AQS51/61-KAM COMBINED CO
2
-/TEMPERATURE DUCT SENSOR/CONTROLLER
EN0B-1023 GE02R0500
4
OPERATION
General
Each of these devices can be used as transmitter for
measurement of CO
2
concentration and temperature or as a
very flexible controller for proportional and integral control of
mixed air dampers or variable speed controlled fans in stand
alone applications.
The relay output can be used for CO
2
limit monitoring or
plant/system ON/OFF control.
If used as a transmitter, it converts the actual measured
values of the CO
2
concentration and temperature into
standard output signals 0(2) to 10 Vdc or 0(4)...20 mA
depending on the adjusted measurement ranges.
Directly connected to the analog inputs of Honeywell DDC
systems it allows the required flexibility for a wide range of
applications and the use of different demand controlled
ventilation strategies to match exactly the requirements of the
control system.
If used as a controller the actual measured values are
compared with the programmed setpoints. Depending on the
deviation the control output values are calculated and
converted into two separate 0(2)...10Vdc or 0(4)...20mA
outputs which can drive directly final control devices. The
proportional band settings control the output spans.
In this application the AQS-USP22 software package can be
used to configure the available two analog outputs for
temperature and ventilation control, and to assign for each
output a number of functions to provide different ventilation
control strategies.
All sensor measurements can be addressed to these
functions and mixed together by this software to form two
independent and intelligent P+I controllers.
The relay output contact CM-NO is closed, if the CO
2
level
exceeds the factory adjusted limit of 1000ppm and the
contact CM-NC is closed, if the CO
2
level is equal or below
900ppm. These parameters are programmable within the
specified measurement range.
APPLICATION ADVICE
For rooms where are the occupants the source of the main
air pollution, a CO
2
concentration of max. 1200ppm should
not be exceeded.
MOUNTING
The AQS51-KAM and AQS61-KAM sensor/controllers are
supplied with the sensor printed circuit board already
mounted into the aspiration box.
Mount the unit in the return or outside air duct in a position
far away from external heat sources and where it is easy
accessible for service and maintenance purposes.
Since there might be a substantial pressure difference
between the duct and ambient air, it is indispensable that the
sealings of the cable entry bushings, the cable feed through,
the box cover and the duct entrance are absolutely tight to
avoid ambient air from suction into the aspiration box. The
duct entrance may need additional sealing paste in order to
prevent leakage.
Fig. 2 Parts list and mounting of the aspiration box to the sampling probe
1
8
4
3
2
9
6
7
10
5
Open
Closed
1 Sampling probe
6 O-ring
2 Sealing gasket
7 PG9 cable entry bushing
3 Duct flow direction label
8 PG7 cable entry bushing
4 2 washers BRB 5.3x10x1
9 PCB (factory supplied mounted in the box)
5 2 screws RXS 4.8x16
10 Snap-in lid
