Computer Aided Engineering & Measurement Systems

Features & Capabilities

• Precision Constant Duty Cycle Stroboscope

• Wide operating flash rate 0Hz - 10kHz

• Fine Frequency Resolution of 0.01Hz

• SuperFlux High Power White LED technology

• Collimating Lens with 45° Beam Width

• Long Flash LED Lifetime 50K - 100K Hours

• Wide Range Sync Capability 0.5V - 300V

• Fully Programmable via RS-232

• Four (4) Operating Modes

• Four (4) Parameter Display Modes

• 6 Digit 7-Segment Numeric Display

• Backlit Status Indicators

• Win32 Application Software

• High Capacity Lithium Ion Battery

• Portable Hand Held Battery Operated

• Small & Lightweight Flashlight Size Chassis

• Built-in Universal Charger 85VAC-265VAC

LS310 - Precision High Speed Stroboscope

The LS310 is a portable battery operated hand-held instrument roughly the same size as a flashlight. Shaped as an octagon, it is2 inches across and 7 inches long weighing less than one pound. The LS310 utilizes a rechargeable Lithium Ion battery andfeatures a universal 85-265VAC built-in charger.

The LS310 utilizes the latest in high power LED technology with a 7 Watt SuperFlux high efficiency multi LED and collimatinglens. The intensity is very bright with each flash producing nearly 200 lumens of white light. A strobe based on LEDtechnology has several important advantages over traditional Xeon based strobes: (1) Flash duration can be programmed andcontrolled precisely over an extremely large range from seconds down to sub-micro seconds, (2) the life of the LED is virtuallyunlimited, (3) programmable flash intensity, and (4) lower cost low voltage drive circuitry. The highly controllable LED flashduration enables constant duty cycle operation vs. frequency which is virtually impossible for Xeon based strobes.

The LS310 offers a comprehensive array of features to examine surface vibrations of transducer diaphragms, among othergeneral purpose strobe applications. A stroboscope allows a moving or vibrating object to be viewed as if it was stationary. Byflashing a short burst of light at the same time during each periodic vibration of the driver, the diaphragm appears stationary.This allows changes in the surface to be observed at any frequency of interest.

LinearX Systems Inc • 9500 SW Tualatin-Sherwood Rd. • Tualatin, OR 97062-8586 USA • TEL: (503) 612-9565 • FAX: (503) 612-9344

www.linearx.com • sales@linearx.com

Precision Stroboscope

LS310 testing a woofer

While common acoustic frequency response testing of drivers can quicklyshow peaks, nulls, or resonances in the response, it does not indicate thesource of the problem. A stroboscope can be invaluable for this purposeoften showing exactly the mechanical cause of the response defect.

Typically the driver is swept using a sine wave stimulus across a frequencyrange. The stroboscope is synchronized to the same signal, flashing atexactly the same frequency and at the same phase of each period.

A variety of motional problems can be quickly observed including:resonance deformations in the surround, resonance modes in the spider,flexing of dust caps, improper or loose glue seams, standing waves in leadwires, and rocking motions of the cone.

Description

The LS310 contains (4) push-button switches, (2) display windows, (3) 3.5mm stereo jacks forconnection, and an IEC-C8 2-pin AC power adapter inlet. The four push-buttons control: Up,Down, Mode, and Display. The Up/Down switches change frequency or phase, while the Modeswitch selects various operating modes, and the Display switch controls which numericparameter is displayed in the readout window.

Operating Modes

■ ManualIn this mode the external sync input is not used or required. The flash frequency of the strobe is controlled solely by the Up/Down buttons. This mode can be very useful for general work, or for determining the frequency of a moving/rotating object,driver, motor, fan, etc.

■ Sync - FrequencyIn this mode the external sync input is used to provide the base frequency of the strobe. However the actual strobe frequency canbe offset by a user defined value. For example, if a frequency offset of +1.00Hz is used the strobe will flash at a rate 1Hz higherthan the sync frequency. As the signal is swept across frequency, the strobe will always flash 1Hz higher than the sweepfrequency. This allows the user to view the diaphragm in a 1Hz motion at any driven stimulus frequency. A very useful mode.

■ Sync - PhaseIn this mode the external sync input is used to provide the exact frequency of the strobe. However the actual phase position ofthe flash can be offset/stepped through the entire 360 degree period. This mode can be very useful in examining the motionalbehavior across the entire periodic cycle of the driver. Resolution / step size is adjustable from 1 degree to 45 degrees.

■ FlashlightIn this mode the strobe flashes at a high rate to provide general illumination. This mode is useful when you wish to illuminatethe object without any synchronous flashing. The actual frequency can be changed thus providing a secondary manual mode.

Display Modes

■ Flash/Sec (Hz)This mode displays the actual strobe frequency in flashes per second, or Hertz.

■ Flash/Min (RPM)This mode displays the actual strobe frequency in flashes per minute, or RPM.

■ Frequency Offset (Hz)This mode displays the strobe frequency offset in flashes per second, or Hertz.

■ Phase Offset (Deg)This mode displays the strobe phase offset in degrees.

Connections

■ Sync InputThe LS310 can sync to any periodic signal ranging from 0.5VRMS to 300VRMS. The LS310 employs patented circuitry whichadjusts itself to the incoming signal strength instantaneously. The Sync input can be attached directly to the driver speakerterminals to obtain the sync.

■ Trigger OutputThe trigger output by default provides a pulse identical to the flash pulserate of the strobe. Future enhancments provide for other special triggerapplications and options as well.

■ RS-232 InterfaceThe RS-232 interface allows connection to a PC for update of firmwareand modification of control parameters through the Win32 applicationsoftware, or for custom programming by the user..

High Precision Phase ControlBoth of the sync modes require that an external signal be applied to theSync Input. In the Sync-Phase mode, the LS310 locks on to the externalinput frequency precisely, and then flashes at various phase offsets withinthe 360 period.

The default phase resolution is 10 degrees. For each period of 360degrees this means there will be 36 possible steps. The strobe will flashfor a duration of 10 degrees or 1/36 of each period. Where in the periodthe strobe flashes is controlled by this phase offset.

The sequence of scope photos on the right shows the phase offset steppedthrough 10, 20, 30, 40, and 50 degree offsets. The Yellow trace is the syncinput signal and the Green trace is the trigger output. The strobe flashesduring the positive pulse.

For electroacoustic work the Sync-Phase mode will produce a visualdisplay of the moving diaphragm frozen at a particular position. As thephase offset is changed, the diaphragm will be frozen at different positionsof its travel through the entire period. As the frequency is changed thephase offset position is always maintained.

The phase resolution is in effect during all operating modes. If theresolution is set to 10 degrees, then the flash duty cycle is 10/360 or 1/36or 2.78%. Thus the continuous light power of the strobe is reduced by afactor of 36. The user can change the phase resolution from 1 degree to45 degrees, thus providing highly different resolutions, number of steps,flash duty cycle, and equivalent light intensity.

There is an inherent trade-off between the phase resolution and flashintensity. While it is desirable to have the smallest possible resolution toprovide a clear frozen visual image, it also reduces the effective strobelight power proportionally. For example, a phase resolution of 1 degreeproduces extremely narrow flashes but also reduces the flash power to 1/360 or 0.278% duty cycle. Using a resolution of 10 degrees generallyprovides the best trade-off between the competing requirements.

Windows Application SoftwareThe LS310 has additional parameters which can be controlled through theprovided Windows application. The LS310 is fully programmable via RS-232 commands. The user can control the strobe remotely through customRS-232 software or the Win32 DLL interface.

LINEARX SYSTEMS INC9500 SW Tualatin-Sherwood RdTualatin, OR 97062-8586 USA

Tel: 503-612-9565 Fax: 503-612-9344www.linearx.com sales@linearx.com

Visit our web site or contact the factory fora list of International Dealers.

All specifications subject to change without notice.© 2007 All Rights Reserved.Printed in the U.S.A.MAR-15-2007

Specifications

■ FunctionsFlash Power Full, 1/2, 1/4, 1/8, 1/16 powerOperating Modes Manual, Sync-Freq, Sync-Phase, FlashlightDisplay Modes Flashes/Sec (Hz), Flashes/Min (RPM), Freq Offset, Phase OffsetPhase Resolution 1, 2, 3, 5, 7½, 10, 15, 20, 30, 45 degreesFrequency Resolution 0.01Hz

■ OpticalLight Source 7W SuperFlux LEDBeam Width 45 DegreesFlash Intensity 200 LumensFlash Pulse Width >250mSec to <300nSecColor Grade WhiteColor Temperature 5500KLifetime 50K-100K Hours

■ ElectricalSync Input 3.5mm JackSync Voltage 0.5VAC to 300VACSync Frequency Range DC to > 10kHzSync Input Impedance >5K Ohms, self adjustingRS-232 Interface 3.5mm JackRS-232 Protocol TX/RX 9600 Baud, 8/1/NTrigger Output 3.5mm JackTrigger Level Bipolar ±5V, TTL, LVTTLMicroprocessor 60MHz, ARM-7, 32 Bit MCUOperating Time 10-12 Hours typCharge Time 3-4 HoursUniversal Charger 5W, 85-265VAC, 50/60HzBattery Lithium Ion 18650, 2.4AHr/3.6V

PrecisionStrobescope

PrecisionStrobescope

DISPLAY MODE

DN

OFF ON

UP

MANUAL

SYNC-FRQ

SYNC-PHS

FLASHLIGHT

CHARGING

FLASH/SEC

FLASH / MIN

FREQ OFS

PHASE OFS

INTERFACE OUTPUT

TRIGRS232

INPUT

SYNC

CHARGER85-265VAC

50/60HZ 5W

■ SoftwareWin32 ApplicationDLL programming interfaceRS-232 comand protocol

■ MechanicalLength 7.1 Inches (180mm)Width 2 Inches (50mm)Height 2 Inches (50mm)Weight 12oz (300g)Finish Black AnodizedMaterial AluminumCase Black Plastic w/Foam

■ Cables(2) 2M 3.5mm to BNC(1) 2M 3.5mm to DB-9F(1) 2M IEC-C7 to USA