PRODUCT DATA Piezoelectric Charge Accelerometer Types 6-A and 6-A- Types 6-A and 6-A- are triaxial piezoelectric accelerometers with three independent outputs for simultaneous high-level measurements in three mutually perpendicular directions. The accelerometers feature the ThetaShear design and each transducing element is individually calibrated. The accelerometers have the same rectangular shape and UNF connectors. The main differences between the models lie in the housing material, weight, temperature range and dielectric strength (flash over voltage). Uses and Features Uses General purpose vibration testing and analysis Multi-axis vibration and shock measurements Measurements in confined spaces Measurements in high-temperature environments Features Triaxial High sensitivity-to-weight ratio Low sensitivity to environmental factors Electrically insulated for ground-loop protection High resonance frequency Easily fitted to test objects using mounting clips Versions Table Comparison of Type 6 versions Type Housing Material Maximum Temperature Weight Sensitivity 6-A Hard-anodized aluminium 75 C (7 F) grams.6 pc/ms ±% 6-A- Titanium C (6 F) 7 grams.6 pc/ms ±% Description These piezoelectric accelerometers may be treated as charge sources. Their sensitivity is expressed in terms of charge per unit acceleration (pc/ms, pc/g). ThetaShear Design The ThetaShear design consists of a slotted cylindrical post holding a central seismic mass flanked by two piezoelectric plates. This assembly is clamped rigidly by the cover. To ensure optimum accuracy and reliability, molecular adhesion is the only bonding agent used to hold the assembly together. The ThetaShear design provides a combination of high measurement stability, excellent sensitivity-to-weight ratio and low sensitivity to extraneous environmental effects.
A remarkable feature of the principle behind ThetaShear is that the transverse resonance frequency is always outside the % frequency limit. This ensures minimum interference from orthogonal vibration components in the useful frequency range of the accelerometer. The ThetaShear design also provides excellent immunity to other environmental effects such as base strains, magnetic fields and acoustic fields. Fig. Dimensions of Types 6-A and 6-A- Centre of gravity of accelerometer: 5. from mounting surface, perpendicular to the Z-axis.6 M, depth:.8. 9. 6.5.5 7.9 7 9.5 Y Z X All dimensions in millimetres Centre of gravity of seismic mass:. from mounting surface, perpendicular to the Z-axis, for each seismic mass Y M, depth: X Z Hole:., Counter bore:. Depth:. 89 Mounting Types 6-A and 6-A- are mounted with adhesive, with or without the use of mounting clips, M screws or M studs. The various mounting clips are designed to suit a variety of mounting surfaces and are attached to the test object with glue or double-sided adhesive tape. The accelerometer is mounted in a clip via grooves in its housing, making the accelerometer easy to fit or remove. Common Specifications for Mounting Clips Temperature range: For brief use (< hour): Maximum acceleration: Perpendicular to mounting surface: Material: 5 to +5 C ( 65 to + F) 5 to +8 C ( 65 to +76 F) g peak 7 g peak Glass reinforced polycarbonate Fig. Mounting Clip UA-8 (set of ) Upper limiting frequency (±%): Mounted with grease:. khz Dry mounting:. khz Weight:. g
Fig. Mounting Clip with Thick Base UA-7 (set of ). The base can be filed down to suit your mounting surface (far right) Upper limiting frequency (±%): Mounted with grease:. khz Dry mounting:. khz Weight:.9 g Fig. Mounting Clip with Swivel Base UA-7 (set of ) Upper limiting frequency (±%): The accelerometers are mounted with grease and excited along accelerometer s main axis of sensitivity with the mounting surface of the hemisphere: Perpendicular to the direction of excitation:. khz At 5 to to the direction of excitation:. khz Weight: 5 g Fig. 5 Spirit Level UA-8 Max. dimensions: 85 7 mm Material: Black, anodized aluminium Specifications for High-temperature Mounting Clip Temperature range: 55 to +75 C ( 67 to +7 F) If discolouring can be accepted: 55 to +5 C ( 67 to +8 F) Maximum acceleration: g peak Perpendicular to mounting surface: 5 g peak Material Base: Anodized aluminium Spring: Stainless steel Weight: g Fig. 6 High-temperature Mounting Clip UA-56 (set of 5)
Calibration Frequency Compensation for REq-X Each accelerometer is calibrated using random excitation and 6-line FFT transformation to provide a high-resolution (amplitude and phase) frequency response. This yields a unique characterization and secures the integrity of your vibration measurements. The sensitivity given on the calibration chart is measured at 59. Hz with 95% confidence level using coverage factor k =. The upper frequency limits given on the calibration chart are frequencies where the deviation from the reference sensitivity at 59. Hz is within ±%. The upper frequency limit is approximately % of the mounted resonance frequency. This assumes that the accelerometer is correctly mounted on the test structure poor moun ng can have a marked effect on the mounted resonance frequency. REq-X stands for Response Equalization Extreme, which is a technique that allows you to flatten the frequency response of a transducer in real time (see Fig. 7). This flattening is done by filtering the time signal of a transducer by the inverse of the frequency response. Fig. 7 Individual frequency responses for each axis with and without REq-X applied Sensitivity [%] Amplitude Phase REq-X Amplitude REq-X Phase Individual Frequency Response X Phase [degrees] 5 5 5 k k 5k k k [Hz] Sensitivity [%] Amplitude Phase REq-X Amplitude REq-X Phase Individual Frequency Response Y Phase [degrees] 5 5 5 k k 5k k k [Hz] Sensitivity [%] Amplitude Phase REq-X Amplitude REq-X Phase Individual Frequency Response Z Phase [degrees] 5 5 5 k k 5k k k [Hz] 77
The calibration chart includes individual TEDS values that, together with a general formula, best fit the measured frequency response. The expression can be used for frequency response compensation in the specified frequency range. The relative frequency response, including amplitude and phase is: where S rel () f f a j------ ----------- f hp f ln = ----------------------- ---------------------- f + j------ + j----- f ------------------------------------------------------ j------- f j ------- f + + j------------ f ref f hp f lp f = Frequency f lp = Low-pass Cut-off Frequency f ref = Reference Frequency Q = Quality Factor f hp = High-pass Cut-off Frequency a = Relative Change/Decade f res = Resonance Frequency Combining this equation with the amplitude sensitivity S ref and f ref, results in: f res Qf res Implementation of this formula in either real-time data acquisition systems or in post-processing will extend the usable frequency range, improve accuracy or allow a combination of the two. Brüel & Kjær s Triaxial Charge Accelerometer Family S rel () f S() f = S ref ------------------------ S rel ( f ref ) Types 6-A and 6-A- are part of a family of triaxial charge accelerometers. To find the triaxial accelerometer that fits your needs, visit www.bksv.com. Table Comparison of Brüel & Kjær triaxial charge accelerometers 6-A 6-A- 57-C Temperature C ( F) 75 (7) (6) 5 (8) (6) Number of Connectors Weight g 7 55 6 Isolated Yes No No Capacitance pf 9 Frequency Range * Mounting Hz X: to 9 Y: to 8 Z: to 6 Mounting clip Adhesive M screws M stud X:. to Y:. to Z:. to M screws X: to Y: to Z: to 8 M stud Adhesive Sensitivity pc/ms.6..6 Product Data BP BP BP 55 * Lower limiting frequency is determined by the amplifier used Ground Insulation Ground-loop noise, particularly troublesome in multichannel measurements, is avoided by electrically insulating the sensing elements from the common housing. Types 6-A and 6-A- are electrically insulated with respect to signal ground and have a resistance of more than MΩ. 5
The electrical insulation of Type 6-A comes from its fully hard-anodized common housing with insulation at the three cylindrical mounting holes. The hard-anodized mounting surfaces provide additional insulation. The electrical insulation of Types 6-A- comes from the special mounting technique for the three sensing elements. A non-conductive glue is used to bond the sensing elements to the holes in the common housing. The three individually insulated sensing elements ensure that no ground-loop currents are induced in the measurement setup. This is particularly beneficial to engine test applications. Cabling Compliance with Standards When using accelerometers, the cable can affect the measurement result. Forces exerted on the connector by the cable can cause amplitude irregularities in the output at frequencies up to approximately Hz. This can be reduced by using a flexible cable. To effectively reduce the problem at low frequencies, it is recommended to clamp the cable. One way of doing this is to make a small loop in the cable close to the accelerometer (max. diameter mm) and clamp the cable beside the base of the accelerometer with mounting wax or double-sided tape. This also reduces the possibility of dynamically induced noise generated by the cable. Safety EMC Emission EMC Immunity Temperature Humidity The CE marking is the manufacturer's declaration that the product meets the requirements of the applicable EU directives RCM mark indicates compliance with applicable ACMA technical standards that is, for telecommunications, radio communications, EMC and EME China RoHS mark indicates compliance with administrative measures on the control of pollution caused by electronic information products according to the Ministry of Information Industries of the People s Republic of China WEEE mark indicates compliance with the EU WEEE Directive EN/IEC 6 : Safety requirements for electrical equipment for measurement, control and laboratory use ANSI/UL 6 : Safety requirements for electrical equipment for measurement, control and laboratory use EN/IEC 6 6 : Generic emission standard for residential, commercial and light industrial environments EN/IEC 6 6 : Generic emission standard for industrial environments CISPR : Radio disturbance characteristics of information technology equipment. Class B Limits FCC Rules, Part 5: Complies with the limits for a Class B digital device This ISM device complies with Canadian ICES (standard for interference-causing equipment) EN/IEC 6 6 : Generic standards Immunity for residential, commercial and light industrial environments EN/IEC 6 6 : Generic standards Immunity for industrial environments EN/IEC 66: Electrical equipment for measurement, control and laboratory use EMC requirements Note: The above is only guaranteed using accessories listed in this document IEC 668 & IEC 668 : Environmental Testing. Cold and Dry Heat Operating Temperature: 6-A: 55 to +75 C ( 67 to +7 F) 6-A-: 55 to + C ( 67 to +6 F) Storage Temperature: 5 to +7 C ( to +58 F) IEC 668 78: Damp Heat: 9% RH (non-condensing at C ( F)) 6
Specifications Piezoelectric Charge Accelerometer Types 6-A and 6-A- All values are typical at 5 C unless measurement uncertainty is specified Type Number 6-A 6-A- General Weight gram (oz) (.6) 7 (.6) Charge Sensitivity (at 59. Hz) pc/ms.6 ±% pc/g. ±% Frequency Range (±% limit) Hz X: to 9 Y: to 8 Z: to 6 Mounted Resonance Frequency khz X: 7 Y: Z: 8 Max. Transverse Sensitivity (at Hz, ms ) % <5 Transverse Resonance Frequency khz X, Y, Z: > Max. Operational Continuous Sinusoidal Acceleration (peak) Electrical kms g Residual Noise Level (measured with mms. 5.6 NEXUS Type 69- in the specified frequency range) mg..56 Capacitance (excluding cable) pf Case (signal ground) Insulation to Base MΩ > Min. Leakage Resistance (at C) GΩ > Environmental C 55 to +75 55 to + Operating Temperature Range F 67 to +7 67 to +6 Temperature Coefficient of Sensitivity %/ C X and Y:.8 * Z:.5 * Temperature Transient Sensitivity ( Hz Low. Lim. Freq. ( db, 6 db/octave)) Base Strain Sensitivity (at 5 µε in the base plane) Magnetic Sensitivity (5 Hz,.8 T) Max. Non-destructive Shock (± peak) ms / C. g/ F. ms /µε. g/µε. ms /T 5. g/kg.5 kms g Mechanical Housing Material Anodized Aluminium Titanium ASTM Grade Piezoelectric Sensing Element PZ Construction ThetaShear Sealing Welded Electrical Connector UNF-A Mounting Mounting clip, adhesive, M screws or M studs * In the temperature range 5 to +5 C Mounted in mounting clip 7
Overload Conditioning Amplifier B 7/6-'89 K Equipment Configuration Fig. 8 Configurations for Brüel & Kjær s family of triaxial charge accelerometers Female (F) 57-C AO-767 (5 C) Male (M) Brüel & Kjær X Y JJ- AO-8 (5 C) 67-A/B/C/D/D- UA-5-6 Z UA-6-6-A AO-6 (5 C) JP-5 7 8 UA--6 AO-9 (5 C) 9 5 6 6-A- AO-8 (5 C) 5 6 5 AO- (5 C) 6 AO-8 (5 C) AO- (UNF: 5 C, TNC: C) JP-6 69 Brüel & Kjær NEXUS Ch. Out Unit U/Pa.6 V/ms - V/ms - 6 V/ms - 5 Ordering Information Type 6-A Triaxial piezoelectric charge accelerometer Type 6-A- Triaxial piezoelectric charge accelerometer All types include the following accessories: Carrying box Calibration chart One mounting clip Optional Brüel & Kjær Accessories CABLING AO-8-x-yyy * Super low-noise cable, UNF (M), 5 C (8 F) AO--x-yyy * Super low-noise, robust double-screened cable, UNF (M), 5 C (8 F) AO--x-yyy * Super low-noise cable, UNF (M) to TNC (M), 8 C (56 F) AO-6-x-yyy * Low-noise, double-screened cable, UNF (M) to BNC (M), 5 C (8 F). Includes JP-5 AO-8-x-yyy * Low-noise, double-screened cable, UNF (M), 5 C (8 F) AO-9-x-yyy * Very light and flexible low-noise coaxial cable with UNF (M), 5 C (8 F) JP-5 Plug adapter, UNF (F) to BNC (M) JP-9 Adapter, UNF (M) to -pin (F) QA-5 Cable accessory set, tools for cable and connector assembly UA- Connector, UNF (M) for mm to mm cable jacket (set of 5) UA-86 Extension connector, UNF (F) (set of 5) UA-7 Connector, UNF (M) for mm (max.) cable jacket (set of 5) UA- Red/green/yellow cable markers, for.9 mm to. mm cable jacket ( pieces) * x = D (decimetres) or M (metres); yyy = length in decimetres or metres Please specify cable length when ordering MOUNTING QS-7 Tube of cyanoacrylate adhesive UA-75 Mounting magnet and two insulating discs, M, mm, length.6 mm (set of 5) UA-8 Mounting clip, big (set of ) UA-7 Mounting clip with swivel base, big (set of ) UA-7 Mounting clip with thick base, big (set of ) UA-8 Spirit level for all swivel bases UA-56 High-temperature mounting clip, big (set of 5) UA-65 Steel stud, M 5 mm (set of ) YJ-6 Beeswax for mounting YQ-85 Screw, stainless steel, M. mm YQ-7 Screw, hex socket set with cup point, M 8 mm CONDITIONING AND FRONT ENDS Type 5-B- LAN-XI -ch. Input Module 5.6 khz (CCLD, V) UA-6- LAN-XI Front Panel, -channel Charge, UNF (F) microdot connectors (Gain: mv/pc) Type 5-A-6 LAN-XI 6-ch. Input Module 5. khz (Mic, CCLD, V) UA-5-6 LAN-XI Front Panel, Charge Accelerometer, 6-ch. for the family of Charge to CCLD Converter Type 67 Type 67-A/B Charge to CCLD Converter Type 69 NEXUS Conditioning Amplifier CALIBRATION Type 9 Vibration Exciter DV-6 Calibration clip, big Brüel & Kjær Calibration Services ACC-T-CAI ACC-T-CAF ACC-T-CFF ACC-T-CTF Accredited initial calibration Accredited calibration Factory standard calibration Traceable calibration Brüel & Kjær and all other trademarks, service marks, trade names, logos and product names are the property of Brüel & Kjær or a third-party company. ËBP----ÆÎ BP 8 8-8 Brüel & Kjær. All rights reserved. Brüel & Kjær Sound & Vibration Measurement A/S DK-85 Nærum Denmark Telephone: +5 77 Fax: +5 5 8 5 www.bksv.com info@bksv.com Local representatives and service organizations worldwide Although reasonable care has been taken to ensure the information in this document is accurate, nothing herein can be construed to imply representation or warranty as to its accuracy, currency or completeness, nor is it intended to form the basis of any contract. Content is subject to change without notice contact Brüel & Kjær for the latest version of this document.