Application manual
KNX room temperature controller EK-EQ2-TP
Release 3.00 - Updating: 27/06/2017
Application Manual
© SBS S.p.A. - All rights reserved
Page 90
9.1.1.6
2 points control with hysteresis for auxiliary stage
The systems for heating and cooling have different values of inertia depending on the type of transfer of
thermal energy. To shorten the time necessary to reach the comfort conditions, a low inertia heating / cooling
system may be used, supporting the main system when in the starting phase the difference between the
setpoint temperature (T
set
) and the measured temperature (T
room
) is accentuated.
The system, defined as second stage or auxiliary stage, contributes in the early phase to heat up / cool down
the room, then stops its action when the difference between T
set
and T
room
can be addressed satisfactorily by
the main system only. The auxiliary stage is operated generally by a 2 points control algorithm with
hysteresis.
Heating conduction mode
When the measured temperature (T
room
) is lower than the value (T
set
− ΔT
Offset
− ΔT
hysteresis
), where ΔT
hysteresis
identifies the differential heating control, the device activates the auxiliary heating stage by sending a
corresponding telegram to the dedicated actuator; when the measured temperature reaches the value (T
set
−
ΔT
Offset
) the device disables the auxiliary heating system by sending a corresponding telegram to the
actuator.
Cooling conduction mode
When the measured temperature (T
room
) is higher than the value (T
set
+ ΔT
Offset
+ ΔT
hysteresis
), where ΔT
hysteresis
identifies the differential cooling control, the device activates the auxiliary cooling stage by sending a
corresponding telegram to the dedicated actuator; when the measured temperature reaches the value (T
set
+
ΔT
Offset
) the device disables the auxiliary cooling system by sending a corresponding telegram to the
actuator.
9.1.1.7
Auxiliary stage with fan-coil
An interesting system solution combines an underfloor radiant panel, a high inertia system acting on the
masses of the structure, with an auxiliary fan-coil stage that acts instead on the air volumes: the room
temperature controller EK-EP2-TP and EK-EF2-TP can be easily configured for this type of application.
T room
OFF
ON
Tset
Thysteresis
T room
OFF
ON
Tset
Thysteresis
TOffset
TOffset
Main heating system
(high inertia)
Auxiliary stage
(low inertia)
Supplied
heating power
[W]
t
