AlphaLab GM1-HS Instructions

This magnetometer (gaussmeter) measures DC magnetic field (with polarity) up to + or Operation: Turn the meter on by pressing “Power” for at least 1 second. Note that the last few millimeters at the (black) end of the probe has a square bulge on one side; the other side is flat. from the tip. The brass is on the “flat” side. The center of that square bulge is the location of the Hall is very small (0.2 x 0.2 mm). Place the flat side of the probe’s end (not the square bulge side) against the surface to be measured. A negative sign indicates that the probe is touching the south pole of a magnetized object; in contrast, a north pole will read positive (“positive” is indicated by the sensor is 1.1mm above the flat surface or 1.0mm below the top of the square bulge) and is centered in the center of the square bulge. Below 10 gauss, only three digits (such as “- stronger than +/- 799.99 gauss, the extreme left digit will display. about one hour of battery life remaining. Remove the soft bumper or “boot” if present, and then slide off the battery door on the back side. Replace with a common 9- be removed by holding the meter so that the battery can fall out, and then tapping the meter on a table. 7ma and the LO BATT reads if battery voltage remains below 7V for at least one minute. battery voltage of 5.8V). You may need to press “Power” twice the first time with a new battery. MAKE SURE THE METER TURNS ON AFTER REPLACING THE BATTERY. Offset Adjustment (only necessary if measuring weak fields): The offset controls allow you to add or subtract you are holding the sensor in a certain orientation in space, and you want field is present. Press “Auto Zero” to do this. equivalent of adjusting the “tare” weight of a weight scale, because there may be an a want to subtract out. When turned on, the display will read approximately zero in zero field, but you can more precisely adjust the offset to zero if you do one of two things, either: 1) Place the sensor in a “zero gauss chamber” (not supplied with this meter, but see www.trifield.com) and Zero. 2) Place the sensor end flat on a non-magnetic table or desk with the square bulge facing up. will read the upward-pointing component of the magnetic field. should then read a negative number.) Note the number on the display. down. This 2nd reading should be the negative should be 0.40 (gauss). If the two readings are not the negative of each other, then the a zero reading in zero field. For example, if the 1 gauss (the average of the two readings). Adjust the of opposite sign. Offset is adjusted by pressing the “+” or “ DC Gaussmeter Model GM1-HS Instructions This magnetometer (gaussmeter) measures DC magnetic field (with polarity) up to + or Turn the meter on by pressing “Power” for at least 1 second. Note that the last few millimeters at the (black) end of the probe has a square bulge on one side; the other side is flat. Note also that a small section of brass is visible about 15mm The center of that square bulge is the location of the Hall Place the flat side of the probe’s end (not the square bulge side) against the surface to be gative sign indicates that the probe is touching the south pole of a magnetized object; in contrast, a north pole will read positive (“positive” is indicated by the absence of a polarity sign on the display). The actual center of the the flat surface or 1.0mm below the top of the square bulge) and is centered in the center of the -0.37”) will be displayed. For stronger fields, more digits will appear. 799.99 gauss, the extreme left digit will display. (It is a “1”). If the display reads “LO BATT”, there is Remove the soft bumper or “boot” if present, and then slide off the battery door -volt rectangular battery. Alkaline is preferred. The old battery can most easily be removed by holding the meter so that the battery can fall out, and then tapping the meter on a table. tery voltage remains below 7V for at least one minute. (Accuracy errors will occur below battery voltage of 5.8V). You may need to press “Power” twice the first time with a new battery. MAKE SURE THE METER TURNS ON AFTER REPLACING THE BATTERY. Adjustment (only necessary if measuring weak fields): allow you to add or subtract any field to or from the displayed number of gauss. you are holding the sensor in a certain orientation in space, and you want the display to show “zero”, even though some Press “Auto Zero” to do this. Then you can bring in a magnetized object to measure. equivalent of adjusting the “tare” weight of a weight scale, because there may be an ambient magnetic field that you’ll , the display will read approximately zero in zero field, but you can more precisely adjust the offset to zero if you do one of two things, either: gauss chamber” (not supplied with this meter, but see www.trifield.com) and magnetic table or desk with the square bulge facing up. In this orientation, the meter ng component of the magnetic field. (If the field is instead downward-pointing there, the meter Note the number on the display. Then flip the sensor so the square bulge is facing negative of the 1st reading. That is, if the 1st reading was –0.40 (gauss), then the 2 If the two readings are not the negative of each other, then the offset is not adjusted perfectly for , if the 1st reading is 1.00, and the 2nd reading is 0.00, then the Adjust the offset knob so that the 1st and 2nd readings are the same number but sing the “+” or “-” buttons. If you hold one button down, the offset amount will This magnetometer (gaussmeter) measures DC magnetic field (with polarity) up to + or - 799.99 gauss. Turn the meter on by pressing “Power” for at least 1 second. Note that the last few millimeters at the (black) end of the Note also that a small section of brass is visible about 15mm The center of that square bulge is the location of the Hall-Effect sensor, which Place the flat side of the probe’s end (not the square bulge side) against the surface to be gative sign indicates that the probe is touching the south pole of a magnetized object; in contrast, a north The actual center of the the flat surface or 1.0mm below the top of the square bulge) and is centered in the center of the For stronger fields, more digits will appear. For fields If the display reads “LO BATT”, there is Remove the soft bumper or “boot” if present, and then slide off the battery door The old battery can most easily be removed by holding the meter so that the battery can fall out, and then tapping the meter on a table. Current drain is (Accuracy errors will occur below battery voltage of 5.8V). You may need to press “Power” twice the first time with a new battery. MAKE SURE THE to or from the displayed number of gauss. This feature is used if the display to show “zero”, even though some Then you can bring in a magnetized object to measure. This is the magnetic mbient magnetic field that you’ll , the display will read approximately zero in zero field, but you can more precisely gauss chamber” (not supplied with this meter, but see www.trifield.com) and then press Auto In this orientation, the meter pointing there, the meter Then flip the sensor so the square bulge is facing 0.40 (gauss), then the 2nd is not adjusted perfectly for reading is 0.00, then the offset is off by 0.50 readings are the same number but ” buttons. If you hold one button down, the offset amount will

factory reset by removing the 4 screws in back and taking off the front cover. Turn the small round potentiometer below (nearest the battery) that says “internal offset”. Measurements: This type of meter is often used to check residual (accidental) magnetization of parts. In general, this accidental magnetization is perpendicular to the surface of the part, so the probe can be placed flat against the part, and this is the correct direction for detection of that field. You may need to scan the probe across the surface to find the highest number. This highest reading is usually found at the ends or sharpest points of the part. There are some peculiarities of measuring residual magnetization. Long, thin steel parts will often “amplify” the Earth field by a factor of 10 or so, at the ends of the part. If the long-axis of the part is pointed east-west, or perpendicular to the local indoor field, this is not a problem. The strength of the Earth field is about 0.5 gauss, so you may see up to about +/-5 gauss at the end of a properly demagnetized steel rod if the rod is pointed in the direction of the Earth field. The north pole of the earth is not horizontal in most locations. In most of Asia the magnetic field direction is within about +/-20° of horizontal. In North America if you face north and then look downward from horizontal 20° (Central Mexico) to 55° (Northern US) to as much as 90° down in parts of Canada, that is the direction of magnetic north. You can detect the field strength and direction with the meter. Note that with the bulge in the probe pointing toward the Earth north, you will read a negative number, because it's pointing toward the south pole of a magnet. If you flip the sensor 180° so that the bulge is facing Earth north, you will read a positive number. When scanning the surface of parts, if you want to measure with a resolution of less than five gauss, it’s recommended that you keep the probe end stationary with its thin axis (magnetic sensitivity direction) pointed perpendicular to the local magnetic field direction, and with OFFSET adjusted so the display instantly reads zero. You’ll know it’s correctly zeroed and perpendicular to the local field direction if when you flip the probe end 180°, the display continues to read zero. Then scan the part along the flat surface of the probe and look for the highest number (either positive or negative). SPECIFICATIONS: 1-axis DC Gaussmeter GM1-HS Range/Resolution: 799.99 G/0.01 G; with polarity indicator Accuracy: +/- 1% of reading (16° to 29°C); +/- 2% (-4° to 65°C) Offset: Auto Zero. Also fine offset (0.01 gauss resolution) Probe (non-detachable): 2.1 (thick) x 4.3 x 24 mm Size: 5.2 x 3.6 x 1.6 inches; 132 x 91 x 41 mm Weight: 8 oz Battery: 9 volt alkaline (~ 20 hour life)/ "Low Battery" indicator The warranty period for this meter is one year from the date of delivery. Manufactured in the USA by AlphaLab, Inc. 3005 South 300 West Salt Lake City, Utah 84115 USA www.trifield.com - [email protected] - (801)487-9492