# US 10,502,608 B2 · Through air radar level transmitter with galvanic isolation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,608 B2 - Document ID: US10502608B2 - Status: Granted - Kind: B2 - Application number: 15/676,170 - Filed: 2017-08-14 - Published: 2018-07-26 - Granted: 2019-12-10 - Earliest claimed: 2017-01-24 - Assignees: Magnetrol International, Incorporated - Applicants: Magnetrol International, Incorporated - Inventors: Kevin M. Haynes; Timothy S. Sussman - Web page: https://patentgrep.com/patent/US10502608B2 ## CPC - G01F 23/284: Electromagnetic waves - B08B 3/08: the liquid having chemical or dissolving effect - B08B 5/02: Cleaning by the force of jets, e.g. blowing-out cavities {(airguns or nozzles per se B05B1/005)} - G01S 7/003: {Transmission of data between radar, sonar or lidar systems and remote stations} - G01S 13/10: using transmission of interrupted, pulse modulated waves (determination of distance by phase measurement G01S13/32) - G01S 13/88: Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) - G08C 19/02: in which the signal transmitted is magnitude of current or voltage (G08C19/36, G08C19/38 take precedence) - H01Q 1/22: by structural association with other equipment or articles - H01Q 1/225: {used in level-measurement devices, e.g. for level gauge measurement} - H01Q 13/06: Waveguide mouths (horns H01Q13/02) - H01Q 19/08: for modifying the radiation pattern of a radiating horn in which it is located {(corrugated horns H01Q13/0208; producing a circular polarisation H01Q13/0241)} - H02J 50/10: using inductive coupling - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - G01S 7/027: {Constructional details of housings, e.g. form, type, material or ruggedness} - H01Q 13/02: Waveguide horns - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G08C: TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS (fluid pressure transmitting systems F15B; mechanical means for transferring the output of a sensing member into a different variable G01D5/00; mechanical control systems G05G) - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A loop powered process instrument comprises a control system measuring a process variable and developing a measurement signal representing the process variable. A two-wire circuit, for connection to a remote power source using a two-wire process loop, controls current on the loop in accordance with the measurement signal. A power supply with galvanic isolation is connected to the two-wire circuit and the control system to isolate the two-wire circuit from the control system. The power supply receives power from the two-wire process loop and supplies power to the control system. The power supply comprises a voltage regulator receiving loop power and developing a regulated output voltage. A current switching circuit receives the regulated output voltage and drives a primary of a transformer. A secondary of the transformer is coupled to the control system. A voltage shift control includes an isolator circuit driven by the control system for controlling voltage supplied by the voltage regulator. ## Claims ### Claim 1 A loop powered process control instrument comprising: a control system measuring a process variable and developing a measurement signal representing the process variable; a two-wire circuit, for connection to a remote power source using a two-wire process loop, for controlling current on the loop in accordance with the measurement signal; and a power supply with galvanic isolation, connected to the two-wire circuit and the control system to isolate the two-wire circuit from the control system, for receiving power from the two-wire process loop and supplying power to the control system, wherein the power supply comprises a voltage regulator receiving loop power and developing a regulated output voltage, a current switching circuit receiving the regulated output voltage and driving a primary of a transformer, with a secondary of the transformer coupled to the control system, and a voltage shift control circuit including an isolator circuit driven by the control system for controlling voltage supplied by the voltage regulator. ### Claim 2 (depends on 1) The loop powered process instrument of claim 1 wherein the voltage shift control circuit shifts the voltage regulator voltage to a higher value at lower current levels and to a lower value at higher current levels. ### Claim 3 (depends on 1) The loop powered process instrument of claim 1 wherein the isolator circuit comprises an optical coupler controlled by the control system. ### Claim 4 (depends on 1) The loop powered process instrument of claim 1 wherein the voltage supplied by the voltage regulator is set by plural voltage reference devices and an optical coupler controlled by the control system selectively shifts the voltage. ### Claim 5 (depends on 1) The loop powered process instrument of claim 1 wherein the voltage supplied by the voltage regulator is set by plural voltage reference devices and a plurality of optical couplers controlled by the control system selectively shifts the voltage. ### Claim 6 (depends on 1) The loop powered process instrument of claim 1 wherein the current switching circuit drives the primary of the transformer to provide a one-to-one current ratio of transformer primary current to secondary current. ### Claim 7 (depends on 6) The loop powered process instrument of claim 6 wherein the current switching circuit comprises a switching oscillator of a DC-DC converter circuit and the oscillator drives the primary of the transformer. ### Claim 8 (depends on 7) The loop powered process instrument of claim 7 wherein switching frequency of the switching oscillator is about 150 kHz to pass lower frequency communication signals. ### Claim 9 (depends on 1) The loop powered process instrument of claim 1 wherein the control system controls loop current at the secondary of the transformer. ### Claim 10 (depends on 1) The loop powered process instrument of claim 1 further comprising a dual compartment housing and the two-wire, and the power supply are in an explosion proof compartment of the housing and the control system is in an intrinsically safe compartment of the housing. ### Claim 11 A two-wire transmitter comprising: a dual compartment housing defining a wiring compartment and a control compartment; a control system in the control compartment including a signal processing circuit measuring a process variable and developing a measurement signal representing the process variable; and a two-wire circuit and a power supply in the wiring compartment, the two-wire circuit for connection to a remote power source using a two-wire process loop, for controlling current on the loop in accordance with the measurement signal, the power supply being connected to the two-wire circuit and the control system to isolate the two-wire circuit from the control system, for receiving power from the two-wire process loop and supplying power to the control system, wherein the power supply comprises a voltage regulator receiving loop power and developing a regulated output voltage, a current switching circuit receiving the regulated output voltage and driving a primary of a transformer, with a secondary of the transformer coupled to the control system, and a voltage shift control circuit including an isolator circuit driven by the control system for controlling voltage supplied by the voltage regulator. ### Claim 12 (depends on 11) The two-wire transmitter of claim 11 wherein the voltage shift control circuit shifts the voltage regulator voltage to a. higher value at lower current levels and to a lower value at higher current levels. ### Claim 13 (depends on 11) The two-wire transmitter of claim 11 wherein the isolator circuit comprises an optical coupler controlled by the control system. ### Claim 14 (depends on 11) The two-wire transmitter of claim 11 wherein the wherein the voltage supplied by the voltage regulator is set by plural voltage reference devices and an optical coupler controlled by the control system selectively shifts the voltage. ### Claim 15 (depends on 11) The two-wire transmitter of claim 11 wherein the voltage supplied by the voltage regulator is set by plural voltage reference devices and a plurality of optical couplers controlled by the control system selectively shift the voltage. ### Claim 16 (depends on 11) The two-wire transmitter of claim 11 wherein the current switching circuit drives the primary of the transformer to provide a one-to-one current ratio of transformer primary current to secondary current. ### Claim 17 (depends on 16) The two-wire transmitter of claim 16 wherein the current switching circuit comprises a switching oscillator of a DC-DC converter circuit and the oscillator drives the primary of the transformer. ### Claim 18 (depends on 17) The two-wire transmitter of claim 17 wherein switching frequency of the switching oscillator is about 150 kHz to pass lower frequency communication signals. ### Claim 19 (depends on 11) The two-wire transmitter of claim 11 wherein the control system controls loop current at the secondary of the transformer. ### Claim 20 (depends on 11) The two-wire transmitter of claim 11 wherein the wiring compartment comprises an explosion proof compartment and the control compartment comprises an intrinsically safe compartment.