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Related Manuals for Geometrics G-877
Summary of Contents for Geometrics G-877
- Page 1 G-877 MARINE MAGNETOMETER 25165-OM Rev. B Operation Manual COPYRIGHT © January 2001 GEOMETRICS, INC. 2190 Fortune Drive, San Jose, CA 95131 USA Phone: (408) 954-0522 Fax: (408) 954-0902 Eml: sales@geometrics.com Eml: support@geometrics.com...
- Page 2 G–877 MARINE MAGNETOMETER OPERATION MANUAL...
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Page 3: Table Of Contents
TABLE OF CONTENTS Page INTRODUCTION TO THE G-877 MARINE MAGNETOMETER ..5 WHAT IS A MAGNETOMETER ........................5 G–877 SYSTEM DESCRIPTION, INSTALLATION AND COMMISSIONING......9 SYSTEM INSTALLATION ...........................13 2.2.2 G-886 Installation Hints........................14 CONFIGURING INPUT DEVICES AND DISPLAYS WITH MAGLOG WIZARD......18 ............................18... - Page 4 G–877 MARINE MAGNETOMETER OPERATION MANUAL...
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Page 5: Introduction To The G-877 Marine Magnetometer
The G–877 Proton Precession Magnetometer is a digital device and requires that a customer or Geometrics supplied portable laptop or desktop computer be used for recording and display of the data. To facilitate the use of the system by those individuals new to computer use, we have... - Page 6 A magnetometer is an instrument used to measure the value of the earth’s total magnetic field at a particular location. Many objects including man-made items and geologic structures perturb or distort the normally smooth earth’s magnetic field due to properties of the material from which they are made.
- Page 7 (nT). You may want to obtain more information on the operation, application of magnetometers and data processing procedures for magnetic data. This information can be found in the Geometrics publication, Applications Manual for Portable Magnetometers, by Sheldon Breiner available from our web site www.geometrics.com...
- Page 8 NOTES G–877 MARINE MAGNETOMETER OPERATION MANUAL...
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Page 9: G-877 System Description, Installation And Commissioning
Tow cable and Magnetometer Fish. The Logging and Display Computer should provide two communication ports, one for the Magnetometer input and one for the customer or Geometrics supplied GPS unit. It should be noted that the positional accuracy of the survey data will be determined to a large part on the accuracy of the GPS employed. - Page 10 2.2.1 Magnetometer Fish The Magnetometer Fish is a nose tow body meaning that it is supported underwater from a tow point at the front of the fish. The sensor, with its permanently installed sensor fluid, is contained in tough molded plastic surrounded the four fins. The sensor may be replaced if it is damaged, but this is unlikely as the potting material is extremely strong.
- Page 11 TOW CABLE G-877 CLEVIS SACRIFICIAL ANODE MAGNETOMETER ELECTRONICS INSIDE SENSOR G–877 MARINE MAGNETOMETER OPERATION MANUAL...
- Page 12 Hyperterminal is handy when troubleshooting computer serial port or communications difficulties. The Logging Computer may be customer or Geometrics supplied. In general it should be a high performance Desktop or Laptop computer (PII 500MHz or better) with either Windows 98, ME...
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Page 13: System Installation
(60m or 200 ft) is easily managed by hand. However if longer cables are used (up to a maximum of 400m or 1312 ft), a winch will probably be required. In this case, Geometrics can supply an optional waterproof On-Board Cable (100 or 200 ft – 30m or 60m) that runs from the winch to the Junction Box. -
Page 14: G-886 Installation Hints
MagLogLite Software Manual for setting up proper communications. In general, using MagLogLite Configuration Wizard will result in a quick and flawless system setup of the G-877 and GPS communications and display. G–877 Installation Hints. The G–877 Magnetometer Fish, as in other magnetometer systems, is sensitive to interference from A.C. - Page 15 This field value for your location will be found in the supplied Applications Manual for Portable Magnetometers on page 6 (for instance San Francisco is 50,000 nT). Alternately, you may wish to set the G-877 Tuning Control to AutoTuning. This will afford a quick and easy automatic tuning sequence.
- Page 16 Applications Manual for Portable Magnetometers. Enjoy your new search and survey tool! Contact the factory by email or fax or phone with any comments or questions. support@mail.geometrics.com sales@geometrics.com or TEL 408-954-0522 or FAX 408-954-0902...
- Page 17 NOTES G–877 MARINE MAGNETOMETER OPERATION MANUAL...
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Page 18: Configuring Input Devices And Displays With Maglog Wizard
• GPS device sending NMEA $GPGGA strings to one of PC’s serial ports • Geometrics magnetometers connected to another serial ports. The models supported are: o G-880/881 magnetometers with up to two magnetic sensors and optional pressure transducer and altimeter. - Page 19 Next there appears the Welcome screen: All Wizard screens have a short help file associated with them (duplicated in this document). Next you must specify survey file name. It is recommended if you press Browse button and select the appropriate folder and name (don’t place your survey files in the same folder where maglog.exe executable files reside but in another folder such as C:\DATA\SURVEY1).
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Page 20: Configuring Gps And Its Display
Configuring GPS and its display. The next screen will allow you to configure the GPS. It will work best if the GPS is connected to one of your serial ports now. If this is the case, press "Autoset communication parameters" and MagLog will scan your serial ports to find the GPS port and its baud rate. - Page 21 Interpolator in one of the next screens and why we recommend that you have a good GPS data transmission as you set up the survey. The GPS display can be configured with user selectable background colors and annotation fonts. Also, MagLog has the capability to import ArcInfo shape file maps (more on this in the MagLog Manual).
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Page 22: Configuring Magnetometer Hardware
employing this Maglog feature as large numbers of shape file elements can slow down the program performance. Configuring magnetometer hardware. Next is the magnetometer configuration section. It is recommended that the magnetometer be connected to one of the computer serial ports and sending data. If you know the port and baud rate, set it and press Autoset communication parameters . - Page 23 4. 2 880/881/823 mag system. Same as (1) but two magnetometer sensors connected into the chain. System outputs 4 numbers: Total field for first sensor, its signal level, total field for second sensor and its signal 5. 2 880/881/823 mag with depth sensors Identical to (2) but has two magnetic sensors connected into the chain.
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Page 24: Magnetometer Calibration
At the same screen you should now set the desired cycle rate for magnetometer. Typical values for 880 family would be 0.1 seconds (10 HZ) and typical value for proton magnetometer is 2.0 seconds (0.5 Hz). After all parameters are set and the auto detection sequence has completed you can press the Next button. -
Page 25: Real Time Lay Back Calculations
check the Do not enter calibration coefficients now button and the scale will be set as 1 and bias as 0. Do this if you don’t know calibration coefficients at this time. Note that this screen will not appear if you do not have depth or altimeter sensors in your system. Real time lay back calculations. - Page 26 (for multiple sensors). Note the gradiometer applications are many and varied, primarily associated with wider swath of coverage or removal of the diurnal field variations. Contact Geometrics for more details: Pick the picture which best fits your real geometry. Be ready to enter the values A,B,C,D,C1 and C2.
- Page 27 GPS antenna and magnetometer fish positions. The file can be loaded directly into popular program like Golden Software SURFER or Geometrics MagMap 2000. It is recommended that you note which data in which columns are being logged for future reference during the analysis and interpretation phase of the data reduction and map making.
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Page 28: Data Display Configuration
Data Display configuration. MagLog has different options on how to display incoming data. Primarily, the data is presented as analog chart traces. There can be multiple analog charts on the screen (slots) and they can be oriented in either horizontal or vertical mode. Also each chart (slot) can be set with different rates of speed and full scale values. - Page 29 Here is a typical wizard graphics configuration screen: The next screen allows you to set the scale and grid parameters for the slots, as well as the slot type. MagLog produces an automatic display layout based on your configuration and the following rules: •...
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Page 30: Configuring Printer
Configuring printer. MagLog allows you to produce hardcopy output during data acquisition. This option works with Printrex 8” or 11.5” thermal printers or with standard Epson type dot matrix 8 or 24 pin printers that are ESC/P compatible. Most dot matrix and some jet printers are compatible with this specification, however consult your printer manual regarding your specific printer. -
Page 31: Finishing Setup
Printer setup dialog: Finishing setup. After the final Finish button is clicked (screen not shown here), MagLog tries to set up the survey as it was configured. You should have your GPS and magnetometer up and running at this time. If you don’t have real inputs coming into the serial ports, Maglog still will create a survey, but you won’t be able to run it. - Page 32 NOTES G–877 MARINE MAGNETOMETER OPERATION MANUAL...
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Page 33: Quick Start For The G-886 Magnetometer
APPENDIX A - TECHNICAL MANUAL for FIRMWARE 4.1 Notes on Startup for the G–877 Magnetometer for Installations Not using MagLogLite If you are using Geometrics MagLogLite or MagLogNT please the following information is not required for proper operation. The G–877 Magnetometer communicates via RS-232. Measured Data, as well as all control and setup commands are handled over this link. - Page 34 Tuning Baud and modem setting (9600 Baud is normal factory setting) Inductance of cable and sensor to minimize tuning offsets Abandon Changes Everything Quit, abandon changes (Activates menu to reload default settings) Save parameters Cycle time Format of output Run magnetometer Display all parameters Next (for multi sensor systems) All of the setups are stored in FLASH so they are saved when power is shut off.
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Page 35: Alternative Software
You will use the signal level to tune the magnetometer for maximum signal under actual survey conditions. The value at maximum tune should be between 400 and 500. However, this can vary with ambient field strength (signal amplitude is proportional to field strength, i.e., we would expect half the signal strength value in a 25,000 field compared to a 50,000 field), sensor orientation (you will get more signal going north-south than east-west) and gradients (you will not get a useable signal with the sensor on a steel deck due to high magnetic field gradient). - Page 36 When the system is in the configure mode it will display a prompt that looks like "->", at which the user may type a single character to select the item to be set (character set listed below). When the character is typed, the system will respond with the current value of the parameter and allow the user to edit the value or press return to retain the old value.
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Page 37: G-877 Magnetometer Command Codes
Preamble := [NOTE: This “=“ is used by the MagLogLite software and may be different for other logging software.] The preamble is factory set to “=“ but may be changed to be compatible with other data logging software. Example Configuration file for G-877 s.n.006 12-27-00 Run mode (0=config, 1=magnetometer, 2=mag half duplex) :1 Cycle time in seconds : Initial tuning in kilo gammas : 50.0... - Page 38 fid display position(0=none,1=1st, 2=2nd, .. etc) : 0 fid display format :##### signal display position(0=none,1=1st, 2=2nd, .. etc) : 2 signal display format :#### depth display position(0=none,1=1st, 2=2nd, .. etc) : 3 depth display format :###.## input voltage display position(0=none,1=1st, 2=2nd, .. etc) : 5 input voltage display format :##.# temperature display position(0=none,1=1st, 2=2nd, ..
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Page 39: Cycle Time
input voltage decimals :4 temperature scale factor : temperature bias sign (0 = add, 1=subtract) :0 temperature bias : temperature decimals :0 polarize voltage scale factor : polarize voltage bias sign (0 = add, 1=subtract) :0 polarize voltage bias : polarize voltage decimals :4 Manufacture code :... -
Page 40: Transmitted Data Format
Auto tuning is not recommended if large changes in the field are anticipated, such as those associated with steel target location. The limits on the span of autotuning should be set close to the local field (i.e., ± 10K ) when the auto tuning is employed. The manual tuning uses strings in the form of: T531<enter>... -
Page 41: Pol Off
The following messages may be displayed during the configuration of the magnetometer electronics process. To help the user in properly programming the magnetometer operation, we offer these descriptions. Specific questions should be addressed to Geometrics Customer Service. 1." Invalid character in number "... - Page 42 5." Press "Y" to ignore warning and save to FLASH or any other key to abort: " Some checking of values includes tests for unlikely values. When a value is not illegal but unexpected this message is displayed to inform the user. 6."...
- Page 43 14." Attempt to run aborted due to error " This message is displayed if the checking done when the "R" is pressed discovers an error that precludes running the magnetometer software with the current parameters. 15. " Press: 1 to reload from FLASH 2 to reload factory settings "...
- Page 44 Download latest operational software from our Website regularly (MagLogLite™ and MagMap2000™) Please refer any comments, questions or technical support issues to: Customer Service Ph: 408-954-0522 Fax: 408-954-0902 Eml: support@geometrics.com Web: www.geometrics.com Phone Support Available 8 am to 5 pm Pacific Time Zone G–877 MARINE MAGNETOMETER OPERATION MANUAL...
- Page 45 APPENDIX B - ASSEMBLY/DISASSEMBLY OF THE TOW CABLE TO THE MAGNETOMETER FISH The description below describes how to connect the tow cable to the magnetometer fish. If it is necessary to disconnect the cable from the fish follow the below description on reverse order. To connect the tow cable clevis assembly to the magnetometer fish begin by arraying the parts as show in the picture below.
- Page 46 Insert the tow cable clevis into the nose such that the holes in the clevis line up with the holes in the sides of the nose. Insert the clevis pin as shown from the side of the nose with the smallest diameter counter bore.
- Page 47 Finally slide the locking sleeve over the connector body and screw it onto the bulkhead connector body until it is finger tight. Press on the end of the electronics bulkhead to slide it as far inside the fish as possible, approximately four inches. It will reach a stop.
- Page 48 Gather the sacrificial anode, saddle, a one inch brass screw and the brass locking nut. Assemble them together with the flat side of the anode against the flat side of the saddle and the brass screw through the right hole as shown.
- Page 49 Place the anode and saddle on the fish such that the brass screw is inserted into the right-hand hole of the fish. Place the second brass screw through the left- hand hole to help align the anode to the fish. Take the brass nut and slide it down inside the fish until it is aligned over the end of the right-hand screw.
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