Kinemetrics EpiSensor FBA ES-T User Manual
User Guide
EpiSensor
Force Balance
Accelerometer
Model FBA ES-T
Document 301900
Revision D
October 2005
Trademarks
This manual copyright © Kinemetrics, Inc., 2005. All rights reserved.
Kinemetrics products are covered by U.S. and foreign patents, issued and
pending. Printed in U.S.A.
The trademarks used throughout this manual, registered or not, are:
Kinemetrics, QuickTalk!, QuickLook! , K2! , Mt. Whitney! , Etna! ,
Etna-SI! , EpiSensor!
FerriShield
Microsoft Windows
Kinemetrics, Inc., 222 Vista Avenue, Pasadena, CA 91107 USA
Phone: (626) 795-2220 ! Fax: (626) 795-0868
E-mail: services@kmi.com
Website: www.kinemetrics.com
Kinemetrics SA, Le Tresi 3, 1028 Preverenges, Switzerland
Phone: 21.803.2829 ! Fax: 21.803.2895
E-mail: kmi_sa@bluewin.ch
DOCUMENT 301900, REVISION D
Table of Contents
1. Introduction
The EpiSensor FBA ES-T.............................................................................. 1
Inspecting the EpiSensor................................................................................2
2. Installation Basics
Requirements for Installation......................................................................... 3
Required Tools.......................................................................................3
Required Supplies ..................................................................................4
Required Equipment ..............................................................................4
Mounting & Orienting the EpiSensor............................................................4
Required Cables..................................................................................... 7
Grounding the EpiSensor............................................................................... 7
Safety First............................................................................................. 7
EMI/RFI................................................................................................. 8
Powering the EpiSensor................................................................................. 9
Zero-Adjusting the EpiSensor......................................................................10
Thermal Insulation Shield (Optional) ..........................................................11
3. Operating Basics
Polarity Conventions....................................................................................17
EpiSensor External Features........................................................................ 18
Required Power............................................................................................ 18
Performing a Functional Test with an Altus Recorder ................................19
Sensor Response Test ..................................................................................20
Methods of Measuring the DC Offset.................................................. 10
Performing the Zero Adjustment ......................................................... 10
Note on Full-Scale Range .................................................................... 11
DOCUMENT 301900, REVISION D
EpiSensor Configuration..............................................................................20
Opening the EpiSensor Case................................................................ 21
Pin Numbering System ................................................................................ 21
Jumper Selectable Options........................................................................... 22
Setting the Full-scale Range ........................................................................22
Headers and Connectors on Oscillator Board.............................................. 25
Output Voltage Level................................................................................... 26
Power & Noise Configurations.................................................................... 27
Low-Noise Power Control ...................................................................28
Power Supply Options .........................................................................29
Calibration Coil............................................................................................29
Calibration Coil Disconnect................................................................. 29
Calibration Coil Test Connector ..........................................................30
Closing the EpiSensor Case................................................................. 30
4. Maintenance
Recommended Maintenance........................................................................ 33
Adjust the Accelerometers...................................................................33
Complete a Functional Test ................................................................. 33
Calibration............................................................................................33
Desiccant Replacement........................................................................34
Troubleshooting and Repair................................................................. 34
5. Reference
Theory of Operation..................................................................................... 35
Working Principle................................................................................ 36
Features................................................................................................ 37
Pole Zero Representation of the EpiSensor ................................................ 38
Polarity Conventions....................................................................................40
Electrical Interface....................................................................................... 42
6. Advanced Installations
CE Compliant Installations ..........................................................................43
Using EpiSensors with Altus Instruments ...................................................43
The Etna............................................................................................... 44
The K2 & Mt. Whitney........................................................................44
Dual Gain Systems............................................................................... 44
DOCUMENT 301900, REVISION D
Long Cables ......................................................................................... 45
User-Supplied Cable ............................................................................46
Grounding ............................................................................................ 46
Use with Non-Kinemetrics Data Loggers........................................... 48
Power Supply....................................................................................... 48
Output Voltage.....................................................................................50
Calibration Sequence ........................................................................... 50
Ground Loop Prevention......................................................................51
Custom Cable Assembly.............................................................................. 52
Cable Assembly Instructions .......................................................................55
Identical Assembly Procedures............................................................ 55
Final Assembly of the Recorder End................................................... 60
Testing Connector Assembly #1.......................................................... 62
Figures
Initial Assembly of the EpiSensor End................................................ 64
Final Assembly of the EpiSensor End ................................................. 66
Testing Connector Assembly #2.......................................................... 70
7. Appendix
Figure 1: The EpiSensor ..............................................................................2
Figure 2: Episensor mounting dimensions...................................................5
Figure 3: Drilling EpiSensor mounting hole................................................6
Figure 4: EpiSensor & Packaging Components.........................................12
Figure 5: Large Packaging Piece Installed.................................................13
Figure 6: Cable Installed............................................................................ 13
Figure 7: Second Packaging Piece Installed over Connector Shell ...........14
Figure 8: Final Packaging Piece Installed..................................................15
Figure 9: The EpiSensor. ...........................................................................18
Figure 10: Display of functional test ...........................................................19
Figure 11: Display of functional test using software released prior to
August 1998............................................................................... 20
Figure 12: Pin numbering system. ............................................................... 22
Figure 13: Feedback board...........................................................................23
Figure 14: Full-scale range jumper settings................................................. 24
Figure 15: Top view of oscillator board ......................................................25
Figure 16: Bottom view of oscillator board with headers indicated............26
Figure 17: Jumper configurations ................................................................28
Figure 18: Simplified block diagram of an accelerometer...........................35
DOCUMENT 301900, REVISION D
Figure 19: Amplitude, phase, and step response of the EpiSensor
response model...........................................................................39
Figure 20: X, Y and Z coordinates...............................................................41
Figure 21: EpiSensor to Altus recorder cable..............................................52
Figure 22: Parts for recorder-end mating connector assembly ....................54
Figure 23: Preparing 3/8"-wide foil tape from 1" foil tape.......................... 54
Figure 24: Recorder cable end with outer PVC jacket removed .................56
Figure 25: Recorder cable end with rope and cellophane removed............. 56
Figure 26: Detail of foil shields, drain wires and foil tape ..........................57
Figure 27: Drain wires twisted together.......................................................58
Figure 28: Drain wire-to-black wire connection.......................................... 58
Figure 29: Outer foil tape and drain-wire shrink tubing.............................. 59
Figure 30: Schematic of EpiSensor cable to both mating connectors .........59
Figure 31: Foil tape and stripped-and-tinned wires ..................................... 60
Figure 32: Wrapping the connection with PVC tape................................... 60
Figure 33: Wrapping foil tape around outside of the connection ................61
Figure 34: Slipping Shrink-n-Shield tubing into place................................ 61
Figure 35: Shrink-n-Shield tubing in correct position (after shrinking) ......61
Figure 36: Completed assembly of recorder-end of cable 840356.............. 62
Figure 37: Parts for EpiSensor-end mating connector assembly................. 64
Figure 38: Preparing 3/8"-wide foil tape from 1" foil tape.......................... 65
Figure 39: Example of a daisychain.............................................................66
Figure 40: Connection wrapped with PVC tape .......................................... 67
Figure 41: Wrapping foil tape around outside of the connection ................68
Figure 42: Cable with Shrink-n-Shield tubing (outer tubing trimmed
back to show screen mesh) ........................................................68
Figure 43: Shrink-n-Shield tubing shrunk and in position...........................69
Figure 44: Completed assembly of EpiSensor end of cable 840356 ........... 69
Tables
Table 1: Reasonable zero offset voltages ..................................................11
Table 2: Range/sensitivity calculations ..................................................... 23
Table 3: Output voltage-level jumper settings ..........................................27
Table 4: Amplifier configuration............................................................... 27
Table 5: Function of headers X21 and X22............................................... 28
Table 6: Calibration coil disconnect header ..............................................29
Table 7: Calibration coil test headers ........................................................ 30
Table 8: Input connections ........................................................................42
Table 9: EpiSensor cabling requirements (1 foot = 0.3048 meters).......... 46
Table 10: Current requirements ................................................................... 49
Table 11: Current requirements ................................................................... 50
Table 12: Parts for recorder mating connector assembly.............................53
Table 13: Part order, recorder cable end...................................................... 55
Table 14: Parts for EpiSensor-end mating connector assembly ..................64
Table 15: Slide parts over cable jacket in this order:...................................66
Table 16: EpiSensor specifications..............................................................73
Symbols & Terms
The following symbols may appear on Kinemetrics equipment or in this
manual.
Safety
!
When you see this symbol, pay careful attention. Refer to the similarly
marked, relevant part of this manual before servicing the instrument.
This symbol means a low-noise earth ground. The noted item should be
grounded to ensure low-noise operation, and also to serve as a ground return
for EMI/RFI and transients. Such a ground does not work as a safety
ground for protection against electrical shock!
~ This symbol means an alternating current (AC) power line.
This symbol means a direct current (DC) power line derived from an AC
power line.
This symbol indicates an electrostatic sensitive device (ESD), meaning that
when handling the marked equipment you should observe all standard
precautions for handling such devices.
These safety-related terms appear in this manual:
Note: statements identify information that you should consider before
moving to the next instruction or choice.
Caution statements identify conditions or practices that could result in
damage to the equipment, the software, or other property.
WARNING! statements identify conditions or practices that could result in
personal injury or loss of life.
EPISENSOR USER GUIDE SAFETY 1
SAFETY 2 EPISENSOR USER GUIDE
Specific Precautions
Follow the precautions below to ensure your personal safety and prevent
damage to the EpiSensor.
Power Source
The EpiSensor must be supplied with power either from a recorder or from
a customer-supplied " 12V or " 15V power supply (or a + 12V supply for
the single-supply option).
If you plan to power the EpiSensor from a recorder, connect the recorder to
a power supply/charger supplied by Kinemetrics, as described in each
recorder's user manual.
To supply power directly to the EpiSensor, you need a low-noise, regulated
" 12V or " 15V power supply (or a + 12V supply for the single-supply
option) that is safely grounded and meets all applicable local regulations.
The EpiSensor will be damaged if the power is connected with the wrong
polarity.
User- Supplied Power/Charging System
If you supply your own power/charging system, be sure that the system
provides the correct voltage and current required by the EpiSensor under all
operating conditions. You are responsible for the safety of your charging
system. If you get power from the mains supply, be sure you have supplied
adequate grounding for all the equipment. If you supply your own batteries,
follow the manufacturer’s safety recommendations.
Sensor Grounding and Cabling
In some cases the EpiSensor will be a long distance from the recorder. In
these installations it is possible, due either to faulty AC wiring or extremely
high earth-return currents, for a high potential difference to exist between
the grounds at the two locations. When the cable is grounded at one end a
potentially lethal voltage can exist between the other end of the cable and
ground. Consider this danger during installation and get help from a
qualified electrician if this danger exists.
Do Not Operate in Explosive Atmosphere
The EpiSensor provides no explosive protection from static discharges or
arcing components. Do not operate the equipment in an atmosphere where
explosive gases are present.
!
Symbole & Begriffe
Diese Symbole können auf Kinemetrics Geräte oder in diesen Manuel
erscheinen:
Sicherheit
Bedeutet Achtung! Wenn sie dieses Symbol auf ein Gerät sehen, muss den
!
gleich markierten Teil dieses Manuels beachet werden. Bevor irgend eine
Unterhaltsarbeit angefangen wird, muss dieser Teil des Manuels gelesen
werden. Wenn Sie dieses Symbol sehen, bitte besondere Achtung geben.
Bedeutet Erdung. Das erwaente Teil sollte geerdet werden, um eine “lownoise” operation zu versichern, und dann auch als Erdung für EMI/ FRI und
Transienten und solch eine Erdung wird nicht als Sicherheit gegen
elektrischen Schock dienen!
~ Bedeutet Wechselstromzufuhr (AC) mit Elektroschock Gefahr.
Bedeutet Gleichstromzufuhr von AC Versorgung herkommend.
Bedeutet Elektrostatisch Sensibeles Element (ESD) für dessen Handhabung
alle vorbeugende Vorsichtsmassnahmen genommen werden müssen.
Folgende Darstellungen werden in diesen Manuel erscheinen:
Note: Darstellung welche Informationen Sie erhalten, die besonders
beachtet werden müssen, bevor sie zum nächsten Schritt gehen.
Caution: Darstellung bei dem die Missachtung in der Regel Gefahr für
Defekte und Störungen im Gerät, Programm oder Zubehör besteht.
WARNING! Darstellung bei dem die Missachtung in der Regel
Verletzungs – oder Lebensgefahr besteht.
EPISENSOR USER GUIDE SAFETY 3
Spezielle vorbeugende
Massnahmen
Alle vorbeugende Massnahmen müssen beachtet werden. Für Ihre
persönliche Sicherheit, und um Schäden im EpiSensor zu vermeiden.
Stromversorgung
Die EpiSensor muss entweder mit Strom von einem Accelerograph oder
Ihrer eigenen Stromquelle "12 V versorgt werden.
Sollten Sie planen, die EpiSensor mit Strom von einem Recorder zu
versorgen, verbinden Sie den Recorder mit unserem Kinemetrics
Stromladegerät, wie es in unserem “User Manuel” beschrieben ist.
Um die EpiSensor direkt mit Strom zu versorgen, müssen Sie ein Ladegerät
"12 V, welches mit allen Sicherheitsbedingunge ausgestattet ist, benutzen.
Optionelles Stromversorgungs/Ladegerät
In manchen Fällen wird die EpiSensor eine lange Strecke von dem Recorder
entfernt Sein, wo es dann möglich sein könnte, dass durch beschädigte ACWiring oder Hohe Erdbewegungen, ein Spannungsunterschied besteht. Es
ist daher unbedingt notwendig, dass alle angeschlossenen Instrumente am
gleichen Spannungspotential geerdet sind. Bitte folgen Sie den vom
Hersteller gegebenen Empfehlungen.
Verkablung und Erdung vom Sensor
!
Wenn das Kabel an einem End geerdet ist, kann ein verhältnismässig
grosser Unterschied in der Voltage bestehen, welcher sehr gefährlich ist.
Bitte beachten Sie Diese Gefahr und wenn nötig, ziehen Sie das Gutachten
eines qualifizierten Elektrikers Ein.
Nicht in explosionsgefährdete Umgebung gebrauchen
Der EpiSensor hat keinen Explosions-schutz von statischen Entladungen
oder funkgefährdeten Bauteilen. Benutzen sie die Geräte nicht in
Umgebungen mit explosiven Gasen.
SAFETY 4 EPISENSOR USER GUIDE
Símbolos & Términos
Estos símbolos podrían aparecer en los equipos Kinemetrics o en este
manual:
Seguridad
Significa poner atencion! Cuando Usted vea este símbolo en el instrumento,
!
~
referirse a las partes de este manual marcadas similarmente. Antes de
intentar cualquier servicio en este instrumento, Usted tiene que leer las
partes relevantes de este manual. Si Usted ve este símbolo, ponga atención
cuidadosamente.
Significa un polo a tierra de bajo ruido. El ítem referido debe estar
polarizado a tierra para asegurar la operación a bajo ruido y además sirve
como un retorno a tierra para el EMI/RFI y transitorios. Tal polo a tierra no
trabaja como un polo a tierra de seguridad para protección contra choques
eléctricos!
Significa una línea de energía de Corriente Alterna (AC).
Significa una línea de energía de Corriente Directa derivada de una línea de
energía AC.
Significa una Unidad Sensitiva a Electrostática (Electrostatic Sensitive
Device ESD), indicando que usted debe tener cuidado y observar todas las
precauciones para el manejo de tales unidades.
Estos términos aparecerán en este manual:
Note: sentencias identificando información que Usted debe considerar
cuidadosamente antes de dirigirse a la siguiente instrucción u
opción.
Caution: sentencias identificando condiciones o practicas que podrían
resultar en daño del equipo, el software u otra propiedad.
EPISENSOR USER GUIDE SAFETY 5
WARNING! sentencias identificando condiciones o practicas que podrían
resultar en una lesión personal o la perdida de la vida.
Los últimos dos términos mencionados arriba podrían también aparecer en
el equipo Kinemetrics que Usted ha comprado, pero no necesariamente #
indiferentemente, Usted debe definitivamente tomar notas serias de las
precauciones y advertencias en este manual.
Precauciones Específicas
Siga las precauciones a continuación para garantizar su seguridad personal y
prevenir daños al EpiSensor.
Fuente del poder
El EpiSensor debe ser alimentado con energía ya sea desde un registrador o
desde una fuente de " 12V provista por el usuario.
Si usted planea alimentar el EpiSensor desde un registrador, conecte el
registrador a una fuente de poder/cargador suministrado por Kinemetrics,
como se describe en cada manual del usuario para el registrador.
Para suministrar energía directamente al EpiSensor, usted necesita una
fuente de poder de bajo ruido y regulado " 12V, el cual debe ser
apropiadamente conectado a tierra y cumplir con todas las regulaciones
locales que apliquen.
Sistema de Poder/Carga Provisto por el Usuario
Si usted provee su propio sistema de poder/carga, usted tiene que estar
seguro, que el sistema proporciona el voltaje correcto y la corriente
requerida por el EpiSensor bajo todo las condiciones de operación. Usted es
responsable por la seguridad de su sistema de carga.
Si usted deriva energía de suministro principal, usted tiene que asegurarse
que ha provisto un polo a tierra adecuado para todo el equipo. Si usted
suministra sus propias baterías, siga las recomendaciones de seguridad del
fabricante.
Cableado y Polo a Tierra del Sensor
En algunos casos el EpiSensor estará a una distancia lejos del registrador.
!
En estas instalaciones existe la posibilidad de una elevada diferencia de
potencial entre dos localidades de polo a tierra, debido ya sea a fallas en el
alambrado del AC o corrientes de un extremadamente alto retorno de tierra.
Cuando el cable esta polarizado a tierra en uno de sus lados terminales, un
voltaje potencialmente letal puede existir entre el otro lado terminal del
cable y el polo a tierra. Considere este peligro durante la instalación y
obtenga ayuda de un electricista calificado si este peligro existe.
SAFETY 6 EPISENSOR USER GUIDE
No Opere en Atmósferas Explosivas
El EpiSensor no proporciona ninguna protección explosiva para descargas
estáticas componentes que generen arcos eléctricos. No operar el equipo en
una atmósfera de gases explosivos.
EPISENSOR USER GUIDE SAFETY 7
Symboles & Terminologie
Les symboles suivant peuvent figurer sur les équipements Kinemetrics ou
dans ce manuel:
Sécurité
!
Signifie Attention! Quand vous rencontrez ce symbole sur un instrument,
veuillez vous référer à la section de ce manuel signalée par la même
marque. Avant même d’effectuer la première opération sur l’instrument,
vous devez lire la section correspondante de ce manuel. Faite attention si
vous voyez cet symbole.
! Indique une mise à la terre “faible bruit”. Les objets portant cette
marque doivent être reliés à la terre afin d’assurer un
fonctionnement optimal. Elle est aussi utilisée pour les éléments de
protection contre les interférences magnétiques, les perturbations
hautes fréquences radio et contre les surtensions. Cette mise à terre
n’est pas une mise à terre de sécurité pour une protection contre
les choques électriques!
~ Indique une alimentation en courant alternatif (AC).
Indique une Alimentation en courant continu (DC) dérivée d’une
alimentation alternative
Indique la présence d’un composant sensible aux décharges électrostatiques
(ESD), Cela signifie qu’il faut observer toutes les précautions d’usage en
manipulant ce composant.
Les termes suivant apparaissent dans ce manuel:
Note: Indique la présence d’une information que vous devez
Caution: Indique une condition ou opération qui peut entraîner des
dommages à votre équipement, au logiciel ou à d’autres propriétés .
SAFETY 8 EPISENSOR USER GUIDE
particulièrement considérer avant de passer à la prochaine
instruction or operation.
WARNING! Indique une condition ou opération qui peut entraîner des
blessures corporelles ou la perte de la vie.
Les deux derniers termes mentionnés peuvent apparaître sur les
équipements de Kinemetrics que vous avez acquis, mais pas nécessairement
# indifféremment, il est conseillé de prendre au sérieux les avertissements
de ce manuel.
Précautions Spécifiques
Observez toutes les précautions suivantes afin d’assurer votre sécurité
personnelle et d’éviter des dégâts aux composants de votre capteur
EpiSensor.
Alimentation
Le EpiSensor doit être alimenté avec un courant de "12 VDC fourni par
l’enregistreur ou par votre propre système d’alimentation.
Si vous alimentez le EpiSensor avec l’enregistreur, connectez l’enregistreur
en utilisant le système d’alimentation fourni par Kinemetrics, et decrit dans
le manuel d’utilisation délivré avec l’enregistreur.
Pour fournir une alimentation au EpiSensor, vous avez besoin d’une source
à faible bruit " 12V avec une mise a la terre adéquate et qui remplit les
conditions de la reglementation locale.
Option Systéme d’ alimentation fourni par l’ utilisateur
Si vous fournissez votre système d’alimentation, vous devez vous assurez
que le système fournit une tension et un courant requis par le EpiSensor.
Veuillez noter que vous serez seul responsible pour la sécurité de votre
système d’alimentation. Si vous utilisez le courant du réseau d’alimentation
principal, vous devez vous assurez d’installer les mises a la terre adéquates
pour tout votre equipement. Si vous utilisez vos batteries, vous devez vous
référer aux recommendations fournis par le fournisseurs.
Mise à la terre et connection du capteur
!
Dans certain cas, le capteur EpiSensor est installé à distance de
l’enregistreur. Dans ces installations il est possible, soit a cause d’une
connection défectueuse au système d’alimentation principale où d’un fort
courant de retour à la terre, pour une difference de potentiel qui existe entre
la mise à la terre aux deux locations. Quand le cable est mise à la terre d’un
coté, une tension potentiellement fatale peut exister entre l’autre coté du
cable et la terre. Considerez ce danger pendant l’installation et demandez
l’aide d’un electricien si ce danger existe.
EPISENSOR USER GUIDE SAFETY 9
Ne Pas Utiliser en Atmosphère Explosif
Le EpiSensor ne comprend pas de protection contre les explosions dues aux
décharges statiques ou aux composants pouvant provoquer des arcs. Ne pas
utiliser ces composants en présence de gaz explosifs.
SAFETY 10 EPISENSOR USER GUIDE
DOCUMENT 301900, REVISION D
1. Introduction
This document is the User’s Guide to EpiSensor Model FBA ES-T, an
external, triaxial sensor. Kinemetrics also produces a uniaxial EpiSensor
FBA, the FBA ES-U, and the FBA ES-SB (shallow) and FBA ES-DH
(deep) triaxial borehole packages. Kinemetrics’ strong motion
accelerographs feature a triaxial EpiSensor Altus deck.
This manual refers only to EpiSensor Model FBA ES-T but will be referred
to simply as the EpiSensor throughout the rest of this manual.
Kinemetrics is committed to ensuring a successful installation. For
assistance with planning, installation, operation or maintenance, contact
Kinemetrics at the locations listed in the front of this manual. Kinemetrics
also has an extensive Services Group that can install, maintain, and analyze
the data from your EpiSensor.
This chapter provides an overview of the EpiSensor and inspection
instructions.
The EpiSensor FBA ES-T
The EpiSensor is a triaxial accelerometer optimized for earthquake
recording applications. Inside the waterproof, anodized-aluminum housing
are three orthogonally mounted low-noise EpiSensor force balance
accelerometer modules.
The EpiSensor has user-selectable full-scale recording ranges of ±4g, ±2g,
±1g, ±1/2g or ±1/4g. The EpiSensor bandwidth of DC to 200 Hz is a
significant improvement over earlier generations of sensors. The output
voltage levels are user-selectable at either ±2.5V or ±10V single-ended, or
±5V or ± 20V differential.
The EpiSensor is normally powered with a ±12V external DC power source.
It is optionally available with a single +12V supply option.
Full specifications for the unit can be found in the Appendix.
EPISENSOR USER GUIDE 1
DOCUMENT 301900, REVISION D
Inspecting the EpiSensor
Note: If you expect to ship the EpiSensor again, save the shipping
container and packing material. The shipping container can also
function as a thermal shield for the EpiSensor, so do not throw the
high density foam packing away!
Carefully remove the EpiSensor from its shipping container. Keep the
shaped packing material.
Although Kinemetrics takes every precaution in packing its systems,
shipping damage can still occur. If you find a problem, note the condition of
the shipping container. Then contact the freight forwarder and Kinemetrics
as soon as possible.
One of three screws
securing EpiSensor case
Caution: Damage to sensors. Dropping the EpiSensor onto a hard surface
can damage the sensors.
Figure 1: The EpiSensor
Z sensor adjustment access hole
Grounding screw
Electrical connector
Y sensor
adjustment hole
Flat edge of case -- aligns with
Y north/south sensor axis
Leveling bubble
Examine the EpiSensor. Its case should appear securely sealed, showing no
sign of dents or scratches, and the bubble level glass should appear
undamaged.
2 EPISENSOR USER GUIDE
One of three leveling feet
Mounting bracket
X sensor adjustment access hole
DOCUMENT 301900, REVISION D
2. Installation Basics
Requirements for Installation
Listed below are the tools, supplies and equipment required to install the
EpiSensor in a typical configuration (remotely from a Kinemetrics recorder,
and attached to that recorder via cable). However, certain installations may
require additional tools, supplies or equipment, depending on specific sites
and needs.
If you need to assemble the cable for the EpiSensor you will need additional
tools and supplies. Refer to Chapter 6 for information on cable assembly.
These instructions assume that all civil engineering works (concrete pad,
conduit, etc.) have been finished and that the EpiSensor has been correctly
configured for your installation at our facility. If you need to change the
full-scale range output level or select the low-noise option, refer to Chapter
3 before proceeding.
Required Tools
! Screwdrivers (1/8" flat blade, 1/4" flat blade)
! 5/64" or 2mm hex ball driver (for zero adjustment)
! Long-nose pliers
! AC-powered masonry percussion drill with 1/4" bit for drilling the
anchor stud hole or fully charged battery-powered drill
! 7/16" open end wrench for 1/4-20 bolt
! Hammer
! Safety glasses
! 1/8" hex driver for leveling feet
EPISENSOR USER GUIDE 3
DOCUMENT 301900, REVISION D
Required Supplies
! Adequate length and appropriate type of pre-assembled cable for
connecting the EpiSensor to the recorder. If custom cable is
required, refer to Chapter 6. Depending on the length required, you
might have purchased either Kinemetrics P/N 700045 or the
Belden cable stocked by Kinemetrics as P/N 840356.
! Heat-shrink tubing (1/4" diameter), cable tie-wraps, and electrical
tape.
! Mounting anchor (supplied with the EpiSensor).
! FerriShields (optional)
! EpiSensor Packing Foam for Thermal Shield (optional supplied
with the EpiSensor)
! Heavy Duty Aluminum Duct Tape (optional for Thermal Shield)
Required Equipment
! Battery-powered digital volt meter (DVM)
! Compass for checking the orientation of the sensors.
! Camera to photograph the completed installations for the
commissioning report (recommended).
Mounting & Orienting the
EpiSensor
Determine which direction to orient the EpiSensor: true north or "alignedwith-structure." True north is typical of most free-field EpiSensor
installations.
If the instrument is installed in a structure, it is normally aligned parallel to
the structure's main axis. If possible, keep the same orientation for all
EpiSensors installed in the same building.
Anchor the EpiSensor to a concrete floor or slab or a secure, structural
element such as a steel beam in a building.
Note: To accurately record strong ground motions of > 0.1g, it is
essential that the EpiSensor be anchored to the structure or slab.
This is contrary to weak motion installations where sensors are just
placed on the ground and leveled. In weak motion, the weight of
the instrument and friction between the feet and floor ensure
accurate reproduction of ground motion. This is not the case at high
acceleration levels, which can cause an unsecured instrument to
move relative to the ground.
Keep a permanent record of the orientation you choose. This information is
crucial to the proper analysis of EpiSensor data.
4 EPISENSOR USER GUIDE
DOCUMENT 301900, REVISION D
Use the EpiSensor mounting kit to attach the sensor to the mounting
surface. The kit includes a heavy-duty wedge-type expansion anchor stud
with 1/4-20 thread and a nut/washer unit.
Decide on the location of the EpiSensor, keeping in mind the working space
dimensions in Figure 2.
Remember:
The anchor stud is 2-1/4" long and 3/8" to 1/2" must remain above the slab.
Use the following instructions and figures below to install the anchor stud.
Figure 2: Episensor mounting dimensions
EpiSensor
mounting hole
8" minimum
Wall
Electrical
connector
EpiSensor
orientation
EpiSensor
orientation
8" minimum
Note: Follow all recommended safety precautions when using power tools.
We recommend wearing safety glasses while drilling.
1. Use a 1/4" (6.4mm) masonry bit and drill to a depth of at least
1-3/4" with a percussion or hammer drill (if possible).
Note: You may want to wrap a little masking tape 1-3/4" up from the
EPISENSOR USER GUIDE 5
point of the drill bit to mark how deeply to drill. The depth of the
hole can be checked with a nail or narrow screwdriver. The hole
should be vertical – take care not to drill at an angle!
DOCUMENT 301900, REVISION D
Figure 3: Drilling EpiSensor mounting hole
Concrete pad
Percussion or hammer drill
Drill bit with diameter to fit
anchor stud
Drill slightly deeper than
length of anchor stud (>2")
Hammer
Nut aligned with
top of anchor bolt
Concrete anchor
3/8" – 1/2"
2. Clean debris out the hole. (Blowing through a straw is an
easy way to do this.)
3. Screw the nut/washer onto the stud until the top of the nut is flush
with the top of the stud. This will make is easier to hammer in the
stud and prevent damage to the threads.
4. Gently tap the top of the anchor stud with a hammer. The stud is
now in position but not firmly seated.
6 EPISENSOR USER GUIDE
5. Check that the leveling screws are only about halfway into their
mounting holes on the lower flange of the EpiSensor.
DOCUMENT 301900, REVISION D
6. Slip the EpiSensor mounting bracket around the anchor stud and
push all the way to the rear. Be sure that the nut remains above the
mounting bracket.
7. Align the Y arrow on top of the EpiSensor case with true north or
the main axis of the structure.
8. The flats on the flange are parallel to the Y direction and can be
used to ensure an accurate orientation. Tighten the stud nut "finger
tight" with a 7/16" end-wrench and check the bubble level window.
Note: If you use a compass to determine the true north-south axis, make
sure to correct for the difference between magnetic north indicated
by the compass, and true north (magnetic declination). This
deviation depends on your location; find the correct deviation on a
local topographical map.
Installation is now a matter of adjusting the leveling feet so that the
EpiSensor is level and tightening the anchor stud nut. Tighten the nut and
make adjustments to the leveling feet gradually until the EpiSensor is level
and the nut tightened to a torque of 20-26 inch pounds (2.26-2.94 N.m). As
you tighten the nut, the stud will move slightly, forcing the locking cone to
firmly grip the concrete.
Required Cables
If you purchased pre-made cables from Kinemetrics, you can proceed with
the following instructions. If you are making your own cables, please see
page 6-10 in the Advanced Installations section for instructions on custom
cable fabrication.
Grounding the EpiSensor
Grounding sensitive instrumentation is a complex problem. It is difficult to
give universally acceptable solutions for all installation types and site
conditions because "grounding" really has five goals – some of which can
be mutually exclusive. These goals are:
! Prevent life threatening voltages in or on the equipment
! Immunity from EMI/RFI interference (susceptibility)
! Prevent radiation of EMI/RFI from the equipment (interference)
! Prevent damage to the equipment from transient events such as
lightning and ESD
! Low-noise Operation
Safety First
Obviously, the most important goal of any grounding scheme is to ensure
the safety of operating personnel. Design and evaluate your grounding
system with this in mind.
EPISENSOR USER GUIDE 7
DOCUMENT 301900, REVISION D
Since the EpiSensor contains no high voltage circuitry and is not connected
to AC power, safety concerns arise from the instrument-end of the
connection cable.
When using your own power system, be sure that AC power is fully isolated
from the DC power supplied to the EpiSensor and that the power supply is
safely grounded.
If the EpiSensor is separated from the recorder or power supply by a long
distance, observe the precautions discussed in the section on long cables.
EMI/RFI
To prevent EMI/RFI susceptibility and interference, an overall shield should
be provided and cables must be carefully constructed to ensure shields
terminate to the connector to provide a full 360$ termination. This provides
a low impedance path for high frequency noise to ground and does not
allow the high frequency to "leak" onto unprotected wiring in the cable.
The case of the instrument and the shields should generally be grounded to
a low impedance earth ground.
The EpiSensor contains transient protection circuitry that will shunt
damaging currents to its case ground connection and prevent damage from
ESD and lightning-induced transients.
Use the stainless steel screw on the flange of the instrument as the case
ground connection point. To be effective, this point must be connected to a
low impedance earth ground.
Providing a low-impedance earth ground can be challenging, because a
safety earth ground for AC wiring is not necessarily a good low impedance
ground! A safety earth ground is designed to provide a path for AC fault
current to flow to ground, trip the fuses in the power system and prevent
electrocution.
Since AC power is only at 50 or 60Hz, the primary factor restricting the
flow of current is the DC resistance of the ground. Lightning, ESD, and
EMI/RFI are high frequency currents. The flow of these currents is
restricted by the impedance of the ground at the frequency of interest, and
rather than being dominated by DC resistance, the inductance of the
connection is the primary component of this impedance.
Thus, we require both a low impedance ground and a low impedance
connection to that ground. To provide low impedance connection to the
ground:
Attach the EpiSensor grounding screw to the ground with a heavy-gauge
wire 3 mm in diameter (<10 AWG) or thicker, or a tinned copper braid at
least 1.2 cm (1/2") in width.
To be effective this wire or braid must be as short as possible and should
have no sharp turns. The connection to the grounding point should have a
large-area connection that is tightened and not subject to corrosion. Special
8 EPISENSOR USER GUIDE
DOCUMENT 301900, REVISION D
clamps are available from electrical supply houses to make these
connections.
The requirements and techniques for producing the low impedance ground
will depend on the installation and its location. In a building or structure
where close lightning strikes are unlikely, a metallic water pipe, exposed
section of rebar, or an AC safety ground may be adequate.
For a remote installation subject to significant lightning activity such as a
mountain peak, much greater effort is required to provide an adequate
ground.
In lightning-prone conditions, a copper clad grounding rod inserted into the
ground is an acceptable solution if the climate is relatively humid or if the
rod is embedded in a marsh, clay, or wet sand ground where soil resistivity
is less than 50-100 ohms.
A 1-cm (0.5") diameter rod 4 meters long (12 feet) will assure an acceptable
grounding resistance of about 10 ohms. Grounding rods are generally
available in a variety of lengths and can be connected together to get overall
depths exceeding 12 meters (40 feet).
In dryer regions, arrays of copper rods driven into the earth help to reduce
the grounding resistance. However, the total ground resistance is not
reduced in direct proportion to the number of rods in the array, and the rods
should be spaced apart by double their length to avoid "saturation."
In a high lightning threat area, a star configuration of radial metal straps
buried just below the surface with a 2 meter grounding rod at the end of
each radial is a good approach. A 6-to-8-leg star of 50 m (150 feet) length
with a grounding rod at each end provides a ground resistance of less than
10 ohms even in a soil with resistively of several thousand ohms.
In desert areas, chemical doping and drip irrigation techniques may be
required to provide adequate grounding.
The Grounds for Lightning and EMP Protection by Roger Block, second
edition, published by Polyphaser Corporation provides an excellent
practical treatment of grounding techniques.
In sites exposed to high levels of EMI/RFI, such as, hill top “Antenna
Farms” additional EMI/RFI protection may be required. The Kinemetrics
EpiSensor Protection Enclosure (KMI 301931) can be purchased for such
sites.
Powering the EpiSensor
When the cable has been made and tested, you can apply power to the
sensor. If you are providing power, please refer to Chapter 6 for detailed
requirements.
EPISENSOR USER GUIDE 9
DOCUMENT 301900, REVISION D
First, apply power to the system without connecting the cable to the
EpiSensor and then verify that the power connections are correct.
For a dual supply EpiSensor, verify that +12V is present on Pin J and –12V
is present on Pin H, both referenced to power common Pin K.
For a single supply option, verify that +12V is present on Pin J referenced
to power common Pin K. Be sure that Pin H is not connected in this
configuration.
Caution: Connecting incorrect voltages or wrong polarities ( > " 15.75V )
will seriously damage your EpiSensor, as will making a connection to Pin H
in the single supply configuration.
Zero-Adjusting the EpiSensor
After the EpiSensor has been installed, leveled, and connected to the correct
power, measure the DC offset of each accelerometer. The DC offset should
be as close as possible to zero so that the recorded data has minimal offset.
With minimal offset the full range of the EpiSensor and recorder can be
utilized.
Methods of Measuring the DC Offset
If the EpiSensor is near the recorder, you may zero the accelerometers
by using the recorder as if it were a DVM. If you are using an Altus
recorder, use the AQ DVM command in QuickTalk's terminal mode.
If the EpiSensor is located at the end of a long cable, build a "break-out"
cable in order to access and measure voltages in each of the wires in the
EpiSensor cable. Be sure you are supplying the EpiSensor with "12 VDC
or +12 VDC for the single power supply option.
Performing the Zero Adjustment
Refer to Figure 9 to see the three access screws that, when removed, provide
access to the zero adjustment screws on the sensor modules.
Make the first zero-adjustment on the Z-axis accelerometer. Use one of the
methods described above to measure the sensor's zero output voltage.
Naturally, it is impossible to achieve zero offset. The table below will tell
you the ES-T acceptable range for DC offset for each possible
configuration. (If desired, smaller offsets can be achieved with some
patience.)
To zero balance the Z- axis:
10 EPISENSOR USER GUIDE
1. Remove the zero balance access screw on the top of the
EpiSensor case.
DOCUMENT 301900, REVISION D
2. Gently insert a hex ball (5/64" or 2mm) wrench, perpendicular to
the case, as far as it will go into the adjustment hole and make very
minimal adjustments – counterclockwise for negative adjustments
and clockwise for positive.
Important: Give the unit a moderate tap with a screwdriver
handle. The adjustment screws can have a residual
stress that may cause an offset in data during a large
earthquake. Tapping eliminates this residual stress.
3. When the offset is in an acceptable range based on the above table,
carefully remove the hex wrench and replace the access hole screw.
Note: One turn changes the output by about 1g.
Repeat this process for the X and Y axes.
Table 1: Reasonable zero offset voltages
Full-scale
range
1/4g 50 mV 200 mV 100 mV 400 mV
1/2g 25 mV 100 mV 50 mV 200 mV
1g 25 mV 50 mV 25 mV 100 mV
2g 25 mV 25 mV 25 mV 50 mV
4g 25 mV 25 mV 25 mV 25 mV
Single-ended
" 2.5V output
Single-ended
" 10Voutput
Differential low-
noise amp.
Differential
" 20V output
Note on Full-Scale Range
All of our full-scale ranges are stated as the voltage you would measure
with a voltmeter between the + and – outputs for the sensor when full-scale
acceleration is applied to the unit. For example, with a differential low-noise
amplifier and output of " 20V on a range of 1g, you would measure +20V if
you applied 1g to the sensor. If you applied –1g you would measure –20V.
Thermal Insulation Shield
(Optional)
The EpiSensor possesses a very large dynamic range and increasingly we
are finding customers are interested in recording both strong motion and
weaker motion signals on the instrument. To fully exploit the performance
of the instrument for recording weak motion it is necessary to treat it more
like a broadband seismometer than a strong motion accelerometer! One
important area is to thermally insulate the unit so that variations in ambient
temperature and air currents do not cause “noise” by causing temperature
EPISENSOR USER GUIDE 11
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