MICROTESLA DIGITIZED SURFACEMOUNT SENSORS

General Description / Magnetometer / Accelerometer / Digital Interface / Power Control Section / Calibration / Specifications

General Description

The MicroTesla Digitized Surfacemount Sensor combines a new analog-to-digital converter board design with MicroTesla’s proprietary directional sensor technology to provide a digital output directional measurement solution. The revised circuit board design uses surface mount boards and qualified integrated circuit components. The sensor is designed to allow direct connection to a microprocessor based data acquisition system via dedicated serial interface connections. The magnetometer, accelerometer and associated electronics are all mounted on a rigid one piece chassis. A variety of end connections are available to meet customer specific requirements. The ruggedized sensor design is well suited to Measurement-While-Drilling and Oil Field Wireline applications and can now be packaged using the patented Ulti-pak method.

Magnetometer

The magnetometers used in the sensor are the MicroTesla proprietary flux gate design. The magnetometer design uses proprietary sampling and filtering methods which make it particularly suitable for operation over wide temperature ranges. Recent advances in ringcore material combined with specialized winding techniques have improved the sensor reliabililty. Over the specified operating range, the magnetometer outputs are almost linear and very repeatable. Low bias and scale factor variations versus temperature virtually eliminates the need for the third order temperature corrections.

Accelerometer

Three single-axis accelerometers are provided. These ruggedized quartz flexure servo devices have been used successfully in Measurement-While-Drilling applications.

Digital Interface

The new surface mount digital interface consists of a serial analog-to-digital converter used to measure the three-axis magnetometer outputs, the three axis accelerometer outputs, the sensor temperature and one user specified channel. The digital interface also has a serial non-volatile memory for storage of a user specified K-factor table. The analog-to-digital converter and nonvolatile memory may be controlled directly via multiple serial input/output connections. Sensor control and data acquisition may also be accomplished via serial interface connections to a UART port on a dedicated micro-controller.

Power Control Section

The optional power supply is a high temperature design with options to allow operation from a variety of customer supplied DC power sources. Typically, this power source is either a Lithium battery pack and/or an alternator power source.

Calibration

MicroTesla can calibrate the complete sensor package and will provide the K-Factor table in a customer specified format.