CDD4 Duct Carbon Dioxide Transmitter
Installation Manual
May 27, 2013
3
Start-up
Verify the device is properly wired and connections are
tight. Ensure the V/I switch is set for the correct signal
type. Apply power and the LCD will indicate the software
version number, the output signal type, the relay setpoint
(if installed), the CO2 measurement range and then the
sensor will begin reading the CO2 level, output the correct
analog signal and display the value on the LCD.
Output
The CO2 output is scaled such that 4-20 mA (or 0-5/0-10
Vdc) equals 0 to Out_High. Depending on the model, the
factory default is either 0-2000 ppm or 0-20,000 ppm.
Out_High can be changed in the Setup Menu and the
output is scaled accordingly. If using voltage output type,
the default is 0-5 Vdc (0-10 can be selected in the menu).
Operation
The output signal is available on the
CO2
terminal and is
connected to the BAS analog input which reads the signal
and calculates the CO2 ppm value using correct scaling for
the range and signal type. This CO2 value is used to
control output ventilation devices or initiate alarms. The
CO2 value is also displayed locally on the optional LCD.
If a relay is installed it can control a small fan or alarm by
setting the trip value and hysteresis to appropriate values.
If a temperature sensor is installed it will be wired to an
analog input of the BAS that is set for the specific
resistance type. This could be a 10 K
thermistor, a 1000
ohm RTD or other sensor values. The BAS reads the
resistance signal and converts it to a temperature value.
Calibration
Calibration with gas requires a field calibration kit with
pressure regulator, necessary tubing and appropriate
bottles of CO2 gas. Note that the procedure depends on the
device model. The standard model requires only a single
point 1000 ppm calibration to meet specified accuracy due
to the Automatic Calibration mode and other technology
incorporated into the CDD4A model.
The CDD4B dual-channel sensor with extended range
requires a 3-point calibration with 0, 1000 and 20,000 ppm
gas (in order).
0 PPM Calibration (For the CDD4B model only)
Turn the regulator knob off and attach it to the Nitrogen
gas bottle and hand tighten. Remove the cover of the unit
to be calibrated to expose the gas sensor chamber. The
tubing from the gas bottle can be connected to either port
on the chamber after the plastic cap is removed. Gently
remove one cap and connect the tubing, note that strong
shock or vibration can affect calibration.
Ensure the device has been operating normally for at least
five minutes before applying gas. Turn the valve knob on
the regulator to start the gas flow. The regulator will
restrict the flow rate to the specified 100 ml/min. After a
brief period the gas will flow into the chamber. Wait 1 to 2
minutes until the CO2 stabilizes.
Enter the Setup menu and use the <MENU> key to
advance to
Calibrat 0 PPM
. Press and hold the <SAVE>
key for 2 seconds and the display will change to
Waiting
Calibrat
then to
Waiting 5 minute
to indicate that the
process of setting the internal calibration is taking place.
This takes about 5 minutes while the LCD counts down.
Do not disturb the unit or the gas flow. When complete the
unit will display the ppm value and
Cal Done
.
Press
<SAVE> to resume normal operation and shut the gas off.
1000 PPM Calibration (For all CDD models)
Connect the 1000 ppm CO2 gas bottle and apply the gas as
before. The CO2 reading on the LCD will begin to
approach 1000 ppm. Wait 1 to 2 minutes until the CO2
reading stabilizes.
Enter the Setup menu and use the <MENU> key to
advance to
Calibrat 1000 PPM
. Press and hold the
<SAVE> key for 2 seconds and the display will change to
Waiting Calibrat
then to
Waiting 5 minute
to indicate
that the device is calibrating. Again, this process takes
about 5 minutes. When calibration is complete the unit will
display the ppm value and
Cal Done
.
Press the <SAVE>
key to return to normal operation and shut the gas off.
20,000 PPM Calibration (For the CDD4B model only)
Connect the 20,000 ppm CO2 and apply the gas as before.
The LCD will begin to approach 20,000 ppm. Wait 1 to 2
minutes until the CO2 reading stabilizes.
Enter the Setup menu and use the <MENU> key to
advance to
Calibrat 20,000 PPM
. Press and hold the
<SAVE> key for 2 seconds and the display will change to
Waiting Calibrat
then to
Waiting 5 minute
.
Again, wait 5 minute and when calibration is complete the
unit will display the ppm value and
Cal Done
.
Press
<SAVE> to resume normal operation and shut the gas off.
Disconnect the tubing and replace the cap on the sensor
chamber as calibration is complete.
DISC
ONTINUED
