Two-wire process control loop diagnostics
First Claim
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1. A diagnostic device for coupling to a two-wire process control loop of an industrial process control or monitoring system, comprises:
- digital communication circuitry configured to receive a digital communication signal from the two-wire process control loop, the digital communication signal comprising a digitally modulated analog signal on the two-wire process control loop which is modulated to a plurality of discrete analog signal levels representative of digital values; and
diagnostic circuitry configured to diagnose operation of the two-wire process control loop based upon the digitally modulated analog signal.
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Abstract
A diagnostic device for coupling to a process control loop includes digital communication circuitry configured to receive a digital communication signal from the process control loop. The digital communication signal is a digitally modulated analog signal on the process control loop which is modulated to a plurality of discrete analog signal levels representative of digital values. Diagnostic circuitry diagnoses operation of the process control loop which may include field devices of the process control loop based upon the digitally modulated analog signal.
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Citations
25 Claims
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1. A diagnostic device for coupling to a two-wire process control loop of an industrial process control or monitoring system, comprises:
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digital communication circuitry configured to receive a digital communication signal from the two-wire process control loop, the digital communication signal comprising a digitally modulated analog signal on the two-wire process control loop which is modulated to a plurality of discrete analog signal levels representative of digital values; and diagnostic circuitry configured to diagnose operation of the two-wire process control loop based upon the digitally modulated analog signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for diagnosing a two-wire process control loop of the type used in an industrial process control or monitoring system, comprising:
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receiving digital communication signals from a plurality of devices coupled to the two-wire process control loop, the digital communication signals comprising a digitally modulated analog signal which is modulated to a plurality of discreet analog signal levels representative of digital values; measuring a property of the digitally modulated analog signal; diagnosing operation of the two-wire process control loop based upon the measured property of the digitally modulated analog signal; and providing an output based upon the diagnosing. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification