Frequency feedback on a current loop of a current-to-pressure converter
US4665938A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1986 |
| Grant date | May 19, 1987 |
| Priority date | — |
| Expiry date | Sep 30, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/7761
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A current-to-pressure (I/P) converter provides an output pressure as a function of the magnitude of a variable input DC current. The I/P converter includes a pressure sensor which produces a feedback signal representative of the output pressure. Based upon the feedback signal and the magnitude of the input DC current, an electrical control signal is produced which controls a device for varying the output pressure. The I/P converter also includes a circuit for generating a time-varying signal which is sent back over the current loop wires through which the input DC current flows. The time-varying signal provides an indication of whether the I/P converter is functioning properly. This permits diagnosis of possible causes of control system malfunctions without having to inspect the I/P converter itself.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.