Dwyer CDSN Carbon Dioxide Transmitter Instruction Manual
- June 3, 2024
- Dwyer
Table of Contents
Dwyer CDSN Carbon Dioxide Transmitter Instruction Manual
The Model CDSN Carbon Dioxide Transmitter accurately monitors the CO2 concentration and temperature in schools, office buildings, and other indoor environments to help achieve LEED® certification and energy savings. In order to achieve a higher level of accuracy, the Model CDSN includes digital barometric pressure adjustment. The CO2 universal output allows users to select the transmitter output to be 4-20 mA, 0-5 VDC, or 0-10 VDC to work with virtually any building management controller. In addition, the housing security feature reduces the likelihood of physical tampering.
BENEFITS/FEATURES
- Minimize inventory and save time by combining CO2 and temperature measurement, as well as DIP switch selectable current/voltage outputs
- Integral passive temperature reduce number of devices mounted in the space
- Requires minimal maintenance with Automatic Baseline Correction (ABC) to account for sensor drift
- Reduce operation costs using a low energy, reliable, and repeatable CO2 sensor
- Simplify installation with backplate electrical connections
APPLICATIONS
- Demand control ventilation in schools
- Indoor air quality monitoring in office buildings
INSTALLATION
Disconnect power supply before installation to prevent electrical shock and equipment damage.
Make sure all connections are in accordance with the job wiring diagram and in accordance with national and local electrical codes. Use copper conductors only.
Use electrostatic discharge precautions (e.g., use of wrist straps) during installation and wiring to prevent equipment damage.
Avoid locations where severe shock or vibration, excessive moisture or corrosive fumes are present.
Do not exceed ratings of this device. Exceeding the listed ratings may result in permanent damage not covered by warranty.
Upon powering the transmitter, the firmware version will flash on the display. A warm-up period of 30 minutes is required for the transmitter to adjust to the current CO2 concentration.
Self-calibration feature requires exposure to normal, outdoor equivalent carbon dioxide level once every 30 days.
Figure 1: Removal of cover from backplate
MOUNTING
- Select the mounting location, away from diffusers, lights, radiators, windows, or other external influences.
- Push the tabs on the top and bottom of the backplate then pull the cover from the backplate (see Figure 1).
- Mount transmitter on a vertical surface or a standard electrical box using the two #6 M2C type screws provided.
- Pull wires through the oval hole in the backplate and make necessary connections. See Figure 2 for wiring diagram.
- (Optional) If a temperature measurement is desired, connect wires to the appropriate terminal, see Figure 2. See Resistance Table on page 3.
- Reinstall cover to backplate.
- Take extreme caution not to touch the sensor when handling the device. This can cause the sensor’s calibration to shift.
WIRING
Use maximum 18 AWG wire for wiring to terminals. Refer to Figure 2 for wiring information.
Included passive sensor:
Sensor A – 10K Ω type 3 NTC thermistor
Sensor B – 10K Ω type 2 NTC thermistor
Sensor F – 20K Ω NTC thermistor
Figure 2: Active output wiring diagram
DIP SWITCH SETTINGS
To access the DIP switch panel, remove the cover of the unit as shown in Figure 1. The panel is located on the back of the circuit board as shown in Figure 3.
Figure 3: DIP switch location
The factory default output for the transmitter is 0-10 V. See the output range table to configure the desired output.
Figure 4: DIP switches
DIP Switch Positions: Output Range Selection
ON: Up position
OFF: Down position
Current/Voltage Outputs
The CDSN can be configured to provide CO2 readings via current or voltage output by adjusting the DIP switches.
AUTOMATED CO2 BASELINE CORRECTION (ABC)
The CDSN transmitter is a maintenance-free instrument that automatically adjusts its calibrated zero point in spaces that are intermittently occupied, such as office buildings. The Automated Baseline Correction (ABC) feature accounts for long-term sensor drift by making small adjustments to the zero calibration point based on the lowest captured CO2 readings.
RESISTANCE VS TEMPERATURE TABLE
MAINTENANCE/REPAIR
After the transmitter is installed, no routine maintenance is required. The Model CDSN is not field serviceable or field repairable. Field repair should not be attempted and may void warranty.
WARRANTY/RETURN
Refer to “Terms and Conditions of Sale” in our catalog and on our website. Contact customer service to receive a Return Materials Authorization (RMA) number before shipping the product back for repair. Be sure to include a brief description of the problem plus any additional application notes.
NOTES
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: 219-879-8000
Fax: 219-872-9057
www.dwyer-inst.com
e-mail: info@dwyermail.com
References
Read User Manual Online (PDF format)
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