VDH Products PROBA, Инструкция по установке и эксплуатации, Страница: 6 / 78

VDH Products BV Document 063319 - version 3.12 Page: 6 of 78
During a number of days (the length of the program, in this case 4) a temperature setpoint is setup for each day. On a given
day, the
PROBA110 regulates the temperature in the ripening room to be equal or close to that particular value. The length
of a ripening program can be varied from 1 to 9 days.
After setting up and starting a program the PROBA110 starts at day 1. In the example the temperature setpoint is now
17.5

C, so the PROBA110 regulates the temperature to become 17.5

C. At the end of each day (24 hours) the temperature
setpoint is changed into that of the next day of the program. After all days of the program are past, the PROBA110 goes to
the STANDBY mode. The STANDBY temperature is also adjusted in the ripening program. The STANDBY mode remains
active until the user stops the ripening program or starts a new one.
Finally a warming-up phase can take place before the ripening program starts. For convenience this precursion time is called
day 0. The length of precursion time is variable and temperature control during the precursion time is possible.
Optional gas, humidity, pressure or CO2 sensors can be connected to the PROBA110 .
If a gas concentration sensor is used, gasification can be carried out on gas level. An alarm will follow if the programmed
level is not reached within a certain time. If the gas level is too high, the ventilation can be started automatically.
The relative humidity sensor measures the relative humidity in the room. Depending on the desired level the humidification
can be switched on automatically. When exceeding the minimum or maximum alarm levels an alarm will be generated.
Based on the pressure difference across a pallet the pressure fans can be switched on and off. Also an alarm will follow if the
pressure difference is too low.
With a CO2 sensor ventilation can be started when the level of CO2 exceeds the maximum set value.
1.3 Methods of temperature control
Up to nine temperature sensors can be connected to the PROBA110 .
The PROBA110 can control the temperature in the ripening room by two ways. The first method is based on the average
pulp temperature in the ripening room. In the second method the air temperature is controlled in each section.
1.3.1 Temperature control based on the average pulp temperature
This method of control makes use of a maximum of nine, but mostly three, product sensors which are placed in
selected boxes of bananas (pulp temperature). These use product sensors type
SM8500 which are connected via
coiled leads to the connection boxes.
The temperature is controlled on the average of the present and active product sensors. The cooling and heating
are driven simultaneously for the whole ripening room.
The product sensors are also used to signal warnings and alarms.
As an option, mostly two alarm sensors type
SM8000/2m , can be connected. These sensors control the minimum
and maximum temperature of the airflow coming out of the evaporator. The evaporator can be temporarily switched
off if the alarm levels are exceeded.
In Appendix A (see page 43) a schematic drawing is given of this method of temperature control.
1.3.2 Temperature control based on air temperature
With this method of regulation the ripening room is divided into a maximum of three zones. The air temperature
within each zone is regulated separately. So the cooling and the heating are controlled per zone.
For each zone one control sensor is used, and is placed in the airflow from the product (or entering the evaporator).
These make use of air sensors type
SM8300 .
The control sensors are also used to signal warnings or alarms.
Next to the control sensors there are, as an option per zone sensors available for warning and alarm functions
(temperature too high or too low). These sensors are placed in the airflow entering the product.
In Appendix B (see page 44) a schematic drawing is given of this method of temperature control.