Transmitter with internal serial bus
First Claim
1. A transmitter comprising:
- a serial bus;
a detector module connected to the serial bus and including;
a plurality of sensing means for coupling serial sensor signals representative of sensed parameters to the serial bus, one of the sensing means being capable of providing an interrupt signal over the serial bus to indicate when a sensing means has a digital signal to be sent; and
means for selectively enabling the plurality of sensing means, in a selected order, to send their digital signals over the serial bus; and
an output module connected to the serial bus and including;
digital computer means for processing the digital sensor signals to produce a control signal; and
means for producing a transmitter output signal as a function of the control signal.
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Accused Products
Abstract
An industrial process control transmitter has a modular construction, with a detector module and an output module electrically connected together by a serial bus. The output module includes a microcomputer, a modem for digital communication over the two-wire loop, analog output circuitry for controlling loop current, a digital-to-analog converter, and a memory for storing calibration factors and D/A characterization factors.
The detector module includes several sensors with associated circuitry to convert the sensor signals to digital signals. The detector module also includes a memory which contains characterization factors unique to the sensors which can be used by the microcomputer to correct the digital values provided by the detector circuitry. The microcomputer of the output module is considered the master unit, and all of the circuits of the detector board which interface with the serial bus are considered slave units. Data is collected by the microcomputer when a selected detector circuit provides an interrupt over the serial bus. The microcomputer then provides a select signal requesting data. The detector module provides data from the sensor circuits in a selected order in response to the select signal.
147 Citations
15 Claims
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1. A transmitter comprising:
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a serial bus; a detector module connected to the serial bus and including; a plurality of sensing means for coupling serial sensor signals representative of sensed parameters to the serial bus, one of the sensing means being capable of providing an interrupt signal over the serial bus to indicate when a sensing means has a digital signal to be sent; and means for selectively enabling the plurality of sensing means, in a selected order, to send their digital signals over the serial bus; and an output module connected to the serial bus and including; digital computer means for processing the digital sensor signals to produce a control signal; and means for producing a transmitter output signal as a function of the control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A transmitter providing a transmitter output representative of a process fluid pressure, comprising:
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isolator means having an isolator diaphragm coupled between a process fluid and an isolator fluid for isolatingly coupling the pressure therebetween; a plurality of pressure sensors receiving the pressure from the isolator fluid and providing a plurality of sensor outputs indicative of pressure over pressure ranges of different magnitudes for each sensor; selection means coupled to the sensor outputs for selecting the sensor output of a sensor having a pressure range including the present process fluid pressure; correction means in the transmitter for providing a corrected sensor output as a function of correction data stored in the correction means and the selected sensor output; and output means coupled to the correction means for providing the transmitter output as a function of the corrected sensor output. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification