Dwyer Instruments CDT-2W44-LCD, CDTR-2W4A4-LCD Installation And Operating Instructions Manual

Series CDT and CDTR Wall Mount Carbon Dioxide/

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®

Temperature Transmitter

Specications - Installation and Operating Instructions

Bulletin AQ-CDT/CDTR-W

Series CDT and CDTR Wall Mount Carbon Dioxide Temperature Transmitters
accurately monitor the CO
and other indoor environments to help achieve LEED

Series CDTR also measures ambient relative humidity. For increased sensor life,
a single- beam dual-wavelength non-dispersive infrared (NDIR) sensor is used to
automatically correct the measurement in both occupied and unoccupied buildings
against aging effects. The single-beam dual-wavelength sensor technology provides
the highest level of accuracy compared to Automatic Baseline Correction methods,
which can unintentionally shift the calibration based on CO
pressure conditions. In order to achieve a higher level of accuracy, the Series CDT
includes digital barometric pressure adjustment and the ability to eld-calibrate the
sensor.

Universal outputs allow users to select the transmitter output to be 4 to 20 mA, 0 to
5 VDC, or 0 to 10 VDC to work with virtually any building management controller. An
optional relay with user adjustable set points can be used to control exhaust fans, open
actuated windows or dampers, or signal a light or horn.

For applications that require visual indication, the Series CDT and CDTR can be ordered
with an integral LCD display or the Model A-449 remote LCD display that can plug into
the mini-connector port on the side of the transmitter. Both the CDT and CDTR can be
congured to display temperature only, CO

The CDTR can also display relative humidity or CO

Push buttons are standard on the transmitters for access to the menu structure, but
the transmitter can be ordered without the buttons. To prevent tampering, the action of
the buttons can be locked out using an internal jumper selection. Menu items that can
be accessed include: engineering units, relay output set points, display conguration,
transmitter output scaling, ambient barometric pressure and eld calibration of the
transmitter.

2 concentration and temperature in schools, ofce buildings,

2 only, or CO2 and temperature together.

®

certication. Additionally, the

2 levels and barometric

2 and relative humidity together.

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SPECIFICATIONS
Range: CO

units congured with humidity output); Temperature: 32 to 122°F (0 to 50°C);
Accuracy: ±40 ppm +3% of reading; RH: ±2% (for units congured with humidity
output); Temperature: ±1°C @ 25°C.

Temperature Dependence: ±8 ppm / °C at 1100 ppm.
Non-Linearity: 16 ppm.
Pressure Dependence: 0.13% of reading per mm of Hg.
Response Time: 2 minutes for 99% step change.
Temperature Limits: 32 to 122°F (0 to 50°C).
Humidity Limits: 10 to 95% RH (non-condensing).
Power Requirements: 16 to 35 VDC / 19 to 28 VAC.
Power Consumption: Average: 2 watts; Peak: 3.75 watts.
Sensor: Single-beam, dual-wavelength NDIR.
Output: Current: 4 to 20 mA (max 500 Ω); Voltage: 0 to 5 VDC or 0 to 10 VDC

(min 500 Ω); Relay: SPST NO 2A @ 30 VDC; RTD or thermistor per r-t curves
(depending on model).

Weight: 5.6 oz (158.8 g).

INSTALLATION

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.

2: 0 to 2000 or 0 to 5000 ppm (depending on model); RH: 0 to 100% (for

WARNING

CAUTION

1-13/32

Disconnect power supply before installation to prevent electrical
shock and equipment damage.

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

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Single-beam dual-wavelength sensor advantages:

• Automatically corrects for aging effects in occupied and unoccupied buildings
◦ Perfect for hospitals and manufacturing plants that are occupied 24 hours per day

• Measures actual unltered light intensity directly
◦ Eliminates error from incorrect assumptions of gas concentration in theoretical
logic assumption methods

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.

CAUTION

CAUTION

NOTICE

transmitter to adjust to the current CO

NOTICE

days.

Avoid locations where severe shock or vibration, excessive
moisture or corrosive fumes are present.

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

Upon powering the transmitter, the rmware version will ash on
the display. A warm up period of 30 minutes is required for the

Self calibration feature of the transmitter requires exposure to
normal outdoor equivalent carbon dioxide level once every thirty

LEED® is a registered trademark of the U.S. Green Building Council

Phone: [phone]

Fax: [phone]

2 concentration.

www.dwyer-inst.com

e-mail: [e-mail]

TURE

POWER

TEMP OR RH

HINGE

COVER

TO REMOVE COVER

PJ2

PJ5

CURRENT

VOLTAGE

CCVV

4 to 20 mA

0 to 20 mA

0 to 10 mA

2 to 10 mA

APPLY PRESSURE TO
BOTTOM TAB WHERE
INDICATED AND THE
TWO PARTS WILL
BECOME UNHINGED
AT TOP

REVERSE PROCESS
TO APPLY COVER

BOTTOM TAB

Figure 1: Removal Of Cover From Back Plate

MOUNTING

1. Push tab on bottom of cover and lift cover from back plate (See Figure 1).

2. Select the mounting location, away from diffusers, lights or any external inuences.

3. Mount transmitter on a vertical surface to a standard electrical box using the two
#6 M2C type screws provided.

4. Pull wires through sub base hole and make necessary connections.

5. Reattach cover to base plate.

WIRING

Use maximum 18 AWG wire for wiring to terminals. Refer to Figure 5 for wiring
information.

PJ4

MOUNTING

SCREWS

SELF-LATCHING

PJ1

MOUNTING
BACK PLATE

Current / Voltage Outputs
On the CDT, the transmitter may be wired for current or voltage output for both carbon
dioxide and temperature. On the CDTR, the transmitter may be wired for current or
voltage output for both carbon dioxide and humidity. The transmitter can be powered
with either 16 to 35 VDC or 19 to 28 VAC. Wire the transmitter according to Figure 5.

NOTICE

Remote Display

For models that are ordered without an integral LCD display, remote display Model
A-449 can be used to display the temperature, humidity, and carbon dioxide. The mini
USB plug of the remote display plugs into the receptor on the side of the housing.
After a short warm up time, the display will begin to show the current temperature and
carbon dioxide measurements unless congured by the user to show humidity and
carbon dioxide, only temperature, only humidity, or only carbon dioxide.

EDITING MENU PARAMETERS

Optional relay can be used as either a dry contact or low voltage
switched circuit up to 2 A at 30 VDC.

SUPPLY

Figure 5: Active Output Wiring Diagram

RECEIVER

CO2

RECEIVER

RELAY
CONTACT

PASSIVE
TEMPERA
SENSOR

Figure 2: Diagram Of Circuit Board

Selection of Current and Voltage Outputs

Prior to wiring, verify that the current/voltage selection jumpers (PJ1, PJ2, and PJ5)
are set to the desired output type. Refer to Figure 2 to locate the selection jumpers.
See Figure 3 for diagram of the current/voltage selection jumper. For voltage output
selection, the output can be 0 to 10 VDC, 0 to 5 VDC, 2 to 10 VDC or 1 to 5 VDC. See
Figure 4 for the type of voltage output selection jumper (PJ5).

OUTPUT

0 to 5 V

2 to10 V

OUTPUT

Figure 3: Current/Voltage Output

Selection Jumper (PJ1 and PJ2)

0 to 10 V

Figure 4: Output Range Selection Jumper (PJ5)

1 to 5 V

ENABLED

MENU MENU

PJ4

OFFON

Figure 6: Menu Lockout Jumper

Before any adjustment can be made to the transmitter, the Menu Lockout Jumper
(PJ4) must be set to the ˝On˝ position (See Figure 6).

ACCESSING MENU PARAMETERS

Step 1: To enter the menu structure, press
seconds (display will show RON parameter).

Step 2: Press

Step 3: Press
display).

Step 4: Press

Step 5: Press

Step 6: Repeat Steps 2 through 5 for each of the parameters.

Step 7: To exit the menu at any time, press and hold
for 5 seconds or wait 10 seconds without pushing any buttons.

or to cycle between menu items.

to edit the value for the displayed menu item (SET will appear on

or to adjust the value of the menu item.

to save the changes (SET will disappear).

DISABLED

PJ4

OFF

ON

and simultaneously for 5

and simultaneously

Menu Descriptions

Relay on set point

RON

Sets the CO

2 concentration which the optional relay is energized.

HOL

Humidity low output range (CDTR only)
Sets the temperature for the lowest output (4 mA or 0 VDC).

Low limit: 0 PPM
Factory setting: 1000 PPM
High limit: 2000/5000 PPM (depending on model)

Relay off set point

ROF

Sets the CO2 concentration which the optional relay is de-energized. Setting

value lower than RON provides direct action for detecting high concentrations

2. Setting value higher than RON provides indirect action for detecting

of CO

low concentrations of CO

2. or on the LCD display will be lit to

indicate when the relay is energized.

Low limit: 0 PPM
Factory setting: 950 PPM
High limit: 2000/5000 PPM (depending on model)

Display conguration

DSP

Determines the LCD display conguration during normal operation. The LCD

display can indicate the CO

(CDTR only) and CO

2 concentration, temperature, relative humidity

2 concentration combined with temperature or relative

humidity (CDTR only).

CH CO

CT CO
C CO

2 concentration and relative humidity (CDTR only)
2 concentration and temperature
2 concentration only

T Temperature only

H Relative humidity only (CDTR only)

Units selection

UNI

Temperature and barometric pressure measurements can be displayed in US
engineering units or SI engineering units. The factory default is to display US
engineering units.

US units °F for temperature and in Hg for barometric pressure
SI units °C for temperature and hPa for barometric pressure

COL

Sets the CO

2 concentration for the lowest output (4 mA or 0 VDC).

2 low output range

CO

Low limit: 0 PPM
Factory setting: 0 PPM
High limit: 2000/5000 PPM (depending on model)

CO

COH

2 high output range

Sets the CO

2 concentration for the highest output (20 mA, 5 VDC or 10 VDC).

When COH is set above COL, the transmitter is direct acting and the output
will increase with an increase in CO

2 level. When COH is below COL, the

transmitter is reverse acting and the output will increase with a decrease in

2 level.

CO

Low limit: 0.0%
Factory setting: 0.0%
High limit: 100.0%

HOH

Humidity high output range (CDTR only)
Sets the temperature for the highest output (20 mA, 5 VDC or 10 VDC).
When HOH is set above HOL, the transmitter is direct acting and the output
will increase with an increase in temperature. When HOH is below HOL, the
transmitter is reverse acting and the output will increase with a decrease in
temperature.

Low limit: 0.0%
Factory setting: 100.0%
High limit: 100.0%

BAR

Barometric pressure
Sets the typical barometric pressure for the location where the transmitter is
mounted. The factory setting is for standard pressure at sea level. Adjusting the
barometric pressure gives a more accurate measurement, especially at higher
elevations. Refer to the elevation charts in Figure 9 for typical barometric
pressures at a given elevation.

Low limit: 20.0 in Hg / 600 hPa
Factory setting: 29.9 in Hg / 1013 hPa
High limit: 32.0 in Hg / 1100 hPa

CAL

Calibration
Calibrates the carbon dioxide sensor to a known gas value. Read calibration
instructions before using this feature. Hold

for 5 seconds.

CALIBRATING SENSOR

Step 1: Remove the cover as shown in Figure 1.
Step 2: Slide the calibration tubing through the slots on the back plate and attach to
one of the nipples on the CO2 sensor (See Figure 7).
Step 3: Carefully re-attach the cover to the back plate without pinching the tubing
between the back plate and the cover.
Step 4: Follow the steps in the accessing parameter section to access the
calibration parameter (CAL).
Step 5: Press the

button.
Step 6: Flow zero reference gas at 0.3 SLPM for 5 minutes.
Step 7: Press and hold the

button for 3 seconds.
Step 8: Flow the full scale reference gas at 0.3 SLPM for 5 minutes.
Step 9: Press and hold the

button for 3 seconds.
Step 10: Exit the parameter menu.
Step 11: Remove cover as shown in Figure 1.
Step 12: Remove tubing from sensor and re-attach the gas nipple cover to the sensor.
Step 13: Re-attach the cover to the back plate.

Low limit: 0 PPM
Factory setting: 2000/5000 PPM (depending on model)
High limit: 2000/5000 PPM (depending on model)

Temperature low output range (CDT with active temperature only)

TOL

Sets the temperature for the lowest output (4 mA or 0 VDC).

Low limit: 32.0°F / 0.0°C
Factory setting: 32.0°F / 0.0°C
High limit: 122.0°F / 50.0°C

Temperature high output range (CDT with active temperature only)

TOH

Sets the temperature for the highest output (20 mA, 5 VDC or 10 VDC).
When TOH is set above TOL, the transmitter is direct acting and the output
will increase with an increase in temperature. When TOH is below TOL, the
transmitter is reverse acting and the output will increase with a decrease in
temperature.

Low limit: 32.0°F / 0.0°C
Factory setting: 122.0°F / 50.0°C
High limit: 122.0°F / 50.0°C

MAINTENANCE/REPAIR

CO2 SENSOR

Upon nal installation of the Series CDT and CDTR, no routine maintenance is
required. The Series CDT and CDTR are not eld serviceable and should be returned
if repair is needed. Field repair should not be attempted and may void warranty.

This symbol indicates waste electrical products should not be disposed
of with household waste. Please recycle where facilities exist. Check with
your Local Authority or retailer for recycling advice.

WARRANTY/RETURN

Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact
customer service to receive a Return Goods Authorization number before shipping the
product back for repair. Be sure to include a brief description of the problem plus any
additional application notes.

RESISTANCE VS TEMPERATURE TABLE

Figure 7: Calibration

Series CDT -2 N 4 4 -LCD Example: CDT-2W44-LCD
Range 2

Conguration W Wall
CO

2 Output 4 4 to 20 mA / 0 to (5 or 10) VDC

Temperature

Output

Options LCD

Series CDTR -2 W 4 A 4 -LCD Example: CDTR-2W4A4-LCD
Range 2

Conguration W Wall
CO

2 Output 4 4 to 20 mA / 0 to (5 or 10) VDC

Temperature

Output

RH Output 4 4 to 20 mA / 0 to (5 or 10) VDC
Options LCD

©Copyright 2019 Dwyer Instruments, Inc. Printed in U.S.A. 1/19 FR# 443800-20 Rev. 3

5

0
4
A
B

C
D
E

F

Figure 8: CDT Model Chart

5

Figure 9: CDTR Model Chart

0 to 2000 ppm CO
0 to 5000 ppm CO

None
4 to 20 mA / 0 to (5 or 10) VDC
10 KΩ NTC thermistor type III
10 KΩ NTC thermistor type II
3 KΩ NTC thermistor
Pt100 Ω RTD
Pt1000 Ω RTD
20 KΩ NTC thermistor

LCD display

RLY

Relay

NBC

No buttons

0 to 2000 ppm CO
0 to 5000 ppm CO

0
A
B

C
D
E

F

None
10 KΩ NTC thermistor type III
10 KΩ NTC thermistor type II
3 KΩ NTC thermistor
Pt100 Ω RTD
Pt1000 Ω RTD
20 KΩ NTC thermistor

LCD display

RLY

Relay

NBC

No buttons

2 range
2 range

2 range
2 range

Temperature Resistance Curves (in Ohms)
°C °F A B C D E F

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5
0

5

10
15
20

25

30
35
40
45
50

55

60
65
70
75
80

85

90
95
100
105
110
115
120
125
130
135
140
145
150

US Customary Units

ft in Hg

0
400
800
1200
1600
2000
2400
2800
3200
3600
4000
4400
4800
5200
5600
6000
6400
6800
7200
7600
8000
8400
8800
9200
9600
10000

-67.0

607800.00

-58.0

441200.00

-49.0

323600.00

-40.0

239700.00

-31.0

179200.00

-22.0

135200.00

-13.0

102900.00

-4.0

78910.00

5.0

61020.00

14.0

47540.00

23.0

37310.00

32.0

29490.00

41.0

23460.00

50.0

18780.00

59.0

15130.00

68.0

12260.00

77.0

10000.00

86.0

8194.00

95.0

104.0

113.0

122.0

131.0

140.0

149.0

158.0

167.0

176.0

185.0

194.0

203.0

212.0

221.0

230.0

239.0

248.0

257.0

266.0

275.0

284.0

293.0

302.0

6752.00

5592.00

4655.00

3893.00

3271.00

2760.00

2339.00

1990.00

1700.00

1458.00

1255.00

1084.00

SI Units
m hPa

29.92

29.50

29.10

28.69

28.29

27.90

27.51

27.13

26.76

26.39

26.02

25.66

25.30

24.95

24.60

24.26

23.93

23.60

23.27

22.94

22.63

22.31

22.00

21.70

21.40

21.40

Figure 9: Elevation Chart

963849.00

670166.00

471985.00

336479.00

242681.00

176974.00

130421.00

97081.00

72957.00

55329.00

42327.00

32650.00

25392.00

19901.00

15712.00

12493.00

10000.00

8057.00

6531.00

5326.00

4368.00

3602.00

2986.00

2488.00

2083.00

1752.00

1480.00

1255.00

1070.00

939.30

816.80

712.60

623.60

547.30

481.80

425.30

376.40

334.00

297.20

265.10

237.00

Figure 10: Resistance vs Temperature

915.50

786.60

678.60

587.60

510.60

445.30

389.60

341.90

301.00

265.80

235.30

208.90

186.10

0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500

289154.70

201049.80

141595.50

100943.70

72804.30

53092.20

39126.30

29124.30

21887.10

16598.70

12698.10

9795.00

7617.60

5970.30

4713.60

3747.90

3000.00

2417.10

1959.30

1597.80

1310.40

1080.60

895.80

746.40

624.90

525.60

444.00

376.50

321.00

274.65

235.98

203.58

176.28

153.18

133.59

116.88

102.57

90.30

79.74

70.59

62.67

55.83

78.32

80.31

82.29

84.27

86.25

88.22

90.19

92.16

94.12

96.09

98.04

100.00

101.95

103.90

105.85

107.79

109.74

111.67

113.61

115.54

117.47

119.40

121.32

123.24

125.16

127.08

128.99

130.90

132.80

134.71

136.61

138.51

140.40

142.29

144.18

146.07

147.95

149.83

151.71

153.58

155.46

157.33

1013
1002
990
979
968
957
946
935
924
914
904
893
883
873
863
853
844
834
824
815
806
797
787
779
770
761

783.2

803.1

822.9

842.7

862.5

882.2

901.9

921.6

941.2

960.9

980.4

1000.0

1019.5

1039.0

1058.5

1077.9

1097.4

1116.7

1136.1

1155.4

1174.7

1194.0

1213.2

1232.4

1251.6

1270.8

1289.9

1309.0

1328.0

1347.1

1366.1

1385.1

1404.0

1422.9

1441.8

1460.7

1479.5

1498.3

1517.1

1535.8

1554.6

1573.3

2394000.00

1646200.00

1145800.00

806800.00

574400.00

413400.00

300400.00

220600.00

163500.00

122280.00

92240.00

70160.00

53780.00

41560.00

32340.00

25360.00

20000.00

15892.00

12704.00

10216.00

8264.00

6722.00

5498.00

4520.00

3734.00

3100.00

2586.00

2166.00

1822.60

1540.00

1306.40

1112.60

951.00

815.80

702.20

606.40

525.60
N/A
N/A
N/A
N/A
N/A

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.

Phone: [phone]

Fax: [phone]

dwyer-inst.com

e-mail: [e-mail]