Bard 8403-096 Owner's manual

Page 1 of 6
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
www.bardhvac.com
Manual: 7960-902
Supersedes: NEW
Date: 3-1-21
8403-096 Carbon Dioxide Transmitter
(Dwyer®CDT-2N40-LCD-RLY 002 Sensor)
SUPPLEMENTAL INSTRUCTIONS
Series CDT Wall Mount Carbon Dioxide Temperature
Transmitters accurately monitor the CO2 concentration and
temperature in schools, ofce buildings, and other indoor
environments to help achieve LEED® certication. 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 CO2 levels and barometric 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 4-20 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 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.
The CDT can be congured to display temperature only,
CO2 only or CO2 and temperature together. 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 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.

Manual 7960-902
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SPECIFICATIONS
Sensor: Single beam, dual-wavelength NDIR.
Range: CO2: 0 to 2000 or Oto 5000 PPM (depending on
model); Temperature: 32 to 122°F (0 to 50°C).
Accuracy: CO2: ±40 PPM ±3% of reading; 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: 16-35 VDC or 19-28 VAC.
Power Consumption: Average: 2 w; Peak: 3.75 w.
Output: Current: 4-20 mA (max. 500 O); Voltage: 0-5
VDC or 0-10 VDC (min. 500 O); Relay: SPST NO rated
2A@ 30 VDC; RTD or thermistor per r-t curves on page 6
(depending on model).
Weight: 4.4 oz (125 g).
Agency Approvals: CE.
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,
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 transmitter to adjust to the current
CO2 concentration.
Self calibration feature of the transmitter
requires exposure to normal outdoor
equivalent carbon dioxide level once every
30 days.
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.
FIGURE 1
Removal of Cover from Back Plate
WIRING
Use maximum 18 AWG wire for wiring to terminals. Refer
to Figure 4 for wiring information.
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.
FIGURE 2
Diagram of Circuit Board
DIP Switch
FIGURE 3
DIP Switches
4. Pull wires through sub base hole and make necessary
connections.
5. Reattach cover to base plate.

Manual 7960-902
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DIP Switch Position 1: CO2 Output Selection
ON: Output set to voltage output
OFF: Output set to current output
DIP Switch Position 2: Temperature 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 ON OFF
0-10 V
0-20 mA OFF OFF
0-5 V
0-10 mA OFF ON
1-5 V
2-10 mA ON ON
DIP Switch Position 5: Menu Access
ON: Menu Enabled
OFF: Menu Disabled
CURRENT/VOLTAGE OUTPUT
On the Series CDT, the transmitter may be wired for
current or voltage output for both carbon dioxide and
temperature. The transmitter can be powered with either
16-35 VDC or 19-28 VAC. Wire the transmitter according
to Figure 4.
Optional relay can be used as either a dry
contact or low voltage switched circuit up
to 2 A at 30 VDC
FIGURE 4
Active Output Wiring Diagram
POWER
SUPPLY TEMP
RECEIVER
CO2
RECEIVER
REMOTE DISPLAY
For models that are ordered without an integral LCD
display, remote display Model A-449 can be used to
display the temperature, 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 only temperature 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)
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.
FIGURE 5
Side View of Transmitter

Manual 7960-902
Page 4 of 6
MENU DESCRIPTIONS
RON Relay on set point
Sets the CO2 concentration which the optional relay
is energized.
ROF Relay off set point
Sets the CO2 concentration which the optional
relay is de-energized. Setting value lower than
RON provides direct action for detecting high
concentrations of CO2. Setting value higher than
RON provides indirect action for detecting low
concentrations of CO2. 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)
DSP Display conguration
Determines the LCD display conguration during
normal operation. The LCD display can indicate
the CO2 concentration, temperature and CO2
concentration.
CT CO2 concentration and temperature
C CO2 concentration only
T Temperature 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
COL CO2 low output range
Sets the CO2 concentration for the lowest output
(4 mA or O VDC).
Low limit: 0 PPM
Factory setting: 0 PPM
High limit: 2000/5000 PPM (depending on model)
COH CO2 high output range
Sets the CO2 concentration for the highest output
(20 mA, 5 VDC or 1O VDC). When COH is set above
COL, the transmitter is direct acting and the output
will increase with an increase in CO2 level. When
COH is below COL, the transmitter is reverse acting
and the output will increase with a decrease in CO2
level.
Low limit: 0 PPM
Factory setting: 2000/5000 PPM (depending on
model)
High limit: 2000/5000 PPM (depending on model)
AAC Average Atmospheric Carbon Dioxide value
Sets the value at which the sensors automatic
background calibration will reference. Factory
setting derived from research from the National
Oceanic and Atmospheric Administration (NOAA).
Low limit: 200 PPM
Factory setting: Current NOAA value
High limit: 9999 PPM
TOL Temperature low output range (Series CDT with
active temperature only)
Sets the temperature for the lowest output (4 mA or
O VDC).
Low limit: 32.0°F/0.0°C
Factory setting: 32.0°F/0.0°C
High limit: 122.0°F/150.0°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/150.0°C
High limit: 122.0°F/150.0°C
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 Table 1
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 CALIBRATING SENSOR below before
using this feature. Hold Enter button for 5 seconds.
RST Reset to Factory Defaults
Resets all menu settings lo 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

Manual 7960-902
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CALIBRATING SENSOR
Step 1: Remove the cover as shown in Figure 1.
Step 2: Remove one of the gas nipple covers on the CO2
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: Flow zero reference gas at 0.3 SLPM for 5
minutes.
Step 6: Press and hold the Up and Down buttons
simultaneously for 5 seconds to enter the menu
parameters. The display will show the “RON”
parameter.
Step 7: Press the Up or Down button to access the
calibration parameter menu which will display as
“CAL”.
Step 8: Press the Enter button. “SET” will then appear
on the display.
Step 9: Press the Down arrow for 3 seconds. All dashes
will appear on the display, then release the
button. Then after 10 seconds “SET” will
disappear.
Step 10: Exit the parameter menu by pressing and holding
the Up and Down buttons simultaneously for 5
seconds or wait 10 seconds.
Step 11: Flow the full scale reference gas at 0.3 SLPM for
5 minutes.
Step 12: Repeat steps 6 through 8.
Step 13: Press the Up arrow for 3 seconds. All dashes will
appear on the display, then release the button.
Then after 10 seconds “SET” will disappear.
FIGURE 6
Calibration
Step 14: Exit the parameter menu by pressing and holding
the Up and Down buttons simultaneously for 5
seconds or wait 10 seconds.
Step 15: Disconnect the power supply from the power
source and remove the terminal block from the
circuit board.
Step 16: Remove tubing from sensor and re-attach the gas
nipple cover to the sensor.
Step 17: Re-attach the cover to the back plate.
MAINTENANCE
Upon nal installation of the Series CDT, no routine
maintenance is required. The Series CDT 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.

Manual 7960-902
Page 6 of 6
TABLE 1
Elevation
US
Customary Units
ft in Hg
0 29.92
400 29.50
800 29.10
1200 28.69
1600 28.29
2000 27.90
2400 27.51
2800 27.13
3200 26.76
3600 26.39
4000 26.02
4400 25.66
4800 25.30
5200 24.95
5600 24.60
6000 24.26
6400 23.93
6800 23.60
7200 23.27
7600 22.94
8000 22.63
8400 22.31
8800 22.00
9200 21.70
9600 21.40
10000 21.40
SI
Units
m hPa
0 1013
100 1002
200 990
300 979
400 968
500 957
600 946
700 935
800 924
900 914
1000 904
1100 893
1200 883
1300 873
1400 863
1500 853
1600 844
1700 834
1800 824
1900 815
2000 806
2100 797
2200 787
2300 779
2400 770
2500 761
TABLE 2
Resistance vs. Temperature
Temperature Resistance Curves (in Ω)
°C °F A B C D E F
-55 -67.0 607800.00 963849.00 289154.70 78.32 783.2 2394000.00
-50 -58.0 441200.00 670166.00 201049.80 80.31 803.1 1646200.00
-45 -49.0 323600.00 471985.00 141595.50 82.29 822.9 1145800.00
-40 -40.0 239700.00 336479.00 100943.70 84.27 842.7 806800.00
-35 -31.0 179200.00 242681.00 72804.30 86.25 862.5 574400.00
-30 -22.0 135200.00 176974.00 53092.20 88.22 882.2 413400.00
-25 -13.0 102900.00 130421.00 39126.30 90.19 901.9 300400.00
-20 -4.0 78910.00 97081.00 29124.30 92.16 921.6 220600.00
-15 5.0 61020.00 72957.00 21887.10 94.12 941.2 163500.00
-10 14.0 47540.00 55329.00 16598.70 96.09 960.9 122280.00
-5 23.0 37310.00 42327.00 12698.10 98.04 980.4 92240.00
0 32.0 29490.00 32650.00 9795.00 100.00 1000.0 70160.00
5 41.0 23460.00 25392.00 7617.60 101.95 1019.5 53780.00
10 50.0 18780.00 19901.00 5970.30 103.90 1039.0 41560.00
15 59.0 15130.00 15712.00 4713.60 105.85 1058.5 32340.00
20 68.0 12260.00 12493.00 3747.90 107.79 1077.9 25360.00
25 77.0 10000.00 10000.00 3000.00 109.74 1097.4 20000.00
30 86.0 8194.00 8057.00 2417.10 111.67 1116.7 15892.00
35 95.0 6752.00 6531.00 1959.30 113.61 1136.1 12704.00
40 104.0 5592.00 5326.00 1597.80 115.54 1155.4 10216.00
45 113.0 4655.00 4368.00 1310.40 117.47 1174.7 8264.00
50 122.0 3893.00 3602.00 1080.60 119.40 1194.0 6722.00
55 131.0 3271.00 2986.00 895.80 121.32 1213.2 5498.00
60 140.0 2760.00 2488.00 746.40 123.24 1232.4 4520.00
65 149.0 2339.00 2083.00 624.90 125.16 1251.6 3734.00
70 158.0 1990.00 1752.00 525.60 127.08 1270.8 3100.00
75 167.0 1700.00 1480.00 444.00 128.99 1289.9 2586.00
80 176.0 1458.00 1255.00 376.50 130.90 1309.0 2166.00
85 185.0 1255.00 1070.00 321.00 132.80 1328.0 1822.60
90 194.0 1084.00 915.50 274.65 134.71 1347.1 1540.00
95 203.0 939.30 786.60 235.98 136.61 1366.1 1306.40
100 212.0 816.80 678.60 203.58 138.51 1385.1 1112.60
105 221.0 712.60 587.60 176.28 140.40 1404.0 951.00
110 230.0 623.60 510.60 153.18 142.29 1422.9 815.80
115 239.0 547.30 445.30 133.59 144.18 1441.8 702.20
120 248.0 481.80 389.60 116.88 146.07 1460.7 606.40
125 257.0 425.30 341.90 102.57 147.95 1479.5 525.60
130 266.0 376.40 301.00 90.30 149.83 1498.3 N/A
135 275.0 334.00 265.80 79.74 151.71 1517.1 N/A
140 284.0 297.20 235.30 70.59 153.58 1535.8 N/A
145 293.0 265.10 208.90 62.67 155.46 1554.6 N/A
150 302.0 237.00 186.10 55.83 157.33 1573.3 N/A