Sensor communication system
US4567466A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1982 |
| Grant date | Jan 28, 1986 |
| Priority date | — |
| Expiry date | Dec 8, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K7/08
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A sensor communication system uses a shared analog signal to duty cycle converter for producing a comparison between a predetermined free-running triangular waveshape and a selected output signal from a plurality of analog signal sources such as process sensors, to convert the amplitude of the analog signal to a variable duty cycle signal. The variable duty cycle signal is subsequently converted to a digital signal which may be represented by a count stored in a counter counting clock pulses during the occurrence of the pulse width waveshape of the variable duty cycle signal. The digital signal is utilized as a digital word by a microprocessor operating in accordance with a stored program to produce a characterized digital output signal for use in a communication after conversion to a 4-20 ma control signal for communication and control in an industrial process control system. One of the signal sources may be from a circuit having temperature and time drift components whereby the corresponding digital word is used by the microprocessor to compensate the digital words from the other analog signal sources.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.