3-Axis Simple Aurora Monitor (SAM-III) Description and Specifications
The 3-axis Simple Aurora Monitor (SAM-III) magnetometer system is a sophisticated semi-professional geomagnetometer designed by Dirk Langenbach (hardware) and Karsten Hansky (software).
The primary application of the SAM-III is in the sensing and study of geomagnetism, but it is possible to use the SAM-III in other applications requiring magnetic sensing. The correspondences between geomagnetic storms, solar events and solar wind, aurora and radio propagation anomalies are well-known. The SAM-III will be a useful instrument to radio astronomers, radio amateurs, aurora photographers and experimenters.
Click here for a Geomagnetism Tutorial
The original SAM and the newer SAM-III forms the basis for a magnetometer network in Europe. We wish to expand this to a worldwide amateur geomagnetometer network, and our goal is to deploy the SAM or SAM-III on every continent. The southern hemisphere is under-represented even in professional geomagnetometer chains and networks, so we are particularly interested in deploying the SAM-III in southern latitudes. To become a member of the SAM network, internet access is required.
Click here for SAM-III ordering information
The orginal sensors used with the SAM-III were model the FGM-3 fluxgate magnetometer sensor manufactured by Speake & Co Llanfapley. Click here for detailed information. These fluxgates sensors are no longer available and have been replaced by an equivalent model FG3+. The sensor signals are processed by a Microchip PIC16F877 microcontroller operating at 16 MHz and associated logic circuitry. Click here for Frequently Asked Questions (FAQ) associated with the SAM-III.
Sensor outputs, K-index and time and date are shown on a liquid crystal display. Additional interface circuitry provides serial data, analog K-index and alarm outputs for external processing and display on a PC or voltmeter. The processor can be set to provide a dry contact alarm relay closure when the K-index exceeds a predetermined value. The alarm function is useful to aurora photographers and radio amateurs because it could indicate aurora picture and radio propagation opportunities.
The SAM-III may be operated in an autonomous (standalone) mode or it may be used with a PC for logging and viewing.
The basic specifications for the SAM-III magnetometer system are
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Range: Approximately ± 50000 nT
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Resolution: 1 ~ 2 nT
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Connection of 1, 2 or 3 sensors
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Microprocessor controlled, 16 MHz clock
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Data displayed on backlit 4x20 LCD (STN yellow/green standard)
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Measured data transmitted over EIA-232 serial interface as ASCII text
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K-Index available on one analog output (adjustable 0 ...+5 V or -2.5 ...+2.5 V)
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Real-time clock with backup battery
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Form A relay output for K-index alarm (maximum contact rating 30 V dc or V ac-peak, 1.0 a dc or a ac-peak, in a combination not exceeding 20 w)
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Opto-isolated input for detection of external voltage condition to deactivate measurements
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Software setup and measurement logging via EIA-232 serial interface
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Power: 12 V dc at 60-100 mA (depending on number of sensors connected)
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Dimensions (optional enclosure): 165 mm x 125 mm x 76 mm
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Temperature sensing capability
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Connectors:
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I/O: Pluggable terminal block, 8-pin
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Sensor: Pluggable terminal block, 10-pin
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EIA-232: DB-9M
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dc power coaxial 2.1 mm x 5.5 mm, center +
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Keyboard controls:
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Command mode (F1)
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Calibration mode (F2)
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Software reset (F3)
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Display backlight (F4)
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Application software:
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SAM_VIEW
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SAM_INI
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SAM_BROWSER
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SAM_STAT
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PC operating systems: Windows XP, 7, 8 and 10
The setup software used with the SAM-III allows the user to adjust the SAM-III onboard parameters for standalone operation. When the SAM-III is connected to a PC running the included logging and viewing software, the software collects data from the SAM-III and provides additional downstream processing and archiving of magnetometer data. The software also produces a graphics file that may be viewed locally by any graphics viewing program or transmitted by File Transfer Protocol (FTP) to a web server for viewing on the internet.
Click here to download the SAM-III construction manual and software setup manual and other information.
Logging and viewing software
screenshot showing the effects of a coronal hole high-speed stream.Click on the image to go to real time
data from our
Anchorage observatory.
Because of the magnetometer sensor sensitivity to both temperature and man-made disturbances, it normally is installed at a remote location and buried in the ground. We are aware of sensor installations greater than 60 m from the SAM-III processor. The documents above including the SAM-III Construction Manual provide information for siting the sensor and for constructing a sensor fixture. For information on calculating the burial depth in soil to reduce temperature variations, see Burial Depth of SAM-III Magnetometer Sensors.
The SAM-III consists of a main controller printed circuit board (PCB), keyboard PCB and Liquid Crystal Display (LCD) module and up to three sensors The controller PCB is shown below.
Although the SAM-III includes viewing and logging software specifically designed for it, it can be used with other logging methods. When in standalone mode (not connected to a PC), SAM-III only displays the real time data and does not remember it. If a user needs to log data but does not wish to have SAM-III connected to a PC, the EIA-232 serial interface can be connected to a serial data recorder.
The SAM-III has been tested with the Acumen Instruments SDR2-CF serial data recorder, which uses a compact flash card to save the serial data. When set to a 1 Hz sampling rate (the fastest rate available), the SAM-III produces approximately 3.7 MB of ASCII text data per day or about 115 MB per month. Each data sample includes a time/date stamp and magnetic induction values followed by Carriage Return/Line Feed characters.
The SAM-III also has an analog output that can be used to display or record the K-index. The analog output can be adjusted for a range of 0 to +5 v or -2.5 to +2.5 v.
Some users have written custom application programs that use the EIA-232 serial port to collect data for analysis and display but we presently do not have any information on these applications.
Click here for real time display of the SAM-III running in our Anchorage observatory