Abstract: A process fluid temperature calculation system includes a first temperature sensor disposed to measure an external temperature of a process fluid conduit. The process fluid temperature calculation system has a stem portion having a known thermal impedance. A second temperature sensor is spaced from the first temperature sensor by the stem portion. Measurement circuitry is coupled to the first and second temperature sensors. A microprocessor is coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to provide an estimate of temperature of process fluid within the process fluid conduit using a heat flux calculation.

Abstract: A process fluid temperature calculation system includes a first temperature sensor disposed to measure an external temperature of a process fluid conduit. The process fluid temperature calculation system has a stem portion having a known thermal impedance. A second temperature sensor is spaced from the first temperature sensor by the stem portion. Measurement circuitry is coupled to the first and second temperature sensors. A microprocessor is coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to provide an estimate of temperature of process fluid within the process fluid conduit using a heat flux calculation.

Abstract: A process fluid temperature estimation system includes a mounting assembly configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. A sensor capsule has at least one temperature sensitive element disposed therein. Measurement circuitry is coupled to the sensor capsule and configured to detect an electrical characteristic of the at least one temperature sensitive element that varies with temperature and provide sensor capsule temperature information. A controller is coupled to the measurement circuitry and is configured to obtain a reference temperature and employ a heat transfer calculation with the reference temperature, the sensor capsule temperature information and the known thermal conductivity of the process fluid conduit to generate an estimated process fluid temperature output.

Abstract: A process fluid temperature estimation system includes a mounting assembly, a sensor capsule, measurement circuitry, and a controller. The mounting assembly is configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. The sensor capsule has an end that is configured to contact the external surface of the process fluid conduit to form an interface having a contact region and an air gap. The sensor capsule also has at least one temperature sensitive element disposed therein. The measurement circuitry is coupled to the sensor capsule and configured to detect an electrical characteristic of the at least one temperature sensitive element that varies with temperature and provide at least process fluid conduit skin temperature information. The controller is coupled to the measurement circuitry and is configured to obtain the process fluid conduit skin temperature information from the measurement circuitry and to obtain reference temperature information.

Abstract: A process fluid temperature estimation system includes a mounting assembly that is configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. A sensor capsule has at least one temperature sensitive element disposed therein. Measurement circuitry is coupled to the sensor capsule and is configured to detect a characteristic of the at least one temperature sensitive element that varies with temperature and provide sensor capsule temperature information. A high temperature spacer has a known thermal conductivity and is configured to be interposed between the external surface of the process fluid conduit and the at least one temperature sensitive element.

Abstract: A pipe diagnostic system includes a sensor capsule, measurement circuitry and a controller. The sensor capsule is configured to be coupled to an exterior surface of a pipe and has at least one temperature sensitive element disposed therein. The measurement circuitry is coupled to the sensor capsule and is configured to measure an electrical characteristic of the at least one temperature sensitive element and provide an indication of the measurement. The controller is coupled to the measurement circuitry and is configured to obtain a transmitter reference measurement and employ a heat transfer calculation with the transmitter reference measurement and the indication to generate an estimated process fluid temperature. The controller is further configured to obtain an indication of process fluid temperature and provide a pipe diagnostic indication based on a comparison of the estimated process fluid temperature and the obtained indication of process fluid temperature.

Abstract: A sensor capsule for a heat flux sensor includes a hot end and a cold end. The sensor capsule includes a thermal conductor extending from the hot end toward the cold end, and a plurality of temperature sensors coupled to the thermal conductor at different distances from the hot end.

Abstract: A heat flow sensor configured to provide an indication of temperature relative to a process fluid is provided. The sensor comprises a first resistance temperature detector (RTD) element and a second RTD element spaced within a sheath from the first RTD element. The sensor also includes a set of leads comprising a first subset and a second subset, wherein the first subset is coupled to the first RTD element and the second subset is coupled to the second RTD element.

Abstract: A heat flow sensor configured to provide an indication of temperature relative to a process fluid is provided. The sensor comprises a first resistance temperature detector (RTD) element and a second RTD element spaced within a sheath from the first RTD element. The sensor also includes a set of leads comprising a first subset and a second subset, wherein the first subset is coupled to the first RTD element and the second subset is coupled to the second RTD element.

Abstract: A process fluid temperature measurement system includes a thermowell configured to couple to a process fluid conduit and extend through a wall of the process fluid conduit. A temperature sensor assembly is disposed within the thermowell and includes a first temperature sensitive element and a second temperature sensitive element. The first temperature sensitive element is disposed within the thermowell adjacent a distal end of the thermowell. The second temperature sensitive element is spaced apart from the first temperature sensitive element along a spacer having a known thermal conductivity. Transmitter circuitry is coupled to the first and second temperature sensitive elements and is configured to perform a heat flux calculation to provide a process fluid temperature output.

Abstract: A process fluid temperature calculation system includes a first temperature sensor disposed to measure an external temperature of a process fluid conduit. The process fluid temperature calculation system has a stem portion having a known thermal impedance. A second temperature sensor is spaced from the first temperature sensor by the stem portion. Measurement circuitry is coupled to the first and second temperature sensors. A microprocessor is coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to provide an estimate of temperature of process fluid within the process fluid conduit using a heat flux calculation.

Abstract: A thermal imaging system is provided. The thermal imaging system includes an explosion-proof housing with an optical window configured to contain an explosive pressure. The optical window allows electromagnetic thermal energy to pass. A thermal imaging sensor is disposed within the explosion-proof housing. Thermal imaging electronics are coupled to the thermal imaging sensor and configured to provide at least one thermal image based on a signal from the thermal imaging sensor. A lens assembly is disposed at least in front of the optical window external to the explosion-proof housing. A composite optical window for thermal imaging is also provided. In another embodiment, a thermal imaging system includes an explosion-proof housing having an optical window configured to contain an explosive pressure. An infrared (IR) camera is disposed within the explosion-proof housing. A reflector reflects electromagnetic thermal energy to the IR camera, but prevent an object from impacting the optical window.

Abstract: An explosion-proof thermal imaging system is provided. The system include an explosion-proof housing having a window that is configured to allow thermal radiation therethrough. An infrared camera is positioned within the explosion-proof housing and is disposed to receive and image thermal radiation that passes through the window. An emissivity target is disposed within a field of view of the infrared camera, but on an opposite side of the window from the infrared camera. A temperature sensor is operably coupled to the infrared camera and is configured to provide an indication of temperature proximate the emissivity target.

Abstract: A process temperature transmitter is operable with at least one temperature sensor having a plurality of leads. The temperature transmitter includes measurement circuitry operably coupleable to the at least one temperature sensor to provide an indication of an electrical parameter of the at least one temperature sensor. A controller is coupled to the measurement circuitry to obtain the indication and provide a process temperature output. A current source applies a test current to the plurality of leads simultaneously. Diagnostic circuitry measures a voltage response on each lead in order to provide a diagnostic indication of the temperature sensor.

Abstract: A preexisting voltage across a sensor is latched to a storage capacitor prior to any excitation current being applied to the sensor. Once the excitation current is applied, the voltage on the storage capacitor is directly subtracted from a differential voltage across the sensor. The subtraction is done before a measurement is converted to a digital value and passed to a transmitter. The subtraction is performed in hardware, and a time required to sample and hold the preexisting voltage across the storage capacitor is within a settling time used for collecting any sensor measurements.

Abstract: A process variable transmitter includes a memory that stores a filtered sensor value that is calculated based on a prior received sensor value and a filtered rate of change value that is calculated based on a prior rate of change value. The process variable transmitter also includes a controller that receives a sensor value and compares it to the filtered sensor value to obtain a rate of change value. The controller also compares the rate of change value to the filtered rate of change value to obtain a deviation value, and generates an output indication, such as a sensor failure warning output, based on the deviation value. This is done within the process variable transmitter.

Abstract: A process variable transmitter is used to measure a process variable, and, in doing so, dynamically changes the resolution of the A/D converter based upon the measured value of the analog input signal. This can be done by automatically adjusting the configurable resolution gain adjustment based on the value of the analog signal being measured, by normalizing the input signal being measured so that it is centered in an optimal resolution window of the A/D converter, or by adjusting a voltage reference provided to the A/D converter.

Abstract: A process variable transmitter controls a signal on a communication loop. A diagnostic component on the transmitter compares an expected signal level on the communication loop with an actual value to detect on-scale errors.

Abstract: A process variable transmitter for measuring a temperature of an industrial process, includes a first electrical connector configured to couple to a first wire of a thermocouple, the first electrical connector includes a first electrode and a second electrode. The first and second electrodes are configured to electrically couple to the first wire of the thermocouple. A second electrical connector is configured to couple to a second wire of the thermocouple, the second electrical connector includes a third electrode and a fourth electrode. The third and fourth electrodes are configured to electrically couple to the second wire of the thermocouple. The second wire is of a different material than the first wire. Measurement circuitry is coupled to the first and second electrical connectors configured to provide an output related to a temperature of the thermocouple.

Abstract: A process temperature transmitter is operable with at least one temperature sensor having a plurality of leads. The temperature transmitter includes measurement circuitry operably coupleable to the at least one temperature sensor to provide an indication of an electrical parameter of the at least one temperature sensor. A controller is coupled to the measurement circuitry to obtain the indication and provide a process temperature output. A current source applies a test current to the plurality of leads simultaneously. Diagnostic circuitry measures a voltage response on each lead in order to provide a diagnostic indication of the temperature sensor.