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CONTROL SYSTEM
Functions available for the user
Set point
The set point value in COOLING and in HEATING can be set. These values must come within a predetermined max. and min. value.
The task of the controller is to keep the inlet air temperature as close as possible to the set value by activating the available compres-
sors according to an on-off logic.
Operating mode selection
Operating mode (cooling or heating) selection can occur in two ways :
• selection from keyboard (Pa H49 = 0)
• selection from digital input (Pa H49 = 1)
Serial communication
The device is configured to be able to communicate on a serial line using the MODBUS protocol. When connecting the device it must
be given an address univocally identifying it among all the devices connected to the same serial line ( “Modbus individual address” ).
This address must be between 1 and 247 and is configurable by means of the parameters Pa H67 and Pa H68 (see the section on
serial communication).
Operation with heat pump
The parameter Pa H10 enables operation with heat pump when it assumes value 1. This parameter must assume value 0 for all
cooling-only units. It is possible to set an outside air temperature value (Pa r13) below which operation with heat pump is blocked (the
heaters, hot water coil or the gas-fired heating module remain active in any case, if present).
Heaters
Antifreeze
The heating elements are activated according to a specific set point, differentiated for heating (Pa r07) and cooling (Pa r08) mode.
These values must come within a predetermined max. and min. value. Adjustment occurs on the inlet air temperature.
Integration
The parameter Pa r15 enables operation of the heating elements to integrate the heat pump when it assumes value 1.
Free cooling
To enable the free cooling function the parameter Pa L01 must assume value 1.
Shutter minimum opening
The minimum opening of the outside air shutter can be set by means of the parameter Pa L07 (between 0 and 100%) according to
the required percentage of renewal air and the characteristics of the inlet duct. For the shutter to open, free cooling must be enabled
(Pa L01 = 1).
Dehumidification
In cooling mode the dehumidification function can be managed if an inlet air humidity probe is provided for (or if the enthalpic free
cooling option was selected). The humidity set point can be set between 0 and 100% by means of the parameter Pa L19.
If the heaters or hot water coil are present it can be enabled during dehumidification (to obtain after-heating) by setting the parameter
Pa r16 to 1.
Night purging
This function enables an inside air change to be carried out and can only be activated by means of the remote thermostat (EKF400
RT type keyboard). If the outside air temperature is higher than the night purging set point (Pa L24) the outside air shutter is opened
100% and the internal fan is activated for a time indicated by the parameter Pa L23. The function is not available if any other type of
temperature control is in progress.
Air quality control (CO2)
This function controls opening of the outside air shutter according to the quantity of CO2 measured in the inlet air. The set point can be
set by means of the parameter Pa L26, between 0 (corresponding to 0 ppm) and 100 (corresponding to 1000 ppm).
Ventilation mode
This function enables activation of the internal fan, deactivating all the adjustment logics except for free cooling (if enabled : Pa L01 =
1). It can only be activated by means of the remote thermostat (EKF400 RT type keyboard).
Economy mode
This function allows the set point in cooling and in heating to be modified by adding or subtracting a delta (Pa L25) to guarantee more
efficient operation of the unit. It can be activated by means of the digital input ID8 or the remote thermostat (EKF400 RT type keybo-
ard). Economy mode remains activated while the digital input is active (contact open).
Shutter forced opening
This function enables forced opening (100%) of the outside air shutter, irrespective of the other active adjustment logics (this function
also has priority over the alarms). The digital input used is ID9. If the input is active (contact open) the shutter is completely open.
Remote ON - OFF
This function allows the machine to be switched on or off at a distance. The digital input used is ID10. If the input is active (contact
open) the controller switches off all loads and the display shows “ E00 ”.
The unit remains OFF while the input is active and cannot be controlled from keyboard.
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