User`s Manual Digital Sound Level Meter Model 407768
Contents
1. Dimensions Weight 10 6 x 2 7 x 1 1 0 63 Ibs 268 x 68 x 29mm 285g Meter Description 1 Microphone 2 LCD Display 3 Power Hold and Min Max buttons 4 Max Weighting Response Time amp Range buttons 5 AC output jack 6 Calibration potentiometer 7 RS 232 PC interface jack 8 Battery compartment tilt stand and tripod mount on rear 2 407768 Version 2 0 06 06 Sound Level Meter Operation Meter Power 1 The meter is powered by a 9V battery The battery compartment is located on the rear of the meter and the compartment cover is secured by one Phillips screw When the battery icon appears on the top left corner of the meter s display replace the battery 2 Press the POWER button to turn the meter on Note that the Meter is equipped with an Auto Power Off feature that shuts the meter off after 10 minutes To defeat Auto Power Off put the meter in Record mode by pressing the REC MAX MIN button 3 Press the POWER button to turn the meter off Default Configuration 1 The meter s default configuration is as follows Auto Range A Frequency Weighting and FAST Response Time 2 The lower portion of the LCD will reflect the meter s configuration i e A Fast Auto Measurement Considerations 1 Use a windscreen not included to cover the microphone in windy conditions Calibrate the meter often especially if the meter has been idle for a long period of time Do no2. the 9V battery slide the cover on and replace the screw Calibration and Repair Services Extech offers complete repair and calibration services for all of the products we sell For periodic calibration NIST certification or repair of any Extech product call customer service for details on services available Extech recommends that calibration be performed on an annual basis to insure calibration integrity Saw n Support Hotline 781 890 7440 Tech support Ext 200 Email support extech com Repair Returns Ext 210 Email repair extech com Website www extech com Warranty EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment a six month limited warranty applies on sensors and cables If it should become necessary to return the instrument for service during or beyond the warranty period contact the Customer Service Department at 781 890 7440 ext 210 for authorization or visit our website at www extech com click on Contact Extech and go to Service Department to request an RA number A Return Authorization RA number must be issued before any product is returned to Extech The sender is responsible for shipping charges freight insurance and proper packaging to prevent damage in transit This warranty does not apply to defects resulting from action of the user such as misuse improper wiring operation outside of specification impr
3. User s Manual EXT INSTRUMENTS Digital Sound Level Meter Model 407768 EXTECH 407768 Introduction Congratulations on your purchase of the Extech 407768 Sound Level Meter This Auto Range Sound Level Meter meets ANSI and IEC Type II accuracy standards Professional features include programmable Frequency Weighting and Time Response Min Max Memory Max Hold Analog output and RS 232 PC Interface Careful use of this meter will provide years of reliable service Specifications Display 5 Digit LCD with overload low battery and multifunction indication Frequency bandwidth 31 5 Hz to 8 KHz Microphone 0 5 Electret Condensor Microphone Output terminals Optically isolated RS 232 port and AC output Measurement ranges Auto Range 30 to 130dB Manual Ranges 30 to 80dB 50 to 100dB 80 to 130dB Frequency weighting A and C Programmable Applicable standards ANSI IEC Type 2 Response time Resolution 0 1dB Maximum Minimum record Highest and lowest readings are stored for later recall Data Hold Displayed reading is held when HOLD key is pressed Max Hold Highest reading displayed only Fast 125ms Slow 1s Programmable AC Analog output Power 0 5VAC rms full scale 600Q output impedance 9V Battery Consumption 6mADC approx Operating temperature 32 to 122 F 0 to 50 C Operating humidity Less than 80 RH
4. e The output impedance is 600Q maximum The mono 3 5mm mini jack is located in the output calibration compartment on the right side of the instrument Use a phono plug 3 5mm mono to connect to the output jack 4 407768 Version 2 0 06 06 PC Interface The optically isolated RS 232 PC Interface port is located in the output calibration compartment situated on the lower right side of the meter The supplied Data Acquisition Software package includes Windows M 95 98 NT 2000 XP compatible software and a meter to PC interface cable Instructions for use can be found on the included software CD Important Note on the Automatic Power OFF feature The 407768 Sound Level Meter has an AUTO POWER OFF feature that turns the meter off after approximately 10 minutes This feature must be disabled before starting a datalogging session to avoid having the meter automatically shut off in the middle of a session Disable it by pressing the REC MAX MIN button to activate the Record mode While the meter is in the Record mode the AUTO POWER OFF feature is disabled 5 407768 Version 2 0 06 06 Battery Replacement The 9V battery that powers the Sound Level Meter is housed in the rear battery compartment When the battery icon appears on the top left corner of the meter s LCD it is time to replace the battery 1 Open the battery compartment by first removing the Phillips screw and then sliding the compartment cover down and off 2 Replace
5. hat application Auto Manual Range Press the RANGE button to scroll through the following ranges Auto 30 80dB 50 100aB and 80 130dB The display will reflect the range for each button press Calibration The Sound Level meter should be calibrated before each use an external sound level meter calibrator is required Set the meter to the Manual range 50 100dB FAST response and A weighting before starting 1 Place the external calibrator over the Sound Level Meter s microphone and turn the Calibrator on 3 407768 Version 2 0 06 06 2 The meter should read close to or exactly the calibrator s dB output level Typical Calibrator output levels are 94dB and 114aB 3 If the meter is within 0 2 dB of the calibrator s output no adjustment is necessary Adjust the calibration pot in the output calibration compartment if necessary to bring the meter display in line with the calibrator output signal Taking Measurements 1 Hold the meter in hand place it on a desktop using the rear tilt stand or mount it ona tripod using the tripod mount on the rear of the meter 2 Point the microphone toward the source of noise sound to be measured 3 Read the measurement in dB units on the LCD display Data Hold 1 Press the HOLD button to freeze the displayed reading The LCD will display the icon HOLD when Data Hold is engaged 2 Press the HOLD button to de activate this feature The HOLD icon will extinguish 3 Note
6. oper maintenance or repair or unauthorized modification Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct indirect incidental or consequential damages Extech s total liability is limited to repair or replacement of the product The warranty set forth above is inclusive and no other warranty whether written or oral is expressed or implied Copyright 2006 Extech Instruments Corporation All rights reserved including the right of reproduction in whole or in part in any form 6 407768 Version 2 0 06 06 Appendix Typical A Weighted dB levels 140 50 HP Siren 100 130 Jet take off 200 120 Riveting machine 110 100 Chain saw Subway 20 90 Boiler room Pneumatic drill 50 80 Freight train 100 Vacuum cleaner 10 70 Speech 1 Large store 60 Large Office Small office 50 Residence Residential area 40 night 30 Whisper 5 3i Sound studio 10 Threshold of hearing 0 Frequency Weighting Graph Frequency Weighting Dnon A Weighting C Weighting dB relative N oO 10 100 1000 10000 Frequency Hz 7 407768 Version 2 0 06 06
7. t store operate the meter in areas of high temperature or humidity Keep the meter and the microphone dry a pon Avoid severe vibration when using the meter 6 Remove the battery when the meter will be stored for long periods of time Frequency Weighting Change the Frequency Weighting by pressing the A C button The A or C icon will display on the lower left hand area of the LCD Note With A weighting selected the meter responds like the human ear boosting and cutting the noise amplitude over the frequency spectrum see Appendix A weighting is used for environmental measurements OSHA regulatory testing law enforcement and workplace design Select C weighting for flat response measurements no boost or cut C weighting is suitable for the sound level analysis of machines engines etc Most OSHA related testing is performed using A Weighting and SLOW Response Time settings Response Time Change the Response Time by pressing the FAST SLOW button The FAST or SLOW icon will display on the lower left hand area of the LCD Note Select FAST to capture noise peaks and noises that occur very quickly In FAST mode the meter responds in 200ms Select the SLOW Mode meter responds in 500ms to monitor a sound source that has a reasonably consistent noise level or to average quickly changing levels Selection of Fast or Slow is determined by the application and any directives or standards related to t
8. that Data Hold is not available while the meter is in the Max Min Record mode Max Hold 1 Press the MAX HOLD button to activate this feature The LCD will display PH when Max Hold is engaged 2 The meter will now display only the highest reading Each time a higher reading is encountered the display will update 3 Press the MAX HOLD button again to de activate this feature The PH icon will extinguish 4 Note that Max Hold is not available while the meter is in the Max Min Record mode Max Min Data Recording The Max Min feature stores the maximum reading and minimum reading while the user takes measurements The Max and the Min readings can later be recalled 1 Press the REC MAX MIN button to activate this feature The LCD will display the icon REC and the meter will begin monitoring the highest Max and lowest Min readings 2 After measurements are made press the REC button again to view the Max reading The MAX icon will appear on the LCD along with the highest reading 3 Press the REC to view the minimum MIN reading The MIN display icon will appear on the LCD along with the lowest reading 4 To exit this mode press and hold the REC button until the REC indicator extinguishes 5 To clear a Max or Min reading press the HOLD key while viewing either the MAX or MIN value Note that exiting the Record mode also clears the MAX and MIN values Analog Output The AC analog output transmits 0 5V AC rms full scal
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