FULL FUNCTION TEST FOR IN SITU TEST OF SENSORS AND AMPLIFIERS

• US 20090284263A1
• Filed: 05/13/2008
• Published: 11/19/2009
• Est. Priority Date: 05/13/2008
• Status: Active Grant

• Current Assignee: Brüel & Kjær Sound & Vibration Measurement A/S (Spectris PLC)
• Original Assignee: Brüel & Kjær Sound & Vibration Measurement A/S (Spectris PLC)
• Inventors: KIRKELUND, Morten, KOFOED, Lars Munch
• Granted Patent: US 7,936,175 B2
• Time in Patent Office: Days
• US Class Current: 324/523
• CPC Class Codes: G01H 3/005 Testing or calibrating of detectors covered by the subgroups of G01H3/00 calibrating geophysical instruments, e.g. seismic receivers G01V13/00
• CPC Class Codes: G01P 15/09 by piezoelectric pick-up
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: H04R 29/00 Monitoring arrangements; Testing arrangements for hearing aids H04R25/30; detection of loudspeaker connection H04R5/04; sound-field adaptation dependent on speaker detection H04S7/308

Abstract

The present invention provides a method and an apparatus for in situ test of transducers comprising sensing elements and associated conditioning preamplifiers. The invention makes it possible to evaluate the characteristics of the complete transducer by means of higher integration of the transducer circuitry. Tests can be performed from a remote central location without additional wiring and while the transducer is in operating environment. Testing is performed by superposing test signals and test sequence control signals on the wiring for the transducer output signal, hereby offering flexibility without sacrificing simplicity. Test signalling is by additional circuitry in the transducer interpreted and routed to the input of the conditioning preamplifier based on signalling from the remote test generator, and the signals engendered from the test signals can be analyzed from a remote analyzing system for complete qualifications of the transducer under test.

Claims

1. A method for test of a transducer comprising a sensing element and an associated conditioning preamplifier by means of introduction of a test signal into the input of said preamplifier, characterized in that said test signal is concomitant to a control signal which is superposed on the same transducer terminal and constituting test signalling, and said control signal is decoded in a local circuit in said preamplifier and enables routing of said test signal into said input of said preamplifier, whereby the electrical properties of said transducer can be analyzed in detail from a remote location.

2. A method for test of a transducer according to claim 1, characterized in that said test signalling is introduced through and superposed on the output terminal of said transducer.

3. A method for test of a transducer according to claim 1, characterized in that said test signalling is introduced remotely from a central generator.

4. A method for test of a transducer according to claim 1, characterized in that said test signalling is decoded and said test signals are routed to the input terminal of said preamplifier based on the decoded control signals.

5. A method for test of a transducer according to claim 1, characterized in that said test signal is routed to the non-inverting input of said preamplifier.

6. An apparatus comprising a sensor and a matching conditioning preamplifier characterized in that said conditioning preamplifier comprises additional circuitry in order to be able self-supportingly to accept and decode test signalling comprising test signals and test signalling sequences, and route the decoded test signals into an input terminal of said conditioning preamplifier in accordance with the decoded test signalling sequences.

7. An apparatus according to claim 6, characterized in that the power supply for said preamplifier is a constant current supply and the output signal of said preamplifier is superposed said constant current power supply.

8. An apparatus according to claim 6, characterized in that the power supply for said preamplifier is a constant voltage supply and said output signal is wired separately from said constant voltage power supply.

9. An apparatus according to claim 6, characterized in that said test signalling comprising test signal and test sequence signal can originate from a remote central test generator.

10. An apparatus according to claim 6, characterized in that said remote test signal and said remote test sequence signal originating from said remote central test system is superposed said output signal.