Transmitter with internal serial bus
US4818994A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1987 |
| Grant date | Apr 4, 1989 |
| Priority date | — |
| Expiry date | Oct 22, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08C19/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
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 i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.