Frankfurt Laser Company MDK User manual

MDK
EVALUATION KIT FOR
METHANE DETECTION
INSTRUCTION MANUAL
rev. 250516

2
TABLE OF CONTENTS
General Information
3
Application
3
Packaging arrangement
3
Operation conditions
3
Brief overview of the components included
4
Recommended operation mode for the kit
5
Operation instructions
6-8
Precautions
8
Appendices
9
Appendix 1: Lms34LED main parameters
9
Appendix 2: Lms36PD-05 main parameters
10
Appendix 3: Drivers Applicable for the MDK Evaluation Kit
11

3
GENERAL INFORMATION
Application
MDK is an evaluation kit for CH4detection based on mid-infrared LED-PD optopair,
which includes all the needed components for quick and simple start. The possibility to
change the parts within the kit easily makes the kit a flexible and utility solution.
Packaging arrangement
MDK includes:
Light-emitting diode Lms34LED-RW
Photodiode Lms36PD-05-RW with a built-in PD preamplifier
D-41i/D-51i/mD-1p LED Driver (depends on customer request)
SDM synchronous detector
acrylic glass optical chamber (optional)
Operation conditions
Indoor operation only. Ingress Protection Rating IP00.

4
BRIEF OVERVIEW OF THE COMPONENTS INCLUDED
Light-emitting diode
Light-emitting diode Lms34LED-RW –LMSNT light-emitting diode with 3.4 µm peak
wavelength, in TO-18 package with a parabolic reflector. Main LED parameters are
pointed in Appendix 1. For detailed information and set of characteristics please refer
to the appropriate technical passport.
Photodiode with a built-in preamplifier
Photodiode Lms36PD-05-RW-PA –LMSNT photodiode with 3.6 µm cut-off wavelength,
with a built-in preamplifier, mounted in an aluminum tube with a parabolic reflector.
PD preamplifier amplifies the current generated by photodiode and converts it into
pulse voltage signal. There is straight correspondence between PD current and resulting
output voltage, i.e. if the photocurrent from photodiode is a meander, the converted
signal will be a meander too with the same frequency and pulse duration.
Main photodiode parameters are pointed in Appendix 2. For detailed information and
set of characteristics please refer to the appropriate technical passport.
D-51i/D-41i/mD-1p LED Driver (depends on customer request)
LED Driver is a power supply for an LED. D-41i/D-51i driver types have a
set of adjustable parameters to customise the desired operation mode
of an LED. mD-1p driver provides operation at one fixed pulse mode.
For brief information about drivers pleas e refer to Appendix 3. For
comprehensive information about the driver please refer to the driver’s
Instruction Manual.
SDM Synchronous Detector
SDM synchronous detector 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.
For comprehensive information about the synchronous detector please
refer to the appropriate Instruction Manual.
SDM
Synchronous
Detector
D-51i LED Driver

5
RECOMMENDED OPERATION MODE FOR THE KIT
Driver settings (for D-41i/D-51i models)
LED current
I, A
0.2-1
Pulse duration
τ, µs
10-20
Frequency
f, kHz
0,5
SDM synchronous detector settings
Signal gain
times
x5
Averaging time
ms
200

6
OPERATION INSTRUCTIONS
1. Connect the preamplifier output with an input of SDM synchronous detector.
Green cord –to the signal input “+”; Yellow cord – to the signal input “0”
2. Connect a 5V power output of the SDM synchronous detector to the preamplifier
power input.
White cord –to the power output “+”; Brown cord –to the power output “0”
Note!
- Please check your connection circuit before turning the PD on.
- Please do not connect the PD to the multimeter.
- Please do not touch the glass covering
- Pay your attention to the colours of the cords; actual colours may differ from ones
pointed in the present manual, follow the instructions pointed in the technical data
provided with the order.
3. Select the needed signal gain and averaging time on the SDM synchronous
detector.
Note! You can find out more about adjustment of the signal gain and averaging time in
the appropriate SDM synchronous detector manual.
SDM synchronous
detector
photodiode with a built-in
preamplifier
synchronous detector signal
input terminal block
photodiode with a built-in
preamplifier
5V power output
terminal block
SDM synchronous
detector
averaging time
jumper
signal gain
jumper
SDM synchronous
detector

7
OPERATION INSTRUCTIONS
4. Connect the LED pins to the LED connection terminal block of the LED driver.
Note! All driver connections in this manual are pointed for D-51i LED driver;
connections with other drivers should be done similarly.
CAUTION! The pin with red dot must be connected to the “+” sign of the driver terminal
block.
5. Connect the synchronisation output of the LED driver with the synchronisation
input of the synchronous detector via synchronisation cable.
6. Select the needed mode of the LED driver.
Note! You can find out more about driver modes and their adjustment in the
appropriate Driver Instruction Manual.
D-51i LED driver
synchronisation
output terminal
block
synchronisation
input terminal
block
SDM
synchronous
detector
D-51i LED driver
LED connection
terminal block
LED
current adjustment
jumper
frequency
adjustment jumper
pulse duration
adjustment jumper

8
OPERATION INSTRUCTIONS
7. Connect signal output terminal block of the SDM synchronous detector with
signal observing device (multimeter, oscillograph or PC via ADC).
8. Connect a 12V DC stabilised power supply to the LED driver and SDM
synchronous detector (red wire to the “+”; black wire to the “‒”).
signal output
terminal block
oscilloscope
SDM
synchronous
detector

9
PRECAUTIONS & NOTES
Turn on the power supply of the LED Driver and SDM synchronous detector only
after all connections are made and tested.
Do not switch driver regimes during operation.
Do not use multimeter to control and adjust current of the LED.
Do not bend and/or twist LED and photodiode pins; otherwise the optical system
will be damaged.
Note! Please refer to your provider if you have any questions.

10
APPENDIX 1
Lms34LED Main Parameters (QCW operation mode, f=0.5 kHz, T=300 K)
Parameters
Units
Conditions
Ratings
Min
Typ
Max
Peak emission wavelength
m
T=300 K, I = 150 mA qCW
3,30
3,40
3,49
FWHM of the emission band
nm
I = 150 mA qCW
400
500
600
Quasi-CW Optical Power
W
I = 200 mA qCW
25,0
35,0
45,0
Pulsed Peak Optical Power
W
I=1 А, f=1 kHz, duty cycle 0.1%
320
400
480
Voltage
V
T=300 K, I=200 mA
0,2
-
0,5
Spectra at different currents (qCW, T=300 K)
Spectra at different temperatures (qCW, I=150 mA)
LED Typical Current-Voltage Characteristics (T=300K)
LED Power Characteristic (quasi-CW mode, T=300K)
0
10
20
30
40
50
60
2700 3000 3300 3600 3900 4200
Intensity, a.u.
Wavelength, nm
50mA
100mA
150mA
200mA
0
10
20
30
40
50
60
70
2700 3200 3700 4200
Intensity, a.u.
Wavelength, nm
2°C
22°C
50°C
-50
0
50
100
150
200
250
-1000 -500 0 500 1000 1500
Current, mA
Voltage, mV
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
050 100 150 200
Power, W
Current, mA

11
APPENDIX 2
Lms36PD-05 Main Parameters (T=300 K)
Photodiode
Parameters
Conditions
Symbol
Value
Units
Cut-off wavelength
T=300 K
λcut
3.6
mm
Max. sensitivity
wavelength (>90%)
T=300 K
λp
2.2 ― 3.4
mm
Dark current
T=300 K, Vr=-0,1 V
Id
0.5 ― 1
mA
Shunt resistance
T=300 K, Vr=-10 mV
Rsh
0.2 ― 0.8
kΩ
Capacitance
T=300 K, λ=λp
C
600 ― 1400
pF
Sensitivity
T=300 K, λ=λp
S
1.0 ― 1.5
A/W
Detectivity
T=300 K, λ=λp
D*
(4-14)*109
cm.Hz1/2.W-1
Spectral response (typical)
Temperature shift of spectral response
0
0,2
0,4
0,6
0,8
1
2000 2500 3000 3500 4000
Sensitivity, arb. u.
Wavelength, nm
0
0,2
0,4
0,6
0,8
1
3000 3200 3400 3600 3800
Sensitivity, arb. u.
Wavelength, nm
11°С
25°С
50°С
Water absorption

12
APPENDIX 3
Drivers Applicable for the MDK Evaluation Kit
LED driver D-41i
D-41i Driver provides Pulse mode operation. Using this
mode it is possible to choose one of five current values
(0.2/0.6/1/1.5/1.9 A) and select one of four frequencies
(0.5/1/2/4 kHz) and choose pulse duration within five values
(5/10/20/50/150 µs).
LED driver D-51i
D-51i Driver has the same characteristics as D-41i but also
has another important feature:
Temperature control –possibility to define LED p-n
junction temperature using current-voltage dependence.
Driver generates the low current signal for plugged LED,
measures and outputs the voltage. Using the obtained
voltage value it is possible to calculate the intrinsic LED
temperature.
mD-1p minidriver
mD-1p minidriver is a cost-effective driver that enables LED
operation at fixed driving mode: 2 A current, 2 kHz frequency
and 5 µs pulse duration.