Product Specification

aSENSE and aSENSE RL

Carbon dioxide and temperature transmitters

Article numbers: 045-8-0xxx

 

 

 

1.       General description of devices

 

The aSENSE are CO2 and temperature sensors. The aSENSE RL has a programmable output for relay control of of e.g. mixed air dampers, humidifier and fans. Designed for CO2 based ventilation it measures CO2 concentration and temperature in the ambient air in rooms and in ventilation ducts. The data is transmitted to a BMS system or stand-alone controller using industry standard output signals and communications protocols.

 

Item

aSENSE specification

Measured gas

Carbon dioxide (CO2)

Operating Principle

Non-dispersive infrared (NDIR) waveguide technology

OUT1 CO2

0 - 10VDC, 0 - 2000ppm CO2

Accuracy CO2

±30 ppm ±3% of measured value3

Response time (T1/e) CO2

< 3 min. diffusion time

Pressure Dependence

+1,6% reading per kPa deviation from normal pressure, 100kPa

OUT2 Temp

0 - 10VDC, -20 – +60 oC

Accuracy Temp

±1°C

Operation Temperature Range

0-50 oC

Operation Humidity Range

0-85 %RH (non-condensing)

Operating environment

Residential, commercial1

Storage temperature

-40 to +70 °C (display models: -20 to +50 °C) 1 

Dimensions wall mounted (mm)

120 x 82 x 30

Dimensions duct mounted (mm)

152 x 85 x 47 (Probe length: 245mm)

Dimensions industrial housing (mm)

152 x 85 x 47

Power supply

24VDC or 24VAC (50 - 60Hz) ± 20%, half-wave rectifier input

Power consumption

< 1 W average

Life expectancy

>15 years 2, 5

Yearly drift

< +-150ppm  @1000ppm 6

< +-100ppm  @0ppm 6

 

(can't difine amount of drift during power-off)"

Conformance with standards

EMC 2004/108/EC directive

EN 61000-6-1:2001 “Immunity for residential, commercial and light industrial environments”

EN 61000-6-3:2001 “Emissions standards for residential, commercial and light industrial environments”

RoHS directive 2011/65/EU

Serial communication

UART (Modbus protocol)

Maintenance

No maintenance required as Auto Background Calibration, ABC, is used. 2,4

Table 1: Key technical specification for the aSENSE and aSENSE RL

 

Note 1: SO2 enriched environments are excluded.

Note 2: This device generation of heat (self-heating due to power consumption) does not influence/violate temperature    accuracy specification of this device, as long as CO2 measurement (lamp blink) interval is ≥ 15s.

Note 3: Accuracy is specified over operating temperature range. Specification is referenced to certified calibration mixtures. Uncertainty of calibration gas mixtures (+-2% currently) is to be added to the specified accuracy for absolute measurements.

Note 4: In normal IAQ applications, accuracy is defined after minimum 3 weeks of continuous operation with ABC.

Note 5: Repeatability is included. Uncertainty of calibration gases (+-2% currently) is added to the specified accuracy.

Note 6: Yearly drift of unpowered sensor is not defined

 

2.       Drawings

 

  

Figure 1 Housing of wall mounted sensors

 

Figure 2 Duct housing measured in mm and (inches)

 

 

3.       Terminals and outputs description

 

The table below specifies cable connections of the aSENSE.

 

Cable connections

Descriptions and ratings

Power supply

 

Positive pole of DC power supply is connected to +~. Sensor performs half wave rectification of supplied AC voltage. Power supply lines are protected by varistor from voltage spikes and over voltage. A fuse and a diode protect the electronics.

Nominal specification:24VDC, 24VAC +-20%,50-60Hz

Absolute minimum to maximum ratings 16.5 to 40VDC

Connected to sensor’s ground.

Negative pole connection for DC power supply

Outputs for both aSENSE and aSENSE RL

Out(1)

Factory setting is linear output, 0-10VDC for 0-2000ppm CO2

Out(2)

Factory setting is linear output, 0-10VDC for 0-20oC

Outputs for aSENSE RL

5 NC

Relay output Normally Open

6 COM

Relay Output Common

7 No

Relay Output Normally Open

8

Not used

Indicators

 

Yellow status LED

OFF = OK, Lit = Fault.

 

Red status LED

Lit when the relay is closed

LCD

LCD is dedicated to represent measured values and status of the sensor.

Jumpers

 

Start point jumper

Jumper in top position gives 0-100% output, 0-10V as default

Jumper in lower position gives 20-100% output, 2-10V as default

Out(1)

Jumper in left position gives mA output

Jumper in right position gives V output, default

Out(2)

Jumper in left position gives mA output

Jumper in right position gives V output, default

Serial Communication

UART (TxD, RxD)

Available from JP3.

5V CMOS logical levels, ModBus communication protocol. Logical levels corresponds 5V powered logics.

 

Protection 56R resistors are added on RxD and TxD lines

RxD line is configured as digital input.

Input high level is 2.1V min
Input low level is 0.8V max
TxD line is configured as digital output.

Output high level is 4.0V
Output low level is 0.75V max

 

RxD input is pulled up to DVCC = 5V by 56kΩ
TxD output is pulled up to DVCC = 5V by 56kΩ

 

4.       General PCB overview

 

 

Figure 3 The aSENSE PCB with jumpers and terminal area enlarged at right

 

 

Figure 4 The aSENSE RL PCB with jumpers and terminal area enlarged at right

 

5.       Calibration

 

The aSENSE and aSENSE RL are maintenance free in normal environments thanks to the built-in self-correcting ABC algorithm (Automatic Baseline Correction). This algorithm constantly keeps track of the sensor’s lowest reading over a 7.5 days interval and slowly corrects for any long-term drift detected as compared to the expected fresh air value of 400 ppm CO2.

 

Rough handling and transportation might, however, result in a reduction of sensor reading accuracy. With time, the ABC function will tune the readings back to the correct numbers. The default “tuning speed” is however limited to about 30-50ppm/week.

 

An internal self-adjusting calibration function takes care of normal long term drift associated to the CO2 sensor. To secure the highest accuracy, a time interval of five years is recommended between CO2 calibrations, unless some special situations have occurred.

 

A zero calibration can be performed by use of pure nitrogen or air that has passed through a chemical absorber and a PC together with the UIP software version 5 (or higher) or by shortening of holes marked in figure 5 for at least 10 seconds. The sensor needs stable gas flow for at least 3 minutes before zero calibration. The Zero Calibration bag can be used to produce carbon dioxide free air. The software can be free downloaded from www.senseair.com. The RS232-cable and the zero calibration bag can be ordered from SenseAir. The cable is to be connected to the UART port slide connector (see Fig. 3 or 4). For change of control parameters and re-calibration of temperature this PC tool has to be used. Zero calibration can be done with PC and UIP software version 5 or by shorting marked holes in figure 5. The check can be done on site without interfering with the ventilation system.

 

A Back-ground calibration is an easy way to correct a sensor’s zero point. The sensor needs fresh air (380-420 ppm CO2). Shorten holes marked in figure 5 for at least 10 seconds.

 

This is for sensors with measuring ranges 0-2000 ppm:

When a zero calibration shall be executed a plastic tube with 2.2 mm outer diameter and 0.8 mm inner diameter shall be inserted in marked holes of the sensor. Plastic tubing is connected to the tube. The gas flow should be between 0.3 and 1.0 l/min. The sensor needs stable gas flow for at least 3 minutes before zero calibration. Shorten marked holes for at least 10 seconds. A successful calibration is acknowledged by 5 flashes of the yellow LED. If unsuccessful, please release input and waits at least 10 seconds before repeating the procedure again. Make sure that the sensor environment is steady and calm!

 

 

Figure 5 Holes to shorten for calibration

 

6.       Self-diagnostics

 

The system contains complete self-diagnostic procedures. A full system test is executed automatically every time the power is turned on. In addition, constantly during operation, the sensor probes are checked against failure by checking the valid dynamic measurement ranges. All EEPROM updates, initiated by the sensor itself, as well as by external connections, are checked by subsequent memory read back and data comparisons. These different system checks return error bytes to the system RAM. The error codes are available by connecting a PC with a special RS232 cable connected to the UART port slide connector. The error codes are shown in the software UIP (version 5 or later). Warm up and Out of Range are the only bits that are reset automatically after return to normal state. All other error bits have to be reset manually after return to normal by power off/on.

 

The yellow LED lights yellow at heating phase after power up and if an error has been detected.

 

 

Error code and action plan

 

Bit #

Error code

Error description

Suggested action

0

N/A

Fatal Error

Try to restart sensor by power OFF/ON. Contact local distributor

1

2

Reserved

 

2

4

Algorithm Error.

Indicate wrong EEPROM configuration.

Try to restart sensor by power OFF/ON.

Check detailed settings and configuration with UIP software version 5 and higher.

Contact local distributor.

3

8

Output Error

Detected errors during output signals calculation and generation.

Check connections and loads of outputs.

Check detailed status of outputs with UIP software version 5 and higher.

4

16

Self-Diagnostic Error.

Algorithm timeout

Check detailed self-diagnostic status with UIP software version 5 and higher.

Contact local distributor

5

32

Out of Range Error

Accompanies most of other errors.

 

Resets automatically after source of error disappearance.

 

Try sensor in fresh air.

Check connections of temperature and relative humidity probe.

Check detailed status of measurements with UIP software version 5 and higher.

 

See Note 1!

6

64

Memory Error

Non-fatal error during memory operations.

Check detailed settings and configuration with UIP software version 5 and higher.

7

128

Warm Up state

Is always set after power up or power failure. Resets after restart sequence.

If it doesn’t disappear in half a minute, check power stability.

Table IV Error codes

 

Note 1.  Any probe is out of range. Occurs, for instance, during over exposure of CO2 sensor, in which case the error code will automatically reset when the measurement values return to normal. Could also indicate the need of zero point calibration. If the CO2 readings are normal, and still the error code remains, the temperature sensor can be defect or the connections to it are broken.                          

 

Remark: If several errors are detected at the same time the different error code numbers will be added together into one single error code!

 

PLEASE NOTE! The sensor accuracy is defined at continuous operation (at least 3 weeks after installation)

 

7.       Materials

 

Part

Material

Color

Requirement

Min. UL Rating

Wall mounted sensors

Novodur P2H-AT

White/Offwhite

 

UL94-HB

Duct mounted sensor base

Plastic PC/ABS Bayblend FR3000

Black

 

Minimum

UL94-5V

Duct mounted sensor tube

Plastic PC/ABS Bayblend FR3000

Black

 

Minimum

UL94-5VB

Cable gland

Plastic polyamide based

Black

 

UL94-V2

Duct mounted sensor lid

Plastic Polycarbonate Makrolon 6555

Transparent

QMFZ2

UL94-V0

 

8.       User instructions

 

Please see manual.

 

9.       List of standards applied

 

Applicable standards:

EN 61326-1:2006 "Electrical equipment for measurement, control and laboratory use"

Emission: EN 61326-1:2006 class B equipment
Immunity: EN 61326-1:2006. Tested for basic immunity test requirements (table 1, part 6.2)

 

 

Compliant standards:

EN 61000-6-1:2001 " Immunity for residential, commercial and light-industrial environments"

EN 61000-6-3:2001 "Emission standard for residential, commercial and light-industrial environments"

 

 

Accordingly tests have been performed as specified in the following standards:

Basic standard

Compliant

Test of

CISPR 11:2007

Yes, class B, group 1

Radiated emission

CISPR 11:2007

Yes, class B, group 1

Conducted emission

IEC 61000-3-2:2005

Not applicable. Note 1

Harmonics at power terminals

IEC 61000-3-3:2008

Not applicable. Note 2

Flicker at power terminals

Note 1: Less than 75W.  Note 2: Unlikely to produce significant voltage fluctuations or flicker

 

Basic standard

Compliant

Test of immunity to

IEC 61000-4-3:2006

Yes

Radiated Radio Frequency Fields

IEC 61000-4-6:2008

Yes.

Conducted disturbances induced by radio frequency fields

IEC 61000-4-4:2004

Yes.

Electrical fast transients, Burst

IEC 61000-4-5:2005

Yes.

Surge

IEC 61000-4-2:1995

Yes.

ESD

IEC 61000-4-11:2004

Yes.

Voltage dips

 

RoHS and SVHC: EN 50581. Technical documentation for the assessment of electrical and electronic products with respect to the restriction of hazardous substances.

 

10.   Markings and labels

 

The sensors are marked with article number, connecting power, standard output configurations, production date, the crossed-out wheeled bin of the WEEE directive and the CE mark. The wall mounted sensors are marked with a label on the inside of the back plate. The terminal and jumpers are on a label in the top cover of the sensor. The duct mounted sensors have a label on the outside of the housing. The terminal and jumpers are on a label on the inside of the lid.

 

11.   Test report

 

The PCB used in all these sensors has been tested for EMC and passed the test. Test report for the PCB used in all these sensors is Test report #10248P from Jan Linders Ingenjörsfirma. The test report is marked K45 platform aSENSE.

 

All components on the PCB are RoHS compliant. Proof is material declarations or declarations of conformity to RoHS from suppliers. All housing parts are also RoHS compliant.

 

 

12.   Internal production control

 

All PCBs are individually calibrated and verified. After mounting in the housing all sensors are finally tested.

 

13.   Declaration of conformity

 











 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SenseAir® AB

SenseAir® North America

SenseAir® Chengdu Gas Sensors Ltd.

Box 96

29030 SW Town Center Loop East

First floor 8th of Xingke Road

Stationsgatan 12

Suite 202 - #169

Hi-Tech Industry Park

SE- 82060 Delsbo

Wilsonville, OR  97070

Jinniu district, Chengdu

Sweden

USA

Sichuan province

 

 

China

 

 

 

Phone: +46(0)653 – 71 77 70

Phone:  +1 52.0.349.7686

Phone: +86-028 - 875 928 85

Fax:      +46(0)653 – 71 77 89

 

Fax:      +86-028 – 875 928 85

E-mail: info@senseair.com

E-mail: infoamerica@senseair.com

E-mail:  info@senseair.asia

Web page: www.senseair.com

 

Web page: www.senseair.asia

                     

 

 

 

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