Digitally modified resistive output for a temperature sensor
View Patent ↗A method for digitally controlling the resistive output of a temperature probe is disclosed. The system is comprised of a temperature sensor, a processor and a means under the control of the processor for modifying the resistive output such as a digital potentiometer. In one embodiment, the processor reads the temperature sensor and adjusts the potentiometer based on a correlative or predictive technique so as to provide a modified output that matches that of a standard resistive temperature probe and is compatible for display on a multiparameter monitor.
1. An interface for a monitor and a temperature probe including a temperature sensor comprising:
a logic circuit for determining a modified resistive output for the temperature sensor and
a means for providing the modified resistive output, wherein the means for providing the modified resistive output is compatible with the monitor such that the monitor can display a temperature that corresponds to the modified resistive output from the temperature probe, said means including a FET coupled to said logic circuit via a first terminal and via a feedback arrangement, said means providing a FET resistance corresponding to the modified resistive output.
2. The interface of claim 1 wherein the logic circuit is programmed to execute a predictive or a correlative algorithm.
3. The interface of claim 2 wherein the logic circuit is a microprocessor.
4. A temperature probe comprising:
a temperature sensor having a resistive output,
a processor for determining a modified resistive output for the temperature sensor, the processor being programmed to execute a predictive or a correlative algorithm, and
a FET for providing the modified resistive output in response to a signal from the processor,
wherein the algorithm is a predictive algorithm that converts the resistive output of the temperature sensor during a thermally unstable condition to a modified resistive output representative of a predicted temperature during a condition of thermal stability.
5. The temperature probe of claim 4 wherein the processor executes an algorithm to convert the resistive output of the temperature sensor to a modified resistive output that can be displayed by a monitor.
6. The temperature probe of claim 4 wherein the probe includes two FETs.
7. A method for digitally modifying the resistive output of a temperature sensor which comprises inputting the resistive output from the temperature sensor to a logic circuit, implementing a predictive or a correlative algorithm using the logic circuit to determine a modified resistive output, controlling a gate of a FET to adopt a setting corresponding to the modified resistive output, and outputting a resistance corresponding to the modified resistive output.
8. The method of claim 7 further including measuring a FET voltage with a first amplifier, measuring a resistor voltage of a first resistor having a first resistance, calculating a FET current using the first resistance and the resistor voltage, calculating a FET resistance using the FET voltage and the FET current, comparing the FET resistance to the modified resistive output and applying a difference between the FET resistance and the modified resistive output as a negative feedback to the gate.
9. A temperature probe comprising:
a temperature sensor that provides a resistive output,
a logic circuit for determining a modified resistive output for the temperature sensor, and
a means for providing the modified resistive output including a FET,
wherein the logic circuit is a microprocessor programmed to execute a predictive or a correlative algorithm, and
wherein the microprocessor includes an output and the FET includes a gate, where the output of the microprocessor controls the gate of the FET such that the FET provides a FET resistance corresponding to the modified resistive output.
10. The temperature probe of claim 9 wherein the microprocessor further includes:
a first input from a first amplifier, where the first amplifier measures a FET voltage of the FET, and
a second input from a second amplifier, where the second amplifier measures a resistor voltage of a resistor having a first resistance,
where the microprocessor calculates a FET current using the first resistance and the resistor voltage from the second input, calculates a FET resistance using the FET voltage from the first input and the FET current, compares the FET resistance to the modified resistive output and applies a difference between the FET resistance and the modified resistive output as a negative feedback to the gate.
11. An interface for a monitor and a temperature probe including a temperature sensor comprising:
a logic circuit for determining a modified resistive output for the temperature sensor and
a means for providing the modified resistive output, wherein the means for providing the modified resistive output includes a FET, and
wherein the logic circuit includes an output and the FET includes a gate, where the output of the logic circuit controls the gate of the FET such that the FET provides a FET resistance corresponding to the modified resistive output.
12. The interface of claim 11 wherein the logic circuit further includes:
a second input from a second amplifier, where the second amplifier measures a resistor voltage of a resistor having a first resistance,
where the logic circuit calculates a FET current using the first resistance and the resistor voltage from the second input, calculates a FET resistance using the FET voltage from the from the first input and the FET current, compares the FET resistance to the modified resistive output and applies a difference between the FET resistance and the modified resistive output as a negative feedback to the gate.
13. A temperature probe comprising:
a temperature sensor having a resistive output,
a processor for determining a modified resistive output for the temperature sensor, the processor being programmed to execute a predictive or a correlative algorithm, and
a FET for providing the modified resistive output in response to a signal from the processor,
wherein the processor includes an output and the FET includes a gate, where the output of the processor controls the gate of the FET such that the FET provides a FET resistance corresponding to the modified resistive output.
14. temperature probe of claim 13 wherein the processor further includes:
a first input from a first amplifier, where the first amplifier measure a FET voltage of the FET, and
a second input from a second amplifier, where the second amplifier measures a resistor voltage of a resistor having a first resistance,
where the processor calculates a FET current using the first resistance and the resistor voltage from the second input, calculates a FET resistance using the FET voltage from the first input and the FET current, compares the FET resistance to the modified resistive output and applies a difference between the FET resistance and the modified resistive output as a negative feedback to the gate.