Specialist in Optoelectronics

Optical Cell Evaluation Kit (OCEK)

The new technology of mid-IR-LED's measuring gas concentration requires special drive and detector circuitry, fast A/D converters and micreoprocessor control to optimise for your application. We provide all of that in the OCEK. Simply select LED current, pulse width, number of pulses and duty cycle and you are starting to make measurements. Select Hi or Lo gain on the preamps or fit your own opamps into out preamp sockets to test your ideas. Multiple test points and link options allow you to select detector type, op-amp configuration and check, with an oscilloscope, all input and output signals, quickly and easily.

The evalution kit can evalute IR optical gas cells and will also operate with visible and UV optical cells.Alternatively, fast response black body sources can be controlled with this OCEK.

The OCEK consists of a pre-wired gas cell in a screened metal box, with evaluation circuitry and a RS232 interface. You need only provide a ±8 volt power supply and IBM compatible PC to get the system operating. Supplied with PC software which is easy to install and operate with drop down menus.

The RS232 output to the OCEK software, with drop down menus and mouse driven usage. Output is to printer, plotter or export. Easy user configuration of experiment parameters, file control and export, and can be used with general comms software.


Gas Hydrocarbons CO2 CO Water
Wavelength (micron) 3.2-3.4 4.2 4.7 1.85
Maximum
Range
Resolution
Accuracy

0-100%
0.1%
1%

0-100%
0.1%
1%

0-10%
0.1%
1%

0-10%
0.1%
1%
Typical
Range
Resoulation
Accuracy

0-5%
0.05%
0.1%

0-10%
0.05%
0.2%

0-1%
50ppm
200ppm

0-1%
50ppm
200ppm
Low
Range
Resolution
Accuracy

0-100ppm
10ppm
10ppm

0-3000ppm
5ppm
50ppm

0-500ppm
5ppm
10ppm

0-500ppm
5ppm
10ppm

The above table shows approximate capabilities of optical IR gas cells, using LMS IR-LED's.

The IR cell includes cell body with 5cm pathlength, gas cell optics, 1.8, 3.3, 3.4, 3.8, 4.2 or 4.7 micron LED, and photoconductive detectors: one for reference, one for gas detection.



Specifications

Computer IBM compatible
Usable Timing Ranges
Pulse Width
Pulse Repition Rate
Pulses Per Cycle)
Dead Time

20microsecond to 10msec
50microsecond (20KHz) to 20msec (50Hz)
1 to 2000
65 to 500msec
LED Current Ranges
Maximum average emitter current
0 - 2.55A
1.0A
Bias Voltage (Photoconductive Detector mode)
Ripple
0 - 95V
1.2mV (approx) 1KHz at 80V
On-board amplifiers
-3dB bandwidth, sine wave i/p
Noise, i/p s/c, bias at 80V

0.4 Hz to 147 KHz
6.6 nVHz^1/2

Options:

{short description of image} LMS ±8VDC Power Supply Unit

{short description of image} Thermoelectric cooler controller

{short description of image} Gas sampling pump


OCEK advantages:
Infrared LED's can be pulsed at high frequency for optimising signal-to-noise ratio and power consumption. Narrow bandwidth LED's eliminate the need for filters. Evaluation Kit accepts pyroelectric, photoconductive and photovoltaic detectors. Optional thermoelectric controller with PC control for easy evaluation of Peltier cooled emitters and detectors. Software includes experiment programming, graphics, customed linearisation.

Typical Applications:

{short description of image} Water vapor concentration at low temperature

{short description of image} Hydrocarbon concentration from 1000ppm to 100% methane

{short description of image} Carbon dioxide from 300ppm to 25%.

Two gas monitoring:

{short description of image} Carbon dioxide and methane at landfill sites

{short description of image} Nitrous oxide/ carbon dioxide monitoring in greenhouses and horticultural uses

{short description of image} Leak detection: petroleum and natural gas facilities

{short description of image} Combustion analysis for TOC etc

{short description of image} Alarm detection where interfaces with electrchemical cells invalidate their use.

This evaluation kit will operate with visible and UV optical cells.

For applications advice, or to place your order, please contact:
Laser Monitoring Systems



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