Single axis fluxgate magnetometer for mounting on theodolite for measurement of Declination and Inclination of the geomagnetic field.
The D&I Fluxgate Magnetometer Model G was developed for use at the Danish and Greenlandic Magnetic Observatories.
It uses a Pandect fluxgate sensor with a low noise electronic giving a digital output stable to 0.1 nT and an initial offset lower than 10 nT.
The external power supply may be either 12V AC or DC. Its back-lighted digital voltmeter allows easy reading in most conditions.
Installation and calibration
The sensor should be mounted on top of the telescope of the theodolite in such a way that no movements of the sensor axis are possible in normal use of the theodolite. Sensor housing is not included. The housing should allow alignment within 10 min of arc. Alignment to a few min of arc is preferred by many users, since it reduces the number of necessary fine-adjustments of the theodolite circles during the DI-measurements.
Alignment better than 10 min of arc however does not improve the accuracy of the measurements in any way.
The digital voltmeter is back-lighted to ease the reading. In case you want to decrease the power consumption of the instrument (portable use) it is possible to remove the back-light and save 1/3 of the power.
The buzzer is used to easily find the null positions of the theodolite without having to look at the digital display. The buzzer may be shut off on the external switch or the sound may be attenuated using the potentiometer on the printed circuit board.
Output: digital reading:
|+- 199.9 nT|
Size of electronics:
|100x70x160 mm, 0.8 kg |
|11-15 V DC or AC, 2W |
|-10 to 40°C |
Size of sensor:
|80 x ø10 mm|
Length of sensor cable:
|Length of extension cable:
||5 meter |
Lars W. Pedersen