Carel Clima User Manual

25
ENG
clima +030220641 - rel. 1.0 - 07.12.2007
Control calculation:
Based on the proportional error (Temperature measured – set 1.
point) and the integral error, the clima automatically calculates
the water outlet set point. The calculation uses the parameters
corresponding to the active operating mode (cooling or
heating) active: tHH, tHL, tAH, tAL, where dIF = tAH–tAL.
The integral error is only calculated within the control interval,
tAH–tAL according to parameter tIn (integration time).
The  gure shows an example where when the room temperature =
room set point and the total error is null, the water outlet set point is
34 °C (for radiant  oors).
The ON/OFF output (R1) is activated when the room temperature
2.
is less than the maximum limit tAH. This output sends the signal to
activate the system controller.
The water outlet temperature is controlled based on the set 3.
point calculated (in point 1) and with a  xed di erential of 4 °C.
The control functions use the remote sensor, installed on the outlet
manifold:
If the water temperature is greater than or equal to the set point
•
calculated, the valve is closed.
If the water temperature is less than (set point – 4 °) the valve is •
completely open.
In intermediate situations the valve is open proportionally to the •
deviation from the set point calculated.
To avoid excessive  oor temperatures, the maximum water 4.
temperature is compensated, which may be lower than the
maximum value set for tHH. This occurs when the system responds,
during heating, with excessively fast variations of the room
temperature. In the  gure this operation is indicated by the dashed
line, the line at the bottom, for example, de nes a water set point
of around 29 °C rather than 34 °C for the same room temperature.
The calculation of the maximum value for tHH is based on parameter
tr, which de nes an observation time in minutes on the value of the
integral error:
If within the time tr control is active (valve open) and there is an •
increase in temperature greater than 0.5 °C => tHH is decreased
by 1 °C.
If, always in the observation period (tr), the variation was less than •
0.5 °C but the integral error is positive (>20% of dIF) => tHH is again
decreased by 1 °C.
If, on the other hand, the variation is less than 0.5 °C but the integral •
error is negative (>20% of dIF) => tHH is increased by 1 °C.
Recommended value of tr = 30 min., yet this depends on the inertia •
of the system and the integral error set (tIn).
Note: the value of tHH is not modi ed as a parameter, rather an
o set is added or subtracted.
The purpose of the maximum set point compensation for the water
temperature is to make the system work with the lowest possible  oor
temperature.
In operating conditions outside of the room temperature limits, tAH or
tAL, the initial conditions are restored for tHH.
Note: When the temperature is read on the SMALL  eld,
the H2O symbol is shown to indicate that this is the system water
temperature.
Note: Parameter LE=1 or 2 has no in uence on the settings of the
parameters.
Cooling control logic
4 °C
Temp. acqua
Output
Set point calcolato
Fig. 5.r
Fig. 5.s
The same rules apply as for heating control, with the following
di erences:
The values of the parameters are di erent for cooling, in particular tHH •
and tHL;
The control of the modulating valve is reversed with reference to the •
water temperature set point: if the temperature is greater than the set
point, the valve is open.
The compensation of the temperature limit is activated using tHL •
rather than tHH, and the logic is reversed: tHL is increased rather than
decreased.
There is also another limit on the water temperature set point: based •
on the estimated dewpoint, the set point is limited to values greater
than Temp_dew + ddP (dewpoint di . parameter).
Note: the value of tHL is not modi ed as a parameter, rather an
o set is added or subtracted.
The purpose of the minimum set point compensation for the water
temperature is to make the system work with the lowest possible  oor
temperature, so as to maximise cooling.
In operating conditions outside of the temperature limits greater than
tAH or less than tAL, the initial conditions are restored for tHL.
Humidity control for proportional radiant operation:
Code ADCF000610 also uses the humidity sensor, for two functions:
In cooling mode, it is used for the estimate the dewpoint.
•
It can also be used for ambient humidity control, via relay 2, connecting •
an external humidi er/dehumidi er.

Carel Clima Specifications

General

Brand	Carel
Model	Clima
Category	Thermostat
Language	English