BE-140 AD

Overview

Simultaneously measures CO, unburned HC (as n-hexane), and CO2 in automotive exhaust, using NDIR technology. Highly reliable with a long service life, BE-140 AD is certified for the three-gas portion of BAR-97 when incorporated into an exhaust-gas analysis system with sampling and control functions. Consists of solid-state infrared detectors, a microprocessor, and miniature mechanical components in a compact package. An optional galvanic cell measures O2. The unit can be wired for NO measurements, using either BE-220 or a electrochemical sensor. The microprocessor provides fully calibrated gas concentration values with compensation for atmospheric-pressure changes. Concentrations are output via RS-232C. In addition, it:

  • adjusts gain control for the detector signals.
  • performs automatic zero and electrical calibration without standard gases or mechanical checkers.
  • reads span-gas data, computes a correction factor for each gas, and stores the factors in EEPROM.
  • informs the user of alarms and self-checks.

Field-proven, accurate, and very reliable, BE-140 AD is the heart of HORIBA's MEXA-324 J/554 J series portable analyzers as well as many third-party analyzers.

Features

Applications

For OEM integration into:

  • Inspection-maintenance analyzers and systems
  • Repair-grade analyzers

BE-140 AD is certified for BAR-97 applications and conforms to the following standards and specifications:

  • OMIL (R99) Class 0
  • ISO/FDIS 3930: 2000(E)
  • DRIR (France)
  • TNO (Netherlands)
  • TUV/PTB (Germany)

Features

  • Simultaneously measures up to three components - CO, HC and CO2 - with minimum interference from coexisting gases.
  • Includes options for O2 and NO measurement.
  • 6 analog inputs and 8 digital input/outputs are freely definable by customer.
  • Solid-state, dual infrared detectors automatically compensate for common-mode temperature effects.
  • Integrated field-effects transistor (FET) minimizes noise.
  • Requires no optical adjustment.
  • 5-minute warm-up time.

Operating Principle

Based on the principle of non-dispersive infrared analysis, BE-140 AD includes:

  • Broad-band infrared light source.
  • Chopper motor.
  • Four detectors - one reference and one each for CO, CO2, and HC.

Light emission from the broad-band infrared light source passes through the sample cell containing the gases to be analyzed. As the light beam passes through the sample cell, the gases absorb some of its intensity. The attenuated beam - modulated by the chopper motor - sequentially passes into each of the four detectors.

Each detector has a narrow band-pass filter which isolates a spectral region specific to the corresponding gas (CO, CO2, or HC). The reference detector is insensitive to all three gases.

When a non-absorbing gas (like nitrogen) flows through the sample cell, the same amount of light emission reaches the reference and sample detectors. When absorbing gases (CO, HC, CO2) flow through the sample cell, less intensity reaches the sample detectors than the reference detector.

Each detector produces an electrical signal corresponding to the changes in energy absorption. The difference between sample and reference signals represents concentration of the respective components, and an output is generated.

BE-140 AD uses precision dual-detectors. Only one dual element is exposed to the modulated light path, automatically compensating for common-mode temperature effects. A field-effects transistor (FET) is built into the detector enclosure. Together, the detector and FET provide a high-level, low-noise signal over a relatively wide range of detector temperature fluctuations.

Manufactured by HORIBA

Specifications

Measured Components and Ranges

CO: 0 to 10 vol%
HC (n-Hexane): 0 to 10,000 ppm
CO2: 0 to 20 vol%
O2: 0 to 25 vol% (option)
NO: 0 to 5000 ppm (option)

Measurement Principle

CO, HC, CO2: Non-dispersive infrared absorptiometry
O2: Galvanic cell (option)
NO: Wet chemistry sensor or BE-220 NDIR (options)

Response Time

T90 less than 3.5 s at 2 L/min of sample flow (NDIR only)

Interference

Within ± 4 ppm for HC, ± 0.03 vol% for CO, ± 0.20 vol% for CO2, and ± 25 ppm for NO, under presence of these gases:

16 vol% CO2
75 ppm H2S
1600 ppm Hexane
75 ppm SO2
10 vol% CO
3000 ppm NO
9 vol% CO and 18 vol% CO2
Water-saturated air (Water maintained at 20°C ± 2°C)

Sampling Requirement

Filtered (< one micron) exhaust gas from gasoline or LPG powered vehicle with no liquid carry-over or condensation.

Sample Flow Rate

2.0 L/min to 3.0 L/min

Warm-up Time

5 minutes

Ambient Conditions

10 to 50°C, R.H. less than 90% R.H., non-condensing
Atmospheric Pressure: 75 kPa to 105 kPa (within ± 2500 Pa)
Altitude: -300 m to 2500 m
Wind Speed:1 to 3 m/s, stable filtered air for cooling

Dimensions and Weight
(W X H X D)

225 x 140 x 103 mm
8.9 x 5.5 x 4.1 in

Approx 1.0 kg / 2.2 lb

Power

23 W max. (analog circuit ± 15V)
20 W max. (analog circuit ± 12V)

Light Source
+5 V DC ± 0.1 V, 1.5A max.

Digital Circuit
+5 V DC ± 5%, 0.7A max.

Analog Circuit
+15 V DC ± 5%, 0.7 A max.
-15 V DC ± 5%, 0.1 A max.
or
+12 V DC ± 5%, 0.6 A max.
-12 V DC ± 5%, 0.1 A max.

Output

RS-232C Serial interface 9600 Baud 3 wires

 

 

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