Temperature measurement system and method

• US 20070019707A1
• Filed: 07/25/2005
• Published: 01/25/2007
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Gozloo, Bahman, Gottshall, Paul
• Granted Patent: US 7,322,743 B2
• Time in Patent Office: Days
• US Class Current: 374/163
• CPC Class Codes: G01K 1/026 arrangements for monitoring a plurality of temperatures, e.g. by multiplexing

Abstract

A temperature measurement system is provided to measure temperatures using temperature sensors. The temperature measurement system may include a controller having a plurality of address lines, a sensor configured to provide a plurality of inputs, and a connector configured to accept the inputs from the sensor. The temperature measurement system may also include a first multiplexer coupled with at least one input from the sensor and including a plurality of selector lines, and a second multiplexer coupled with one or more other inputs from the sensor and including a plurality of selector lines. The selector lines of the second multiplexer may be respectively coupled to the address lines of the controller. The temperature measurement system may also include a selector logic device coupled between the selector lines of the first multiplexer and the address lines of the controller such that the at least one input coupled to the first multiplexer corresponds to a variable number of inputs from the one or more other inputs coupled to the second multiplexer.

Claims

1. A temperature measurement system, comprising:

a controller including a plurality of address lines;

a sensor configured to provide a plurality of inputs;

a connector configured to accept the inputs from the sensor;

a first multiplexer coupled with at least one input from the sensor and including a plurality of selector lines;

a second multiplexer coupled with one or more other inputs from the sensor and including a plurality of selector lines, wherein the selector lines of the second multiplexer are respectively coupled to the address lines of the controller; and

a logic device coupled between the selector lines of the first multiplexer and the address lines of the controller such that the at least one input coupled to the first multiplexer corresponds to a variable number of inputs from the one or more other inputs coupled to the second multiplexer.

2. The temperature measurement system according to claim 1, further including:

an amplifier, wherein a positive input of the amplifier is coupled to an output of the first multiplexer and a negative input of the amplifier is coupled to an output of the second multiplexer.

3. The temperature measurement system according to claim 2, wherein:

the controller is coupled to an output of the amplifier to accept signals corresponding to sensor measurement from the amplifier; and

the controller controls the logic device through a control line such that the logic device correlates the selector lines of the first multiplexer and the address lines of the controller based on the value of the control line.

4. The temperature measurement system according to claim 1, further including:

a current source coupled to an output of the first multiplexer to provide current to the sensor; and

a low pass filter coupled between the output of the first multiplexer and an output of the second multiplexer.

5. A temperature measurement system, comprising:

a connector configured to accept a plurality of temperature sensor channels, each having a first input and a second input;

a first multiplexer having a plurality of input lines respectively coupled to the first inputs of the plurality of temperature sensor channels;

a second multiplexer having a plurality of input lines respectively coupled to the second inputs of the plurality of temperature sensor channels;

a controller having address lines coupled to selector lines of the first multiplexer and selector lines of the second multiplexer; and

a logic device, coupled between the selector lines of the first multiplexer and the address lines, configured to correlate a first input selected by the first multiplexer with a variable number of second inputs selected by the second multiplexer.

6. The temperature measurement system according to claim 5, further including:

an amplifier, wherein a positive input of the amplifier is coupled to an output of the first multiplexer and a negative input of the amplifier is coupled to an output of the second multiplexer.

7. The temperature measurement system according to claim 5, wherein the controller controls the logic device through a control line such that the logic device correlates the selector lines of the first multiplexer and the address lines of the controller based on the control line.

8. The temperature measurement system according to claim 5, further including:

a current source coupled to an output of the first multiplexer to provide current to the plurality of temperature sensor channels.

9. The temperature measurement system according to claim 8, further including:

a low pass filter coupled between the output of the first multiplexer and an output of the second multiplexer.

10. The temperature measurement system according to claim 5, further including:

a plurality of current sources respectively coupled to the first inputs of the plurality of temperature sensor channels.

11. The temperature measurement system according to claim 10, further including:

a plurality of low pass filters respectively coupled between the respective first inputs and second inputs of the plurality of temperature sensor channels.

12. The temperature measurement system according to claim 6, further including:

a diagnostic circuit coupled between the positive input of the amplifier and the controller to provide connection information of one or more temperature sensors connected to the connector.

13. The temperature measurement system according to claim 5, wherein the controller further includes:

a flash memory device configured to store calibration information of one or more temperature sensors connected to the connector;

a processor configured to;

select a first channel from the plurality of temperature sensor channels for both the first multiplexer and the second multiplexer;

select a second channel from the plurality of temperature sensor channels for the second multiplexer; and

obtain sensor information based on voltage information between the first input and the second input of the first channel and voltage information between the first input of the first channel and the second input of the second channel.

14. The temperature measurement system according to claim 5, wherein the logic device correlates the first input of a first temperature sensor channel with the second input of the first temperature sensor channel and the second input of a second temperature sensor channel.

15. A method used by a controller for temperature measurement, comprising:

selecting a first temperature sensor channel corresponding to a first input and a second input of a temperature sensor by setting a first value for a plurality of address lines;

obtaining a first voltage information between the first input and the second input;

selecting a second temperature sensor channel corresponding to a third input of the temperature sensor by setting a second value for the plurality of address lines;

selectively combining the first channel and the second channel to obtain a second voltage information between the first input and the third input; and

determining a detection voltage of the temperature sensor based on the first voltage information and the second voltage information.

16. The method according to claim 15, further including:

calibrating the temperature sensor; and

storing calibrating information in a flash memory device.

17. The method according to claim 15, further including:

determining a connection condition of the temperature sensor by using a diagnostic circuit.

18. The method according to claim 15, further including:

calculating a temperature reading based on the detection voltage.

19. A work machine, comprising:

an engine configured to provide power to the work machine;

a plurality of sensors configured to measure temperature; and

a temperature measurement system configured to accept the plurality of sensors for temperature measurement, wherein the temperature measurement system includes;

a controller;

a connector configured to accept inputs from a sensor;

a first multiplexer coupled with at least one input from the sensor;

a second multiplexer coupled with one or more other inputs from the sensor, wherein selector lines of the second multiplexer are respectively coupled to address lines of the controller; and

a logic device coupled between selector lines of the first multiplexer and the address lines of the controller such that the at least one input coupled to the first multiplexer corresponds to a variable number of inputs from the one or more other inputs coupled to the second multiplexer.

20. The work machine according to claim 19, wherein the controller further includes:

a flash memory device configured to store calibrating information of the sensor.