Model 378B02 ICP Microphone System Installation and Operating
Contents
1. PCB PIEZOTROMCS Model 378B02 ICP Microphone System Installation and Operating Manual This manual contains the 377B02 426E01 installation and operating manuals that comprise a Model 378B02 ICP Microphone System kit For assistance with the operation of this product contact PCB Piezotronics Inc Toll free 800 828 8840 24 hour SensorLine 716 684 0001 Fax 716 684 0987 E mail info pcb com Web www pcb com gt PCB PIEZOTROMCS A PCB GROUP COMPANY Warranty Service Repair and Return Policies and Instructions The information contained in this document supersedes all similar information that may be found elsewhere in this manual Total Customer Satisfaction PCB Piezotronics guarantees Total Customer Satisfaction If at any time for any reason you are not completely satisfied with any PCB product PCB will repair replace or exchange it at no charge You may also choose to have your purchase price refunded in lieu of the repair replacement or exchange of the product Service Due to the sophisticated nature of the sensors and associated instrumentation provided by PCB Piezotronics user servicing or repair is not recommended and if attempted may void the factory warranty Routine maintenance such as the cleaning of electrical connectors housings and mounting surfaces with solutions and techniques that will not harm the physical material of construction 1s acceptable Caution shoul2. PCB PIEZOTROMICS PRODUCT GUIDE 377 SERIES MICROPHONES 426 SERIES PREAMPLIFIERS Contents tO ANTIOCH CT G0 essere Ee EEE 1 20 S E E E EES 3 0 Setting up a Microphone Measurement System 1 4 0 Taking Measurements eeeesssseeseeeennnnnneeenen nnne 2 S MEME e O a 3 o0 INPXIOLGIIAEI OG eerie usi stuspa scade mua E dm uius osr etu mE TPPUUE DUEER 3 Ka a nDralON ess ENE EEE 4 S0 Waramy and SEFUIOE scence n Eeen o etm iu 4 1 0 Introduction Thank you for your purchase of a PCB high quality microphone These microphones offer highly accurate and reliable acoustic measurements and are typically used in research and design applications They are accurate enough for laboratory usage yet rugged enough for field testing Sound within the typical 20 to 20 000 Hz audible range of a healthy human ear can either be pleasing to the ear as in music or unpleasant or harmful as in noise As a result many applications from the de velopment of consumer products to research in acoustics measure sound even sound outside the range of human hearing The instrument typically used to measure sound is the microphone which is designed like the human ear to transform pressure oscillations into a corresponding voltage oscillation 2 0 Standards Before selecting an acoustical instrument it is important to identify which acoustical standards are appro priate for the application in which the instrument will
3. others For information on standard recalibration services or special testing contact your local PCB Piezotronics distributor sales representative or factory customer service representative Returning Equipment Following these procedures will insure that your returned materials are handled in the most expedient manner Before returning any equipment to PCB Piezotronics contact your local distributor sales representative or factory customer service representative to obtain a Return Materials Authorization RMA Number This RMA number should be clearly marked on the outside of all package s and on the packing list s accompanying the shipment A detailed account of the nature of the problem s being experienced with the equipment should also be included inside the package s containing any returned materials A Purchase Order included with the returned materials will expedite the turn around of serviced equipment It 1s recommended to include authorization on the Purchase Order for PCB to proceed with any repairs as long as they do not exceed 50 of the replacement cost of the returned item s PCB will provide a price quotation or replacement recommendation for any item whose repair costs would exceed 50 of replacement cost or any item that 1s not economically feasible to repair For routine calibration services the Purchase Order should include authorization to proceed and return at current pricing which can be
4. interest of constant product improvement specifications are subject to change without notice PCB and ICP are registered trademarks of PCB Group Inc Sensor Line is a service mark of PCB Group Inc All other trade marks are properties of the respective owners Manual Number 27042 Manual Revision C CPCB PIFZOTROMCS A ECO 42502 Printed in the U S A odel Number evision A Performance ENGLISH Sl OPTIONAL VERSIONS Nominal Microphone Diameter 1 2 1 2 Optional versions have identical specifications and accessories as listed for the standard model Frequency Response Characteristic at 0 incidence Free Field Free Field except where noted below More than one option may be used Open Circuit Sensitivity 50 mV Pa 50 mV Pa 3 Open Circuit Sensitivity 1 5 dB 26 dB re 1 V Pa 26dBre1V Pa 3 TLD TEDS Capable of Digital Memory and Communication Compliant with IEEE 1451 4 Frequency Range 1 dB 7 to 10 000 Hz 7 to 10 000 Hz Optional Accessory Model ACS 63 Calibration with TEDS of Precision Condenser Frequency Range 2 dB 3 75 to 20 000 Hz 3 75 to 20 000 Hz Microphones and Preamplifiers together mated pair 1 replaces Model ACS 42 Lower Limiting Frequency 3 dB 1 0 to 3 0 Hz 1 0 to 3 0 Hz Inherent Noise Linear lt 18 5 dB re 20 uPa lt 18 5dB re 20 Pa Inherent Noise lt 16 5 dB A re 20 lt 16 5 dB A re 20 uPa uPa Dynamic Range 3 Distortion Limit gt 135 dB re 20 uPa 135 dB re 20 uPa Dynamic Range Maximum without C
5. obtained from a factory customer service representative Warranty All equipment and repair services provided by PCB Piezotronics Inc are covered by a limited warranty against defective material and workmanship for a period of one year from date of original purchase Contact PCB for a complete statement of our warranty Expendable items such as batteries and mounting hardware are not covered by warranty Mechanical damage to equipment due to improper use is not covered by warranty Electronic circuitry failure caused by the introduction of unregulated or improper excitation power or electrostatic discharge is not covered by warranty Contact Information International customers should direct all inquiries to their local distributor or sales office A complete list of distributors and offices can be found at www pcb com Customers within the United States may contact their local sales representative or a factory customer service representative A complete list of sales representatives can be found at www pcb com Toll free telephone numbers for a factory customer service representative in the division responsible for this product can be found on the title page at the front of this manual Our ship to address and general contact numbers are PCB Piezotronics Inc 3425 Walden Ave Depew NY 14043 USA Toll free 800 828 8840 24 hour SensorLine 716 684 0001 Website www pcb com E mail info pcb com
6. very thin proprietary material and should be kept clean of dust dirt moisture and free any type of imperfection scratch dent etc The microphone s grid cap is designed to let the true sound pressure level through to the diaphragm while preventing items from coming in contact with it We do not recommend that you ever remove the grid cap or clean the microphone If you take the precautionary measures to keep the microphone clean and dry it should not be necessary Use of accessories like windscreens and desiccants will help keep moisture off the microphone and maintain the specified sensitivity level Nose cones will help keep turbulence off the microphone diaphragm and allow the sound pressure to be measured with greater accuracy Keep the microphone and preamplifier assembled while preparing for testing Keep the rubber mainte nance caps on the preamplifier s electrical connector only Do not place these rubber caps over the micro phone This will create a vacuum and undo pressure on the microphone diaphragm which can stretch the diaphragm and cause a change in sensitivity Store the microphones and preamplifiers in their protective cases when not in use With proper maintenance the microphone and preamplifier should provide stable and accurate results for years to come Dust rain oil moisture or exposure to extreme temperatures may adversely affect the microphone and preamplifier s performance If the microphone or the inside of th
7. 2014 Date 5 7 2014 Date 5 7 2014 57824 7 All specifications are at room temperature unless otherwise specified In the interest of constant product improvement we reserve the right to change specifications without notice cp B Pl EZOTRON WES Alis oa 4 ET n ICP is a registered trademark of PCB Group Inc 3425 Walden Avenue Depew NY 14043 E Mail info pcb com tha hearmeston eeciesedi seen KENET He Po REVISIONS 0 0 the information disclosed hereon Neither it nor any R EVIS lO NS without the written consent of PCB Piezotronics Inc REV DESCRIPTION DIN RELEASED TO DRAFTING 42362 64 16 4 MICROPHONE CARTRIDGE 5 746 POTT 3 19 81 1 PREAMPLIFIER 3 62 91 9 5 03 8 A43 10 9 n BNC CONNECTOR OUTPUT A nS UNLESS OTHERWISE SPECIFIED TOLERANCES ARE DRAWN CHECKED encer DIMENSIONS IN INCHES DIMENSIONS IN MILLIMETER DECIMALS XX 1 03 DECIMALS X 0 8 TITLE XXX 010 XX 0 25 PCB PIEZOTROMICS 3425 WALDEN AVE DEPEW NY 14043 716 684 0001 E MAIL sales pcb com Cope DWG NO ANGLES 2 DEGREES e 57746 FILLETS AND RADII FILLETS AND RADII 003 005 0 07 0 13 SCALE l 5X SHEET 1 OF 2 09 03 12 23 2013 OUTLINE DRAWING 1 2 ICP MICROPHONE SYSTEM ANGLES 2 DEGREES morawski
8. IEC 17025 and ANSI NCSL Z540 1 complies with ISO 10012 1 and former MIL STD 45662A and uses equipment directly traceable to one or more of the following National Labs NIST PTB or DFM Our investment in equipment traceability and conformance to industry standards ensures accurate calibra tion against relevant specifications We also carry a line of acoustic calibrators that can be used to cali brate microphone sensitivity on site as needed 8 0 Warranty and Service All equipment and repair services provided by PCB Piezotronics Inc are covered by a warranty against defective material and workmanship under a Total Customer Satisfaction policy If at any time for any reason you are not completely satisfied with any PCB product PCB will repair replace or exchange it at no charge You may also choose to have your purchase price refunded See the supplemental sheet con tained with this manual for information on our service repair and return policies procedures and instruc tions When unexpected problems arise call our 24 Hour SensorLine 716 684 0001 to speak with an Application Engineer Visit www pcb com for a complete statement of our warranty 3425 Walden Avenue Depew NY 14043 2495 24 hour SensorLine M 716 684 0001 E Mail info pcb com U S A Fax 716 684 0987 Website www pcb com Toll free in the U S A 800 828 8840 A PCB GROUP COMPANY ISO 9001 CERTIFIED A2LA ACCREDITED to ISO 17025 2014 PCB Group Inc In the
9. be used Whether for legal purposes or for quality assurance programs these standards will help determine the required quality accuracy and consistency of the instrument Standards that correspond to the performance requirements dimensions and characteris tics of acoustical components are established for microphones sound level meters calibrators or other related components The most common organizations producing these standards are the American Na tional Standards Institute ANSI and the International Electrotechnical Commission IEC IEC 1094 4 establishes specifications for the mechanical dimensions and certain electroacoustic characteristics for standard industrial microphones The performance specification sheet supplied with each PCB micro phone identifies the standards to which the microphone is compliant 3 0 Setting up a Microphone Measurement System After the proper microphone has been selected the corresponding preamplifier cabling power supplies signal conditioning and data acquisition selections are ready to be installed Not all of these components are required for all test set ups The figures below show typical set ups for externally polarized and pre polarized microphone systems A prepolarized microphone can be used with a standard Microphone Power Supply designed for external ly polarized microphones and its preamplifier provided the supply voltage is set to zero 1 Prepolarized Microphone System 4 0 Taki
10. d be observed to insure that liquids are not permitted to migrate into devices that are not hermetically sealed Such devices should only be wiped with a dampened cloth and never submerged or have liquids poured upon them Repair In the event that equipment becomes damaged or ceases to operate arrangements should be made to return the equipment to PCB Piezotronics for repair User servicing or repair is not recommended and if attempted may void the factory warranty Calibration Routine calibration of sensors and associated instrumentation 1s recommended as this helps build confidence in measurement accuracy and acquired data Equipment calibration cycles are typically established by the users own quality regimen When in doubt about a calibration cycle a good rule of thumb 1s to recalibrate on an annual basis It is also good practice to recalibrate after exposure to any severe temperature extreme shock load or other environmental influence or prior to any critical test PCB Piezotronics maintains an ISO 9001 certified metrology laboratory and offers calibration services which are accredited by A2LA to ISO IEC 17025 with full traceablility to N LS T In addition to the normally supplied calibration special testing is also available such as sensitivity at elevated or cryogenic temperatures phase response extended high or low frequency response extended range leak testing hydrostatic pressure testing and
11. d in conjunction with an ICP preamplifier to provide A weighting for acoustical measurements The filter s frequency response is weighted according to the A weighting filter portion of both ANSI 1 4 and IEC 60651 Type 1 Sound Level Meter Standards ICP signal conditioners of 4 mA or greater are recommended when using inline filters Windscreens and Nose cones Wind induced noise can be reduced by using a windscreen This can offer some protection against dust particles and mechanical damage In the presence of high speed airflow from a well defined direction such as wind tunnels a nose cone is recommended When using windscreens and noise cones the fre quency response of the microphone will be attenuated at higher frequencies Clamps and stands When holding a microphone in place it is important to minimize the influence of the stand on the sound being measured This can be accomplished by using low profile stands and clamps available from PCB Cables and Electronics PCB carries LEMO cables as well as coaxial cables with BNC and 10 32 connectors Traditional exter nally polarized microphone power supplies along with a variety of ICP signal conditioners are available that will fit almost any need 6 0 Maintenance Microphones are very stable over long periods of time provided they are handled and stored properly The microphone contains fragile components that can be damaged by misuse in particular the diaphragm which is made up of a
12. e connection area of the preamplifier be comes contaminated use a light pressure rubber bulb to gently blow clean dry air onto the unit in order to remove the dust In the event that you absolutely must take off the grid cap and clean the microphone dia phragm we recommend using a blow bulb or a light pressure clean and dry air hose to gently blow con tamination off the diaphragm The direction of the air should be parallel with the diaphragm not directly 0 degree incidence pointed at the diaphragm Do not touch the microphone s diaphragm with your fin gers or let it come in contact with any sharp or pointed object Please note that any contact to the micro phone s diaphragm can negatively impact the sensitivity and long term stability of the microphone If the microphone is ever dropped or comes into contact with any contamination or 1s exposed to extreme temperatures we recommend immediate recalibration of the microphone Please note that heat from your hands can affect the calibration results It is always good practice to wait a minimum of 30 seconds after placing the microphone on a test system before taking a calibration reading in order to minimize the effect that heat from your hands has on the calibration 7 0 Calibration PCB offers recalibration services for our precision microphones as well as units produced by other A2LA manufacturers Our internal metrology laboratory is certified to ISO 9001 accredited by A2LA to AN SI
13. h a microphone system may be limited by other parts of the system such as the preamplifier signal conditioner or instrumentation Conversely the Cartridge Thermal Noise CTN specification provides the lowest measurable sound pres sure level that can be detected above the electrical noise inherent within the microphone 2 Temperature and pressure will affect the sensitivity of a microphone but these effects can be accounted for by adjusting the recorded microphone values using the coefficients specified for each microphone model Simply calculate the difference in temperature and ambient pressure from those recorded during calibration and multiply this value by the proper coefficient to determine the sensitivity offset In most cases the offset will be very small and is therefore unnecessary 5 0 Accessories Transducer Electronics Data Sheet TEDS Preamplifiers can incorporate TEDS devices which have a built in read write memory that contains rele vant information about the sensor and its use Information includes manufacturer name model number serial number sensitivity etc The operation of TEDS devices is defined by IEEE P1451 4 A TEDS mi crophone system includes a microphone mated with a preamplifier that contains the TEDS memory pro grammed with both the microphone and preamplifier information This is particularly helpful when using large channel count systems and array set up A Weight Inline Filter The inline filter is use
14. lipping 138 dB re 20 uPa 138dBre20uPa 2 4 NOTES TEDS Compliant Yes Yes 5 1 Prepolarized Environmental 2 Typical Temperature Range Operating 40 to 176 F 40 to 80 C 3 re 250 Hz Temperature Coefficient of Sensitivity 14 to 158F 10 to 70 C 0 005 dB F 0 009 dB C 2 3 4 Peak Static Pressure Coefficient 0 013 dB kPa 0 013 dB kPa 2 3 5 TEDS Capable Digital Memory and Communication compliant with IEEE P1451 4 Humidity Coefficient of Sensitivity 0 to 100 non condensing 0 001 dB RH 0 001dB RH 9 6 Venting through Preamp Influence of Axial Vibration 0 1g 1 m s 63dBre20uPa 63dBre20yPa 2 l See PCB Declaration of Conformance PS064 for details Electrical Polarization Voltage OV OV 1 Excitation Voltage 20 to 30 VDC 20 to 30 VDC Constant Current Excitation 2 to 20 mA 2 to 20 mA Output Bias Voltage 10 to 14 VDC 10 to 14 VDC Output Impedance lt 50 Ohm lt 50 Ohm Maximum Output Voltage 7 Vpk 7 Vpk Physical Housing Material Stainless Alloy Stainless Alloy Venting Rear Rear Electrical Connector BNC Jack BNC Jack Mounting Thread Grid 0 5 60 UNS 0 5 60 UNS Size Diameter x Height with grid 0 52 in x 3 62 in 13 2 mm x 91 9 mN SUPPLIED ACCESSORIES Size Diameter x Height without grid 0 50 in x 3 58 in 12 7 mm x 90 9 Model ACS 42 Calibration of microphone with preamplifer 1 mm Weight 1 63 oz 45 8 gm 2 Engineer MJN Sales MV Approved MT Spec Number C Date 5 7
15. ng Measurements The following formula is used to calculate the pressure measured by the microphone from the output volt age signal The sensitivity of a microphone 1s typically measured at 250 Hz Pressure Pa Voltage mV Sensitivity mV Pa The lowest amplitude a healthy human ear can detect is 20 millionths of a Pascal 20uPa Another scale more commonly used to describe sound pressure level is the decibel dB To convert the output voltage signal measured in Vrms to sound pressure level measured in decibels use the following formula V ms d B ref SPL 20Log where S is the sensitivity of the microphone in mV Pa and P is the reference pressure in air which is 20 x 10 Pa The decibel scale is logarithmic and more closely matches the response reactions of the human ear to the pressure fluctuations Some examples of typical sound pressure levels are shown in the table below dB Pressure Example 0 00002Pa ThresholdofHearing 60 002Pa Business Office 80 02Pa Shop Noise At very high pressure amplitudes the microphone s diaphragm will start to distort the measured sound pressure The maximum rated sound pressure level of a microphone 1s expressed as the amplitude at which the Total Harmonic Distortion THD reaches a specified amount typically 3 THD It is im portant to note that the highest sound pressure level that can be measured wit
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