Diagnostics for resistance based transmitter
First Claim
1. A transmitter in a process control system, comprising:
- a resistance sensor sensing a process variable and providing a process variable output;
sensor monitoring circuitry coupled to the resistance sensor providing a secondary signal related to a condition of the resistance sensor;
analog to digital conversion circuitry coupled to the process variable output and the sensor monitoring circuitry and providing a digitized primary process variable output and a digitized secondary signal;
output circuitry coupled to a process control loop for transmitting a residual life estimate;
a memory storing a set of expected results related to the secondary signal and to the sensor; and
diagnostic circuitry coupled to the digitized secondary signal and to the memory, for providing the residual life estimate as a function of the expected results in the memory, the digitized process variable output and the digitized secondary signal.
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Accused Products
Abstract
Transmitter in a process control system includes a resistance sensor sensing a process variable and providing a sensor output. Sensor monitoring circuitry coupled to the sensor provides a secondary signal related to the sensor. Analog-to-digital conversion circuitry coupled to the sensor output and the sensor monitoring circuitry provides a digitized sensor output and a digitized secondary signal. Output circuitry coupled to a process control loop transmits a residual life estimate related to residual life of the sensor. A memory stores a set of expected results related to the secondary signal and to the sensor. Diagnostic circuitry provides the residual life estimate as a function of the expected results stored in the memory, the digitized sensor output and the digitized secondary signal.
229 Citations
22 Claims
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1. A transmitter in a process control system, comprising:
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a resistance sensor sensing a process variable and providing a process variable output; sensor monitoring circuitry coupled to the resistance sensor providing a secondary signal related to a condition of the resistance sensor; analog to digital conversion circuitry coupled to the process variable output and the sensor monitoring circuitry and providing a digitized primary process variable output and a digitized secondary signal; output circuitry coupled to a process control loop for transmitting a residual life estimate; a memory storing a set of expected results related to the secondary signal and to the sensor; and diagnostic circuitry coupled to the digitized secondary signal and to the memory, for providing the residual life estimate as a function of the expected results in the memory, the digitized process variable output and the digitized secondary signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for providing a residual life estimate of a sensor, the method comprising:
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sensing and digitizing a process variable output of the sensor to provide a digitized process variable sensor output; sensing and digitizing a property of the sensor related to the lifetime of the sensor to provide a digitized secondary output; storing an expected output related to the life of the sensor and the secondary output; and calculating a residual lifetime estimate as a function of the expected output, the digitized secondary output and the digitized primary process variable sensor output. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification