System and method for calibrating a control system operating an electric heater

Patent metadata

Field	Value
Publication number	US-12004267-B2
Application number	US-202016894236-A
Country	US
Kind code	B2
Filing date	Jun 5, 2020
Priority date	Jun 7, 2019
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

A method for calibrating a control system configured to control a two-wire heater includes providing power to a load electrically coupled to the control system, generating, an initial measured characteristic and a calibrated measured characteristic of the load by the control system and a controller calibration system, respectively. The method further includes defining a calibrated measurement reference based on a correlation of the initial measured characteristic and the calibrated measured characteristic. With the calibrated measure reference, the control system is further calibrated to define a resistance-temperature calibration reference for determining a working temperature of the two-wire heater based on a measured resistance of the two-wire heater.

First claim

What is claimed is:

1. A method for calibrating a control system configured to control a two-wire heater, the two-wire heater being operable to generate heat and to function as a sensor for measuring electrical characteristics of the two-wire heater, the method comprising:
providing, by the control system, power to a load electrically coupled to the control system;
generating, by the control system, an initial measured characteristic of the load, wherein the initial measured characteristic is indicative of an electrical characteristic of the load, wherein the electrical characteristic of the load includes a voltage, a current, a resistance, or a combination thereof;
generating, by a controller calibration system coupled to the load, a calibrated measured characteristic of the load that is indicative of the electrical characteristic of the load, wherein the controller calibration system is separate from the control system, and wherein the calibrated measured characteristic is generated concurrently with the initial measured characteristic;
correlating the initial measured characteristic with the calibrated measured characteristic; and
defining a calibrated measurement reference based on the correlation of the initial measured characteristic and the calibrated measured characteristic, wherein the control system employs the calibrated measurement reference to provide precise measurements for controlling the two-wire heater.

2. The method of claim 1 , wherein:
generating, by the control system, the initial measured characteristic further comprises measuring, by the control system, an initial voltage and an initial current of the load, wherein the initial measured characteristic includes the initial voltage and the initial current, and
generating, by the controller calibration system coupled to the load, the calibrated measured characteristic further comprises measuring, by the controller calibration system, a calibrated voltage and a calibrated current of the load, wherein the calibrated measured characteristic includes the calibrated voltage and the calibrated current,
wherein the initial voltage and the calibrated voltage are concurrently measured, and the initial current and the calibrated current are concurrently measured.

3. The method of claim 2 further comprising:
calculating an initial resistance of the load based on the initial voltage and the initial current of the load, wherein the initial measured characteristic further includes the initial resistance; and
calculating a calibrated resistance of the load based on the calibrated voltage and the calibrated current of the load, wherein the calibrated measured characteristic further includes the calibrated resistance.

4. The method of claim 1 , wherein:
the power is provided to the load at a plurality of power setpoints,
for each of the plurality of power setpoints, the initial measured characteristic is generated by the control system and the calibrated measured characteristic is generated by the controller calibration system to provide a plurality of initial measured characteristics and a plurality of calibrated measured characteristics,
the plurality of initial measured characteristics is correlated with the plurality of calibrated measured characteristics, and
the calibrated measurement reference is defined based on the correlation of the plurality of initial measured characteristics and the plurality of calibrated measured characteristics.

5. The method of claim 1 , wherein the load is a controllable load having an adjustable resistance, wherein the method further comprises:
setting the resistance of the load to a plurality of resistance setpoints, wherein,
for each of the plurality of resistance setpoints, the initial measured characteristic is generated by the control system and the calibrated measured characteristic is generated by the controller calibration system to provide a plurality of initial measured characteristics and a plurality of calibrated measured characteristics,
the plurality of initial measured characteristics is correlated with the plurality of calibrated measure characteristics, and
the calibrated measurement reference is defined based on the correlation of the plurality of initial measured characteristics and the plurality of calibrated measured characteristics.

6. The method of claim 1 , with the control system electrically coupled to the two-wire heater, the method further comprises:
controlling, by the control system, the two-wire heater to a temperature setpoint from among a plurality of temperature setpoints;
concurrently acquiring voltage and current (V-I) characteristics of the two-wire heater from the control system and temperature dataset of the two-wire heater from a temperature sensor system, wherein the V-I characteristics and the temperature dataset are acquired for each of the plurality of temperature setpoints;
determining, for each of the plurality of temperature setpoints, a resistance of the two-wire heater based on the V-I characteristics acquired and the calibrated measurement reference;
calculating, for each of the plurality of temperature setpoints, a temperature metrology data based on the temperature dataset acquired;
correlating the resistances of the two-wire heater and the temperature metrology data for the plurality of temperature setpoints; and
defining a resistance-temperature calibration reference for determining a working temperature of the two-wire heater based on a measured resistance of the two-wire heater.

7. The method of claim 6 , wherein acquiring the V-I characteristics of the two-wire heater from the control system and the temperature dataset of the two-wire heater from the temperature sensor system further comprises:
measuring, by a sensor circuit of the control system, the V-I characteristics of the two-wire heater; and
measuring, by the temperature sensor system, a plurality of temperature measurements of the two-wire heater at the temperature setpoint, wherein the plurality of temperature measurements is provided as the temperature dataset for the temperature setpoint.

8. The method of claim 6 , wherein the temperature metrology data includes a mean temperature, a median temperature, a temperature variance, a standard deviation, a maximum temperature, a minimum temperature, a temperature range, a 3-sigma value, or a combination thereof.

9. The method of claim 1 , wherein the load is an active load bank operable to set a known resistance.

10. A method for calibrating a control system with a controller calibration system separate from the control system, wherein the control system is configured to control a heater, the heater being operable to generate heat and to function as a sensor for measuring electrical characteristics of the heater, the method comprising:
generating, by the controller calibration system coupled to a load, a calibrated measured characteristic of the load that is indicative of an electrical characteristic of the load, wherein the calibrated measured characteristic is generated concurrently with an initial measured characteristic;
correlating the initial measured characteristic with the calibrated measured characteristic; and
defining a calibrated measurement reference based on the correlation of the initial measured characteristic and the calibrated measured characteristic, wherein the control system employs the calibrated measurement reference to provide precise measurements for controlling the heater.

11. The method of claim 10 , wherein:
generating, by the control system, the initial measured characteristic further comprises measuring, by the control system, an initial voltage and an initial current of the load, whe

Assignees

• Watlow Electric Mfg

Inventors

• Yender Matthew
• Geer Brian
• Meech Eric
• Breitlow Stanton H
• Kidney Adam

Classifications

• H10P72/0602

  Temperature monitoring · CPC title

• H10P72/0432

  mainly by conduction · CPC title

• H05B1/023 Primary

  Industrial applications · CPC title

• H05B3/26

  heating conductor mounted on insulating base {(for transparent areas H05B3/84, H05B3/86)} · CPC title

• H05B1/0233 Primary

  for semiconductors manufacturing · CPC title