CTDT2 DATASHEET

CTDT2
CTDT2
CO
2
and temperature transmitter for duct
mounting
Transmitter for measuring carbon dioxide concentration
and temperature in air. Measuring range 0...2000
ppm and CO
2
output signal 0...10 V DC or 4...20 mA
(settable). Passive PT1000 output and 0...10 V DC for
temperature.
CTDT2 has a probe in the shape of a so-called venturi
tube with two air channels. The CO
2
sensor element
is mounted in the cover part of the casing and the
temperature sensor element is located inside the probe.
The air in the ventilation duct is transported to the CO
2
sensor element through one half of the probe and then
back to the duct through the other half. The temperature
sensor is located inside the probe.
Mounting
To ensure proper function, make sure that the cover is
properly fastened and that the cable gland makes a tight
seal around the cable.
Place the transmitter in the air flow direction of the
ventilation duct according to the marks on the cover.
The air flow direction is either from right to left (as in the
example above) or from left to right.
Applications
The carbon dioxide level gives a direct indication of
the indoor air quality. This information can be used to
control ventilation with high precision and improve the
air quality. By increasing the air exchange only when it is
necessary, it is possible to minimise energy costs.
CTDT2 can for example be used to control ventilation in
residential and office areas.
Measuring principle
The CO
2
concentration is measured using infrared light.
This technique has many advantages:
• Very high accuracy
• Exact identification of the detected gas
• Low risk of contamination
• Short response time
• Excellent long-term stability
Automatic calibration
CTDT2 has automatic CO
2
calibration, which means that
manual recalibration is not required during the lifetime of
the transmitter.
Supply voltage and output signal
The supply voltage is 24 V AC or 15...35 V DC and the
output signal is 0….10 V DC.
Settable CO
2
output signal
Flipping an internal DIP-switch inside CTDT2 will
change the CO
2
output signal from 0...10 V to 4...20 mA.
This change will not affect the CO
2
output range.
revision
01 2016
Air ow direction
Sensor element,
temperature
Sensor element,
CO
2
Short facts about CTDT2
• Combined CO
2
and temperature transmitter
• Infrared technology (NDIR)
• CO
2
concentration 0...2000 ppm measuring
range
• Excellent long-term stability
• Easy installation and service-friendly housing
• Probe only 12 mm
• Automatic CO
2
calibration