IRSC Zone
http://www.zennio.com
Technical Support:
http://zennioenglish.zendesk.com
25
THERMOSTATIC CONTROL FOR COOLING
The thermostatic control for cooling, whose parameterization determines how IRSC
Zone does its calculation when the zone is ON and the selected working mode is Auto,
Cool, Fan or Dry, permits two algorithms for controlling the temperature (as the
thermostatic control for heating also does): 2-Point Hysteresis control and PI (PWM
modulation).
The first one (2-point hysteresis control) determines whether to open (“Zone x – Grille
control” = 1) or to close (“Zone x – Grille control” = 0) the grille, according to the
diagram shown in Figure 13.
Regarding the second method (PI control), it consists in the continuous execution of
the “PI control” mathematic algorithm, which permanently determines, depending on
how the setpoint and the reference temperatures of the zone differ, the proper opening
level for the grille valve. Considering that not every grille permits partial opening, this
percentage is then interpreted as the ratio between the time the grille will stay open
and the time it will stay closed, given the parameterised cycle time.
Figure 13.
Grille behaviour during the "2 point hysteresis" thermostatic control for cooling
T
REF
> T
SETPOINT
+ H
Upper
Yes
(“it is hot”)
No
(“it is cold”)
Grille is open?
Grille is closed?
Do nothing
Yes
Yes
No
Open grille
No
Close grille
