COMPUTER CONTROLLED AUTOMATED SAFE TO MATE METHOD AND APPARATUS

• US 20170074909A1
• Filed: 09/15/2015
• Published: 03/16/2017
• Est. Priority Date: 09/15/2015
• Status: Abandoned Application

• Current Assignee: U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration
• Original Assignee: U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration
• Inventors: NGUYEN, PHUC H., SCOTT, MICHELLE B., JOHNSON, THOMAS K., LEUNG, YUKLUN, LIN, MICHAEL R.
• Application Number:
  US14/855,001
• Publication Number:
  US 20170074909A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 15/12 Circuits for multi-testers , i.e. multimeters, e.g. for measuring voltage, current, or impedance at will
• CPC Class Codes: G01R 19/15 Indicating the presence of current
• CPC Class Codes: G01R 31/2834 Automated test systems [ATE]; using microprocessors or computers G01R31/317 takes precedence; ATE for detection of defective computer hardware G06F11/2736
• CPC Class Codes: G01R 31/66 Testing of connections, e.g. of plugs or non-disconnectable joints testing for incorrect line connections G01R31/55
• CPC Class Codes: G01R 31/68 Testing of releasable connections, e.g. of terminals mounted on a printed circuit board
• CPC Class Codes: G01R 31/69 of terminals at the end of a cable or a wire harness; of plugs; of sockets, e.g. wall sockets or power sockets in appliances

Abstract

A method of safe to mate testing includes providing a file of netlist signals where each signal defines a first connection to one or more components of a unit under test, connecting a first terminal of a measuring device to a first netlist signal and connecting a second terminal of the measuring device to a second netlist signal, performing a plurality of first resistive measurements by applying power having a first polarity between the first and second netlist signals, performing at least one second resistive measurement by applying power having a second polarity to the first and second netlist signals, and recording an average of the first resistive measurements and, if the second polarity measurement yields a negative result, an indication that a reactive load is connected between the first and second netlist signals.

Claims

1. A method of safe to mate testing comprising:

providing a file of netlist signals where each signal defines a first connection to one or more components of a unit under test;

connecting a first terminal of a measuring device to a first netlist signal and connecting a second terminal of the measuring device to a second netlist signal;

performing a plurality of first resistive measurements by applying power having a first polarity between the first and second netlist signals;

performing at least one second resistive measurement by applying power having a second polarity to the first and second netlist signals; and

recording an average of the first resistive measurements and, if the second polarity measurement yields a negative result, an indication that a reactive load is connected between the first and second netlist signals.

2. The method of claim 1, comprising limiting an output of the measurement device while performing the resistive measurements.

3. The method of claim 1, wherein the plurality of first resistive measurements comprise three measurements.

4. The method of claim 1, wherein performing the plurality of first resistive measurements comprises performing first resistive measurements repetitively until the resistance measurement is constant within a predetermined tolerance range or until a predetermined measurement count is reached.

5. The method of claim 1, further comprising:

connecting the second terminal to a third netlist signal;

performing the first and second resistive measurements; and

recording an average of the first resistive measurements and, if the second resistive measurement yields a negative result, an indication that a reactive load is connected to between the first and third netlist signals.

6. The method of claim 1, further comprising:

providing a file of harness signals, where one or more of the harness signals defines a second connection between components of a test system and at least one of the netlist signals;

verifying that the first connections defined by each individual netlist signal have less than a continuity threshold resistance with respect to each other;

verifying that the first connections defined by different netlist signals have more than a first isolation threshold resistance with respect to each other; and

verifying that the harness signals not defining a second connection have more than a second isolation resistance with respect to each of the netlist signals;

7. The method of claim 6, wherein the continuity threshold resistance is approximately 20Ω

.

8. The method of claim 6, wherein the first isolation threshold resistance is approximately 1MΩ

.

9. The method of claim 6, wherein the second isolation threshold resistance is approximately the same as the first isolation threshold resistance.

10. A safe to mate test system comprising:

a measurement device;

a switch multiplexer connected to first and second terminals of the measuring device; and

control circuitry operable to;

load a file of netlist signals, where each signal defines a first connection to one or more components of a unit under test;

cause the switch multiplexer to connect the first and second terminals of the measuring device to a first and second netlist signal, respectively;

cause the measuring device to perform a plurality of first resistive measurements by applying power having a first polarity to the first and second netlist signals, and to perform at least one second resistive measurement by applying power having a second polarity to the first and second netlist signals; and

record an average of the first resistive measurements and, if the second polarity measurement yields a negative result, an indication that a reactive load is connected between the first and second netlist signals.

11. The system of claim 10, comprising a resistor connected in parallel with the first and second terminals to limit an output of the measurement device while performing the resistive measurements.

12. The system of claim 10, wherein the plurality of first resistive measurements comprise three measurements.

13. The system claim 10, wherein the control circuitry is further operable to cause the measurement device to perform the first resistive measurements repetitively until the resistance measurement is constant within a predetermined tolerance range or until a predetermined measurement count is reached.

14. The system of claim 10, wherein the control circuitry is further operable to:

cause the switch multiplexer to connect the second terminal to a third netlist signal;

cause the measuring device to perform the first and second resistive measurements; and

record an average of the first resistive measurements and, if the second resistive measurement yields a negative result, an indication that a reactive load is connected between the first and third netlist signals.

15. The system of claim 10, wherein the control circuitry is operable to:

load a file of harness signals, where one or more of the harness signals defines a second connections between components of a test system and at least one the netlist signals;

cause the switch multiplexer to connect the first and second terminals of the measuring device between the first connections defined by each individual netlist signal to measure a continuity threshold resistance between each first connection defined by each individual netlist signal;

cause the switch multiplexer to connect the first and second terminals of the measuring device between each first connection defined by different netlist signals to measure a first isolation threshold resistance between each of the first connections defined by the different netlist signals; and

cause the switch multiplexer to connect the first and second terminals of the measuring device between each harness signal not defining a second connection and each netlist signal to measure a second isolation threshold resistance between each harness signal not defining a second connection and each netlist signal.

16. The system of claim 15, wherein the continuity threshold resistance is approximately 20Ω

.

17. The system of claim 15, wherein the first isolation threshold resistance is approximately 1MΩ

.

18. The system of claim 15, wherein the second isolation threshold resistance is approximately the same as the first isolation threshold resistance.