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Summary of Contents for Geometrics Memory-Mag G-856AX
- Page 1 G-856AX Memory-Mag Proton Precession Magnetometer P/N 18101-02 Rev. E Operation Manual GEOMETRICS, INC. 2190 Fortune Drive, San Jose, CA 95131 Phone: (408) 954-0522 Fax: (408) 954-0902 Email: sales@mail.geometrics.com Web: www.geometrics.com COPYRIGHT © 2007...
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Page 3: Table Of Contents
AGNETIC SURVEYING Standard operation ....................30 Gradiometer operation ..................32 DATA RETRIEVAL ....................33 ..............33 OMPUTER CONNECTION AND DOWNLOAD ..................34 ANUAL RANSCRIPTION MAINTENANCE ......................35 ....................35 NSTRUMENT STORAGE ....................35 OLTAGE INDICATOR .........................35 ATTERIES ....................36 CELLS BATTERIES ....................37 CELL BATTERIES Geometrics, Inc G-856AX Operation Manual... - Page 4 Figure 20. G-856AX console display and keypad............16 Figure 21. Magnetic Field Intensity Variation, (nT)............20 Figure 22, Typical survey layout...................31 Figure 23. Location of console’s internal programming switch........46 Figure 24. Internal reset switch..................50 Geometrics, Inc G-856AX Operation Manual...
- Page 5 List of Tables Table 1. An example of the console memory stack............23 Table 2. Battery endurance comparison................36 Table 3. RS-232 cable connector pin assignment............43 Table 4. Summary of programmable switch settings.............47 Geometrics, Inc G-856AX Operation Manual...
- Page 6 Geometrics, Inc G-856AX Operation Manual...
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Page 7: Introduction
Introduction This manual provides operating instructions for Geometrics G-856AX portable proton- precession magnetometer. It includes step-by-step instructions on magnetometer set-up, survey usage, measurement data retrieval, and maintenance. What is a total field magnetometer? A total magnetometer is an instrument that measures the scalar intensity of the local magnetic field. -
Page 8: Terms Used In This Manual
Software Programs are available from Geometrics to help the user process and interpret survey data. These programs include MagMap2000 and MagPick and are available for download from our website: www.geometrics.com. - Page 9 In that event, you may find variations between this manual and the operation of your actual instrument operation. Such variations will have no adverse effect and should be recognizable as you familiarize yourself with operation. Geometrics, Inc G-856AX Operation Manual...
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Page 11: Magnetometer Set-Up
Tighten the plug just enough to prevent leakage - over tightening may crack or damage the sensor housing. Sensor is now ready for use. Geometrics, Inc G-856AX Operation Manual... -
Page 12: Standard System Assembly
Geometrics does not recommend the use of gasoline (petrol) as a sensor fluid. Experience as shown that local formulation of gasoline may include additives that can damage the sensor. -
Page 13: Figure 2. Sensor Staff Sections
Electrical connection Figure 3. Sensor preparation. Note: Geometrics recommends using non-magnetic tools for this task and it is important to use the original brass nuts and washers supplied with the instrument as substitutes could be contaminated with ferrous material. 3) Mount the sensor on the threaded staff section. As shown in Figure 4a and b,... -
Page 14: Figure 4. Staff / Sensor Assembly
Tighten the terminal nuts finger-tight and then tighten an additional 1/8 turn (between 18 in-lb and 24 in-lb). Connect the signal cable to the magnetometer. 6) Put the console harness on as shown in Figure 6a. Hold the console to your chest Geometrics, Inc G-856AX Operation Manual... -
Page 15: Figure 7. G-856 Shoulder Harness
8) Verify that the console is powered and properly connected to the sensor by momentarily depressing the key. The position of this key is shown in READ Figure 8. The displays will light, turn off, then light again for 5 seconds. If the Geometrics, Inc G-856AX Operation Manual... -
Page 16: Gradiometer Assembly
Proceed with gradiometer assembly as follows: 1) Start by removing the standard (single sensor) cable from the top sensor. This will require removal of the sensor clamp and brass stud nuts as shown in Figure 10a and b. Geometrics, Inc G-856AX Operation Manual... -
Page 17: Figure 11 Removing Standard Sensor Cable From Top Sensor
Figure 10 Removing standard sensor cable from top sensor. Note: Geometrics recommends using non-magnetic tools for this task and it is important to use the original brass nuts and washers supplied with the instrument as substitutes could be contaminated with ferrous material. -
Page 18: Figure 14. Connection Of Threaded Staff Adaptors
Remote Start Switch may be connected to the G-856AX front panel connector. As shown in Figure 15, attach the Velcro strip to the top of the G- 856AX black front panel bezel. Mount the Remote Start box to this mating Velcro strip. Geometrics, Inc G-856AX Operation Manual... -
Page 19: Base-Station Assembly
The sensor should also be mounted on a stable structure in order to minimize wind-induced motion of the sensor. Geometrics provides a base-station kit that can be used with the G-856AX staff sections to construct a stable base-station tripod. -
Page 20: Sensor Orientation
Earth's field and produce optimum signal. When surveying in regions when the Earth’s field is inclined at less than +/-40° the sensor should be mounted with its cylindrical axis horizontal as shown in Figure 18c. Geometrics, Inc G-856AX Operation Manual... -
Page 21: Figure 18. Alternate Orientation For G-856Ax Sensor Mount
Figure 20, the sensor’s cylindrical axis should be oriented vertically. Outside of this green region the sensor should be mounted so that is cylindrical axis is horizontal. Figure 18. Magnetic Inclination of the Earth’s field. Geometrics, Inc G-856AX Operation Manual... -
Page 22: Console Set-Up
SHIFT Accesses the key’s numeric value instead of its function. ENTER Designates the end of a key sequence and transfers command to console’s processor. Also increments memory location displayed during recall operations (see RECALL). Geometrics, Inc G-856AX Operation Manual... -
Page 23: System Checkout
CLEAR entered will be erased. 2 - Setting the internal clock To set the magnetometer’s internal clock to the Julian date and time press AUTO, TIME, SHIFT Geometrics, Inc G-856AX Operation Manual... -
Page 24: Setting The Line Number Marker
(See Magnetic Surveying, in the Field Operation chapter for further details). When in Survey Mode, a three-digit number indicating the line number appears in the display when the key is depressed. When in STATION/DAY TIME Geometrics, Inc G-856AX Operation Manual... -
Page 25: Manual Tuning Of The Magnetometer
Check the magnetometer’s tuning by pressing and releasing the key. You will see TUNE something like the following: FIELD/TIME STATION/DAY After about one second this display will be succeeded with something like: tunE FIELD/TIME Geometrics, Inc G-856AX Operation Manual... -
Page 26: Figure 21. Magnetic Field Intensity Variation, (Nt)
μT (micro Tesla, the three most significant digits of the full reading in Press to take a reading and note of its value READ Press and hold and note the signal level (number between 0.0 and 9.9) TUNE Geometrics, Inc G-856AX Operation Manual... -
Page 27: Automatic Tuning
FIELD/TIME A tunE STATION/DAY To deactivate the automatic tuning function press: AUTO, TUNE, CLEAR The following displays will appear: Auto FIELD/TIME STATION/DAY Geometrics, Inc G-856AX Operation Manual... -
Page 28: Acquiring And Storing A Magnetic Field Reading
The G-856AX can also be configured to store survey measurements automatically. In this mode you will only need to press in order for the console to read and store the READ measurement. To enable automatic storage press: Geometrics, Inc G-856AX Operation Manual... -
Page 29: Table 1. An Example Of The Console Memory Stack
In a large stack of data, it is not necessary to keep depressing RECALL until the desired reading is found. In cases where you wish to look at a particular ENTER reading (nn for example) you would press: Geometrics, Inc G-856AX Operation Manual... -
Page 30: Erasing Magnetometer Readings
8 - Erasing magnetometer readings The G-856AX will allow you to erase the last reading, the last group of readings, or the entire memory. To erasing just the last reading press: READ, RECALL, ERASE, ERASE Geometrics, Inc G-856AX Operation Manual... -
Page 31: Automatic Reading Set-Up
Julian (numerical) Day of the year. Note that this feature is not present in survey mode. In survey mode, the three-digit number doesn't increment automatically because it is most often used as a line number designator. Geometrics, Inc G-856AX Operation Manual... -
Page 32: Retrieving Magnetic Field Readings
USB adapter. We recommend using Geometrics MagMap2000 program to retrieve and process the data stored in the G-856AX. If you have installed this software you should run it now. (See the MagMap2000 operation manual or the Data Retrieval chapter for installation and specific operating instructions.) When prompted by MagMap2000, or when your... - Page 33 You can also transfer just a portion of the stored data. To do this, press: OUTPUT, SHIFT ‘n’,’n’,’n’, ENTER The G-856AX will begin transmitting data from station number “nnn” to the last recorded measurement. Geometrics, Inc G-856AX Operation Manual...
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Page 35: Field Operation
All articles carried by the operator should be considered suspect until they have been checked with the magnetometer. See the following section for the recommended magnetic screening procedure. Geometrics, Inc G-856AX Operation Manual... -
Page 36: Magnetic Environment
This survey design insures that the measurement points (stations) will define a grid that samples the magnetic field strength at a uniform spatial density. An example of this survey geometry is shown in Figure 21. Geometrics, Inc G-856AX Operation Manual... -
Page 37: Figure 22, Typical Survey Layout
If the current reading is in question do not press – take another reading and store it if appears that its value is reasonable. STORE Figure 21, Typical survey layout. Geometrics, Inc G-856AX Operation Manual... -
Page 38: Gradiometer Operation
The typical location for a base station is near or within the survey area. The base station should be placed away from buildings, traffic, and power lines to provide the best results. Base station setup using Geometrics tripod is shown in Figure 16. Base station recording is started by entering Automatic Mode. To do this press: ‘n’,’n’,’n’,... -
Page 39: Data Retrieval
Computer connection and download The G-856AX is designed to be used with personal computer running one of the MS Windows operating systems. Geometrics provides its MagMap2000 software to facilitate data download from the G-856AX and for processing the measurement results. -
Page 40: Manual Transcription
Flags discussed in item 4 above are also reproduced on the 2-D and 3-D map data plots. 6. Survey results can be exported as a file in ASCII (Text) format for processing or plotting using other analysis programs such as Geometrics MagPick program, Geosoft or Surfer. Manual Transcription If no computer is available for data retrieval it may be necessary to simply archive the data with pencil and paper. -
Page 41: Maintenance
This lithium battery maintains clock and memory functions when the main batteries are disconnected or discharged. Geometrics, Inc G-856AX Operation Manual... -
Page 42: D-Cells Batteries
Photoflash and "Energizers" batteries are not designed for this type of application but may be used until other batteries are available. Battery capacity decreases rapidly below 0°C for most battery types but Photoflash and “Energizers” will recover when warmed above 0°C. Geometrics, Inc G-856AX Operation Manual... -
Page 43: Gel-Cell Batteries
The lithium cell should be changed about every 6 to 10 years. It is soldered into and underneath the top circuit board. When the time has come to replace Geometrics, Inc G-856AX Operation Manual... -
Page 44: Sensor Fluid
3. Fill with acceptable sensor fluid to within 1 cm. from the top. Acceptable Fluids for Proton Magnetometers include: Shell SOL-71 (Shell Oil Co. product) Note:. This is the preferred fluid. Charcoal Lighter Fluid (Kingsford, Wizard, etc.) Geometrics, Inc G-856AX Operation Manual... - Page 45 Geometrics does not recommend the use of gasoline (petrol) as a sensor fluid. Experience as shown that local formulation of gasoline may include additives that can damage the sensor.
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Page 47: Appendix
Appendix Magnetic field inclination (degrees) Magnetic field intensity variation (nT) Geometrics, Inc G-856AX Operation Manual... -
Page 48: Troubleshooting
3. Incorrect or invalid key or 3. Consult Chapter 1. Depress key key sequence depressed. sequence again. Display reads "data Err" 1. Internal memory error 1. Print out or transcribe all stored data, then depress ERASE, ERASE. Geometrics, Inc G-856AX Operation Manual... -
Page 49: Rs-232 Interface
The RS-232C standard specifies voltage levels and protocol for the data lines as ±12V nominal, with voltages from 5V to 25V being acceptable. A logical "1" (mark, off or false state) is indicated when the voltage at the interface point is more negative than -3V; Geometrics, Inc G-856AX Operation Manual... -
Page 50: Front Panel Connector Pin Assignment
Each line of data transmitted by the G-856AX consists of 29 ASCII characters. Listed in order, the data fields and their count is as follows: Space or asterisk (*) - 1 Line number - 3 Geometrics, Inc G-856AX Operation Manual... -
Page 51: External Power
To operation from external power, connect the positive terminal of the external source to pin R, and the negative terminal to pin D (ground). Alternatively you can obtain an external power/signal/data cable from Geometrics (P/N 16652-05). If you plan to construct your own external power cable we recommend including a 1.5-2 Ampere fuse in the power input line. -
Page 52: Internal Programming Switches
To gain access to the programming switch, remove the instrument from its case just as you would to replace batteries. Look near the right rear corner on the top circuit board. You will find a rectangular switch with eight small levers. The switch is small and you Geometrics, Inc G-856AX Operation Manual... -
Page 53: Polarize And Count Time - Switches 1 Through 4
High polarization current and/or high ambient magnetic field strength will produce more precession signal but high magnetic field gradient will cause the signal to collapse more rapidly. Geometrics, Inc G-856AX Operation Manual... - Page 54 ON to improve the signal to noise ratio. Because of the length of the total cycle time needed to perform 3-reading averaging, this setting is most applicable to base station recording. Increased power is needed for long polarization Geometrics, Inc G-856AX Operation Manual...
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Page 55: Internal Reset Switch
G-856AX. Care should be taken when using this switch as all data in memory and all internal settings such as the Clock and Cycle times will be reset to default settings. Make sure you attempt to download the data prior to using this switch. Geometrics, Inc G-856AX Operation Manual... -
Page 56: Specifications
Internal switch selection for faster cycle (1.5 seconds) at reduced resolution or longer cycles for increased resolution. Manual Read - Takes reading on command. Will store data in memory on command. Memory - Stores more than 5700 readings in survey mode, keeping track of Geometrics, Inc G-856AX Operation Manual... - Page 57 Download cable (P/N 16492-01) o Hardcopy operation manual (P/N 18101-02) o Magnetometer CD (P/N 26648-01) Optional accessories: o Tripod kit for base-station operation (P/N 16708-02) o Gradiometer kit (P/N 166651-01) o Gradiometer carry/storage case (16003-01) Geometrics, Inc G-856AX Operation Manual...
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Page 58: Warranty And Service
Geometrics prior to returning equipment. If this instrument or any part of it is returned to the factory for any reason, please complete this form and include it with the instrument or part being returned. - Page 59 IMPORTANT Please explain why this instrument or part is being returned; include a complete description of any malfunction (use additional paper if necessary). SHIP TO: Geometrics Inc. 2190 Fortune Drive, San Jose, CA 95131 Phone: (408) 954-0522 Fax: (408) 954-0902...
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Page 60: Declaration Of Conformity
Amended by 92/31/EEC of 28 April 1992 and 93/68-EEC, Article 5 of 22 July 1993. The Technical documentation required by Annex IV(3) of the Low Voltage Directive is maintained by Christopher Leech of Geometrics Europe (address below). The authorized representative located within the Community is:...
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