63-2546 - C7242A-E Sensor and Controller

C7242A-E Sensor and Controller CARBON DIOXIDE SENSOR PRODUCT DATA

FEATURES • Models available with LCD that provides sensor readings and status information. • Non-Dispersion-Infrared (NDIR) technology used to measure carbon dioxide gas. • Gold-plated sensor provides long-term calibration stability. • Device provides voltage output based on CO2 levels. • Device provides voltage output based on temperature levels. • Models available with SPST relay output.

C7242A

C7242B

APPLICATION The C7242 Sensor and Controller is a carbon dioxide (CO2) sensor for use in determining ventilation necessity with HVAC controllers. The C7242 measures the CO2 concentration in the ventilated space or duct. The C7242 is used in ventilation and air conditioning systems to control the amount of fresh outdoor air supplied to maintain acceptable levels of CO2 in the space.

• Proportional plus Integral (P+I) control algorithm. • Output can be configured using optional software package to provide a more complex ventilation control strategy using CO2 levels in conjunction with temperature. • Models available for wall mounting, duct mounting, or portable (hand-held) use. • Used for CO2 based ventilation control. • Automatic Background Calibration (ABC) algorithm based on long-term evaluation reduces required typical zero-drift check maintenance. • Digital input with programmable delay time for occupancy function using a sensor, push-button, or switch.

Contents Application .......................................................................... Features .............................................................................. Specifications ...................................................................... Ordering Information ........................................................... Installation ........................................................................... Operation ............................................................................ Checkout and Troubleshooting ..........................................

Copyright © 1998 Honeywell Inc. • All Rights Reserved

1 1 2 2 4 6 6

63-2546-1

C7242A-E SENSOR AND CONTROLLER

SPECIFICATIONS

Maximum Power Consumption (no external devices connected): C7242A,B,E: 3W. C7242C: 500 mW. Peak Current (at 20 ms): 600 mA. Relay (for models with relays only): Contact Rating: 1A at 24 V (ac/dc) Class 2. Minimum Permissible Load: 1 mA at 5 Vdc.

Models: See Table 1. Dimensions: See Fig. 1. Operation Principle: Non-dispersive infrared (NDIR) and thermistor.

Analog Outputs (Programmable): AN1: C7242A,B,E: 0-10 Vdc. C7242C: 0-5 Vdc. AN2: C7242A,B (Models without Relay Output): 0-10 Vdc. Relay Models: Normally Open SPST relay contact. C7242C,E: None. See Table 2 for default settings.

Gas Sampling: Diffusion. Range: 0 to 3000 ppm ±5% and ±50 ppm. Response Time: C7242A,C,E: 2 min. C7242B: 10 sec (at 0.007 cfm [0.2 L/min] flow rate).

Other Outputs: Three Status LED indicators.

Temperature Sensor: Thermistor. Range: 14°F to 140°F (-10°C to 60°C) ±0.9°F (±0.5°C). C7242E: Used for internal heater control.

Ambient Operating Range: Temperature: C7242A,B,C: +32°F to +122°F (0°C to +50°C). C7242E: -40°F to +122°F (-40°C to +50°C). Relative Humidity (non-condensing): C7242A,B,C: 0 to 95 percent. C7242E: 0 to 100 percent.

Electrical Ratings: Power Supply: C7242A,B,E: 15-29 V (ac/dc), 50/60 Hz (Class 2). C7242C: 9 Vdc, 120 mAh NiMH battery.

Table 1. C7242 Models. Display

Voltage Outputs

C7242A1014

Model

Wall mount

Mounting

Yes

Two 0 - 10 Vdc

–

Details

C7242A1022

Wall mount

No

Two 0 - 10 Vdc

–

C7242A1030

Wall mount

Yes

One 0 - 10 Vdc

Includes one SPST relay output.

C7242A1048

Wall mount

No

One 0 - 10 Vdc

Includes one SPST relay output.

C7242B1012

Duct mount

Yes

Two 0 - 10 Vdc

Includes 1-3/16 in. diameter, 9-1/16 in. long sampling tube.

C7242B1020

Duct mount

No

Two 0 - 10 Vdc

Includes 1-3/16 in. diameter, 9-1/16 in. long sampling tube.

C7242C1002

Portable

Yes

One 0 - 5 Vdc

9 Vdc, 160 mAh NiMH rechargeable battery. On/Off switch and low battery LED. Includes 120Vac 60Hz transformer/battery charger.

C7242E1007

Wall mount

No

One 0 - 10 Vdc

Outdoor applications (includes heater).

ORDERING INFORMATION When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the TRADELINE® Catalog or price sheets for complete ordering number. If you have additional questions, need further information, or would like to comment on our products or services, please write or phone: 1. Your local Home and Building Control Sales Office (check white pages of your phone directory). 2. Home and Building Control Customer Logistics Honeywell Inc., 1885 Douglas Drive North Minneapolis, Minnesota 55422-4386 (612) 951-1000 In Canada—Honeywell Limited/Honeywell Limitée, 155 Gordon Baker Road, North York, Ontario M2H 3N7. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

63-2546—1

2

C7242A-E SENSOR AND CONTROLLER

3-11/16 (94)

2-3/16 (55)

7-1/16 (180)

2-1/2 (64)

9-1/16 (230)

9-5/8 (245)

2-9/16 (65) M11909

2-3/16 (55)

3 (76)

3-9/16 (90) 5-9/16 (141) 3-5/16 (84) 7-1/16 (180)

1-1/2 (38)

1 (25) 3-15/16 (100)

M11908A

Fig. 1. C7242 Dimensions (in in. [mm]). Calibration Interval (Normal IAQ applications): Five years.

Connections: Wiring: Terminal block: 2.5 sq. mm. Digital Interface: UART Serial port.

Approvals: Underwriters Laboratories Inc. Component Recognition: UL94-5V, File No. E191465. CE. C7242A,C: NEMA1. C7242B,E: NEMA3.

CO2 Pressure Dependence: 1.4% change in reading per 1 kPa deviation from 100 kPa. Automatic Background Calibration (ABC) default: C7242A,B,E: on. C7242C: off.

Accessories: 32002181-001: Zero Calibration and Service Kit. 32002182-001: Duct Mount Housing only. 32002183-001: STRATEGY Configuration Software.

Annual Drift (with automatic self-calibration): Nominal 20 ppm.

3

63-2546—1

C7242A-E SENSOR AND CONTROLLER

INSTALLATION SCREW AND WASHER FOR CORNER MOUNTING (4)

When Installing this Product... 1. Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition. 2. Check the ratings given in the instructions and on the product to make sure the product is suitable for your application. 3. Installer must be a trained, experienced service technician. 4. After installation is complete, check out product operation as provided in these instructions. 5. Follow local codes for installation and application.

CAUTION Health Hazard. Improper use can create dangerous situations. Use in application for sensing carbon dioxide only. For life-safety applications, this device can function only as a secondary or lesser device.

CAUTION Electrical Shock or Equipment Damage Hazard. Can shock individuals or short equipment circuitry. Disconnect all power supplies before installation.

M11911A

Fig. 2. C7242 Wall Mounting.

CAUTION

Using Two Screws (Mounting To A Wall Box)

Equipment Damage Hazard. Electrostatic discharge can short equipment circuitry. Ensure that you are properly grounded before handling the unit.

IMPORTANT Read the following procedure in its entirety prior to performing the instructions. 1. Remove the cover from the C7242. 2. The board attaches to the mounting plate with snap-in latches. Carefully disconnect the printed circuit board from the mounting plate: a. Release the circuit board by pushing out the plastic latches to the left of the board while gently lifting the board.

IMPORTANT A cold start at temperatures below -4°F causes the C7242E to provide incorrect readings. To fix this problem, leave power on for 15 minutes to heat the unit, disconnect power for a brief time, then reconnect power.

Location and Mounting

IMPORTANT Do not flex plastic latches any more than absolute necessary.

C7242 Sensors mount directly on the wall, sheet metal duct, or a panel. When planning the installation, allow enough clearance for maintenance and service. Mount the sensor in a well-ventilated area.

b.

Wall Mounting The C7242 Wall Mount models can be mounted using two or four screws. The four screw method is recommended as it does not require PCB removal.

2. 3. 4.

Using Four Screws For Mounting 1. Remove the cover from the C7242. 2. Feed the wires through the opening in the mounting plate. 3. Mount the sensor to the wall using supplied washers, see Fig. 2. 4. Replace the cover on the C7242.

63-2546—1

5.

4

Lift the left side of the electronic board away from the case enough to prevent the latches from reengaging. c. Pull the board out of the slots that are to the right of the board. Feed the wires through the opening in the mounting plate. Mount the sensor to the wall, see Fig. 2. Reattach the board to the mounting plate: a. Slide the board into the slots on the right side. b. Align the board between the guides at the top and bottom of the mounting plate. c. Gently, but firmly, press the board down on the left side to fit the two latches. Replace the cover on the C7242.

C7242A-E SENSOR AND CONTROLLER

Wiring

Duct Mounting 1. Remove the cover from the C7242. 2. Mount the sensor to the wall. Feed the wires through the opening in the junction box, see Fig. 3.

The factory ships the device with the analog outputs (AN1 and AN2) set with the default settings shown in Table 2. Select one of the default outputs and attach the cables according to the information given in Fig. 4 or 5.

IMPORTANT Leakage into the duct or the C7242 box cover from the room will skew the readings of the sensor. Ensure the box cover and duct seal completely.

You can program the C7242 with different settings. This requires the cable and PC configuration software, see the Specification section for the part number. Use the parts and instructions included with this software to reconfigure the device.

CAUTION Electrical Shock or Equipment Damage Hazard. Can shock individuals or short equipment circuitry. Disconnect all power supplies before installation.

FL

OW

CAUTION Equipment Damage Hazard. Electrostatic discharge can short equipment circuitry. Ensure that you are properly grounded before handling the unit.

IMPORTANT All low voltage connections to this device must be 24 Vac Class 2. 1. All wiring must comply with applicable local codes, ordinances and regulations. 2. Refer to Fig. 4 and 5 for typical wiring diagrams.

M11910

Fig. 3. C7242 Duct Mounting.

Table 2. Default Analog Output Settings. CO2 (in ppm)

Integral Time (seconds)

a

Low End (0 Vdc)

AN1

500

2000

64

0

0

2000

2

0

700

800

2

0

a

AN2 (relay models )

High End (10 Vdc)

Baseline (in percent)

Output AN2

a

a

With relay models, when level drops below the Low End, the contacts open; when level rises above the High End, the contacts close.

NOTE: To change default settings requires STRATEGY Configuration Software accessory.

5

63-2546—1

C7242A-E SENSOR AND CONTROLLER

C7242

C7242

1 L1 (HOT) L2

1 L1 (HOT) L2

ST6008 TIMER ST6008 TIMER

OCCUPIED

OCCUPIED G+ GO DIG1 12 Vdc GND

3

2

AN1 GND AN2 GND

G+ GO DIG1 12 Vdc GND

UNOCCUPIED

UNOCCUPIED

AN1 GND AN2 GND

W7215

AQ

2

W7215

AQ1 AQ

1

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

2

THIS OPTION REQUIRES PROGRAMMING USING THE OPTIONAL SOFTWARE PACKAGE.

3

RELAY MODELS ONLY.

M11906A

Fig. 4. C7242 Wiring using AN1 output.

AQ1

1

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

2

THIS OPTION REQUIRES PROGRAMMING USING THE OPTIONAL SOFTWARE PACKAGE. M11907A

Fig. 5. C7242 Wiring using AN2 output.

OPERATION

CHECKOUT AND TROUBLESHOOTING

Operation LED

Recharging Batteries (C7242C only)

Most models have three different LED indicators: green, yellow, and red. These indicators provide status information even without a computer connection, see Table 3.

A 9 Vdc rechargeable battery supplies the power for the C7242C Portable CO2 Sensor. This battery generally provides power for up to two hours of use. The C7242 includes a low battery indicator. When this red indicator (behind the LCD) lights, approximately 30 minutes of use remain.

Pushbuttons

Recharge batteries using the supplied charger.

Three pushbuttons are located between the wiring terminals and the LCD of the C7242. These buttons are labeled: DISPLAY, + (plus), and – (minus).

CAUTION Equipment Damage Hazard. Use of improper charger can damage batteries beyond repair. Use only the supplied charger to recharge batteries.

The DISPLAY button cycles the display through the various modes: 1. CO2 concentration. 2. Temperature. 3. Alternating CO 2 concentration and Temperature.

IMPORTANT The red LED not only indicates a low battery. It also indicates 100 percent saturation of one of the two outputs.

Table 3. Operation LED indicators. LED Color

Meaning

Green Yellow

OK Call for maintenance

Red

High level indication

63-2546—1

Details Flashes after each successful measurement cycle. Indicates that an error flag has been set. If the error is not fatal, the green light will flash also. One of the two outputs is saturated at 100 percent or low battery indication (C7242C portable units only ).

6

C7242A-E SENSOR AND CONTROLLER

1. Plug the desktop charger into the C7242C. The green LED (next to the pushbuttons) lights. 2. When the green LED turns off, disconnect the charger.

service mode disables the PC connection. Perform all PC maintenance and configurations with the device in operation mode.

NOTES: — — — — —

To enter the service mode: 1. Press and hold both the plus and minus buttons for at least five seconds. 2. When the red and yellow indicators light, release both buttons.

For longer battery life, avoid fully discharging the battery; turn the device off whenever battery voltage runs low. To avoid power loss during use, power the unit with the desktop charger whenever possible. The status of the C7242C on/off switch does not prevent the batteries from charging. With the C7242C off, the batteries will charge faster. If the C7242C does not start, check the battery to ensure it is firmly attached to the battery terminals and that it is fully charged. If the C7242C displays an error code and will not start, turn the power off for a few seconds, then back on.

NOTES: — —

Function test

With the device in Service Mode, the yellow LED remains lit and the red LED intermittently flashes. The device will automatically exit service mode upon completion of the selected operation. Toggling the display beyond the final menu option also reverts the device to operation mode.

IMPORTANT Only qualified service technicians should use the pushbuttons with the device in service mode.

Perform a quick test of the unit with the unit powered: 1. Stand close to the unit and breathe air into the sensor. 2. Check the CO2 level registered by the controller to ensure a strong rise. 3. When connected to a damper in a ventilation system, the controller typically signals an increase in air flow.

Service Operations Pressing the plus button cycles through the menu of service operations. Pressing the minus button executes the current operation. The number of red LED consecutive flashes corresponds with the current menu operation number; for example, when the menu is at Baseline calibration of enabled channels (OP-3), the red LED flashes three times, pauses, then repeats this sequence until the user presses a button.

Service Mode Service Mode allows device modifications using the pushbuttons. The LED indicators provide somewhat different information when in service mode, see Table 4. The device

Table 4. Service Mode LED Indicators. LED Color

Meaning

Details

Green

OK

Flashes after each successful measurement cycle.

Yellow

Maintenance

On continuously with device in service mode. Flashes during menu procedure execution.

Red

Menu Indicator

Signals what action is ready for execution. (The LCD provides more complete information.)

Table 5. Error Values Returned By Full Self-Diagnostic Check. Error Value

Error

Comments

000

None detected

All LED indicators (green, yellow, and red) will flash.

001

Power Low

Analog 5V regulator failure

002

Analog Reference Voltage Failure

004

Lamp Power Control Error

008

Analog 1 Output Error

016

Analog 2 Output Error

032

Sensor Out of Range

064

Memory Checksum Error

128

Plug-in Card Error

Overload or Underload

7

63-2546—1

C7242A-E SENSOR AND CONTROLLER

1. 2. 3. 4. 5. 6. 7.

Full self-diagnostic check (OP-1). Zero calibration of enabled channels (OP-2). Baseline calibration of enabled channels (OP-3). Analog 1 fixed output mode (OP-4). Analog 2 fixed output mode (OP-5). N/A (OP-6). Return to operation mode (OP-7).

IMPORTANT Always check the function of the current operation before pressing the minus button. Full self-diagnostic check (OP-1) Run this to check all system functions. The operation returns errors (see Table 5) to the system memory. When the check finds errors, the yellow LED remains on after the device switches to operation mode. Systems with an LCD show the error as Exxx (where xxx is the value of the error). NOTE: Multiple errors will result in an error that is the sum of the values shown. Zero calibration of enabled channels (OP-2) This operation calibrates the CO2 sensor by reestablishing the zero level. Use the following procedure: 1. Prior to executing this operation, eliminate the CO2 using the 32002181-001 Calibration Kit. 2. Wait for sensor to stabilize (at least one minute). 3. Press the minus button to execute the zero calibration operation.

Baseline calibration of enabled channels (OP-3) This operation calibrates the CO2 sensor using fresh air calibration. Fresh air calibration uses an assumed value of 400 ppm. CO2 level deviation from 400 ppm of the sampled air determines the accuracy of this procedure. Proceed as follows: 1. Prior to executing this operation, expose the sensor to air that is assumed to be near the background level of CO2 (350 ppm to 450 ppm). 2. Wait for sensor to stabilize (at least one minute). 3. Press the minus button to execute the calibration operation. All LED indicators remain lit until the operation is complete. Analog 1 fixed output mode (OP-4) With Analog 1 enabled, this operation provides a fixed Analog 1 output. The output begins at 2 Vdc. Pressing the plus button increases the output 2 Vdc. With the output at 10 Vdc, pressing the plus button returns the sensor to operation mode. Analog 2 fixed output mode (OP-5) With Analog 2 enabled, this operation provides a fixed Analog 2 output. The output begins at 2 Vdc. Pressing the plus button increases the output 2 Vdc. With the output at 10 Vdc, pressing the plus button returns the sensor to operation mode. N/A (OP-6) An unused operation; serves as a placeholder.

All LED indicators remain lit until the operation is complete.

IMPORTANT With CO2 present during calibration, it skews the sensor zero level. This results in incorrect reports of the CO2 level.

Return to operation mode (OP-7) When you cycle past the last service mode (OP-6), the device returns to operation mode. With display model sensors, this operation displays OP-7, then returns to operation mode.

NOTES: —

—

Calibration can be done using a PC instead of the pushbuttons. Connect a PC to the unit using the special RS232 cable included in the maintenance kit. This connection does not interfere with normal operation of the ventilation system. Follow the software directions for calibration. The altitude pressure factor is zeroed when calibration is performed.

Home and Building Control Honeywell Inc. Honeywell Plaza P.O. Box 524 Minneapolis MN 55408-0524

Home and Building Control Honeywell Limited-Honeywell Limitée 155 Gordon Baker Road North York, Ontario M2H 3N7

Honeywell Latin American Region 480 Sawgrass Corporate Parkway Suite 200 Sunrise FL 33325

Honeywell Europe S.A. 3 Avenue du Bourget 1140 Brussels Belgium

63-2546—1 B.B. Rev. 6-98 63-2546—1

Printed in U.S.A. on recycled paper containing at least 10% post-consumer 8 paper fibers.

Honeywell Asia Pacific Inc. Room 3213-3225 Sun Hung Kai Centre No. 30 Harbour Road Wanchai Hong Kong

www.honeywell.com