PCB Piezotronics 088A User manual

Model 088A
Modal punch kit includes modal punch, Model 084A80 extender, Model
Installation and Operating Manual
For assistance with the operation of this product,
contact PCB Piezotronics, Inc.
Toll-free: 800-828-8840
24-hour SensorLine: 716-684-0001
Fax: [phone]
E-mail: [email protected]
Web: www.pcb.com

Manual 21354 Rev E
ECN 50523
Repair and Maintenance
PCB guarantees Total Customer Satisfaction through its
“Lifetime Warranty Plus” on all Platinum Stock Products
sold by PCB and through its limited warranties on all other
PCB Stock, Standard and Special products. Due to the
sophisticated nature of our sensors and associated
instrumentation, field servicing and repair is not
recommended and, if attempted, will void the factory
warranty.
Beyond routine calibration and battery replacements
where applicable, our products require no user
maintenance. Clean electrical connectors, housings, and
mounting surfaces with solutions and techniques that will
not harm the material of construction. Observe caution
when using liquids near devices that are not hermetically
sealed. Such devices should only be wiped with a
dampened cloth—never saturated or submerged.
In the event that equipment becomes damaged or ceases
to operate, our Application Engineers are here to support
your troubleshooting efforts 24 hours a day, 7 days a
week. Call or email with model and serial number as well
as a brief description of the problem.
Calibration
Routine calibration of sensors and associated
instrumentation is necessary to maintain measurement
accuracy. We recommend calibrating on an annual basis,
after exposure to any extreme environmental influence,
or prior to any critical test.
PCB Piezotronics is an ISO-9001 certified company whose
calibration services are accredited by A2LA to ISO/IEC
17025, with full traceability to SI through N.I.S.T. In
addition to our standard calibration services, we also offer
specialized tests, including: sensitivity at elevated or
cryogenic temperatures, phase response, extended high
or low frequency response, extended range, leak testing,
hydrostatic pressure testing, and others. For more
information, contact your local PCB Piezotronics
distributor, sales representative, or factory customer
service representative.
Returning Equipment
If factory repair is required, our representatives will
provide you with a Return Material Authorization (RMA)
number, which we use to reference any information you
have already provided and expedite the repair process.
This number should be clearly marked on the outside of
all returned package(s) and on any packing list(s)
accompanying the shipment.
Contact Information
PCB Piezotronics, Inc.
3425 Walden Ave.
Depew, NY14043 USA
Toll-free: [phone]
24-hour SensorLine: [phone]
General inquiries: in[email protected]
Repair inquiries: [e-mail]
For a complete list of distributors, global offices and sales
representatives, visit our website, www.pcb.com.
Safety Considerations
This product is intended for use by qualified personnel
who recognize shock hazards and are familiar with the
precautions required to avoid injury. While our equipment
is designed with user safety in mind, the protection
provided by the equipment may be impaired if equipment
is used in a manner not specified by this manual.
Discontinue use and contact our 24-Hour Sensorline if:
Assistance is needed to safely operate equipment
Damage is visible or suspected
Equipment fails or malfunctions
For complete equipment ratings, refer to the enclosed
specification sheet for your product.
Definition of Terms and Symbols
The following symbols may be used in this manual:
DANGER
Indicates an immediate hazardous
situation, which, if not avoided, may
result in death or serious injury.

Manual 21354 Rev E
ECN 50523
CAUTION
Refers to hazards that could damage
the instrument.
NOTE
Indicates tips, recommendations and
important information. The notes
simplify processes and contain
additional information on particular
operating steps.
The following symbols may be found on the equipment
described in this manual:
This symbol on the unit indicates that
high voltage may be present. Use
standard safety precautions to avoid
personal contact with this voltage.
This symbol on the unit indicates that
the user should refer to the operating
instructions located in the manual.
This symbol indicates safety, earth
ground.

Manual 21354 Rev E
ECN 50523
PCB工业监视和测量设备 - 中国RoHS2公布表
PCB Industrial Monitoring and Measuring Equipment - China RoHS 2 Disclosure Table
部件名称
有害物质
铅(Pb)
汞
(Hg)
镉
(Cd)
六价铬(Cr(VI))
多溴联苯 (PBB)
多溴二苯醚(PBDE)
住房
O
O
O
O
O
O
PCB板
X
O
O
O
O
O
电气连接器
O
O
O
O
O
O
压电晶体
X
O
O
O
O
O
环氧
O
O
O
O
O
O
铁氟龙
O
O
O
O
O
O
电子
O
O
O
O
O
O
厚膜基板
O
O
X
O
O
O
电线
O
O
O
O
O
O
电缆
X
O
O
O
O
O
塑料
O
O
O
O
O
O
焊接
X
O
O
O
O
O
铜合金/黄铜
X
O
O
O
O
O
本表格依据 SJ/T 11364 的规定编制。
O：表示该有害物质在该部件所有均质材料中的含量均在 GB/T 26572 规定的限量要求以下。
X：表示该有害物质至少在该部件的某一均质材料中的含量超出 GB/T 26572 规定的限量要求。
铅是欧洲RoHS指令2011/65/ EU附件三和附件四目前由于允许的豁免。
CHINA RoHS COMPLIANCE

Manual 21354 Rev E
ECN 50523
Component Name
Hazardous Substances
Lead (Pb)
Mercury (Hg)
Cadmium (Cd)
Chromium VI
Compounds
(Cr(VI))
Polybrominated
Biphenyls (PBB)
Polybrominated
Diphenyl Ethers
(PBDE)
Housing
O
O
O
O
O
O
PCB Board
X
O
O
O
O
O
Electrical Connectors
O
O
O
O
O
O
Piezoelectric Crystals
X
O
O
O
O
O
Epoxy
O
O
O
O
O
O
Teflon
O
O
O
O
O
O
Electronics
O
O
O
O
O
O
Thick Film Substrate
O
O
X
O
O
O
Wires
O
O
O
O
O
O
Cables
X
O
O
O
O
O
Plastic
O
O
O
O
O
O
Solder
X
O
O
O
O
O
Copper Alloy/Brass
X
O
O
O
O
O
This table is prepared in accordance with the provisions of SJ/T 11364.
O: Indicates that said hazardous substance contained in all of the homogeneous materials for this part is below the limit
requirement of GB/T 26572.
X: Indicates that said hazardous substance contained in at least one of the homogeneous materials for this part is above the limit
requirement of GB/T 26572.
Lead is present due to allowed exemption in Annex III or Annex IV of the European RoHS Directive 2011/65/EU.

1
Installation and Operating Manual
Model 088A ICP® Modal Punch
Manual Number 19199
Manual Revision: NR
Contents:
1.0 Introduction …………………………………………… Page 1
2.0 Description ................................………………………. Page 2
3.0 Installation ...............................................……………... Page 2
4.0 Operation .........................................….……………….. Page 3
5.0 Testing ………………………………………………… Page 4
6.0 Calibration……………………………………………... Page 5
7.0 Maintenance ……………………………………………Page 6
8.0 Cautions ……………………………………………….. Page 6
9.0 Customer Service ……………………………………… Page 7
1.0 INTRODUCTION
The PCB® Modal Punch is ideally suited for structural behavior testing. The Modal
Punch allows the user to reach impact locations previously inaccessible by conventional
impulse hammers. Impulse testing the dynamic behavior of mechanical structures
involves positioning the Modal Punch at the desired measurement location on the
structure, then striking the force-instrumented Modal Punch with a standard non-
instrumented hammer and measuring the resultant motion with an accelerometer(s).
Integration of the acceleration signal yields velocity or displacement data for use in
computing classical transfer characteristics such as inertance, compliance, impedance,
and mobility. Structures generally respond as (1) rigid or elastic bodies, (2) finite
elements, lumped constant models, and (3) distributed parameter models conducting
stress-strain (sound) waves.
The impulse generated by the Modal Punch and the user’s standard non-instrumented
hammer consists of a nearly-constant force over a broad frequency range and is therefore
capable of exciting all resonances in that range. The physical properties of the impact
device, including size, weight, material, and velocity at impact determine the amplitude
and frequency content (wave shape) of the force impulse. The impact cap material
generally determines the frequency content. The mass of the Modal Punch and hammer,
along with the velocity at impact, determine the energy content.

2
The type and size of the required impact device is determined by the test structure. The
Model 088A Modal Punch was designed for use on intermediate size structures such as
automotive axles, gearbox shafts, and machine tools. Large, heavy structures such as
locomotive frames, tanks, and bridges require an instrumented sledge hammer (PCB®
model numbers 086D20 or 086D50). Small structures such as compressor blades or
some electrical circuit boards often require a miniature instrumented hammer (PCB®
model number 086D80). Some very large structures may require a special mechanical
ram instrumented with a force-sensing impact head.
The Modal Punch is instrumented with a precision, quartz, ICP®(low impedance) voltage
mode force sensor. The built-in conditioning electronics allow ease of use and test set-
up, while the naturally-polarized quartz sensing element offers long-term stability and
repeatability.
2.0 Description
The Modal Punch consists of an integral ICP® (Integrated Circuit Piezoelectric), quartz
force sensor mounted on the impact head. The sensing element and built-in, solid state
micro-electronics inside the force sensor function to transfer impact force into a low
impedance analog signal for display and analysis. The cable is connected on the side of
the Modal Punch’s Connector Adaptor model number 070A41 (supplied) just below the
impact surface. An Extension Shaft model 084A80 is also supplied to adjust the Modal
Punch to the desired length. Additional shafts may also be purchased. A foam grip is
supplied to provide a comfortable and secure grip and may be replaced when needed.
The striking end of the Modal Punch’s head has a threaded hole to accept a variety of
impact tips. The tip functions to transfer the force of the impact into the sensor and
protects the sensor face from damage. Tips of different stiffness allow the user to vary
the pulse width and frequency content of the force.
All component parts (impact head, extender, and connector adaptor) are laser-welded and
epoxied at the factory to ensure reliable operation in adverse environmental conditions.
3.0 Installation
To assemble the Modal Punch, choose the number of extenders required to reach the
desired impact location, screw the extender onto the force-instrumented impact head, and
attach the connector adaptor to the extender or the force-instrumented impact head, if an
extender is not being utilized. To ensure a proper mechanical coupling between the parts
of the Modal Punch, each piece should be securely screwed together. Care should be
used not to over-torque the parts, which will cause permanent damage to the interface and
connectors. A firm, hand-tight torque is sufficient to ensure a proper coupling. If
desired, a small amount of silicone grease (DC-4 or equivalent) may be applied between
the interfacing parts for an improved coupling.

3
Accelerometers install and connect according to the procedures described in the specific
sensor manual. Accelerometers utilized for impact testing include the 353 Series of
single axis accelerometers, and the 356 Series of triaxial accelerometers. For additional
information regarding sensors to meet your impact testing needs, feel free to contact the
PCB®Vibration Division customer service group by calling toll-free in the USA 888-
684-0013 (or outside the USA by calling 716-684-0001).
In general, sensors connect to the ICP®power unit at the jack labeled “XDCR”. The jack
labeled “SCOPE”is connected to the readout device, FFT analyzer, or computer. Please
consult the ICP®power unit operating guide for proper installation and operating
procedures.
4.0 Operation
Follow the below operation instructions:
1). Assemble the Modal Punch to the desired length using the supplied extension (if
required) and connector adaptor. Please reference the above installation procedures.
2). Choose the impact tip which corresponds to your excitation requirements. In general:
A. A stiffer tip is recommended for higher frequency response.
B. A softer tip is recommended for improved low frequency response.
3). Connect the Modal Punch to an ICP®power supply or equivalent with a coaxial cable
(not supplied). The Modal Punch requires a 10-32 microdot connector plug.
4). Connect the corresponding output cable (not supplied) from your ICP® power supply
to your readout device. This step is not necessary if ICP® power is built into your
readout device. Tighten the cable connectors securely by hand to ensure good electrical
contact.
5). Install accelerometer(s) in the desired measurement location(s), referring to the
appropriate operating guides for the accelerometer(s) and power supplies being used.
6). Switch power on and wait a minute for the sensor amplifier to turn on and the
coupling capacitor to fully charge.
7). Check the ICP® power unit meter for normal operation. Normal operation is indicated
when the meter pointer is pointing in the green area. If the meter reads in the red area,
look for a shorted cable or connection. If the meter pointer is pointing in the yellow area,
look for open cables or connections.
8). When all power unit meters indicate normal operation (meter pointer is pointing in the
green area), proceed with tests, following all sensor, power unit, and analyzer operating
instructions.

4
PCB®’s ICP® constant-current power supply units provide the necessary excitation power
for proper operation of the Modal Punch. These units provide the correct power and have
circuit fault indicating meters and a bias decoupling capability to remove MOSFET turn
on bias voltage from the measurement signal. Power units are available in a variety of
configurations, including battery or AC versions and with additional signal conditioning
features such as gain, filtering, and integration. Some FFT analyzers incorporate the
proper excitation power for direct connection to ICP® sensors. Be certain to confirm that
the excitation from the power supply conforms to the requirements for the specific
sensors being used. The Modal Punch requires 2 to 20 mA constant current and 24 to 27
VDC.
CAUTION: The Modal Punch was designed to operate only with ICP® power supply
units. Do not attempt to troubleshoot the Modal Punch by connecting it to any device,
such as an ohmmeter, which may introduce unregulated voltage, as damage to the
precision internal micro-electronics may occur. If there is any doubt about the
compatibility of a power supply unit or whether a power supply unit is required, feel free
to contact the PCB®Vibration Division customer service group by calling toll-free in the
USA 888-684-0013 (or outside the USA by calling 716-684-0001).
5.0 Testing
To test the behavior of your structure and to tailor the frequency bandwidth of the impact
force, follow the below operation instructions:
1). Position the Modal Punch on the test structure at the desired location. Strike the
punch with a standard non-instrumented hammer and process the results. Always take
several averages to reduce the effects of spurious noises. CAUTION: Never impact
without a tip properly installed on the Modal Punch, as permanent damage of the sensing
element is likely to occur. Also, care should be exercised when striking the punch to
ensure that the impact hammer does not slip and strike the operator’s hand, causing
personal injury.
2). Check the measured results for signal quality (adequate signal-to-noise) and no
overloads (overloads lights or sharp flattening of time history peaks).
3). Analyze the results for frequency content and check to ensure that the reasonably flat
portion of the force spectrum is sufficient to cover the structural resonances of interest
present in the acceleration spectrum. Often, signal energy is sufficient to excite structural
resonances at 20 dB below initial low frequency force levels.
4). Change Modal Punch tips to modify dynamic behavior, if necessary. The following
are general guidelines; the specific test structure plays an integral part in the selection:
A. To obtain higher frequency response, use a stiffer, harder tip and a smaller
hammer mass.
B. To obtain improved low frequency response, use a softer hammer tip and
larger hammer mass.

5
C. To increase signal energy of impact, increase the impact velocity and/or
hammer mass.
5). Repeat steps 1 through 4 until satisfactory results are obtained.
Generally speaking, the impact tips affect the impulse frequency content, while the mass
of the impact device and velocity of impact affect the signal energy level. Frequency
content and energy level are interrelated. Therefore, both will be affected by different
hammer structures and Modal Punch configurations. Hammer velocity at impact will
also affect both. In general, massive structures with lower stiffness require the use of a
soft impact tip and large mass to adequately excite low frequency resonances.
During testing, occasionally check and tighten the electrical and mechanical connections.
Repeated impacting may loosen connections, which may result in erratic, noisy signals.
Multiple impacts or penetration into the structure may occur when using too heavy a
mass on too light a structure. This will appear as a series of peaks of decreasing
amplitude in the time history data. Reject such data. Careful techniques used in the
impact process can avoid this problem. In particular, if the Modal Punch is held against
the test structure and allowed to freely recoil after impact, the double impact phenomena
will be reduced or eliminated. Some skill and practice may be required to perfect this
technique.
Distortion, undershoot, and oscillation of the analyzer display is caused by ringing of the
analyzer’s anti-aliasing filters. This behavior is normal. To view the correct impulse
waveform, switch the analyzer to a higher frequency range.
6.0 Calibration
Calibration involves testing the functional transfer behavior (sensitivity) of the sensor
under controlled laboratory conditions. Sensitivities to various inputs such as force,
temperature, current, and frequency can be derived by relating the corresponding output
to changes in these inputs. For impact hammers and the Modal Punch, the most
important of these relationships is the sensitivity to the force input. The desired behavior
is linear, since ideal sensors treat output and input amplitudes proportionally. In addition,
the nominal sensitivity should be constant (linear frequency response) within the specific
frequency range, and there should be no induced phase shift in the response (no delay in
the signal).
Different Modal Punch and hammer combinations have different sensitivities because the
structure experiences a force greater than the crystal-sensing elements. The force of
impact on the test structure is a function of the total mass of the Modal Punch and
hammer, while the force on the crystals is a function of the mass behind them. The
impact tip is located in front of the crystal. The differences in mass depend on the ratio
of the tip mass to the mass behind the crystal. This is automatically compensated for
when the Modal Punch is properly calibrated.