MDS-4 ON-BOARD EVALUATION SYSTEM

Transcription

1 Electro Optical Components, Inc Skylane Boulevard, Suite D, Santa Rosa, CA Toll Free: 855-EOC MDS-4 ON-BOARD EVALUATION SYSTEM FOR METHANE DETECTION INSTRUCTION MANUAL rev

2 TABLE OF CONTENTS General Information 3 Application 3 Brief overview of the board 3 Operation conditions 4 Operation instructions 5 Precautions 6 Appendices 7-8 Appendix 1: Lms34LED main parameters 7 Appendix 2: Lms36PD-05 Main Parameters 8 Technical characteristic 9 2

3 GENERAL INFORMATION Application MDS-4 is an on-board evaluation system for CH4 detection. The board contains: an LED-photodiode optopair, an LED driving and photodiode signal amplification blocks, processing and synchronizing blocks. Brief Overview of the Board front side driver block synchronous detector block photodiode preamplifier block driver block Driver is a power supply for an LED. It works in the pulse mode and has the following fixed parameters: frequency 0.5 khz pulse duration 20 µs current 1 A photodiode preamplifier block PD preamplifier amplifies the current, generated by the photodiode, and converts it into voltage signal. The block is shielded to avoid noises. synchronous detector block Synchronous detector block measures the voltage signal from the output of photodiode preamplifier and converts it to the DC voltage signal proportional to amplitude of voltage from input. 3

4 GENERAL INFORMATION rear side Light-emitting diode Lms34LED Photodiode Lms36PD-05 Light-emitting diode Lms34LED Standard LMSNT light-emitting diode with 3.4 µm peak wavelength, in TO-18 package with CaF2 lens. For detailed information and set of characteristics please refer to Appendix 1. Photodiode Lms36PD-05 Standard LMSNT photodiode with 3.6 µm cut-off wavelength, in TO-18 package with CaF2 lens. For detailed information and set of characteristics please refer to Appendix 2. The length of the optical path between the LED and the photodiode is ~30 mm. Operation conditions Indoor operation only. Ingress Protection Rating IP00. 4

5 OPERATION INSTRUCTIONS Connections Connect the signal output terminal block with an external signal observing device (multimeter, oscillograph or PC via ADC). 2. Connect the temperature measurement output terminal block with an external signal observing device (multimeter, oscillograph or PC via ADC). Note! On the MDS-4 board there is a thermoresistor that measures preamplifier ambient tamperature. The thermoresistor is situated under the aluminum shielding. The correspondence between the thermoresistor output signal and the ambient temperature is the following: -20 C mV 0 C 0mV 20 C 200mV 3. Choose averaging time using the averaging time adjustment jumper ( 1-100μs, 2-200μs, w/o jumper - 300μs). 4. Choose signal gain using the signal gain adjustment jumper ( 1 5x gain, 2 10x gain, w/o jumper 1x gain). 5. Connect a 12V DC stabilized power supply to the MDS-4 board power input terminal block. The board will turn on. After all connections are made, you will see a constant voltage signal on your signal observing device. The presence of methane and/or other matters which have absorption bands at 3.4 region will attenuate the initial output signal. 5

6 PRECAUTIONS Turn on the power supply of the MDS-4 board only after all connections are made and tested. Do not switch jumpers during operation. Do not disassemble the LED and the photodiode; otherwise the scheme arrangement will be distuned. Do not use multimeter to control and adjust current of the LED. Note! Please refer to your provider if you have any questions. 6

7 Intensity, a.u. Current, ma APPENDIX 1 Lms34LED Main Parameters (QCW operation mode, f=0.5 khz, T=24 C) Parameter Units Conditions Ratings Peak emission wavelength µm 150 ma 3.39 FWHM of the emission band nm 150 ma Temperature drift of emission peak nm/k ma 8,44 Average optical power µw 100 ma 15, ma 22, ma 28, Typical Spectrum at 150 ma Typical C-V characteristic Wavelength, nm Voltage, mv 7

8 Sensitivity, arb. u. CURRENT, ma APPENDIX 2 Lms36PD-05 Main Parameters (T=24 C) Parameter Units Conditions Ratings Sensitive area diameter mm Cut-off wavelength μm Peak sensitivity wavelength μm Dark current ma (Vr = -0.1 V) 250 Shunt resistance Ω (Vr = -10 mv) Typical Spectral Response H 2 O absorption Typical Current-Voltage Characteristic ,8 0,6 0, , Wavelength, nm -600,0-400,0-200,0-10 0,0 200,0 400, VOLTAGE, V 8

9 TECHNICAL CHARACTERISTICS Power supply voltage +12 V, stabilized Voltage tolerance % Power supply current, max 0.1 A Board dimensions mm Output constant voltage signal, max 10 V Adjustable parameters Averaging time 100/200/300 µs Signal gain 1x/5x/10x Operation mode Pulse duration 20 µs Frequency 0.5 khz Current 1 A 9