Dwyer CDW User Manual

Bulletin E-CDW

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C

L

SENSOR

7PIN
CONNECTOR

THERMISTOR

INTERFACE
CONNECTOR

MOUNTING
HOLES

MOUNTING
HOLES

SLOTFOR
WIRING

LED

Series CDW Wall Mount Carbon Dioxide/Temperature Transmitter

Specifications - Installation and Operating Instructions

The Series CDW Wall Mount Carbon Dioxide/Temperature
Transmitter combines accurate CO

2

measurements with a
passive temperature output. The Non-Dispersive Infrared
(NDIR) sensor continuously updates the calibration through a
proprietary logic feature which limits the amount of error due to
drift. The CDW series is ideal for building automation systems
to help control the fresh air intake in a room.

INSTALLATION
Warning: 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.

Caution: Use electrostatic discharge precautions (e.g. use of
wrist straps) during installation and wiring to prevent equipment
damage.

Do not exceed the ratings of this device, permanent damage not
covered by warranty may result.

MOUNTING

1. Press the release button on the bottom of the unit in order to

remove the cover as shown in Figure A.

2. Use the appropriate mounting holes and screws to secure the

base unit to the mounting surface.

3. Slide the wires through the wiring slot and make proper wiring

connections per the wiring diagram in Figure B.

SPECIFICATIONS
Range: 0 to 2000 PPM CO

2

.

Accuracy: ±100 PPM @ 22C.
Temperature Dependence: 0.2% FS per C Stability < 2% of

FS mover life of sensor.

Non-linearity: < 1% of FS.
Pressure Dependence: 0.13% of reading per mm of Hg.
Response Time: 3 to 5 minutes for 90% step change.
Ambient Operating Temperature: 32 to 122°F (0 to 50°C).
Storage Temperature: -4 to 158°F (-20 to 70°C).
Power Requirements: 18 - 30 VAC RMS 50/60 Hz, 18 to 42

VDC polarity protected.

Power Consumption: 1.75 VA average 3.25 VA peak.
Sensor: Non-Dispersive Infrared Sensor.
Output: 0 to 10 VDC for CO

2

; 20K Ohm NTC Thermistor for

temperature.

Weight: 0.5 lb (227 g).
Agency Approval: CE.

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

Figure A

Phone: [phone] www.dwyer-inst.com

WIRING

Use Maximum 18 AWG wire for wiring terminals. Refer to Figure
B for wiring information.

Pin Assignments

1 - Ground

2

2 - CO

Output (0 to 10 VDC)

3 - 24 Volt Input

- Thermistor Output

4
5 - Not Used
6 - Not Used
7 - Not Used

CALIBRATION

The Series CDW is factory set with the proprietary logic
function activated. The logic function allows the sensor to
continuously re-calibrate itself when the indoor concentrations
drop to levels similar to outside air conditions when the building
is unoccupied. The building must be unoccupied for a minimum
of 4 hours or more for this self-calibration to be effective. The
logic allows the sensor to maintain its calibration over the life

f the sensor. If a building is occupied 24 hours a day or there

o
is significant sources of CO

2

while the building is unoccupied,
the transmitter should be ordered with the logic function turned
off.

Drawing of 7 pin terminal block wired to a power supply and
receiver.

7

6

5

4

3

2

1

Figure B Wiring Terminal Layout

LED Indicators (LED Version Only)

The LED on the front of the transmitter is a 3 color LED. The
three colors represent three different PPM levels. Below is a
description of the PPM Levels for each color.

MAINTENANCE

Upon final installation of the Series CDW Wall Mount Carbon
Dioxide/Temperature Transmitter, no routine maintenance is
required. A periodic check of system calibration is
recommended. The Series CDW is not field serviceable and
should be returned if repair is needed (field repair should not be
attempted and may void warranty). Be sure to include a brief
description of the problem plus any relevant application notes.
Contact customer service to receive a return goods
authorization number before shipping.

Colors and the PPM levels represent:
Green- CO

2

levels are less than 1000 ppm, indicating CO

2

concentration is within acceptable limits.

Yellow- CO
hysteresis. As CO

2

levels between 1000 and 1500 ppm, with 100 ppm

2

levels decrease to within limits, the yellow
light will remain on until 100 ppm past the threshold, and turn
back to green at 900 ppm.

Red- CO

2

levels are above 1500 ppm, indicating CO

2

concentration is beyond acceptable limits. As CO2levels
decrease to within limits, the red light will remain on until 100
ppm past the threshold, and turn back to yellow at 1400 ppm.

©Copyright 2013 Dwyer Instruments, Inc. Printed in U.S.A. 5/13 FR# R6-443600-00 Rev. 1

DWYER INSTRUMENTS, INC.

Phone: [phone] www.dwyer-inst.com

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]