8
E 136 - XTA 624 C1 Eng.
22.11.10 AM
REV. 02
We reserve the right to make changes without notice
COSTER
14. OPERATION
XTA 624 is a microprocessor-operated digital controller for temperature control in air handling units
composed of: 2 units with 3-wire or 1, 2 or 3-stage On-Off modulating control.
The units can have the following functions: Preheating; Heating; Cooling.
To adjust the controller to system requirements, proceed as follows:
– configure system according to connected detectors and controls
– assign control outputs Y1, Y2 and Y3 the action they are to perform also according to season
switching, if applicable.
15. TEMPERATURE CONTROL
Temperature control can operate either with:
• Room or extract air detector B3 only:
Fixed point room Heating and Cooling temperature control, or:
• Discharge air detector B1 only:
Fixed point flow Heating and Cooling temperature control, or:
• Room or extract air detector B3 and discharge air detector B1:
Flow Heating and Cooling temperature control according to room temperature deviation
15.
1
Desired temperatures
Desired temperatures for heating and cooling
Can be set in
and
if B3 or B1 and B3 are connected
or in
and
if only B1 is connected
If the set point adjuster Rt° is connected, these values can be changed remotely. The value of the
change expressed in ± °C is displayed next to the set values.
15.
2
Proportional band and Integral Time
Basic temperature control parameters,
Proportional Band
and
Integral Time
, refer to
heating
control (Room: if B3 only or B1 + B3 are connected, or Flow: if B1 only is connected) and can be
changed through the ADJUSTMENT menu.
The Proportional Band parameter (in ± °C) is used for other temperature settings through modifiable
multipliers that adapt it to the different types of controls (Cooling; Preheating; Air Damper).
Examples of PB multipliers with
Pb Flow (heating) = Pb Room (heating) x
5.0
(= ±10 °C)
Pb Cooling (room) = Pb heating (room) x
0.5
(= ±1 °C)
Pb Cooling (flow) = Pb room heating x
0.5
(= ±5 °C)
Pb Preheating = Pb flow heating x
1.0
(= ±10 °C)
Pb Air damper= Pb room heating x
1.0
(= ±2 °C)
dT recuperator = Pb room heatingx
1.0
(= 2 °C)
When detectors
B1
and
B3
are connected, the flow temperature (B1) Integral Time parameter is
displayed on a display page to allow for changes to be made separately from the room temperature
parameter.
T e m p e r . R o o m
P r o p . B a n d : 2 . 0 c
M2.
1
D e t e c t o r s L a y o u t
– – – – –
M3.
1
D e t e c t o r s L a y o u t
– – 3 – – –
M3.
1
D e t e c t o r s L a y o u t
1 – – – – –
D e t e c t o r s L a y o u t
1 – 3 – – –
H e a t . T . R o o m
D e s i r . : 2 0 . 0 c ± 0 . 0
M0.
3
H e a t . T . F l o w
D e s i r . : 2 0 . 0 c ± 0 . 0
C o o l . T . R o o m
D e s i r . : 2 5 . 0 c ± 0 . 0
M0.
5
H e a t . T . F l o w
D e s i r . : 2 5 . 0 c ± 0 . 0
D e t e c t o r s L a y o u t
– – – – 5
M3.
1
T e m p e r . R o o m
P r o p . B a n d : ± 2 . 0 c
M2.
1
T e m p e r . R o o m
I n t e g r . T i m e : 1 0 m
M2.
2
P b C o o l i n g =
P b H e a t i n g x 0 . 5
M3.
15
P b F l o w =
P b R o o m x 5 . 0
M3.
14
P b P r e h e a t i n g =
P b H e a t F l o w x 1 . 0
M3.
16
Y .. : H E A T I N G
M3.
4.6
Y .. - W i n : H E A T I N G
Y .. - S u m : C O O L I N G
F l o w T e m p e r a t u r e
I n t e g r . T i m e : 1 0 m
M2.
3
P b D a m p e r s =
P b H e a t R o o m x 1 . 0
M3.
17
d t R e c u p e r a t o r =
P b H e a t R o o m x 1 . 0
