Series:Advance Optima

  Product Description

  The AO2000-LS25 is a complex instrument that utilizes state-of-the-art electronic and laser technology.The installation and maintenance of instruments require caution and preparation.If not done,it may damage the instrument and void the warranty.1.2 Measurement Principle AO2000-LS25 is a continuous in-situ gas monitoring device,pipeline,process room,or similar,and is based on tunable diode laser absorption spectroscopy(TDLAS).The AO2000-LS25 uses a transmitter/receiver configuration(installed radially opposite each other)to measure the average gas concentration along the line of sight path.The measurement principle is infrared single line absorption spectroscopy,which is based on the fact that each gas has a different absorption line at a specific wavelength.The measurement principle is shown in Figure 1-1.The laser wavelength is scanned on the selected gas absorption line to be measured.Carefully select the absorption line to avoid cross interference from other(background)gases.Due to the absorption of target gas molecules in the optical path between the transmitter and receiver,the detected light intensity changes as a function of the laser wavelength.In order to improve sensitivity,wavelength modulation technology was adopted:the laser wavelength was slightly modulated while scanning the absorption line.The detector signal is decomposed into harmonic frequency components of laser modulation frequency in the spectrum.The second harmonic of the signal is used to measure the concentration of the absorbed gas.The line amplitude and line width are extracted from the second harmonic line shape,which makes the measured concentration insensitive to the linear changes caused by the background gas(line broadening effect).Note:AO2000-LS25 only measures the concentration of free molecules of specific gases,so it is not sensitive to molecules that combine with other molecules to form complexes and molecules attached or dissolved in particles and droplets.Be careful when comparing measurement results with those of other measurement techniques.

  The transmitter unit consists of a laser module with a temperature stabilizing diode,laser,collimating optics,and main electronics in a coated aluminum box.The receiver unit contains a focusing lens,photodetector,and an electronic product housed in a coated aluminum box.

  Both the transmitter and receiver units have an IP66 environmental protection standard optical window that can withstand pressures of up to 5 bar(absolute pressure).This is achieved by sequentially installing the transmitter and receiver units along with the provided purge and calibration devices on the process flange of DN50.Optical alignment is simple and reliable,and cleaning can prevent dust and other pollutants from depositing on optical components and windows.

  The power supply unit converts 100-240V AC power into 24V DC power(which can be directly supplied to the transmitter unit if 24 VDC is available).The power box is connected to the transmitter box through a cable.The 4-20 mA input signal from an external gas temperature/pressure sensor can be connected to the terminals inside the screw power box or directly to the cable connector unit on the transmitter

  The receiver electronic device is connected to the transmitter electronic device through a cable.The absorption signal detected from the photodetector is amplified and transmitted to the transmitter unit through this cable.The power required for the same cable transmission from the transmitter unit to the receiver unit.

  The aluminum box of the transmitter contains the main parts of the electronic equipment.The CPU board performs all instrument control and gas concentration calculations.The main board contains all electronic devices required for instrument operation,such as diode laser current and temperature control,as well as analog-to-digital signal conversion.A.The LCD continuously displays gas concentration,laser beam transmission,and instrument status.The RS-232 port can be used for direct serial communication with a PC.The optional Ethernet board provides TCP/IP communication over a LAN(local area network),which can be used instead of serial communication.All cable connectors are Phoenix VARIOSUB waterproof cables.

  software

  The software of AO2000-LS25 consists of two programs:

  1.A program that is hidden from the user and integrated into the CPU electronic device,running the microcontroller on the CPU card.The program performs all necessary operational calculations and self monitoring tasks.

  2.A Windows based program that runs over an RS-232 connection.This program can achieve communication with the instrument during installation,maintenance,and calibration.The operator only needs to perform installation and calibration,rather than during normal instrument operation.

  Laser classification

  The diode laser used in AO2000-LS25 operates in a near-infrared(NIR)environment with a range between 700 and 2400nm,depending on the gas to be measured.The output power of this laser complies with the latest version of IEC 60825-1,which classifies AO2000-LS25 as a laser first-class product

  application area

  Thermal power plant

  Chemical processing plant