Shallow Borehole EpiSensor
Contents
1. Transconductance Amplifier Coil Functional Test NWN Pulse Calibration Coil Analog Output Amp amp Transient Protection A Span Selection amp Output Amplifier Calibration Control Calibration Coil Enable Control Normally Open illl ill AAN SHALLOW BOREHOLE EPI USER GUIDE 21 DOCUMENT 301934 REVISION B Working Principle The oscillator applies an AC signal of opposite polarity to the two moving capacitor plates also referred to as the moving mass When the accelerometer is zeroed and when no acceleration is applied these plates are symmetrical to the fixed central plate and no voltage is generated An acceleration causes the coil and capacitive sensor plates which are a single assembly mounted on mechanical flexures springs to move with respect to the fixed central plate of the capacitive transducer This displacement results in a signal on the center plate of the capacitor becoming unbalanced resulting in an AC signal of the same frequency as the oscillator being passed to the amplifier The amplifier amplifies this AC signal This error signal is then passed to the demodulator where it is synchronously demodulated and filtered creating a DC error term in the feedback amplifier The feedback loop compensates for this error signal by pas2. MOUNTING TUBE gt OSCILLATOR BOARD LT A Inspecting the SBEPI Carefully remove the SBEPI from its shipping container 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 Examine the SBEPI Its case should appear securely sealed showing no sign of dents or other damage 2 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B SBEPI units should always be transported in the original shipping container to avoid damage The SBEPI is shipped with an accessory kit that includes a zero adjustment tool spare O rings silicone grease replacement desiccant and a special wrench for removing the sensors from the stainless steel housing SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B 2 Installation This chapter contains information relevant to the installation of the SBEPI unit Our Services Group can provide additional expertise and borehole services This chapter covers the following information m Accessory Kit Electrical Connection Functional check and zero offset measurement Accelerometer adjustment SBEPI installation Accessory Kit The SBEPI is shipped with the following accessories These it
3. The higher of 50 milli g offset or a 50mV voltage offset serves as a reasonable threshold for opening the package and re zeroing the sensors but this may vary from application to application Connect the SBEPI to a data logger and perform the functional tests described in Chapter 2 If junction boxes P N 108375 and 105058 are used with the system we recommend that they be connected to the circuit now to be sure that the whole circuit is operational They also allow other voltages to be easily measured Perform a simple tilt test to check that all three axes are functioning properly and that the channels are wired correctly The horizontal sensors will undergo 1g acceleration when tilted through 360 The vertical sensor should measure 1g when the package is tilted on its side and 2g when the unit is inverted If all three accelerometers have acceptable offsets for your application and the tilt and functional response tests agree with the original calibration records proceed with the installation If the offsets and functional responses do not fall within acceptable ranges zero the accelerometers as described in the next section 6 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Accelerometer Adjustments This section describes a step by step procedure to adjust the SBEPI in the field Remove the cylindrical housing from the package using the special spanner wrench 110582 supplied in the accessory kit and
4. 20 0000 E 20 0000 Ch 1 0 0505608Vmax 0 0413972Vnid 0 1333553Vmin 0 1839161Vpp Ch 2 0 1244402Vnax 0 0355572Vmid 0 0533259Vmin 0 1777661Vpp Ch 3 0 1305455Vmax 0 0417608Vmid 0 0470239Vmin 0 1775694 pp Rel to Ch 1 The height of the pulse will depend on the full scale setting of the instrument but will correspond to a g level of approximately 0 125g The exact value will be 2 5V multiplied by the sensor module s calibration coil sensitivity value provided on the sensor s data sheet 14 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Altus software released prior to August 1998 supports functional tests on the earlier generation of Kinemetrics force balance accelerometers but does not support the SBEPI If you perform a functional test or sensor response test on an SBEPI using older software the record will appear as in the screen in Figure 5 Figure 5 Display of Functional Test Using Software Released Prior to August 1998 The record looks like this because the calibration coil enable is only enabled during the undamped portion of the old FBA 11 style functional test Sensor Response Test The sensor response test for the SBEPI using Altus software released after August 1 1998 measures the response of the sensor to white noise input The digital to analog converter in
5. 50 efficiency of the DC to DC converter and voltage ratio and then add this current to the quiescent current The maximum current load on a dual supply for an SBEPI set to a 2g full scale range with a 20V differential low noise output is calculated as below 7 5 mA x 2 20 mA 35 mA 70 mA For the single supply option 7 5 mA x 2 20 mA x 4 130 mA 270 mA These values are very conservative because in normal situations all three axis of the SBEPI are unlikely to see 2g of acceleration at the same time Further examples are found in Table 6 Table 6 Current Requirments Quiescent Max Load Quiescent Max Load Examples Dual 12V Dual 12V Single 12V Single 12V Supply Supply Supply Supply SBEPI 1g low power amplifier 2 5V single ended output 12 mA 25 mA 65 mA 104 mA SBEPI 2g low noise amplifier 20V differential output 35 mA 70 mA 130 mA 270 mA SBEPI 0 25g low noise amplifier 20V differential output 35 mA 57 mA 130 mA 218 mA Resistive Cable Loss Calculations of the required power for a SBEPI must account for resistive loss in the 700422 cable supplied as part of the package and additional cabling the user supplies from the wellhead box to the Digitizer The two tables in this section provide the information to calculate the maximum cable length for SBEPI units in each of the various configurations The standard SBEPI requires a minimum operating voltage of 11 5V to be sure it can s
6. Direct access to the individual coils for calibration verification is not provided in the unit They must be driven from the connector by the recorder or a similar device Caution When the SBEPI is configured for single supply operation do not connect any power source to the negative 12V connection This wire is connected to the PGP instrument case ground through a Ik resistor which connects to the SBEPI s case if it is connected to TP1 Black the power source will be shorted 30 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Power Supply The standard SBEPI requires a well regulated low noise 12V 5 or 15V 5 supply that can provide adequate current for the configuration you are using The supply should be low noise less than 50 mV of ripple The single supply option can tolerate a relatively wide input range from 10 to 18 VDC The supply should be low noise and have less than 100 mV of ripple to ensure low noise performance of the sensor Caution Incorrect power to the SBEPI can cause incorrect readings and may damage the sensor If the voltage is too low the SBEPI will not attain its full scale output and the data will be corrupted Never supply more than 15 75V to the unit and be sure the connections are the correct polarity The SBEPI has no protection against reversed polarity connections Reversed power connections will severely damage the instrument The single supply option re
7. a strap wrench Figure 2 Accelerometer Adjustment Screws SHALLOW BOREHOLE EPI USER GUIDE 7 DOCUMENT 301934 REVISION B Caution Under no circumstances remove the studs and use the threaded holes to unscrew or tighten the package into the housing This could loosen the plastic coating and cause the unit to leak Use the supplied spanner wrench 110582 to loosen the unit by attaching it over the studs Caution Potential electrostatic discharge ESD hazard to equipment Wear a grounded wrist strap with impedance of approximately 1 M 2 when handling the SBEPI circuit boards to protect components from damage Connect the required power to the cable or connect the cable to a recorder Stand the accelerometer framework against a vertical surface Be very careful that it does not fall over The assembly should be level within 0 5 Measure the zero output voltage with a digital voltmeter Adjust the modules using the adjustment holes shown in Figure 2 Adjusting the vertical sensor is more difficult than adjusting the horizontal sensors because the hex wrench is partially obstructed by one of threaded rod supports Turning the adjustment screw clockwise will result in a more positive output After you have adjusted the screw tap the case with the hex wrench or a screwdriver handle to ensure the adjustment screw is set in position To convert the value to units of g divide the measured value by the sensitivity With som
8. handling the SBEPI circuit boards to protect components from damage SBEPI DIP Switch amp J umper Selectable Options The features that are controlled by DIP switches and 2 mm jumpers are m Full scale output voltage level of 2 5V or 10V m Use of low power or low noise post amplifier m Single ended or differential output Access to DIP Switches Figure 8 shows the location of the DIP switches and jumpers when the outer housing is removed Each of the individual DIP switch sections can be placed in the on or off position as desired by using a relatively soft pointed tool such as a toothpick cocktail stick or thin wooden stick Please remember they are delicate On no account should they be forced using a screwdriver or other metal tool SHALLOW BOREHOLE EPI USER GUIDE 27 DOCUMENT 301934 REVISION B Figure 8 Location of DIP Switches and Jumpers Au J Ea tata I Bi Example DIP Switch and J umper Settings The DIP switch and jumper settings for the selectable features of the post amplifier are shown in Table 3 There are three DIP switches S1 S2 and S3 Each DIP switch also has 10 sections 1 10 m DIP switch S2 configures the X axis m DIP switch SI configures the Y axis and m DIP switch S3 configures the Z axis Sections 1 8 select which post amplifier is used standard or low noise Sections 9 and 10 set the gain of the post amplifier at 1 or 4 28 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 3019
9. is necessary Complete a Functional Test Kinemetrics recommends that you perform a functional test on the accelerometer at each service visit to check that the unit is operational and to keep as a baseline record for future visits Refer to Chapter 3 for instructions on performing the functional test If the unit is connected to an Altus or other Kinemetrics recorder refer to the recorder s manual for instructions on performing the functional test Refer to Chapter 6 if the unit is connected to a non Kinemetrics data acquisition system Desiccant Replacement The SBEPI contains two small packages of desiccant that are designed to maintain low humidity level inside the unit and prevent condensation If the instrument is sealed this should never need replacement However if the stainless steel housing is left unsealed in a humid environment for a prolonged period of time the desiccant may be incapable of absorbing more moisture When this happens they should be replaced New desiccant can be ordered from Kinemetrics Be sure to follow electro static discharge ESD precautions when opening the sensor case Caution Potential electrostatic discharge ESD hazard to equipment Wear a grounded wrist strap with impedance of approximately 1 M Q when handling the SBEPI circuit boards to protect components from damage SHALLOW BOREHOLE EPI USER GUIDE 19 DOCUMENT 301934 REVISION B Troubleshooting and Repair If your SBEPI does n
10. output at the cost of additional power This amplifier again amplifies the signal by 1 or 4 to give a single ended output of either 2 5V or 10V 22 SHALLOW BOREHOLE EPI USER GUIDE Features DOCUMENT 301934 REVISION B A second amplifier is also present which inverts the signal from the first and can be connected to the negative output lead via jumpers This allows the unit to give a differential t5V or 20V to match the input to 24 bit digitizers Each EpiSensor module is equipped with a calibration coil Applying a current to this coil simulates the effect of an acceleration applied to the sensor The calibration coils are open circuit in normal use to prevent cross talk and noise pick up To utilize the calibration coil remotely from outside the unit the calibration coil enable signal must be activated by applying a DC voltage of 5V to 12V with respect to ground A voltage signal applied to the calibration line with CCE is active will cause all three EpiSensor modules to respond with an acceleration output of approximately 0 05 g per volt applied The exact calibration coil sensitivity is provided on the data sheet of each module This voltage mode will normally be used for checking the response of the sensor remotely from a digitizer If you wish to use a current source to drive the calibration coils in a laboratory setting they may be accessed by removing the SBEPT s case and partially disassembling the unit This i
11. s curit personnelle et d viter des d g ts aux composants de votre capteur Shallow Borehole EpiSensor SBEPT Alimentation Le SBEPI doit tre aliment avec un courant de 12 VDC fourni par Penregistreur ou par votre propre syst me d alimentation Si vous alimentez le SBEPI avec l enregistreur connectez l enregistreur en utilisant le syst me d alimentation fourni par Kinemetrics et decrit dans le manuel d utilisation d livr avec l enregistreur Pour fournir une alimentation au SBEPI vous avez besoin d une source faible bruit 12V avec une mise a la terre ad quate et qui remplit les conditions de la reglementation locale Option Syst me d alimentation fourni par l utilisateur Si vous fournissez votre syst me d alimentation vous devez vous assurez que le syst me fournit une tension et un courant requis par le SBEPI Veuillez noter que vous serez seul responsible pour la s curit de votre syst me d alimentation Si vous utilisez le courant du r seau d alimentation principal vous devez vous assurez d installer les mises a la terre ad quates pour tout votre equipement Si vous utilisez vos batteries vous devez vous r f rer aux recommendations fournis par le fournisseurs Mise la terre et connection du capteur Dans certain cas le capteur SBEPT est install distance de l enregistreur Dans ces installations il est possible soit a cause d une connection d fectueuse au syst m
12. 1934 REVISION B If the data logger cannot perform a functional test a simple test box can be built to simulate the desired calibration sequence A suggested sequence is as follows 1 Apply OV to the CAL line 2 Apply 12V to CCE 3 Wait 2 seconds 4 Apply 2 5V to CAL for 2 seconds 5 Change CAL to 2 5V for 2 seconds 6 Change CAL to OV for 2 seconds 7 Turn CCE off by connecting it to OV This will produce a positive pulse followed by a negative pulse Caution The CCE line must not be enabled during normal operation severely degraded noise performance can result Applying voltage to the CAL line when the unit is not powered will result in damage Applying voltage above the power supply lines to the CAL line will also damage the unit If you wish to use a current source to calibrate the unit the nominal sensitivity is 0 11 g mA and the resistance of the calibration coil and sensitivity setting resistor is approximately 170002 Never apply currents in excess of 40 mA Apply currents in excess of 5 mA and below 40 mA only for intervals shorter than 20 seconds SHALLOW BOREHOLE EPI USER GUIDE 17 DOCUMENT 301934 REVISION B 4 Maintenance Recommended Maintenance The SBEPI is designed for many years of unattended use but we recommend that you perform a functional test once a year See the Altus recorder manual or Chapter 3 of this manual for more details For an installed Borehole unit only the functional testing
13. 34 REVISION B X21 and X22 are 2 pin headers that apply power to the three low noise amplifiers These jumpers control all three axes X Y and Z The SBEPI is shipped with the two 2 mm shunt installed across X21 and X22 for the low noise amplifiers and with X21 and X22 open for the low power configurations AN configuration Important If you change the configuration these jumpers must be correctly configured X21 and X22 in for the low noise and out for the low power Table 3 DIP Switch and Jumber Settings Single ended Single ended Differential Differential Switch Section 2 5V output 10V output SV output 20V output S2 S1 and S3 Gain 1 Gain 4 Gain 1 Gain 4 X Y and Z Axes Low Power Post Low Power Post Low Noise Post Low Noise Post respectively Amplifier Amplifier Amplifier Amplifier 1 ON ON OFF OFF 2 OFF OFF ON ON 3 ON ON OFF OFF 4 OFF OFF ON ON 5 ON ON OFF OFF 6 OFF OFF ON ON 7 ON ON OFF OFF 8 OFF OFF ON ON 9 ON OFF ON OFF 10 OFF ON OFF ON Jumper all axes X21 OUT OUT IN IN X22 OUT OUT IN IN Note Differential operation of the low power amplifier is not possible Full Scale Voltage Output Voltages Provides the full scale output voltages for each of the possible five full scale sensor ranges SHALLOW BOREHOLE EPI USER GUIDE 29 DOCUMENT 301934 REVISION B Table 4 Range Sensitivity Calcu
14. EPI mit Strom von einem Recorder zu versorgen verbinden Sie den Recorder mit unserem Kinemetrics Stromladeger t wie es in unserem User Manuel beschrieben ist Um die SBEPI direkt mit Strom zu versorgen m ssen Sie ein Ladeger t 12 V welches mit allen Sicherheitsbedingunge ausgestattet ist benutzen Optionelles Stromversorgungs Ladeger t In manchen F llen wird die SBEPI eine lange Strecke von dem Recorder entfernt Sein wo es dann m glich sein k nnte dass durch besch digte AC Wiring 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 verh ltnism ssig grosser Unterschied in der Voltage bestehen welcher sehr gef hrlich ist Bitte beachten Sie Diese Gefahr und wenn n tig ziehen Sie das Gutachten eines qualifizierten Elektrikers Ein Nicht in explosionsgef hrdete Umgebung gebrauchen Der SBEPI hat keinen Explosions schutz von statischen Entladungen oder funkgef hrdeten Bauteilen Benutzen sie die Ger te nicht in Umgebungen mit explosiven Gasen SAFETY 4 SHALLOW BOREHOLE EPI USER GUIDE Seguridad Simbolos amp T rminos Estos simbolos podrian aparecer en los equipos Kinemetrics o en este manual Significa poner atencion Cuando Usted vea es
15. L line when the unit is not powered will result in damage Applying voltage above the power supply lines to the CAL line will also damage the unit Ground Loop Prevention When the SBEPI is used with non Kinemetrics digitizers it is essential that the ground connections be carefully planned in order to prevent ground loops Please see the section in this chapter on grounding This is especially important when using a PC based data acquisition system We recommend using the differential output of the SBEPI to prevent common mode problems When using single ended output the signal returns X Y Z should be connected to the negative input of the analog front end s differential or instrumentation amplifier and not to circuit common The common connection should return to the power supply through only one path When using a separate mains power supply be very careful that it does not provide a separate ground return through the AC mains ground to the data acquisition computer Use a star ground configuration for your system with the power supply data acquisition system and PC all grounded at the same point In our experience most noise problems with any installation are normally a result of power grounding or cable shielding SHALLOW BOREHOLE EPI USER GUIDE 35 DOCUMENT 301934 REVISION B Type Appendix A Table 8 SBEPI Specifications Triaxial force balance accelerometer Dynamic range Bandwidth 155 dB
16. LLOW BOREHOLE EPI USER GUIDE 33 DOCUMENT 301934 REVISION B The output impedance of the SBEPI is 50 Q to ensure the unit is stable under capacitive loading from a long cable Normally data loggers have an input impedance of 100 kQ or more so the 50Q output impedance is insignificant Calibration Sequence To produce a functional test sequence the recorder must control the CAL and CCE line to the SBEPI Even if the recorder cannot produce a functional test it is still very important that these lines be held at the correct potential The CAL line is not connected to the sensor unless the CCE line is active but to provide the best noise performance it should not be left floating We suggest that the CCE line be grounded to power common when the calibration coil is not in use The CCE line drives a transistor that operates an analog switch that connects the CAL line to the sensor module calibration coil The transistor will turn on the analog switches at voltages between 5 to 12V The transistor is not activated at voltages below 0 5V This means aCMOS driver can drive the line or an open collector output pulled up to 12V A transistor transistor logic TTL level will probably work if the sensor is close to the digitizer It is very important that the CCE line is not enabled when the calibration feature is not in use and that it is not powered when the unit is not powered This is because the CAL line is connected to all the sensor coi
17. SBEPI noise model available from Kinemetrics DC to 200 Hz Calibration coil Standard Full scale range Factory selectable at 0 25g 0 5g 1g 2gor 4g Full scale output Linearity User selectable at 2 5V single ended 10V single ended 5V 20V differential lt 1000ug g Hysteresis lt 0 1 of full scale Cross axis sensitivity lt 1 including misalignment Zero point thermal drift lt 2 of full scale 20 to 70 C Zero point drift lt 500ug C ESD RF EMI protection Double stage transient protection with gas arrestor elements Quiescent power consumption 12 mA from 12V standard amp 35 mA from 12V low noise amp Operating temperature 20 to 70 C 40 to 85 C with reduced performance Housing Stainless steel Cabling Output Cable Molded into sensor body standard length of 40m optional 110m available Dimensions 47 6 cm 18 75 inches long x 7 62 cm 3 inches in diameter Pressure rating 140 PSI Weight 2 3 kg 5 pounds SHALLOW BOREHOLE EPI USER GUIDE 37
18. User Guide Shallow Borehole EpiSensor Force Balance Accelerometer Model SBEPI Document 301934 January 2005 Revision B Trademarks This manual copyright Kinemetrics Inc 2002 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 SBEPT 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 301934 REVISION B Table of Contents Safety 1 Introduction A inc 1 Inspecting the SBEPl usage satin rin 2 2 Installation CCSS ltd 5 Inspecting the Cable End u a 5 Electrical CONNEC HOM nee dadas 6 Functional Check amp Zero Offset Measurement 6 Accelerometer Adjustmenis on aaa 7 SBEPI Installation unse pe an ei 9 3 Operating Basics Power Requirements irese ea ia 11 Electrical Connections en tn ne Me este 11 Cable Wire ebene Rahel ati 12 Polarity CONVENTIONS nan ala He 13 CONH UTAUOHS ETES EUR ESS Me ARS ee ne ETEA 14 Performing a Functional Test with an Altus Recorder u eeeeeeeeeereee 14 Senso
19. cased hole The accelerometers should be balanced to within the acceptable tolerance This tolerance will vary with each application If this is not the case it indicates that the hole orientation is not vertical The accelerometers must be compensated for this offset Record the offset at the bottom of the hole remove the package and zero the accelerometers to the negative of the downhole offset SHALLOW BOREHOLE EPI USER GUIDE 9 DOCUMENT 301934 REVISION B Note This procedure will only work if the package can be returned to the same angular orientation down the hole which will require loading poles Although we recommend using loading poles to get a specific orientation it is not absolutely necessary It is possible to utilize earthquakes to determine the orientation of the package after it is installed When the accelerometers are correctly balanced and the package orientation is satisfactory lock it in place with a suitable material such as small glass or smooth rock spheres lt 1 4 inch diameter This material will allow you to retrieve or move the SBEPI package at a future date If you wish to cement the package into place permanently we strongly recommend that you first test the installation for at least two or three weeks If you do choose to cement the package permanently use enough material to fill the cavity between the package and the casing completely and to leave some material on top of the package B
20. e care the channels can be adjusted to an offset of less than 5 milli g This corresponds to a tilt in the horizontal channels of 0 29 more than sufficient for a borehole installation If you decide to leave a higher offset than 5 milli g it will not affect your data quality The only thing a high offset does is reduce the highest signal that you can record but for any reasonable offset this is a very small change For example with a 1g full scale range and a 100mg offset the largest signal you can record will now be 0 9g versus 1g for a perfectly balance accelerometer Replace the cylindrical housing being careful not to damage the O rings or backing rings near the top of the sensor stack If the O Rings are new apply silicon grease 880718 to ensure easy assembly Be very careful not to gall or cross the threads of the stud when screwing the package together If the package appears to jam before it is fully engaged in the tube do not attempt to force the package in further If you encounter resistance unscrew the package remove any debris on the stud threads and be sure there is a thin coat of grease on them Use a strap wrench and the spanner wrench provided with the unit SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B SBEPI Installation When the accelerometers are working correctly the package can be lowered into the hole If you are using Kinemetrics equipment such as loading poles or a hole lock to ins
21. e d alimentation principale o d un fort courant de retour la terre pour une difference de potentiel qui existe entre la mise la terre aux deux locations Quand le cable est mise la terre d un cot une tension potentiellement fatale peut exister entre l autre cot du cable et la terre Considerez ce danger pendant V installation et demandez l aide d un electricien si ce danger existe Ne Pas Utiliser en Atmosph re Explosif Le SBEPI ne comprend pas de protection contre les explosions dues aux d charges statiques ou aux composants pouvant provoquer des arcs Ne pas utiliser ces composants en pr sence de gaz explosifs SAFETY 8 SHALLOW BOREHOLE EPI USER GUIDE The SBEPI DOCUMENT 301934 REVISION B 1 Introduction The User s Guide to the Shallow Borehole EpiSensor contains the information necessary to operate and install the Shallow Borehole EpiSensor SBEPI triaxial borehole seismic sensor Kinemetrics also produces a triaxial EpiSensor FBA ES T a uniaxial EpiSensor FBA ES U and the HypoSensor deep borehole package Kinemetrics strong motion accelerographs feature a triaxial EpiSensor Altus deck Kinemetrics is committed to ensuring a successful installation For assistance with planning installation operation or maintenance contact us at the locations listed in the front of this manual We also have an extensive Services Group that can install maintain and analyze the data from your SBEPI T
22. eased Prior to Ausust 1998 ii ces 15 Figure 6 Simplified Block Diagram of an Accelerometer 21 Figure 7 Amplitude Phase and Step Response of the SBEPI Response Model A Riesen 25 Figure 8 Location of DIP Switches and Jumpers een 28 DOCUMENT 301934 REVISION B Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 A Bine 5 SBEPI Assembly Wiring Chart ses 12 DIP Switch and Jumber Settings oooooocccnnocccnoncncnonnnononccinananinnnos 29 Range Sensitivity Calculations 0 cecceeesececsseceeeeeceeeteceeneeeenes 30 Current Requirements iia 31 Current Requires tii Kasseler 32 SBEPI Cabling Requirements 1 Foot 0 3048 Meters 33 SBEP ES Pec PCa sunshine 37 Safety Symbols amp Terms The following symbols may appear on Kinemetrics equipment or in this manual A 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 gt 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 handling the marked equipment you sh
23. ecause of its rough surface ordinary gravel may not flow into the area between the package and the casing while sand may liquefy in a strong motion event 10 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B 3 Operating Basics The SBEPI is designed as a very flexible low noise accelerometer and can be configured to satisfy a wide variety of acceleration sensing requirements This chapter is organized as follows m Power requirements Electrical connections Polarity conventions Description of configurations Functional test with an Altus recorder Using the calibration coil Power Requirements The SBEPI is supplied in two power configurations The basic unit 08 requires 12 V for operation An optional internal DC DC converter in the 18 unit allows operation with only 12 V The data sheet sent with the unit indicates whether it is a dual or single supply version If it is a single supply unit it is also shipped with a label on the cable end of the sonde Note This label may fall off after repeated installation of the unit f you have any doubt about the power configuration call Kinemetrics It is essential that the unit be supplied with adequate power Be sure to take into account any power loss that might occur due to the cabling Electrical Connection The connections for the SBEPI are described below along with procedures for using the calibration and cal enable signals This information
24. ems are required for installation of the unit Please contact Kinemetrics for replacement kits Table 1 Accessories 110393 1 Allen wrench Tool for adjusting the zero offset 70028 1 142 Seals the sensor to the main housing 110582 Tool for opening unit 870513 2 Backup Ring Seals the sensor to the main housing 700403 Maintain Humidity Free Interior Inspecting the Cable End Before lowering the instrument into its hole inspect the unit and the cable end make sure the cable insulation is not damaged Test the unit by making the electrical connections as follows SHALLOW BOREHOLE EPI USER GUIDE 5 DOCUMENT 301934 REVISION B Electrical Connection Stand the package up so that it is vertical within 1 1 2 Use temporary braces or blocking to keep the package in this upright position while checking its operation A one foot length of 3 PVC casing mounted to a wood base works well as a support Connect power as indicated in the Operating Basics section Functional Check amp Zero Offset Measurement Measure and record the output voltage from each accelerometer with a digital voltmeter Compute the offset of each axis in units of g 1g 9 8 m s m Divide the output voltage V by the sensitivity of the SBEPI V g quoted on the data sheets sent with the unit For example if you have a unit with a sensitivity of 20 V g and an offset voltage of 1 V the offset would be 0 050 g often stated as 50 milli g
25. ep Response 1 4 7 T T 7 1L T nn Output A N nn AAA VE A a E A A S cern 0 0 002 0 004 0 006 0 008 0 01 Time SBEPI Configuration This section describes how to configure certain features of the SBEPI by setting dual inline package DIP switches and jumpers on its oscillator board P N 110525 These jumpers are normally configured by Kinemetrics at the time of manufacture If your SBEPI is set to the correct range the following instructions for re configuring are unnecessary However if you wish to change the settings it is possible to do so in a laboratory environment Kinemetrics recommends that you do not attempt to change these jumpers in the field where debris or water could get into the unit It is possible to change the full scale range of the sensors but this requires that you completely disassemble the SBEPI package and is therefore not recommended These jumpers are configured by Kinemetrics at the time of manufacture Only a trained technician can properly disassemble the SBEPI unit This manual contains no instructions on this procedure We strongly recommend that you return the unit to Kinemetrics to have the range changed and the calibration verified 26 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Opening the SBEPI Case Caution Potential electrostatic discharge ESD hazard to equipment Wear a grounded wrist strap with impedance of approximately 1 M Q when
26. his chapter provides an overview of the SBEPI and inspection instructions The SBEPI is a triaxial accelerometer optimized for seismic applications Inside the stainless steel housing are three orthogonally mounted low noise EpiSensor force balance accelerometer modules The housing cables and connections are rated to 140 PSI 1 MPa equivalent to a depth of 330 feet 100 meters The 01 version comes supplied with a 40 meter cable the 02 with a 110m cable The SBEPI has factory selectable full scale recording ranges of 4g 2g 1g 1 2g or 1 4g The SBEPI 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 SBEPI is normally powered with a 12V external DC power source 8 Versions A single 12V power supply is available as an option 18 Unit The unit has a nominal diameter of 2 640 67 mm and a case length of approximately 9 5 241 mm This allows it to be used with 3 ID cased holes Full specifications for the unit can be found in the Appendix SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Figure 1 The SBEPI ARROW ALIGN NORTH 92 625 ALIGMENT ARROW STUDS GROOVE O RING X AXIS MODULE yo A Y AXIS MODULE EXTERNAL aH Ge HUSING Z AXIS MODULE
27. lations Full scale Single ended Single ended Differential Differential range 2 5V output 10V output SV output 20V output 1 4g 10 V g 40 V g 20 V g 80 V g 1 2g 5 V g 20 V g 10 V g 40 V g lg 2 5 V g 10 V g 5 V g 20 V g 2g 1 25 V g 5 V g 2 5 V g 10 V g 4g 0 625 V g 2 5 V g 1 25 V g 5 V g Voltage values above are as measured across each channel s output pins Pins 1 2 3 4 and 5 6 for axes X Y and Z respectively Pins 1 3 and 5 are and pins 2 4 and 6 are either or ground depending on whether configured for a differential or single ended connection to the recorder For best performance a differential connection to the recorder should be used if the recorder supports differential input connections Factory Configured Power Supply Options The triaxial SBEPI is offered in two power supply configurations the standard dual supply configuration and the optional single supply configuration There are no user settable features associated with the either power supply configuration Calibration Coil Each SBEPI module is equipped with a calibration coil This coil is isolated from other SBEPI circuitry and accurately emulates the effect of an acceleration on the system This coil can be used to verify both the static acceleration sensitivity of the unit and the dynamic response of the system When used with Altus recorders the calibration signals are automatically applied to the sensor
28. ls during the calibration sequence which can result in both additional noise and cross coupling between the sensors The easiest way to prevent power conflicts from the CCE line is to connect it to the power common or the 12V supply of the unit To produce a functional test sequence the data logger needs to control both the CAL and the CCE lines The voltage applied to the CAL line should be limited to 10V The sensor should reproduce any signal applied by the digitizer within the voltage limits and the bandwidth of the sensor Thus the calibration sequence can range from the simple pulses described below to single frequency sine waves or chirped sine signals Caution Be certain that the CAL line is not active when the SBEPI is not powered this could damage the unit If the data logger cannot perform a functional test a simple test box can be built to simulate the desired calibration sequence A suggested sequence is as follows 1 Apply OV to the CAL line 2 Turn CCE to 12V 3 Wait 2 seconds 4 Apply 2 5V to CAL for 2 seconds 34 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B 5 Change CAL to lt 2 5V for 2 seconds 6 Change CAL to OV for 2 seconds 7 Turn CCE off by connecting it to OV This will produce a positive pulse followed by a negative pulse Caution The CCE line must not be enabled during normal operation severely degraded noise performance can result Applying voltage to the CA
29. os dos t rminos mencionados arriba podrian tambi n 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 Especificas Siga las precauciones a continuaci n para garantizar su seguridad personal y prevenir da os al Shallow Borehole EpiSensor SBEPI Fuente del poder El SBEPI debe ser alimentado con energfa ya sea desde un registrador o desde una fuente de 12V provista por el usuario Si usted planea alimentar el SBEPI 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 energfa directamente al SBEPI 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 SBEPI bajo todo las condiciones de operaci n Usted es responsable por la seguridad de su sistema de carga Si usted deriva energia de suministro principal usted tiene que asegurarse que ha provisto un polo a tierra adecuado para todo el equipo Si usted suministra sus p
30. ot appear to be working we suggest you first check that the cabling and power supply are correct If the problem persists we recommend you return the unit to Kinemetrics for repair and re calibration Examining amp Cleaning the O rings The O rings should be cleaned each time the unit is opened and exposed to dirt To clean the O ring remove it from the seal surface wipe away the silicon grease and examine it carefully for any tears abrasion hairs etc that could prevent a seal Also examine the backing ring for any damage Before replacing the O ring clean the seal surface with a cotton swap and examine it carefully for scratches Then reapply a layer of silicon grease from the tube supplied in the accessory kit to the O Ring Carefully re install the O Ring ensuring that it is nearest to the cable and is protected by the backing ring 20 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B 5 Reference Theory of Operation The SBEPI consists of three orthogonally mounted EpiSensor force balance accelerometers FBAs X axis Y axis and Z axis inside a sensor casing Each accelerometer module is identical and plugs into a board that provides the final output circuit and the carrier oscillator The figure below shows a simplified block diagram of the major components of each of the FBAs Figure 6 Simplified Block Diagram of an Accelerometer FI Synchronous eur Demodulator Capacitive Transducer
31. ou supply your own power charging system be sure that the system provides the correct voltage and current required by the SBEPI 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 SBEPI 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 SBEPI provides no explosive protection from static discharges or arcing components Do not operate the equipment in an atmosphere where explosive gases are present SAFETY 2 SHALLOW BOREHOLE EPI USER GUIDE Sicherheit Symbole amp Begriffe Diese Symbole k nnen auf Kinemetrics Ger te oder in diesen Manuel erscheinen Bedeutet Achtung Wenn sie dieses Symbol auf ein Ger t sehen muss den gleich markierten Teil dieses Manuels beachet werden Bevor irgend eine Unterhalt
32. ould observe all standard precautions for amp This symbol indicates an electrostatic sensitive device ESD meaning that when ba 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 SHALLOW BOREHOLE EPI USER GUIDE SAFETY 1 Specific Precautions Follow the precautions below to ensure your personal safety and prevent damage to the Shallow Borehole EpiSensor Power Source The Shallow Borehole EpiSensor SBEPI 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 SBEPI 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 SBEPI 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 SBEPI will be damaged if the power is connected with the wrong polarity User Supplied Power Charging System If y
33. quires 10 18V DC supplied to the positive power connection Exceeding 18 VDC will damage the instrument as will reversing the connections If less than 10V is applied the SBEPI will not attain its full scale output and the data will be corrupted The supply should be capable of supplying the maximum load for the sensor under operating conditions The quiescent current is the best figure to use for sizing batteries or solar charging systems Table 5 Current Requirements Dual 12V Single 12V Sensor Quiescent Current Supply Supply Low power unit 12mA 65 mA Unit with low low noise amplifiers enabled 35 mA 130 mA Sensor Full scale Output Current 1 Axis 3 Axes Restoring current for coils per g 2 5 mA g 7 5 mA g Output amplifier load at 2 5V single ended 0 7 mA 2 1 mA or 5V differential full scale Output amplifier load at 10V single ended 6 6 mA 20 mA or 20V differential full scale To calculate the worst case maximum current required take the full scale range that the unit is set at and multiply by 7 5mA This will give the current required to balance the applied acceleration Add to this the output amplifier load for the output you have selected For a dual supply add this number to the quiescent current to get the worst case current SHALLOW BOREHOLE EPI USER GUIDE 31 DOCUMENT 301934 REVISION B For a single supply option multiply the current by 4 to account for the
34. r The extended bandwidth flat frequency response and polarity of the SBEPI meet these demands Figure 3 SBEPI Polarity Convention ARROW ALIGN NORTH ALIGMENT ARROW STUDS ROOVE OSRING X AXIS MODULE Y AXIS MODUL EXTERNAL 9 616 HUSING Z AXIS MODULE MOUNTING TUBE OSCILLATOR BOAR SHALLOW BOREHOLE EPI USER GUIDE 13 Configurations DOCUMENT 301934 REVISION B The SBEPI can be configured to obtain a variety of output types and sensitivities The variety of configurations is described in more detail in the Reference section of this manual The data sheet provided with your unit indicates the sensitivity of the sensor This can be checked with the results of the functional test described in the next section We recommend that you do not alter the factory settings of the SBEPI Performing a Functional Test with an Altus Recorder Please refer your recorder s user manual for instructions on performing functional tests Altus instrument firmware released after August 1 1998 performs a dual polarity pulse test on SBEPIs as the standard functional test when correctly configured This firmware is available at the Kinemetrics website Figure 4 Display of Functional Test if Kinemetrics QLWIN Version 2 40d 4 18 97 BEES File ZoomSize Pan Chan Screen Header Help C KMI DOCS APPNOTES LOOO1 EVT FT 7 31 1998 212 10 07 10 000 Display 6 3 A0 Rl Dl VO Cond 6 13 1 ZCond 5 95 1 BZ 0 0000 EZ
35. r RESPONSE Test ne male 15 Using the SBEPI Calibration Coll ze a 16 Maintenance Recommended Maintenance sauna diia 19 Complete a Functional Testi Hr 19 DOCUMENT 301934 REVISION B Desiccant Replacement Art ire ie A nn 19 Troubleshooting and Repair nase a ee 20 Examining amp Cleaning the O rings nen 20 5 Reference Theory of Opetation nin en ar Raben 21 Working Principles 22 Pe atures uuitc il lab 23 Pole Zero Representation of the SBEPI eee eeecceceseeeeeneceesteeeeneeees 24 SBEPI Configuration 2a ra 26 Opening the SBEPI Case uussuendenesuikaseeshneseilan 21 SBEPI DIP Switch amp Jumper Selectable Options r 0 27 Full Scale Voltage Output Voltages snnesnnennnnennnen en 29 Factory Configured Power Supply Options uusessensnseneneeennnen 30 Calibration Cola era en een en ns 30 Power Supply ee sinn binnen 31 Resistive Cable 1858 22 ARA A Baie x 32 Using Non Kinemetrics Data Loggers oooococnnocccnoccccnonccononccnnnnccnnnnnos 33 Output Voltage un sanieren 33 Calibration Sequence aia 34 Ground Loop Prevention aae as TS 35 Appendix A Figures Figure 1 The SBEPI 2 2 2a 2 Figure 2 Accelerometer Adjustment Screws 7 Figure 3 SBEPI Polarity Convention Fix Dimensions 13 Figure 4 Display of Functional Test iii 14 Figure 5 Display of Functional Test Using Software Rel
36. ropias baterias siga las recomendaciones de seguridad del fabricante Cableado y Polo a Tierra del Sensor En algunos casos el SBEPI estar 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 instalaci n y obtenga ayuda de un electricista calificado si este peligro existe No Opere en Atm sferas Explosivas El SBEPI no proporciona ninguna protecci n explosiva para descargas est ticas componentes que generen arcos el ctricos No operar el equipo en una atm sfera de gases explosivos SAFETY 6 SHALLOW BOREHOLE EPI USER GUIDE Symboles amp Terminologie Les symboles suivant peuvent figurer sur les quipements Kinemetrics ou dans ce manuel AN Signifie Attention Quand vous rencontrez ce symbole sur un instrument veuillez vous r f rer la section de ce manuel signal e par la m me marque Avant m me d effectuer la premi re op ration sur l instrument vous devez lire la section correspondante de ce manuel Faite attention si vous voyez cet symbole Indique une mise la terre faible bruit Le
37. s not recommended All external connections are passed through double stage transient protection This protection consists of a gas arrestor between the line and protective ground This is followed by a series impedance and solid state low voltage transient protection device connected between the line and protective ground These elements protect the sensor from the effects of lightening induced transients and electro static discharge ESD Each line is also filtered to prevent the entry of electro magnetic interference or radio frequency interference EMI RFI to the sensor Optionally the unit can be equipped with a 12V to 12V converter module allowing the SBEPI to be powered from a single 12 15V supply SHALLOW BOREHOLE EPI USER GUIDE 23 DOCUMENT 301934 REVISION B Pole Zero Representation of the SBEPI SBEPI accelerometers are closed loop force feedback sensors measuring the relative displacement of a moving mass plates with respect to the sensor case The sensor s transfer function TF depends almost entirely on the electronic components rather than on the mechanical components of the sensors The influence on the transfer function of the mechanical damping spring elements and internal RC low pass filter in the trans conductance amplifier stage within the closed loop path of the sensor are negligible for most applications We have determined a good empirical model of the system which uses two pairs of conjuga
38. s objets portant cette marque doivent tre reli s la terre afin d assurer un fonctionnement optimal Elle est aussi utilis e pour les l ments de protection contre les interf rences magn tiques les perturbations hautes fr quences radio et contre les surtensions Cette mise a terre n est pas une mise terre de s curit pour une protection contre les choques lectriques Indique une alimentation en courant alternatif AC ee Indique une Alimentation en courant continu DC d riv e d une alimentation alternative Indique la pr sence d un composant sensible aux d charges lectrostatiques Lia ESD Cela signifie qu il faut observer toutes les pr cautions d usage en manipulant ce composant Les termes suivant apparaissent dans ce manuel Note Indique la pr sence d une information que vous devez particuli rement consid rer avant de passer la prochaine instruction or operation Caution Indique une condition ou op ration qui peut entra ner des dommages votre quipement au logiciel ou d autres propri t s SHALLOW BOREHOLE EPI USER GUIDE SAFETY 7 Les deux derniers termes mentionn s peuvent appara tre sur les quipements de Kinemetrics que vous avez acquis mais pas n cessairement indiff remment il est conseill de prendre au s rieux les avertissements de ce manuel Pr cautions Sp cifiques Observez toutes les pr cautions suivantes afin d assurer votre
39. sarbeit 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 low noise operation zu versichern und dann auch als Erdung f r 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 f r dessen Handhabung alle vorbeugende Vorsichtsmassnahmen genommen werden m ssen Folgende Darstellungen werden in diesen Manuel erscheinen Note Darstellung welche Informationen Sie erhalten die besonders beachtet werden m ssen bevor sie zum n chsten Schritt gehen Caution Darstellung bei dem die Missachtung in der Regel Gefahr f r Defekte und St rungen im Ger t Programm oder Zubeh r besteht WARNING Darstellung bei dem die Missachtung in der Regel Verletzungs oder Lebensgefahr besteht SHALLOW BOREHOLE EPI USER GUIDE SAFETY 3 Spezielle vorbeugende Massnahmen Alle vorbeugende Massnahmen m ssen beachtet werden F r Ihre pers nliche Sicherheit und um Sch den im Shallow Borehole EpiSensor SBEPI zu vermeiden Stromversorgung Die SBEPI muss entweder mit Strom von einem Accelerograph oder Ihrer eigenen Stromquelle 12 V versorgt werden Sollten Sie planen die SB
40. should be sufficient to allow the SBEPI to connect to the user s own equipment or any Kinemetrics recorder SHALLOW BOREHOLE EPI USER GUIDE 11 DOCUMENT 301934 REVISION B Cable Wiring The wiring colors of the SBEPI cable assembly are provided below To aid in connecting this system to a transient protection box P N 108390 the corresponding connections on J3 and J4 in the box are also shown in the table along with connections to an Altus external input board Table 2 SBEPI Assembly Wiring Chart K2 External FBA Option SBEPI Cable 700422 J1 Cable Assembly Wiring Chart ER ion SPa on 700422 Function P3 Pin E E 0 i E 14 O B Ee Note Connect only at sensor end for single supply option N C at recorder end OK to connect sensor to well head box 12 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Polarity Conventions Unlike previous generations of Kinemetrics force balance accelerometers the SBEPI uses a right handed X Y Z coordinate system with a positive output for acceleration along each axis Previous Kinemetrics FBA designs used an alternate coordinate system L V T and produced a negative output for positive acceleration along each axis With modern feedback sensors this convention dating from the days of passive seismic sensors is losing acceptance Today s user requires an accelerometer that produces useful data without regard to the internal workings of the senso
41. sing current through the feedback coil to create a magnetic restoring force to balance the capacitor plates back to their original null position The current traveling through the coil is thus directly proportional to the applied acceleration By passing this current through a complex impedance consisting of a resistor and capacitor it can be converted to a voltage output proportional to acceleration with a bandwidth of approximately 200 Hz Selecting a particular resistor value sets the full scale range The resistor values are determined by a high accuracy network so the range can be set at 0 25g 0 5g 1g 2g and 4g without re calibrating the sensor span The capacitor and overall loop gain are selected along with the resistor to ensure an identical transfer function on each range This is why two sets of jumpers must be changed together to modify the range The voltage output of the resistor capacitor network is set at 2 5V for the acceleration value corresponding to the particular range For example with the 2g range a 1g acceleration would cause a 1 25V output on the 4g range 1g would result in a 0 625V output This voltage is then passed into the amplifier The low power amplifier amplifies this signal by either 1 or 4 selected by jumpers to give a single ended output of either 2 5V or 10V A precision resistor network also determines this gain value The low noise amplifier selected by jumpers provides a lower noise
42. switch that connects the CAL line to the sensor module calibration coil The transistor will turn on the analog switches at voltages between 5 to 12V The transistor is not activated at voltages below 0 5V This means a CMOS driver can drive the line or an open collector output pulled up to 12V A transistor transistor logic TTL level will probably work if the sensor is close to the digitizer It is very important that the CCE line is not enabled when the calibration feature is not in use and that it is not powered when the unit is not powered This is because the CAL line is connected to all the sensor coils during the calibration sequence which can result in both additional noise and cross coupling between the sensors The easiest way to prevent power conflicts from the CCE line is to connect it to the power common or the 12V supply of the SBEPI To produce a functional test sequence the data logger needs to control both the CAL and the CCE lines The voltage applied to the CAL line should be limited to 10V The sensor should reproduce any signal applied by the digitizer within the voltage limits and the bandwidth of the sensor Thus the calibration sequence can range from the simple pulses described below to single frequency sine waves or chirped sine signals Caution Be certain that the CAL line is not active when the SBEPI is not powered this could damage the unit 16 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 30
43. tall the package follow the instructions included with those options The following instructions make a number of assumptions m That the package is lowered into the hole with either the Kinemetrics supplied cable or m The package weight is supported by a stainless steel wire tension member m That the hole has been cased with PVC and filled with water to support the casing Other recommended procedures m Case the holes with 20 foot sections of 3 inch 90 mm schedule 40 3 500 inch OD x 3 042 inch ID PVC pipe glued together with couplings between segments Glue a cap to the bottom segment Grout the casing into the hole with a bentonite mixture that will have the same strength as soil A grout mixture that has proved satisfactory in the past is specified in ASTM D 4428 4428M The proportions are 1 pound bentonite 1 pound Portland cement 3 quarts water m Restrain the package while carefully lowering it through the hole casing to the bottom of the hole The unit can be powered or unpowered during the decent One person can successfully lower the package into holes up to 300 feet if the casing has been filled with water due to the offsetting weight of the buoyancy of the cable and package The apparent weight of the package and 300 feet of cable is only approximately 35 pounds This process is easier if the package is fitted with the appropriate optional centering spiders that keep it centered in a 3 or 4 inch inside diameter
44. te poles to represent the transfer function of the instrument If this transfer function is corrected for the DC sensitivity of the sensor the amplitude agreement is within 0 5 dB over the bandwidth of the sensor The phase agreement is within 2 5 in the 0 100 Hz band and within 5 over the full bandwidth of the instrument This model can be represented as Vis _ k1 k2 A s s pMs ps p Ms P where kl 2 46 x 10 k2 Sensitivity of sensor in V g from Table 3 1 s is the Laplace transform variable p 981 10091 Pole 1 p2 981 10091 Pole 2 p3 3290 12631 Pole 3 pa 3290 12631 Pole 4 V s is the Laplace transform of the output voltage A s 1s the Laplace transform of the input acceleration A more detailed analysis of the system is available on Kinemetrics web site Figure 7 on the next page show the amplitude phase and step response of this pole zero representation 24 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B Figure 7 Amplitude Phase and Step Response of the SBEPI Response Model Frequency Response Amplitude T T T dB ABl __ _ _ 0 50 100 150 200 Frequency Frequency Response Phase 20 MO 80 a a ne oe en J Degrees AU ee ADD Essen en AGO re 180 i i i 0 50 100 150 200 Frequency SHALLOW BOREHOLE EPI USER GUIDE 25 DOCUMENT 301934 REVISION B St
45. te simbolo en el instrumento N 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 simbolo ponga atenci n cuidadosamente Significa un polo a tierra de bajo ruido El tem referido debe estar polarizado a tierra para asegurar la operaci n a bajo ruido y adem s sirve como un retorno a L tierra para el EMI RFI y transitorios Tal polo a tierra no trabaja como un polo a tierra de seguridad para protecci n contra choques el ctricos Significa una l nea de energ a de Corriente Alterna AC Significa una l nea de energ a de Corriente Directa derivada de una l nea de energ a AC Significa una Unidad Sensitiva a Electrost tica Electrostatic Sensitive Device a ESD indicando que usted debe tener cuidado y observar todas las precauciones kad para el manejo de tales unidades Estos t rminos aparecer n en este manual Note sentencias identificando informaci n que Usted debe considerar cuidadosamente antes de dirigirse a la siguiente instrucci n u opci n Caution sentencias identificando condiciones o practicas que podr an resultar en da o del equipo el software u otra propiedad WARNING sentencias identificando condiciones o practicas que podr an resultar en una lesi n personal o la perdida de la vida SHALLOW BOREHOLE EPI USER GUIDE SAFETY 5 Los ltim
46. the recorder drives the calibration coil with an analog voltage corresponding to a pseudo random number sequence The resulting file contains the information needed to compute the sensor response SHALLOW BOREHOLE EPI USER GUIDE 15 DOCUMENT 301934 REVISION B Using the SBEPI Calibration Coil This section contains the information necessary to use the calibration coil with equipment other than Altus recorders such as a spectrum analyzer or a different type of data logger Each EpiSensor module is equipped with a calibration coil This coil is isolated from other circuitry and accurately simulates the effect of an acceleration on the system This coil can be used to verify both the static acceleration sensitivity of the EpiSensor and the dynamic response of the system The Altus recorder functional and system tests use a calibration signal from the recorder s digital to analog converter DAC To produce a functional test sequence the recorder must control the CAL and CCE line to the SBEPI Even if the recorder cannot produce a functional test it is still very important that these lines be held at the correct potential The CAL line is not connected to the sensor unless the CCE line is active but to provide the best noise performance the CAL line should not be left floating We suggest that the CCE line be grounded to power common when the calibration coil is not in use The CCE line drives a transistor that operates an analog
47. upply the 10V output with respect to ground The standard Altus unit s power output even in the worst case is 11 6V A SBEPI with the single supply option requires a minimum of 10 V The calculations for the 2g operating range are provided in the following tables These figures are a conservative limit for all ranges other than 4g The following table shows the resistance and calculated voltage drop for different lengths of the 700422 cable when using three common SBEPI configurations The first two columns show configurations typically used with Altus K2 data recorders The third column shows the configuration most commonly used with non Kinemetrics data loggers which often require a DC DC converter in the 32 SHALLOW BOREHOLE EPI USER GUIDE DOCUMENT 301934 REVISION B sensor Be sure that the data logger uses a regulated 12V supply before using the numbers in the table Note that for a Digitizer located close to the wellhead the supplied cable will work in all configurations for the 40m and 110m cables If you need to exceed these lengths to locate the digitizer away from the wellhead use a regulated power supply that supplies 15 V Calculate the voltage drop in the cable at the maximum supply current and make sure that it meets the minimum operating voltage for the chosen configuration Bear in mind that these figures are very conservative and assume a full 2g load on all three axes simultaneously a situation that is e
48. xtremely unlikely to occur in a borehole seismic application Table 7 SBEPI Cabling Requirements 1 Foot 0 3048 Meters Low power 2g Low noise 2g Low noise 2g 20V Sensor Type 2 5V S E 5V differential differential single supply Sensor minimum operating voltage 10 0 10 10V Maximum supply current 30 0 52 270mA Minimum supply voltage 11 6 11 6 12V Allowed cable voltage drop 1 6 1 6 2V One way allowed cable drop 0 8 0 8 1V One way allowed resistance at full scale output 26 7 15 4 3 7 Ohms Cable Low power 2g 2 5V Low noise 2g 5V Low noise 2g 20V Cable Resistance Single ended Maximum Differential Maximum Differential w Single AWG per 1000 Feet Cable Run in Feet Cable Run in Feet Supply Option Maximum Cable Run in Feet 20 10 90 2400 1400 330 Using Non Kinemetrics Data Loggers If you are using the SBEPI with a non Kinemetrics data logger you must match the power calibration and output of the SBEPI with that of the recorder Kinemetrics Services Group can provide help with this and can also supply conversion boxes to interface to some commonly used seismic instrumentation Output Voltage The SBEPI output is user selectable as is the output amplifier Select the SBEPI output that matches the recorder input If possible use a differential input connection for optimum performance Configuring the correct range and output is described earlier in this chapter SHA
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