Bulletin AQ-CDT/CDTR-E/N-3
[1
1-3/32
®
Series CDT and CDTR Wall Mount Carbon Dioxide/
Temperature Transmitter
Specications - Installation and Operating Instructions
North American DSA* compliant option -S
Series CDT and CDTR Wall Mount Carbon Dioxide Temperature Transmitters
accurately monitor the CO
and other indoor environments to help achieve LEED
2 concentration and temperature in schools, ofce buildings,
®
certication. Additionally, the
Series CDTR also measures ambient relative humidity. In order to achieve a higher
level of accuracy, the Series CDT includes digital barometric pressure adjustment.
Universal outputs allow 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. 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 congured to display temperature only, CO
temperature together. The Series CDTR can also display relative humidity or CO
2 only, or CO2 and
2 and
relative humidity together. Push buttons are standard on the transmitters for access
to the menu structure in models with displays. 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 conguration,
transmitter output scaling, ambient barometric pressure and eld calibration of the
transmitter.
The Series CDT and CDTR CO
2 transmitters are available with a -S option that
provides the necessary attributes and parameters to be e with DSA requirements for
monitoring CO
2 level exceeds 1100 PPM.
CO
Automated CO
The Series CDT and CDTR CO
with the ability to adjust the CO
2 levels in schools. There is a front facing LED that illuminates when the
2 Baseline Correction (ABC)
2 transmitters are maintenance free instruments
2 calibration by using the on-board ABC logic for
intermittently occupied spaces. The ABC algorithm accounts for long term drift by
making small adjustments to it’s zero calibration point based on the lowest CO
readings it measures. CO
2 calibration adjustments are made every eight days by the
ABC algorithm. For environments occupied 24 hours per day it is recommended to
periodically expose the CO
2 sensor to outside ambient air.
4-1/2
14.30]
2-51/64 [71.12]
*Division of the State Architect - California
[27.69]
SPECIFICATIONS
Sensor: NDIR, 15 year life expectancy.
Range: CO
2: 0 to 2000 or 0 to 5000 PPM (depending on model); Temperature: 32
to 122°F (0 to 50°C).
Accuracy**: CO
of reading (5000 PPM CO
2: ±40 PPM + 3% of reading (2000 PPM CO2); ± 50 PPM + 5%
2); RH: ±2% (10 to 90% RH) (for units congured with
humidity output); Temperature: ±1°C @ 25°C.
Response Time: 2 min for 90% step change.
Temperature Limits: 32 to 122°F (0 to 50°C).
Humidity Limits: 0 to 85% (non-condensing).
Power Requirements: 16-35 VDC or 19-28 VAC.
Power Consumption: Average: 2 w; Peak: 3.75 w.
Output: Current: 4-20 mA (max. 500 Ω); Voltage: 0-5 VDC or 0-10 VDC (min. 500
Ω); Relay: SPST NO rated 2A @ 30 VDC; RTD or thermistor per r-t curves on page
4 (depending on model).
Compliance: CE.
**The specied CO
2 accuracy is only guaranteed after three weeks of continuous
operation in environments which are intermittently occupied.
INSTALLATION
CAUTION
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.
NOTICE
Use electrostatic discharge precautions (e.g., use of wrist straps)
during installation and wiring to prevent equipment damage.
NOTICE
2
NOTICE
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.
NOTICE
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.
transmitter to adjust to the current CO
NOTICE
Self calibration feature of the transmitter requires exposure to
normal outdoor equivalent carbon dioxide level once every thirty
days.
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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
inuences.
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
Current/Voltage Outputs
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 16-35 VDC or 19-28 VAC. Wire the transmitter according to
Figure 4.
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 congured by the user to show humidity and
carbon dioxide, only temperature, only humidity, or only carbon dioxide.
Optional relay can be used as either a dry contact or low voltage
switched circuit up to 2 A at 30 VDC
-
POWER
SUPPLY
-
TEMP OR RH
RECEIVER
RECEIVER
123
PWR
Figure 4: Active output wiring diagram
COM
4
OUT1
CO2
5
OUT2
++
RELAY
CONTACT
PASSIVE
TEMPERATURE
6
7
RLY
RLY
SEN
SENSOR
8
SEN
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.
UP = “ON”
DOWN = “OFF”
DIP SWITCH #1
DIP SWITCH
Figure 3
DIP Switch Position 1: CO
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
2-10 V
4-20 mA
0-10 V
0-20 mA
0-5 V
0-10 mA
1-5 V
2-10 mA
Dip Switch Position 5: Menu Access
ON: Menu Enabled
OFF: Menu Disabled
ON OFF
OFF OFF
OFF ON
ON ON
2 Output Selection
DIP SWITCH #6
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).
REMOTE DISPLAY PORT
UP
ENTER
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 MAX 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.
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www.GlobalTestSupply.com
Menu Descriptions
MAX
Maximum CO2 Value
Displays the highest CO
2 concentration value observed by the sensor since
the last power cycle or reset.
Reset the MAX CO
2 concentration by pressing and holding the ENTER button
for 1 second.
RON
Relay on set point
Sets the CO
2 concentration which the optional relay is energized (also
concurrently energizes the front facing LED for -S models).
Low limit: 0 PPM
Factory setting: 1100 PPM
High limit: 2000/5000 PPM (depending on model)
ROF
Relay off set point
Sets the CO
2 concentration which the optional relay is de-energized (also
concurrently de-energizes the front facing LED for -S models). Setting value
lower than RON provides direct action for detecting high concentrations of
2. Setting value higher than RON provides indirect action for detecting low
CO
concentrations of CO
2. Up button and Down button on the LCD display will be
lit to indicate when the relay is energized.
TOL
Temperature low output range (Series CDT with active temperature only)
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
TOH
Temperature high output range (Series CDT with active temperature only)
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
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: 1050 PPM
High limit: 2000/5000 PPM (depending on model)
Display conguration
DSP
Determines the LCD display conguration 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)
UNI
Units selection
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
OFT
Temperature Offset
Allows the user to add an offset to the measured temperature.
Range: ±5°C in 0.5°C increments (±9°F in 1°F increments)
Factory Default: 0°C
OFH
Humidity Offset (CDTR only)
Allows the user to add an offset to the measured relative humidity.
Range: ±10% in 1% increments
Factory Default: 0% RH
COL
CO
2 low output range
Sets the CO
2 concentration for the lowest output (4 mA or 0 VDC).
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 7 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
ABC
Automated Baseline Correction
Enables/disables the Automated Baseline Correction algorithm for disabling in
locations that experience elevated levels of CO
2 due to constant occupancy of
the area. Select “ON” to enable ABC and select “OFF” to disable ABC.
Factory Default: ON
Reset to Factory Defaults
RST
Resets all menu settings to their default value, and clears zero and span.
YES - Press and hold -- button for several seconds to reset settings
NO - Press -- button to exit this menu item without resetting
Low limit: 0 PPM
Factory setting: 0 PPM
High limit: 2000/5000 PPM (depending on model)
COH
CO
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)
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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 obtain a Return Materials Authorization number (RMA) before
shipping the product back for repair. Be sure to include a brief description of the
problem plus any additional application notes.
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
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 7: Elevation chart
SI Units
m hPa
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
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
RESISTANCE VS TEMPERATURE TABLE
Temperature Resistance Curves (in Ω)
°C °F A B C D E F
-55
-67.0
-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
-58.0
-49.0
-40.0
-31.0
-22.0
-13.0
-4.0
5.0
14.0
23.0
32.0
41.0
50.0
59.0
68.0
77.0
86.0
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
607800.00
441200.00
323600.00
239700.00
179200.00
135200.00
102900.00
78910.00
61020.00
47540.00
37310.00
29490.00
23460.00
18780.00
15130.00
12260.00
10000.00
8194.00
6752.00
5592.00
4655.00
3893.00
3271.00
2760.00
2339.00
1990.00
1700.00
1458.00
1255.00
1084.00
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 8: 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
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
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
®
LEED
is a registered trademark of the U.S. Green Building Council
©Copyright 2023 Dwyer Instruments, LLC Printed in U.S.A. 1/23 FR# 444656-00 Rev. 3
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