Magnetometer test arrangement and method
View Patent ↗Manufacturing of magnetometer units employs a test socket having a substantially rigid body with a cavity therein holding an untested unit in a predetermined position proximate electrical connection thereto, wherein one or more magnetic field sources fixed in the body provide known magnetic fields at the position so that the response of each unit is measured and compared to stored expected values. Based thereon, each unit can be calibrated or trimmed by feeding corrective electrical signals back to the unit through the test socket until the actual and expected responses match or the unit is discarded as uncorrectable. In a preferred embodiment, the magnetic field sources are substantially orthogonal coil pairs arranged so that their centerlines coincide at a common point within the predetermined position. Because the test-socket is especially rugged and compact, other functions (e.g., accelerometers) included in the unit can also be easily tested and trimmed.
1. A test socket for a magnetometer, comprising:
a substantially rigid body having therein a cavity adapted to receive the magnetometer in a predetermined position within the body;
one or more magnetic field sources adapted to provide a magnetic field passing through the predetermined position;
electrical connection within or proximate the test socket for temporary electrical coupling to the magnetometer during testing; and
a pressing element adapted to fit into the cavity to hold the magnetometer in the predetermined position electrically coupled to the electrical connection.
2. The test socket of claim 1 , wherein the one or more magnetic field sources comprise one or more electrical coils each having a centerline passing substantially through the predetermined position.
3. The test socket of claim 1 , wherein the one or more magnetic field sources comprise three substantially mutually orthogonal electrical coil pairs, wherein each coil pair has a centerline passing substantially through the predetermined position.
4. The test socket of claim 3 , wherein the centerlines pass substantially through a common point located within the predetermined position.
5. The test socket of claim 1 , wherein the one or more magnetic field sources are substantially fixedly held by the substantially rigid body in predetermined relationship to the predetermined position.
6. The test socket of claim 1 , wherein the magnetometer is temporarily attached to the pressing element when inserted into the test socket.
7. The test socket of claim 1 , wherein the electrical connection to the magnetometer is held by the pressing element.
8. The test socket of claim 1 , wherein the magnetometer has an exterior volume VMAG and the test socket has an exterior volume VTS and a ratio VTS/VMAG is less than 2.8×104.
9. A test socket for a magnetometer, comprising:
a structure having a cavity sized and shaped to retain the magnetometer in a predetermined position during testing;
one or more magnetic field sources embedded in the structure and, when energized, generating a magnetic field passing through the predetermined position; and
one or more electrical connections each having a terminal accessible from the exterior of the structure and extending toward the predetermined position to enable communication with the magnetometer during testing;
wherein the structure comprises:
a socket body in which the cavity is formed; and
a pressing element movable into a position in which the pressing element projects into the cavity to retain the magnetometer in the predetermined position during testing.
10. The test socket of claim 9 , wherein the pressing element comprises a cap configured to be matingly inserted into the cavity to move the magnetometer into the predetermined position.
11. The test socket of claim 10 , wherein the one or more electrical connections comprise a plurality of test pins extending through the cap.
12. The test socket of claim 10 , wherein the cap is configured to be inserted into the cavity along an insertion axis, and wherein the one or more electrical connections comprises a plurality of test pins extending substantially parallel to the insertion axis.
13. The test socket of claim 9 , wherein the one or more electrical connections comprise a plurality of test pins extending through a wall of the socket body.
14. The test socket of claim 13 , wherein the pressing element comprises a cap configured to be matingly inserted into the cavity to situate the magnetometer in the predetermined position, and wherein the plurality of test pins extend away from cap when matingly inserted into the cavity.
15. The test socket of claim 9 , further comprising a slot pair formed in the socket body, and wherein the one or more magnetic field sources comprise a coil pair wound around the slot pair.
16. The test socket of claim 9 , further comprising a wireless interface electrically coupled to the one or more electrical connections and embedded within the structure at a location adjacent the predetermined position.
17. A test socket for a magnetometer, comprising:
a socket body having a cavity sized and shaped to hold the magnetometer in a predetermined position during testing;
a first slot pair formed in an exterior portion of the socket body;
a first coil pair wound around the first slot pair and, when energized, generating a magnetic field passing through the predetermined position; and
an electrical interface disposed adjacent the cavity and configured to enable communication with the magnetometer when moved into the predetermined position.
18. The test socket of claim 17 , wherein the electrical interface comprises one of the group consisting of a wireless interface disposed adjacent the magnetometer when in the predetermined position and a plurality of connector pins positioned so as to contact terminals provided on the magnetometer when in the predetermined position.
19. The test socket of claim 17 , further comprising:
a second slot pair formed in an exterior portion of the socket body; and
a second coil pair wound around the second slot pair and, when energized, generating a magnetic field passing through the cavity;
wherein the first coil pair share a first centerline, wherein the second coil pair share a second centerline, and wherein the first and second centerlines are substantially perpendicular.