Triaxial Fluxgate Magnetometer TriMag 210C25
Features
Data and Performance
Diagrams
Principle
Downloads
Features

Three orthogonal measurement coils together with one permeable core

Three components to be measured simultaneously at one point in space

Internal temperature sensor for thermal modeling from 50℃ to 210℃

Suitable for MWD and LWD
Data and Performance
Diagrams
Configuration Drawings
Electrical wiring diagram
Applications
Azimuthal Tool
Downhole Directional Sensor Module
Principle
The permeable and saturation of magnetic core is excited by the drive circuit. In the permeable state, the magnetic flux is focused to the magnetic core; there is more magnetic flux in the inner of the measurement coils than the outer. In the saturation state, the magnetic flux is diverged from the inner of measurement coils. The magnetic core works as a gate for three measurement coils, which open or close the magnetic flux into inner of each coil, then change the amount of the magnetic flux, and induce a voltage pulse in each coil. In each exciting cycle, the gate state has changed four times, that will induce four voltage pulses: PICKUP1, PICKUP2, PICKUP3 and PICKUP4.
These voltage pulses from each measurement coil have been sampled and integrated in the circuit, accordance to the integration voltage the circuit supply feedback currents respectively to each of the measurement coils, which produce magnetic field completely offset the magnetic field ,as the result, the magnetic field in the inner of three measurement coils is zero. The triaxial fluxgate is closedloop measuring, each of three feedback currents is exactly equal to each of three axis magnetic field components.
Calibration coefficient after thermal modeling
The temperature range of thermal modeling is 50℃ to +210℃,the axis alignment is thermal modeled by zero order polynomial, the bias and scale factor are thermal modeled by third order polynomial.
Each unit will be calibrated before shipping and build up its own calibration coefficients file. To get the accurate X Y Z axis component the triaxial fluxgate output voltage shall be calculated with the calibration coefficient.
Calculation of temperature
TUM is output voltage of the temperature sensor, the unit is V. T is the current temperature, the unit is ℃.
Calculation of Scale and Bias
Calculation of three components of magnetic vector
FXUM, FYUM, FZUM are the output voltage of the triaxial fluxgate, the unit is Voltage. HX, HY, HZ are the three components of magnetic field, the unit is Gauss.
Downloads