MAINTENANCE AND OPERATING MANUAL
Electronic controller
HAS T 070÷140
72
ENGLISH
EN
The data in this manual are not binding and they can be modified by the manufacturer without notice. Reproduction of this manual is strictly prohibited.
KD: derivative coefficient. This is the rate of temperature variation. The contribution of this coefficient increases damping
and stability of the system.
Coefficient KI acts on the regulation only when the reference temperature is within the Wind-up band. The KD coefficient
influences regulation at intervals corresponding to the sampling time.
The sum of contributions of the three parameters generates a regulation variable in relation to which the unit's compressors
are stopped and started.
NEUTRAL ZONE REGULATION
In neutral zone regulation the unit's compressors are started and stopped in accordance with the setpoint and the regulation
band or differential observing the reference time intervals.
Neutral zone means the deviation between the setpoint and the regulation bandwidth.
In chiller mode, if the reference temperature is > Setpoint+Diff, the unit's compressors are started in sequence, in compliance
with the starting time lag outside neutral zone. If the reference temperature is within the neutral zone, the unit's compressors
are started in sequence in compliance with the starting time lag in the neutral zone. Starts occur only if at least one of the
unit's compressors is already running. If the reference temperature is
< Setpoint, the unit's compressors are stopped in
sequence, in compliance with the stopping time lag outside neutral zone.
In heat pump mode, if the reference temperature is > Setpoint-Diff, the unit's compressors are started in sequence, in
compliance with the starting time lag outside neutral zone.
If the reference temperature is within the neutral zone, the unit's compressors are started in sequence in compliance with the
starting time lag in the neutral zone. Starts occur only if at least one of the unit's compressors is already running.
If the reference temperature is
< Setpoint, the unit's compressors are stopped in sequence, in compliance with the stopping
time lag outside neutral zone.
6.7.9 Defrost
The menu is accessible by means of the service level password and with defrost enabled.
During operation in heat pump mode, the unit's condensing coils function as evaporators so there is a risk of their surfaces
icing up. The defrost procedure makes it possible to avoid ice formation on the coils by inverting the operating cycle of the
unit for a defined time interval.
In the DEFROST menu you can define the parameters for control of the procedure, notably the defrost type which can be
chosen from:
• Independent: in defrost conditions each circuit activates the procedure irrespective of the status of the other
circuits;
• Separate: in defrost conditions each circuit checks the status of the other circuits and waits for the termination
of any defrost procedures in progress before starting its own defrost cycle;
The unit can manage a maximum number of defrost cycles per hour which, if exceeded, generates a warning on the
display.
Reduction
Cooling capacity
Neutral
Increase
Cooling capacity
Set
Set+Diff
Temperature
Zone
Reduction
Cooling capacity
Neutral
Increase
Cooling capacity
Set-Diff
Set Temperature
Zone
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