Method of operation an in SITU process probe

1. A method of controlling a temperature of a process combustion transmitter, the method comprising:

detecting an operating temperature of a process probe of the process combustion transmitter, the process probe being disposed within a flow of process combustion exhaust, the process probe having a measurement cell with an operating temperature that is above a flashpoint of process combustion fuel, wherein the process probe includes a heater configured to heat the measurement cell to the operating temperature;

comparing, using electronic circuitry coupled to the measurement cell, the indication of the detected operating temperature to a predetermined heater shutoff threshold;

de-energizing the heater power upon detecting that the heater shutoff threshold has been reached, such that combustion is a sole heat source for the measurement cell;

receiving a reset signal; and

in response to the received reset signal, re-engaging the heater power.

2. The method of claim 1 , wherein the measurement cell includes an oxygen sensor.

3. The method of claim 2 , wherein the oxygen sensor is a heated sensor with an operating temperature at or above 700 degrees Celsius.

4. The method of claim 1 , wherein the reset signal is generated locally at the process combustion transmitter.

5. The method of claim 1 , wherein the electronic circuitry is configured to receive the reset signal via a process communication loop.

6. A method of operating an in situ process combustion transmitter having a measurement cell with an operating temperature above a flashpoint of combustion fuel, the method comprising:

initializing the transmitter, wherein initializing comprises instructing the transmitter to begin providing a process combustion variable output and to heat the measurement cell to the operating temperature;

receiving a temperature measurement, from the transmitter, of a process probe containing the measurement cell, wherein the temperature is measured using a temperature sensor separate from the measurement cell;

determining whether the measured temperature has reached a heater shutoff threshold by comparing the measured temperature to the heater shutoff threshold; and

latching the heater in a de-energized state based on the determination that the measured temperature has reached the heater shutoff threshold such that only a process heat source provides heat to the measurement cell while the transmitter provides the process combustion variable output, and wherein latching the heater in the de-energized state comprises placing the heater in an off condition until a reset signal is received.

7. The method of claim 6 , wherein determining whether the measured temperature has reached a heater shutoff threshold is performed by the process combustion transmitter.

8. The method of claim 6 , wherein the operating temperature is about 700 degrees Celsius.

9. The method of claim 6 , wherein the process combustion variable output is indicative of an oxygen content in combustion exhaust.

10. The method of claim 6 , wherein initializing the process combustion transmitter includes providing a reset signal to the process combustion transmitter.

11. The method of claim 10 , wherein the reset signal is provided locally to the process combustion transmitter.

12. The method of claim 10 , wherein the reset signal is provided to the process combustion transmitter over a process communication channel.

13. The method of claim 1 , wherein the reset signal comprises a command from a technician.

14. The method of claim 1 , wherein the process combustion variable output is provided regardless of an energized state of the heater power.