Dwyer Instruments CDT-2N44-LCD, CDTR-2N4A4-LCD, CDTR Series Installation And Operating Instructions Manual

Series CDT and CDTR Wall Mount Carbon Dioxide/

[92.72]

[71.12]

1.10

®

Temperature Transmitter

Specications - Installation and Operating Instructions

Bulletin AQ-CDT/CDTR-E/N

3.65

North AmericanEuropean

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, Model A-449 or Model A-449A 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
and temperature together. The Series CDTR can also display relative humidity or

2 and relative humidity together. Push buttons are standard on the transmitters for

CO

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 dip
switch 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.

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

* For buildings occupied 24 hours per day, it is recommended that calibration be
veried every 6 to 12 months depending on application.

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

®

certication. Additionally, the

2 levels and barometric

2 only, or CO2

1.08

[27.33]

4.50

[114.30]

3.56

[90.42]

SPECIFICATIONS
Sensor: Single beam, dual-wavelength NDIR.
Range: CO

122°F (0 to 50°C).

Accuracy: CO

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 min 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 or 19 to 28 VAC.
Power Consumption: Average: 2 w; Peak: 3.75 w.
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 rated 2A @ 30 VDC; RTD or thermistor per r-t
curves on page 4 (depending on model).

Weight: 4.4 oz (125 g).
Agency Approvals: CE.

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.

transmitter to adjust to the current CO

days.

2: 0 to 2000 or 0 to 5000 ppm (depending on model); Temperature: 32 to

2: ±40 ppm ±3% of reading; RH: ±2% (10 to 90% RH) (for units

CAUTION

NOTICE

NOTICE

NOTICE

NOTICE

NOTICE

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.

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

2 concentration.

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

2.80

[27.96]

DWYER INSTRUMENTS, INC.

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

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

Phone: [phone]

Fax: [phone]

www.dwyer-inst.com

e-mail: [e-mail]

Current / Voltage Outputs

TURE

POWER

TEMP OR RH

On the Series CDT, the transmitter may be wired for current or voltage output for both
carbon dioxide and temperature. On the Series 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 4.

NOTICE

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

Figure 1: Removal Of Cover From Back Plate

MOUNTING

1. Push tab on top and 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 4 for wiring
information.

Dip Switch

Figure 2: Diagram Of Circuit Board

DIP SWITCH SETTINGS

To access the DIP SWITCH, remove the cover of the unit as shown in Figure 2. The
DIP SWITCH is located on the back of the circuit board.

SUPPLY

RECEIVER

CO2

RECEIVER

RELAY
CONTACT

PASSIVE
TEMPERA
SENSOR

Figure 4: Active Output Wiring Diagram

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

Before any adjustment can be made to the transmitter, the Menu Lockout Dip Switch
must be set to the ˝On˝ position (See Figure 3)

Enter

Remote Display Port

Up

UP = “ON”
DOWN = “OFF”

DIP SWITCH #1

DIP SWITCH #6

DIP SWITCH

Figure 3

DIP Switch Position 1: CO

2 Output Selection

ON: Output set to voltage output
OFF: Output set to current output

DIP Switch Position 2: Temperature (CDT models) / Humidity (CDTR models)
Output Selection

ON: Output set to voltage output
OFF: Output set to current output

DIP Switch Positions 3 & 4: Current or Voltage Output Range Selection

Output Range DIP Switch 3 Position DIP Switch 4 Position
2 to 10 V

ON OFF
4 to 20 mA
0 to 10 V

OFF OFF
0 to 20 mA
0 to 5 V

OFF ON
0 to 10 mA
1 to 5 V

ON ON
2 to 10 mA

Dip Switch Position 5: Menu Access

ON: Menu Enabled
OFF: Menu Disabled

Down

Figure 5: Side View of Transmitter

ACCESSING MENU PARAMETERS

Step 1: To enter the menu structure, press Up button and Down button
simultaneously for 5 seconds (display will show RON parameter).

Step 2: Press Up button or Down button to cycle between menu items.

Step 3: Press Enter to edit the value for the displayed menu item (SET will appear
on display).

Step 4: Press Up button or Down button to adjust the value of the menu item.

Step 5: Press Enter button to save the changes (SET will disappear).

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

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

Menu Descriptions

Relay on set point

RON

Sets the CO

2 concentration which the optional relay is energized.

HOL

Humidity low output range (Series CDTR only)
Sets the humidity 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. Up button and Down button 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

(Series CDTR only) and CO

2 concentration, temperature, relative humidity

2 concentration combined with temperature or

relative humidity (Series CDTR only).

CH CO

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

CT CO

TH Temperature and relative humidity (Series CDTR only)

2 concentration only

C CO
T Temperature only

H Relative humidity only (Series 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.

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

HOH

Humidity high output range (Series CDTR only)
Sets the humidity 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 humidity. When HOH is below HOL, the transmitter
is reverse acting and the output will increase with a decrease in humidity.

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 / 677 hPa
Factory setting: 29.9 in Hg / 1013 hPa
High limit: 32.0 in Hg / 1084 hPa

CAL

Calibration
Calibrates the carbon dioxide sensor to a known gas value. Read
calibration instructions before using this feature. Hold Enter button for 5
seconds.

RST

Reset to Factory Defaults
Resets all menu settings to their default value, and clears zero and span.

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

Temperature low output range (Series 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 (Series 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.

YES - Press & hold -- button for several seconds to reset settings
NO - Press -- button to exit this menu item without resetting

CALIBRATING SENSOR

Step 1: Remove the cover as shown in Figure 1.
Step 2: Remove one of the gas nipple covers on the CO

2 sensor and attach

tubing from the gas pressure regulator to the nipple (See Figure 6).
Step 3: Attach the terminal block accessory to the circuit board so that the power
wires line up with terminals 1 and 2. Plug in the power supply to power
up the transmitter.
Step 4: Hold housing so that the sensor is in the vertical plane as shown in
Figure 6.
Step 5: Follow the steps in the accessing parameter section to access the
calibration parameter (CAL).
Step 6: Press the Enter button.
Step 7: Flow zero reference gas at 0.3 SLPM for 5 minutes.
Step 8: Press and hold the Down button for 3 seconds.
Step 9: Flow the full scale reference gas at 0.3 SLPM for 5 minutes.
Step 10: Press and hold the Up button for 3 seconds.
Step 11: Exit the parameter menu.
Step 12: Disconnect the power supply from the power source and remove the
terminal block from the circuit board.
Step 13: Remove tubing from sensor and re-attach the gas nipple cover to the
sensor.
Step 14: Re-attach the cover to the back plate.

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

European

North American

Figure 6: Calibration

MAINTENANCE/REPAIR

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.

Series CDT -2 N 4 4 -LCD Example: CDT-2N44-LCD
Range 2

Conguration N

CO

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

Temperature

Output

Options LCD

Series CDT -2 N 4 A 4 -LCD Example: CDTR-2N4A4-LCD
Range 2

Conguration N

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# 443800-30 Rev. 8

5

E

0
4
A
B

C
D
E

F

Figure 7: Series CDT Model Chart

5

E

0
4
A
B

C
D
E

F

Figure 8: Series CDTR Model Chart

0 to 2000 ppm CO
0 to 5000 ppm CO
North American Wall Mount
European Wall Mount

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 (wall only)

RLY

Relay

NBC

No buttons (wall only)

0 to 2000 ppm CO
0 to 5000 ppm CO
North American Wall Mount
European Wall Mount

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 (wall only)

RLY

Relay

NBC

No buttons (wall only)

2 range
2 range

2 range
2 range

RESISTANCE VS TEMPERATURE TABLE

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]