WARRANTY First Year Warranty The Gentec-EO thermal power and energy detectors carry a one-year warranty (from date of shipment) against material and /or workmanship defects when used under normal operating conditions. The warranty does not cover recalibration or damages related to misuse. Gentec-EO will repair or replace at its option any wattmeter or joulemeter which proves to be defective during the warranty period, except in the case of product misuse.
TABLE OF CONTENTS WARRANTY........................................................................................................2 TABLE OF CONTENTS ......................................................................................3 LIST OF ILLUSTRATIONS .................................................................................4 1 GENERAL INFORMATION 5 1.1. System Overview 2 5 Lock In Amplifier Theory of Operation 2.1. Mathematical Description of a Lock In Amplifier. 2.2.
LIST OF ILLUSTRATIONS Fig. 1 Input signal ....................................................................................................................... 7 Fig. 2 Reference signal .............................................................................................................. 8 Fig. 3 Result of multiplication ................................................................................................... 8 Fig. 4 Output with 100ms time constant .....................................
1 GENERAL INFORMATION 1.1 System Overview Welcome to the T-Rad-USB Application Software. This software, when coupled with a Gentec-EO T-Rad-USB, provides the user with a versatile measurement system. There are multiple sensors available for the system. When a sensor is mated to the USB module, the module reads the sensor type, sensor calibration, sensor wavelength response, and configures the hardware appropriately.
If we set B to unity and hold it constant, then the result is a signal that is: 1. Proportional to the A, the amplitude of the input signal. 2. Proportional to the cosine of the phase angle between the two signals. 3. Modulated at two times the input signal frequency.
If we square these and add them together we obtain: Now taking the square root gives: The output of the multiplication is no longer phase dependant. 2.2 Time Domain Description of a Lock In Amplifier. The input signal has peak amplitude of 5V (10V peak to peak) and a frequency of 25Hz and is shown in figure 1. Figure 1 Input Signal T-RAD-LEMO-USB Instruction Manual Version 1.0 June.
The reference signal supplied by the lock in signal has peak amplitude of 1V and a frequency of 25Hz and is shown in figure 2. Figure 2 Reference Signal After multiplying the two signals using a circuit called a Phase Specific Detector in ananalog lock in, or by direct math in a digital lock in, the output signal is shown in figure3. Note that its peak to peak amplitude is 5V, or ½ of the input and its frequency is 50Hz,or twice the input frequency.
Figure 4 shows the output using a 100ms time constant. Note that the ripple is still visible on the DC level. Figure 4 Output with 100ms Time Constant Figure 5 shows the output using a 1s time constant. Note that the ripple is greatly reduced. Figure 5, Output with 1s Time Constant T-RAD-LEMO-USB Instruction Manual Version 1.0 June.
2.3 Frequency Domain Description of a Lock In Amplifier. Figure 6 shows the frequency contents of a 25Hz square wave with a 60Hz interference signal and broadband noise at about 1% of the signal. Figure 6 Corrupted Input Signal Since the input is a square wave, there are only odd harmonics. The fundamental is seen at 25Hz, the 3rd harmonic is seen at 75Hz, and the 60Hz interference is seen.
Figure 8 Phase Specific Detector Output Signal The multiplier action moves the signal to the frequencies at the sum and difference of the signal and the reference frequency at 25Hz. Therefore the signal at 25Hz will move to 0Hz and 50Hz, as seen. The 60Hz interference will move to 85Hz and -35Hz, not shown here. The odd harmonic of the input signal at 75Hz moved to 100Hz and 50Hz, where it will add to the frequency shifted signal. These signals can now be low pass filtered to extract the DC component.
There are two BNC’s and one Lemo connector on the instrument. The probe in use is plugged into the Lemo connector and must be plugged in before connecting the USB cable. One BNC is labeled Detector Output, the other is labeled External Trigger In. The Detector Output BNC supplies a buffered signal that is the same value sampled by the instrument’s ADC. The output impedance of this connector is 100Ω. The External Trigger Input is the connection for the reference chopping frequency.
7 Using the Applications Software 7.1 The Main Display Panel The Main Display Panel has five display regions. They are: 1. The Digital Display which is always visible. 2. The Strip Chart, which is on a user selectable tab. 3. The Statistics Display, which is on a user selectable tab. 4. The Tuning Needles, which are on a user selectable tab. 5. The Setup Controls, which are on a user selectable tab. The Digital Display The Digital Display is always visible to the user.
Data Collection Data Collection Control. When active the data is collected for display if the device is triggered. Data Collection is suspended if another control is activated, then resumed when the other control is released. This is done to prevent the communications buffers from overflowing. Do Not disconnect the device when Data Collection is active. Log to File Log data to selected file. if no file is currently open, a prompt will request the file to log data to.
is shown when Collection Mode is set to Time Interval. Time Interval (s) The Time Interval to wait between taking a data point. Intervening data points are discarded. Digital Indicators The Indicators on the Digital Display area are: Live Data Rv Wavelength (nm) Frequency (Hz) Frequency Range Frequency In Range Locked Current Sample Corrections Active Live Data The Main Display for: 2 Power (W) or Irradiance (W/cm ) . Rv Responsivity in V/W of the sensor for the selected Range.
7.2 The Strip Chart Display The Strip Chart Display is visible to the user when its tab is selected. It contains Controls and Indicators for the Strip Chart. Strip Chart Controls The Controls on the Strip Chart area are: Auto Scale There are more Strip Chart Display controls available in the Display Options Menu Auto Scale Auto Scales the Strip Chart Display to the running minimum and maximum values in the data set.
The Statistics Display is visible to the user when its tab is selected. It contains Controls and Indicators for the statistics on the data set. Statistics Controls There is a single control on the Statistics tab; Display as %. Display as % Displays the Std. Dev. as a percentage of the Mean. Statistics Indicators The Indicators on the Statistics tab are: Min Max Mean Standard Deviation Filter Bandwidth Data File Min The minimum value of the current data set.
Standard Deviation The standard deviation of the data set. This can be interpreted as the RMS noise. Standard Deviation and Variance Details: The VI calculates the output values using the following equations. n-1 µ = SUM [ Xi / n ] i=0 where N is mean and n is the number of elements in X. standard deviation = Q^2 n-1 Q^2 = SUM [ ( Xi - N)^2 /( n - 1) ] i=0 where Q is variance, N is mean. Filter Bandwidth The filter bandwidth that results from the selected filter Tau.
Tuning Needles Controls The Controls on the Tuning Needles area are: Tuning Scale Reset Needles Tuning Scale Use this button to select the scaling range of the tuning meter. Min - Max: sets the low end of the scale range to the Minimum value in the data set and the high end of the scale range to the Maximum value in the data set since the last Reset Needles. Zero - Max: sets the scale range from Zero to the Maximum of the measurement Range.
7.4 The Setup Display The Setup Display is visible to the user when its tab is selected. It contains Controls and Indicators for the Setup. Setup Controls The Controls on the Setup area are: Wavelength (nm) % Transmissivity Diameter (Area) Entry Type Display W/cm^2 User Serial Number User Calibration Date Write to Instrument Read From Instrument Zero Baseline Reset Instrument Wavelength (nm) Enter the Wavelength of the light source being measured.
Diameter (mm) or Area (cm2) Enter the Diameter or the Area, based on the Entry Type, of the light source or external aperture being used. Entry Type Change the Diameter control to an Area control. Display W/cm2 Toggles the data displays from Watts to Irradiance. Uses the Area indicator to compute the values. User Serial Number The User Serial Number. Stored in persistent memory User Calibration Date The User Calibration Date.
Firmware Version The Device Internal Firmware Version. Application Menus The T-Rad-USB Application Software has three main menu items, each with its own sub menus. They are: The File Menu The Display Menu The Help Menu The "File" Menu The File menu is used to open, close, and view data sets. The menu items are: Open Data File Close Data File View Existing Data File Print Window Exit Open Data File Opens a File too write data to. User is allowed to name a new file or overwrite an old one.
7.5 The Display Menu The Display menu is used to modify the characteristics of the Digital Display and the Strip Chart. It also displays the Wavelength Correction Table stored in the sensor. The menu items are: Display Options View Wavelength Correction Table Display Options Calls new panel that allows the user to set Cursors on the Strip Chart, Cursor Colors, and Cursor Range. If Auto Track Min/Max is selected, then the Cursors track the min and max values in the data set.
7.7 The Help Menu The Help menu is used to display help for the Application. The menu items are: Help Show Context Help About Help Calls this Help file. Show Context Help Shows a Context Sensitive Help Window when the Mouse Cursor is over a Control or Indicator. About Application Information is Displayed. 24 T-RAD-LEMO-USB Instruction Manual Version 2.
8 DECLARATION OF CONFORMITY Application of Council Directive(s): Manufacturer’s Name: Manufacturer’s Address: 2004/108/EC EMC Directive Gentec Electro Optics, Inc. 445 St-Jean Baptiste, suite 160 (Québec), Canada G2E 5N7 Representative’s Name: Representative’s Address: Laser Component S.A.S 45 bis Route des Gardes 92190 Meudon (France) Type of Equipment: Model No.
T-RAD-LEMO-USB Instruction Manual Version 2.
