
* One configurable locking digital input.
* Four relay outputs of which one 16 (2) A @ 250 Vac relay for one 1½
HP compressor (NO) management and three 6 (2) A @ 250 Vac relays
for evaporator fans (NO), defrost system (resistances or by-pass
valve, change-over) management and cabinet light control (NO).
EK 825A is an ON-OFF digital controller studied for quick-cooler/freezer management through the compressor, evaporator fans, defrost (for time-
temperature) and cabinet light output control.
The instrument basically permits the control, according with the established parameters, automatic cycles of quick cooling/freezing of (pre-cooked
or at environmental temperature) food temperature, using the compressor at its best, in order to preserve the product quality.
The controller has principally six different cycles of functioning configurable according with the norms and selectable through the keys located
on the frontal panel:
quick-cooling (for temperature or time), during which the instrument regulates the quick-cooling of food temperature, verifying that it happens
within the maximum established time
cold-storing, during which the instrument works as a normal thermostat (with evaporator fans and defrost management) and regulating the
cabinet temperature at the established value
quick-cooling (for temperature or time) and cold-storing, during which the instrument at fist executes the phase of quick-cooling and at its
end automatically moves to the phase of cold-storing
quick-freezing (for temperature or time), similar to the cycle of quick-cooling
very cold-storing, similar to the cycle of cold-storing
quick-freezing (for temperature or time) and very cold-storing, during which the instrument at first executes the phase of quick-freezing and
at its end automatically moves to the phase of very cold-storing.
In order to assure a correct execution of a cycle/phase of quick-cooling/freezing for temperature of pre-cooked (hot) food temperature it is necessary
that the needle probe is properly positioned inside the product: so, the instrument, at the beginning of the cycle, executes a test to verify the
proper insertion of the needle probe; the overcoming of this test permits the execution of the cycle/phase, contrary some alarm signals gets
activated.
The four outputs of which one 16 (2) A @ 250 Vac relay with NO contact (compressor output) and three 6 (2) A @ 250 Vca relays with NO contact
(evaporator fans and cabinet light output)) and change-over contact (defrost output) permit the direct management of loads, in small power
refrigeration systems, without using auxiliary relays.
The device is provided of two temperature alarms (that can be disabled): the intervention of this kind of alarm activates the alarm buzzer with intermittent
beep and the contemporary showing on the display of a proper temperature value bur alternated to an alarm code.
Others alarm conditions (not proper kind of probe, defective probe, wrong connection, temperature outside the limits permitted by the used probe,
etc.), activate the alarm buzzer with intermittent and the contemporary showing on the display of univocal alarm codes that permit a sudden
intervention aganist the causes of failure.
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FUNCTIONING:
Pressure on key T 10 determines the start (status "ON", LED L 8 lighted) or the stop (status "STAND-BY", LED L 8 turned off) of the instrument:
at any new restart the last programming will reappear; in case of lack of power-supply, when the voltage recover the last programming will reappear
but an eventual count of a time will start from the beginning.
Pressure on key T 7 during the status "STOP" selects the modality of quick-cooling/freezing of food temperature (for temperature, with LED
L 5 lighted and LED L 6 turned off or for time, with LED L 5 turned off and LED L 6 lighted).
During the status "STOP" it is possible to select the desired cycle of functioning.
Cycle number 1a: Quick-cooling for temperature:
Push the key T 1 to select this cycle and the key T 10 to start it: the LED L 2 turning on.
If the parameter "d4" is set to 1 and if the conditions permit it (the temperature read by the evaporator probe must be below the set established
with the parameter "d2"), the instrument automatically executes a defrost cycle to permit a best performance of refrigerating system: the indicators
DY 1 and DY 2 respectively display the indications "dEF" and the time established with the parameter "c1", the LED L 7 turning on (during
this cycle the defrost will never be activated again).
In order to assure a correct execution of a cycle of quick-cooling it is necessary that the needle probe is properly positioned inside the product:
so, the instrument (after pressure on key T 10), executes a test to verify the proper insertion of the needle probe (see the paragraph Needle
probe properly positioned verify).
If the test has an happy success and if the conditions permit it (the eventual defrost cycle must be finished and the temperature read by the
needle probe must be lower to the set established with the parameter "c8"), the instrument starts the cycle: the indicators DY 1 and DY 2
respectively display the temperature read by the needle probe and the decrease of the time established with the parameter "c1", the LED L 7
flashes to indicate that a count of a time is on run, the outputs concerning get activated.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "cb", the hysteresis can be established with the parameter "c0"; the evaporator fans output
Fig. 1 - User interface
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is forced to the status ON.
When the temperature read by the needle probe reaches the set established with the parameter "c2" the cycle has an happy success, the buzzer
is activated with intermittent beep for the time established with the parameter "c9", the indicators DY 1 and DY 2 respectively display the
indications "End" flashing and "---", the LED L 2 and L 7 turning off, the compressor, evaporator fans and defrost outputs get deactivated:
push the key T 10 to set the instrument for a new cycle; pushing the key T 7 the indicator DY 2 displays the time in minutes occurred to
reach the set established with the parameter "c2".
When the time established with the parameter "c1" ends, if the temperature read by the needle probe is not lower the set established
with the parameter "c2" the cycle does not end, the buzzer is activated till when it is stopped (pressure on key T 9 permit to stop
the buzzer), the indicators DY 1 and DY 2 respectively display the temperature read by the needle probe and the indication
"0" flashing, the concerning outputs remain activated: pushing the key T 7 the indicator DY 2 displays the time in minutes passed
from the start of the cycle.
When the temperature read by the needle probe reaches the set established with the parameter "c2" the cycle ends, the indicators
DY 1 and DY 2 respectively and alternately display the indication "End" and "---", the LED L 2 and L 7 turning off, the compressor,
evaporator fans and defrost outputs get deactivated: push the key T 10 to set the instrument for a new cycle.
Cycle number 1b: Quick-cooling for time:
Push the keys T 1 and T 7 to select this cycle: the LED L 6 turning on, the LED L 5 turning off.
The indicator DY 2 displays the length of the quick-cooling for time: to modify its value push the key T 8 or T 9.
Push the key T 10 to start the cycle: the LED L 2 turning on.
If the parameter "d4" is set to 1 and if the conditions permit it (the temperature read by the evaporator probe must be below the set established
with the parameter "d2"), the instrument automatically executes a defrost cycle to permit a best performance of refrigerating system: the indicators
DY 1 and DY 2 respectively display the indications "dEF" and the during of the quick-cooling for time, the LED L 7 turning on (during this
cycle the defrost will never be activated again).
When the eventual defrost ends the instrument starts the cycle: the indicators DY 1 and DY 2 respectively display the temperature read by
the cabinet probe and the decrease of the length of the quick-cooling for time, the LED L 7 flashes to indicate that a count of a time is on run,
the outputs concerning get activated; pushing the key T 7 the indicator DY 2 displays the time in minutes passed from the start of the cycle.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "cb", the hysteresis can be established with the parameter "c0"; the evaporator fans output
is forced to the status on.
When the length of the quick-cooling for time ends the cycle has an happy success, the buzzer is activated with intermittent beep for the time
established with the parameter "c9", the indicators DY 1 and DY 2 respectively display the indications "End" flashing and "0", the LED
L 2 and L 7 turning off, the compressor, evaporator fans and defrost outputs get deactivated: push the key T 10 to set the instrument for
a new cycle.
Cycle number 2: Cold-storing:
Push the key T 2 to select this cycle and the key T 10 to start it: the LED L 1 turning on.
The indicators DY 1 and DY 2 respectively display the temperature read by the cabinet probe and the indication "---".
The instrument works as a normal thermostat with evaporator fans and defrost management.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "c3", the hysteresis can be established with the parameter "c0"; the temperature that regulates
the evaporator fans activity is the temperature read by the evaporator probe, the set can be established with the parameter "F1", the hysteresis
can be established with the parameter "F2".
Cycle number 3a: Quick-cooling for temperature and cold-storing:
Push the keys T 1 and T 2 to select this cycle and the key T 10 to start it: the LED L 2 turning on.
When the phase of quick-cooling ends (it is related in Cycle number 1a) the instrument moves to the phase of cold-storing (it is related in Cycle
number 2).
Cycle number 3b: Quick-cooling for time and cold-storing:
Push the keys T 1, T 2 and T 7 to select this cycle: the LED L 6 turning on, the LED L 5 turning off.
The indicator DY 2 displays the length of the quick-cooling for time: to modify its value push the key T 8 or T 9.
Push the key T 10 to start the cycle: the LED L 2 turning on.
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When the phase of quick-cooling ends (it is related in Cycle number 1b) the instrument moves to the phase of cold-storing (it is related in Cycle
number 2).
Cycle number 4a: Quick-freezing for temperature:
Push the key T 3 to select this cycle and the key T 10 to start it: the LED L 2 turning on.
If the parameter "d4" is set to 1 and if the conditions permit it (the temperature read by the evaporator probe must be below the set established
with the parameter "d2"), the instrument automatically executes a defrost cycle to permit a best performance of refrigerating system: the indicators
DY 1 and DY 2 respectively display the indications "dEF" and the time established with the parameter "c4", the LED L 7 turning on (during
this cycle the defrost will never be activated again).
In order to assure a correct execution of a cycle of quick-freezing it is necessary that the needle probe is properly positioned inside the product:
so, the instrument (after pressure on key T 10), executes a test to verify the proper insertion of the needle probe (see the paragraph Verify
the proper insertion of the needle probe).
If the test has an happy success and if the conditions permit it (the eventual defrost cycle must be finished and the temperature read by the
needle probe must be lower to the set established with the parameter "c8"), the instrument starts the cycle: the indicators DY 1 and DY 2
respectively display the temperature read by the needle probe and the decrease of the time established with the parameter "c4", the LED L 7
flashes to indicate that a count of a time is on run, the outputs concerning get activated.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "cC", the hysteresis can be established with the parameter "c0"; the evaporator fans output
is forced to the status ON.
When the temperature read by the needle probe reaches the set established with the parameter "c5" the cycle has an happy success, the buzzer
is activated with intermittent beep for the time established with the parameter "c9", the indicators DY 1 and DY 2 respectively display the
indications "End" flashing and "---", the LED L 2 and L 7 turning off, the compressor, evaporator fans and defrost outputs get deactivated:
push the key T 10 to set the instrument for a new cycle; pushing the key T 7 the indicator DY 2 displays the time in minutes occurred to
reach the set established with the parameter "c5".
When the time established with the parameter "c4" ends, if the temperature read by the needle probe is not lower the set established
with the parameter "c5" the cycle does not end, the buzzer is activated till when it is stopped (pressure on key T 9 permit to stop
the buzzer), the indicators DY 1 and DY 2 respectively display the temperature read by the needle probe and the indication
"0" flashing, the concerning outputs remain activated: pushing the key T 7 the indicator DY 2 displays the time in minutes passed
from the start of the cycle.
When the temperature read by the needle probe reaches the set established with the parameter "c5" the cycle ends, the indicators
DY 1 and DY 2 respectively and alternately display the indication "End" and "---", the LED L 2 and L 7 turning off, the compressor,
evaporator fans and defrost outputs get deactivated: push the key T 10 to set the instrument for a new cycle.
Cycle number 4b: Quick-freezing for time:
Push the keys T 3 and T 7 to select this cycle: the LED L 6 turning on, the LED L 5 turning off.
The indicator DY 2 displays the length of the quick-freezing for time: to modify its value push the key T 8 or T 9.
Push the key T 10 to start the cycle: the LED L 2 turning on.
If the parameter "d4" is set to 1 and if the conditions permit it (the temperature read by the evaporator probe must be below the set established
with the parameter "d2"), the instrument automatically executes a defrost cycle to permit a best performance of refrigerating system: the indicators
DY 1 and DY 2 respectively display the indications "dEF" and the during of the quick-freezing for time, the LED L 7 turning on (during this
cycle the defrost will never be activated again).
When the eventual defrost ends the instrument starts the cycle: the indicators DY 1 and DY 2 respectively display the temperature read by
the cabinet probe and the decrease of the length of the quick-freezing for time, the LED L 7 flashes to indicate that a count of a time is on run,
the outputs concerning get activated; pushing the key T 7 the indicator DY 2 displays the time in minutes passed from the start of the cycle.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "cC", the hysteresis can be established with the parameter "c0"; the evaporator fans output
is forced to the status on.
When the length of the quick-freezing for time ends the cycle has an happy success, the buzzer is activated with intermittent beep for the time
established with the parameter "c9", the indicators DY 1 and DY 2 respectively display the indications "End" flashing and "0", the LED
L 2 and L 7 turning off, the compressor, evaporator fans and defrost outputs get deactivated: push the key T 10 to set the instrument for
a new cycle.
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Cycle number 5: Very cold-storing:
Push the key T 4 to select this cycle and the key T 10 to start it: the LED L 1 turning on.
The indicators DY 1 and DY 2 respectively display the temperature read by the cabinet probe and the indication "---".
The instrument works as a normal thermostat with evaporator fans and defrost management.
The kind of temperature regulation is ON-OFF: the temperature that regulates the compressor activity is the temperature read by the cabinet
probe, the set can be established with the parameter "c6", the hysteresis can be established with the parameter "c0"; the temperature that regulates
the evaporator fans activity is the temperature read by the evaporator probe, the set can be established with the parameter "F1", the hysteresis
can be established with the parameter "F2".
Cycle number 6a: Quick-freezing for temperature and very cold-storing:
Push the keys T 3 and T 4 to select this cycle and the key T 10 to start it: the LED L 2 turning on.
When the phase of quick-freezing ends (it is related in Cycle number 4a) the instrument moves to the phase of very cold-storing (it is related
in Cycle number 5).
Cycle number 6b: Quick-freezing for time and very cold-storing:
Push the keys T 3, T 4 and T 7 to select this cycle: the LED L 6 turning on, the LED L 5 turning off.
The indicator DY 2 displays the length of the quick-freezing for time: to modify its value push the key T 8 or T 9.
Push the key T 10 to start the cycle: the LED L 2 turning on.
When the phase of quick-freezing ends (it is related in Cycle number 4b) the instrument moves to the phase of very cold-storing (it is related
in Cycle number 5).
Needle probe properly positioned verify:
The instrument automatically makes a test to verify the proper insertion of the needle probe at any activation of a cycle/phase of quick cooling/
freezing for temperature.
The test is organized on two levels (fast and differential): the happy success of the fast test excludes the differential test.
During the fast test the instrument verifies for five times if the value obtained with the subtraction of the temperature read by the cabinet probe
at the temperature read by the needle probe is higher than the temperature setted with the parameter "c7" (the test is overcoming if at least
3 on 5 verifies has a happy success); the verifies is maked every ten seconds, then the global length of the fast test is 50 seconds.
During the differential test the instrument verifies for height times that the value obtained with the subtraction of the temperature read by the
cabinet probe at the temperature read by the needle probe it is increase compared to the previous verify at least of 1 °C (the test is overcoming
if at least 6 on 8 verifies has a happy success); the verifies is do any 1/8 of the time setted with the parameter "cE" (to exclude the differential
test set the parameter "cE" with a value lower than 4 seconds, to exclude all the test set the parameter "c7" to 0).
If the test have not a happy success, the cycle not ends, the buzzer is activated till when it is stopped (pressure on key T 9 permit
to stop the buzzer), the indicators DY 1 and DY 2 respectively display the indications " " in alternate with the temperature
read by the cabinet probe and the decrease of the time established with the parameter "c1" or "c4": push the key T 6 to manually
confirm the proper insertion of the needle probe.
Hard-Soft quick-cooling:
This temperature quick-cooling modality is only available during a cycle/phase of quick-cooling.
During the quick-cooling, this operation is divided in two parts: a Hard phase (in this phase the compressor work with a very low setpoint to
permit to maximize the temperature quick-cooling speed) and a Soft phase (in this phase the compressor work with a setpoint higher than
the previous setpoint).
To select the Hard-Soft quick-cooling push the key T 5 when the instrument is in STAND-BY status: the LED L 3 turning on.
If a cycle/phase of quick-cooling for temperature is selected, during the Hard phase the working-setpoint of the compressor can be established
with the parameter "cF" (the Hard-phase automatically ends when the temperature read by the needle probe reaches the setpoint established
with the parameter "cd"), during the Soft-phase the compressor works in the same way of the cycle 1a.
If a cycle/phase of quick-cooling for time is selected, during the Hard-phase the working-setpoint of the compressor can be established with
the parameter "cF" (the Hard-phase automatically ends when the time established with the parameter "t1" is passed), during the Soft-phase
the compressor works in the same way of the cycle 1b.
To unselect the Hard-Soft quick-cooling push the key T 1, T 2, T 3 or T 4 during the STAND-BY status: the LED L 3 turning off.
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