Two-wire transmitter
AssigneeAction Instruments Company, Inc.
InventorDavid J. Mate
Life of this patent
Estimating the term…
Abstract
Disclosed is a two-wire transmitter which transmits information over a pair of wires having an external supply connected thereto. The transmitter receives its power from the pair of wires and stores a portion of this power during spaced apart first time intervals. This stored power is used to excite an external sensor during second time intervals that are substantially shorter than the first time intervals and which lie between respective ones of the first time intervals. The excitation response from the sensor is sampled and held in synchronization with this excitation. A variable resistance device is included for insertion in series with the pair of wires. This device is responsive to the held excitation response from the sensor to allow a current representative thereof to flow through the pair of wires.
Claims10
A two-wire transmitter for tramsitting information via a pair of wires having an external power supply connected thereto, said transmitter comprising;
- means for receiving a predetermined amount of power via said pair of wires from said external power supply;
- means for storing a portion of said received power during spaced apart first time intervals;
- means for exciting an external sensor with said stored power during second tie intervals that are substantially shorter than said first time intervals and are spaced between respective ones of said first time intervals;
- means for sampling and holding the excitation output of said sensor in synchronization with said excitation thereof;
- and
- variable resistance means for insertion in series with said pairs of wires and responsive to said held excitation output from said sensor to allow a current representative thereof to flow through said pairs of wires.
A method of transmitting information via a two-wire transmitter comprised of the steps of:
- receiving a predetermined amount of power from a pair of wires having an external power supply connected thereto;
- storing a portion of said received power during spaced apart first time intervals;
- exciting an external sensor with said stored power during second time intervals that are substantially shorter than said first time intervals and are spaced between respective ones of said first time intervals;
- sampling and holding the response of said sensor in synchronization with said excitation thereof;
- and
- varying the resistance of a device in series with said pair of wires such that a current representative of said held response from said sensor flows through said wires.
Dependencies are inferred from the claim text.