Carel k.Air, User Manual, Page: 58 / 192

58
Functions
k.air +030220981 rel. 1.2 - 01.12.2020
9.6 Temperature control
As described under “types of control”, diff erent probes can be selected for temperature control, so as to best adapt to design
requirements. In addition to the main temperature control function, the supply limits are also controlled.
Depending on the selected probe, specifi c control functions will be activated:
C ontrol probes Main control S upply limit control
Supply Sequential PID, single-point control on selected probe -
Return available
Room available
Room + supply Cascaded PID on room or return probe + Sequential PID
on supply probe -
supply -
Tab. 9.i
R if D escription D ev Min Max UoM D ir Modbus BAC net
U N IT
Ac18 Regulation type (0: Supply only; 1:Return only; 2: Room only;
3: Supply; 4: Room + Supply; 5: Disabled)
5 0 5 - R/W HR1307 PIV2815
Ac40 Free cooling PID parameters - Proportional gain 8.0 0.0 999.9 - R/W HR1325 AV2833
Free cooling PID parameters - Integral time 120 0 999 - R/W HR1326 PIV2834
Ac42 Free heating PID parameters - Proportional gain 8.0 0.0 999.9 - R/W HR1327 AV2835
Free heating PID parameters - Integral time 120 0 999 - R/W HR1328 PIV2836
Tab. 9.j
Temperature control on supply, return or room probe
Sequential PID control is used, which progressively activates all of the actuators available on the unit as set in the confi guration
menu.
For correct operation of this function, the following need to be set:
• The PID parameters relating to each individual actuator, considering the type of probe selected; the supply probe will have
fast response times compared to return and room control
• Supply, return or room set point
• With return or room control, evaluate enabling supply limit control.
Room temperature c supply or supply
Two control functions are available. A fi rst cascade control function, controlling the room or return temperature, will calculate
the supply set point, which will be used by the sequential PID to precisely control the supply probe value. This function controls
the return or room temperature by modulating the unit’s heating or cooling capacity via supply control with a fi xed set point.
For correct operation of this function, the following need to be set:
• The PID parameters relating to each individual actuator, used for the sequence managed by the sequential PID
• The PID parameters relating to cascade control, used to calculate the supply set point
• The minimum and maximum supply limits, used as the control range for calculating the supply set point
• Room or return set point
100%
R2
R1
Room_T
Maximum offset %
Offset 1
Offset 2
Offset max
Minimum
Supply
set point
Room
set point
Supply S
e
t
point 2
Supply S
e
t
point 1
30220980_180_R01
time
Key
Minimum supply setpoint Minimum supply set point
Supply setpoint 1/2 Supply set point 1/2
RoomRet_T Room or return temperature
RoomRet_Set Room or return set point
Time Time
Fig. 9.p