1. Manuals
  2. Brands
  3. Geometrics Manuals
  4. Measuring Instruments
  5. Memory-Mag G-857
  6. Operation manual

Geometrics Memory-Mag G-857 Operation Manual

Proton precession magnetometer
Hide thumbs Also See for Memory-Mag G-857:
Table of Contents

Advertisement

Quick Links

Download this manual
G-857 Memory-Mag
Proton Precession
Magnetometer
P/N 18103-02 Rev. C
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 © 2015
.
i
Geometrics, Inc
G-857 Operation Manual

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Memory-Mag G-857 and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Geometrics Memory-Mag G-857

Summary of Contents for Geometrics Memory-Mag G-857

  • Page 1 G-857 Memory-Mag Proton Precession Magnetometer P/N 18103-02 Rev. C 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 © 2015 Geometrics, Inc G-857 Operation Manual...
  • Page 2 Geometrics, Inc G-857 Operation Manual...

  • Page 3: Table Of Contents

    ....................34 AGNETIC SURVEYING GPS Error Messages....................34 Standard operation ....................35 Gradiometer operation ..................... 37 Base station operation ....................38 DATA RETRIEVAL ...................... 39 ..............39 OMPUTER CONNECTION AND DOWNLOAD G-857 format download .................... 39 Geometrics, Inc G-857 Operation Manual...
  • Page 4 Figure 11. Top sensor with gradiometer cable attached ..........13 Figure 12. Bottom sensor with gradiometer cable attached ..........13 Figure 13. Connection of threaded staff adaptors ............13 Figure 14. Completed gradiometer staff ................14 Geometrics, Inc G-857 Operation Manual...
  • Page 5 Table 1. An example of the console memory stack............27 Table 2 GPS Error Messages ..................35 Table 3. RS-232 cable connector pin assignment............56 Table 4. Summary of programmable switch settings............64 Geometrics, Inc G-857 Operation Manual...
  • Page 6 Geometrics, Inc G-857 Operation Manual...

  • Page 7: Introduction

    Introduction This manual provides operating instructions for Geometrics G-857 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 field 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. Such variations will have no adverse effect and should be recognizable as you familiarize yourself with operation. Geometrics, Inc G-857 Operation Manual...
  • Page 10 Geometrics, Inc G-857 Operation Manual...

  • 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-857 Operation Manual...

  • Page 12: Standard System Assembly

    Geometrics does not recommend the use of gasoline (petrol) as a sensor fluid. Experience has shown that local formulation of gasoline may include additives that can damage the sensor.

  • Page 13: Figure 2. Sensor Staff Sections

    Figure 3a shows the location of the sensor fluid fill port and the mounting points of the sensor cable. Any tools used for adding fluid, tightening fasteners or the port plug should either be non-magnetic or have a clean, rust free hard-chromed finish. Geometrics, Inc G-857 Operation Manual...

  • Page 14: Figure 3. Sensor Preparation

    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, there are two ways the sensor can be mounted, either vertically, on its end or horizontally on its side.

  • Page 15: Figure 5. Console Battery Compartment

    6b. Do the same with the waist strap and then repeat this procedure on the other side of the holster. Adjust the harness so that the console is centered on your torso as shown in Figure 6c. Geometrics, Inc G-857 Operation Manual...

  • Page 16: Figure 6. G-857 Shoulder Harness

    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 displays did not light, check battery power or the Troubleshooting Appendix in this manual. Geometrics, Inc G-857 Operation Manual...

  • Page 17: Gradiometer Assembly

    Figure 9 and include:  Gradiometer Box (P/N 16654-01)  Gradiometer sensor (P/N 16076-02)  Lower staff adapter (P/N 16530-02)  Upper staff adapter (P/N 16531-02)  Two Gradiometer sensor cables (P/N 16653-01M) Geometrics, Inc G-857 Operation Manual...

  • Page 18: Figure 9. Gradiometer Components

    Figure 10a and 10b. 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 19: Figure 11. Top Sensor With Gradiometer Cable Attached

    5) The separation between gradiometer sensors is determined by the lengths and number of the staff sections linking the sensors. The minimum separation will always include one of the threaded adaptors and the top (threaded) staff Geometrics, Inc G-857 Operation Manual...

  • Page 20: Figure 14. Completed Gradiometer Staff

    As shown in Figure 15, attach the Velcro strip to the top of the G- 857 black front panel bezel. Mount the Remote Start Switch box to this mating Velcro strip. Figure 15. Attach the gradiometer switch box Geometrics, Inc G-857 Operation Manual...

  • Page 21: 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-857 staff sections to construct a stable base-station tripod.

  • Page 22: Gps Assembly And Setup

    Legacy Off output mode must also be selected. Make sure the Garmin Oregon GPS is set to output NMEA at 9600 Baud with Autopilot on. You can use the following steps to configure the Garmin Oregon GPS. Geometrics, Inc G-857 Operation Manual...

  • Page 23: Sensor Orientation

    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. This will orient the sensor coils for maximum signal when the magnetic field has low inclination. Geometrics, Inc G-857 Operation Manual...

  • Page 24: Figure 18. Alternate Orientations For G-857 Sensor Mount

    Figure 19, 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 19. Magnetic Inclination of the Earth’s field Geometrics, Inc G-857 Operation Manual...

  • Page 25: Console Set-Up

    Figure 20. G-857 console display and keypad. Note that the keys are labeled according to their function and numeric input value. The functions of the keys are summarized as follows: Geometrics, Inc G-857 Operation Manual...

  • Page 26: System Checkout

    4) Open the console case by releasing the plastic snaps on its sides and slide the cover off of the console. Verify that the batteries are connected (rechargeable Gel-cells), and that the battery cover is closed and latched. Reinstall the console cover. Attach the sensor signal cable to the console’s connector. Geometrics, Inc G-857 Operation Manual...

  • Page 27: Operating Procedures

    The Julian date will be indicated in the STATION/DAY display. Compare the magnetometer clock’s time to your watch, time standard, or your base station instrument and decide whether you need to Geometrics, Inc G-857 Operation Manual...

  • Page 28: Setting The Year

    GPS recording. The magnetometer will not record GPS data when GPS recording mode is off even if the GPS is connected and turned on. Note that operating the G-857 in GPS Off mode with the GPS connected will lead to truncated readings. Geometrics, Inc G-857 Operation Manual...

  • Page 29: Manual Tuning Of The Magnetometer

    19.9. The ‘tunE’ display that succeeds the signal strength display shows the current tuning in terms of magnetic field intensity with units of 100 nT. For example, if the display shows ‘ ’then 56,000 nT tuning is indicated. Geometrics, Inc G-857 Operation Manual...

  • Page 30: Figure 21. Magnetic Field Intensity Variation, (Nt)

    500 Once you have obtained a signal strength indicating adequate tune, you can begin your survey. If you wish to increase the signal strength, you will want to be more precise in Geometrics, Inc G-857 Operation Manual...

  • Page 31: Automatic Tuning

    FIELD/TIME A tunE STATION/DAY To deactivate the automatic tuning function press: AUTO, TUNE, CLEAR The following displays will appear: FIELD/TIME Auto STATION/DAY FIELD/TIME A tunE STATION/DAY To determine the instrument’s tuning mode press: Geometrics, Inc G-857 Operation Manual...

  • Page 32: Acquiring And Storing A Magnetic Field Reading

    READ in order for the console to read and store the measurement. To enable automatic storage press: AUTO, STORE, ENTER If you wish to revert to the standard manual store mode press: Geometrics, Inc G-857 Operation Manual...

  • Page 33: Recalling Measurements From Memory

    In a large stack of data, it is not necessary to keep depressing RECALL ENTER until the desired reading is found. In cases where you wish to look at a particular reading (nnn for example) you would press: RECALL, SHIFT, ‘n’, ‘n’, ’n’, ENTER Geometrics, Inc G-857 Operation Manual...

  • Page 34: Erasing Magnetometer Readings

    10 - Erasing magnetometer readings The G-857 will allow you to erase the last reading, the last group of readings, or the entire memory. To erase just the last reading press: READ, RECALL, ERASE, ERASE Geometrics, Inc G-857 Operation Manual...
  • Page 35 When AUTO ERASE mode is OFF, cycling and data storage will stop when the memory is full. Press AUTO, ERASE, CLEAR to end AUTO ERASE mode. Geometrics, Inc G-857 Operation Manual...

  • Page 36: Automatic Reading Set-Up

    Appendix for additional information.) If the selected cycle time is less than 10 seconds then there will be a slight delayed action when commands are keyed. This is because the console processor will be busy taking readings and displaying the results. You may find Geometrics, Inc G-857 Operation Manual...

  • Page 37: Retrieving Magnetic Field Readings

    USB adapter. We recommend using Geometrics MagMap2000 program to retrieve and process the data stored in the G-857. If you have installed this software you should run it now. (See the...

  • Page 38: Clock Set From Gps Time

    Note that console time and GPS time can differ by +/- 2 seconds even after console time has been set from GPS. This is due to the amount of time required to capture GPS data during G-857 read function. Geometrics, Inc G-857 Operation Manual...

  • Page 39: 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-857 Operation Manual...

  • Page 40: Magnetic Environment

    GPS status error messages are displayed instead of field value when GPS mode is enabled and an error condition is detected. You can still view the reading after storing by using the RECALL and ENTER buttons or transfer the readings using the OUTPUT and ENTER buttons. Geometrics, Inc G-857 Operation Manual...

  • Page 41: Standard Operation

    This survey design ensures 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 22. Geometrics, Inc G-857 Operation Manual...
  • Page 42 If you are retrieving data from a base station, you will be recording the data on the basis of measurement time rather than station number. Geometrics, Inc G-857 Operation Manual...

  • Page 43: Gradiometer Operation

    1 through 4 to "off" and 6 through 8 to "on" on the G-857 circuit board. Readings initiated by the Gradiometer box are automatically stored. See the Appendix and Table 4 for details on switch settings. Geometrics, Inc G-857 Operation Manual...

  • Page 44: Base Station Operation

    Base station setup using Geometrics tripod is shown in Figure 16. Base station location and the Survey instrument should be separated by at least 30 feet (9 Meters) to prevent polarize current in one magnetometer interfering with the measurements of the other magnetometer.

  • Page 45: Data Retrieval

    PC’s serial port. (Note: some PC computers are not equipped with serial ports. If this is the case, you will need to connect an adapter – e.g. a USB-serial port converter. Geometrics ships a USB serial port converter with each new G-857).
  • Page 46 Select “G-857 / ASCII ” from the dialog above. Alternatively, user can choose the main menu and select “File / Import ASCII / G-857 Data”: MagMap display RS-232 communication dialog: Geometrics, Inc G-857 Operation Manual...
  • Page 47 The following dialog is displayed, where the user can adjust value as data bits, parity and number of stops bits. These settings are not required for G-857 download. Geometrics, Inc G-857 Operation Manual...
  • Page 48 SURVEY (0) or BASE STATON (1). If user added both types of readings at the beginning of the file, mode is reported as MIXED. 2. GPS availability. MagMap determines if GPS has been recorded as part of the data. Geometrics, Inc G-857 Operation Manual...
  • Page 49 (see below). Use this mode if you don’t wish to use GPS. Survey map window is displayed. 4. Survey mode: Mark positions & console time. Similar to above, but uses no GPS position and time information at all. Use this mode if no GPS Geometrics, Inc G-857 Operation Manual...
  • Page 50 (3) and (4). In this case the user is asked about grid orientation, line and mark spacing. The absolute values of station number are not counted in this case, only differences. Additional grid orientation dialog is displayed in this case: Geometrics, Inc G-857 Operation Manual...

  • Page 51: Legacy Format Download

    MagMap2000 offers many advantages. These include data download, profile plotting, filtering, contouring plotting and the diurnal correction of survey measurements using base station data. The latest version of MagMap2000 can be downloaded free of charge Geometrics, Inc G-857 Operation Manual...

  • Page 52: Manual Transcription

    (www.geometrics.com). The complete operating manual for this program is included in the software as an Adobe PDF document. If necessary you can download the free Adobe Acrobat Reader from www.adobe.com. The following is a brief description of data download and processing using MagMap2000: 1.

  • Page 53: Automatic Transcription In Real Time

    Although only the last reading in the internal memory is updated, magnetic field readings will still be continuously recorded and saved to the PC. Geometrics, Inc G-857 Operation Manual...
  • Page 54 Geometrics, Inc G-857 Operation Manual...

  • Page 55: Maintenance

    There are two kinds of batteries in the G-857. Basic operation is powered by an internal rechargeable Gel-cell battery pack. A lithium battery that is soldered to the console’s circuit board powers the magnetometer’s clock. This lithium battery maintains clock function when the main batteries are disconnected or discharged. Geometrics, Inc G-857 Operation Manual...

  • Page 56: Gel-Cell Batteries

    The lithium cell should be changed about every 8 to 10 years. It is soldered into the circuit board. Use the following procedure for its replacement: Geometrics, Inc G-857 Operation Manual...
  • Page 57 Connection is made with wires running through the center of the board. Replace the circuit board, cables, screws and cover. Install the operating battery. The clock will have to be reset after the battery is in place. Geometrics, Inc G-857 Operation Manual...
  • Page 58 Geometrics, Inc G-857 Operation Manual...

  • Page 59: Appendix

    Appendix Magnetic field inclination (degrees) Magnetic field intensity variation (nT) Geometrics, Inc G-857 Operation Manual...

  • Page 60: Troubleshooting

    1. Check for loose batteries. Bend out contacts and clean. 2. Low battery voltage 2. Remove batteries, then repress reset switch (SW2). 3. Internal memory error. 3. Replace batteries. Low Battery Voltage 1. Low voltage. 1. Replace batteries. Indication Geometrics, Inc G-857 Operation Manual...
  • Page 61 1. Control board 1. Return Circuit board (P/N malfunctioning. 16610-22) for repair. 2. Display board 2. Return Display board (P/N malfunctioning. 655050-4) for repair1 3. Display cable 3. Replace or fix Display cable malfunctioning (P/N 16627-33) Geometrics, Inc G-857 Operation Manual...

  • Page 62: Rs-232 Interface

    -3V; a logical "0" (space, on or true state) is indicated when the voltage is more positive than +3V. The G-857 provides RS 232 logic levels of ± 7 Volts. Geometrics, Inc G-857 Operation Manual...

  • Page 63: Front Panel Connector Pin Assignment

    Future power output Reserved Future ground Data valid Used with Gradiometer End of data Used with Gradiometer Instrument power External Power in. Otherwise jumper to H Synchronization External read/store command Transmit data Part of RS-232 Receive data Geometrics, Inc G-857 Operation Manual...

  • Page 64: Legacy Mode On Output Format

    ‘n’, ‘n’, ‘n’, Enter 2) Optionally you can press Output,Shift ; to begin output from station number “nnn”. Sample Legacy Mode data is below: 0 197 103219 0?510699 0 197 103229 1 510796 0 197 103239 2 510781 Geometrics, Inc G-857 Operation Manual...

  • Page 65: Legacy Mode Off Output Format

     GPSlon – 11 – Longitude from GPS in decimal degrees. Negative values are South. Positive values are North.  Comma character – 1  GPStime – 8 – Time from GPS. Format is hh:mm:ss. This time is usually in Geometrics, Inc G-857 Operation Manual...
  • Page 66 Output, Enter ‘n’, ‘n’, ‘n’, Enter 4) Optionally you can press Shift ; to begin output from station number “nnn”. Sample Legacy Off Mode is below: MODE,LINE,DATE,TIME,STATION,TRUNCATION,MAGFIELD,GPSLAT,GPSLON,GPSTIME,GPSDATE,SIGNAL,GPSS TATUS,RESERVED # G857 v. 1.0 0,0,10/10/14,22:51:55,0,1,48288.7,,,,,08.4,5, 0,0,10/10/14,22:52:05,1,1,48287.6,,,,,09.2,5, 0,0,10/10/14,22:52:15,2,0,48288.4,37.428503,-122.060479,22:52:15,10/10/14,08.6,0, 0,0,10/10/14,22:52:25,3,0,48287.6,37.428498,-122.060466,22:52:25,10/10/14,08.6,0, Geometrics, Inc G-857 Operation Manual...

  • Page 67: Auto Cycle Output Format

    The instrument may be run safely from a suitable external supply as high as 18 volts for Geometrics, Inc G-857 Operation Manual...

  • Page 68: External Magnetometer Control

    To operate 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 69: Internal Programming Switches

    ‘ON’ depending on the switch model. Typically, switches 1 through 5 are off and switches 6 through 8 are on. The functions of these switches and the operation state associated with their settings are summarized in Table 4. Geometrics, Inc G-857 Operation Manual...

  • Page 70: Polarize And Count Time - Switches 1 Through 4

    Switch 1, when ON, will extend the polarize time from under two seconds to almost three seconds. Setting this switch will provide stronger precession signal, but will lengthen the total cycle time and thereby shorten battery life. Geometrics, Inc G-857 Operation Manual...
  • Page 71 Increased power is needed for long polarization and/or the 3-reading average so it is best to use alkaline batteries, rechargeable batteries or external power when these functions are enabled. SWITCH 5 - DISPLAY OFF AFTER 5 MINUTES AUTO CYCLE Geometrics, Inc G-857 Operation Manual...
  • Page 72 This means that a single reading will require as much as three seconds to print on a slow telex machine, or as little as 1/5 of a second to transfer to a computer. Geometrics, Inc G-857 Operation Manual...

  • Page 73: Internal Reset Switch

    Clock and Cycle times may be reset to default settings. Make sure you attempt to download the data then disconnect the download cable prior to using this switch. Figure 24. Internal reset switch. Geometrics, Inc G-857 Operation Manual...

  • Page 74: Specifications

     Special - An internal switch allows: o adjustment of Functions polarization time and count time to improve performance in marginal areas or to improve resolution or speed operation o three count averaging o choice of lighted displays in auto mode. Geometrics, Inc G-857 Operation Manual...

  • Page 75: Warranty And Service

    Geometrics, Inc. will repair or replace the defective item at its facility in California at no charge to the customer for parts and labor. The cost to ship the equipment to Geometrics, Inc.'s factory Geometrics, Inc...
  • Page 76 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 77: Firmware Revisions

    First Production release. 141010 10-OCT-2014 Added GPS; extended memory capacity to 65,000 AUTO or manual stations. 150323 23-MAR-2015 Corrected “real-time” RS232 settings to 7N2; added flash memory wear-leveling; shut off CPU if GPS strings are absent. Geometrics, Inc G-857 Operation Manual...
  • Page 78 May 29, 2014 San Jose, California, USA EC DECLARATION OF CONFORMITY Geometrics, Inc. Geometrics Europe 2190 Fortune Dr. San Jose, CA 95131 USA Tel: (408) 954-0522 FAX: (408) 954-0902 declare under our sole responsibility that our portable magnetometers, models G-856, G-856G...

Table of Contents