Field device charging power regulation

• US 10,461,562 B2
• Filed: 06/27/2017
• Issued: 10/29/2019
• Est. Priority Date: 06/27/2017
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Wienhold, Nicholas Aaron, Wyman, Matthew David, Bronczyk, Andrew James
• Primary Examiner(s): Williams, Arun C
• Application Number:
  US15/634,339
• Publication Number:
  US 20180375363A1
• Time in Patent Office: 854 Days
• Field of Search: 320107
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/25428 Field device
• CPC Class Codes: G05F 1/613 using semiconductor devices in parallel with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A field device for an industrial process includes device circuitry, a shunt circuit, a bulk supply a charging power regulator and a supplemental circuit. The device circuitry is configured to receive power and communicate data over a two-wire process control loop. The shunt circuit is configured to shunt an unused portion of the power to an electrical ground. The charging power regulator is configured to regulate an excess portion of the power to charge the bulk supply based on the unused portion. The supplemental circuit is powered by the bulk supply.

Claims

1. A field device for an industrial process comprising:

device circuitry configured to receive power and communicate data over a two-wire process control loop;

a shunt circuit configured to shunt an unused portion of the power to an electrical ground;

a bulk supply;

a charging power regulator configured to regulate an excess portion of the power to charge the bulk supply based on a magnitude of the unused portion; and

a supplemental circuit powered by the bulk supply.

2. The device according to claim 1, wherein the charging power regulator comprises:

a variable impedance connecting a supply voltage to the bulk supply, wherein the excess portion of the power delivered to the bulk supply varies based on the variable impedance; and

an impedance regulator configured to adjust the variable impedance to regulate the excess portion of the power based on the unused portion.

3. The device according to claim 2, wherein:

the shunt circuit comprises a resistance; and

the impedance regulator adjusts the variable impedance based on a voltage drop across the resistance.

4. The device according to claim 3, wherein:

the impedance regulator outputs a control signal based on the voltage drop across the resistance; and

the variable impedance includes a transistor that adjusts the variable impedance based on the control signal.

5. The device according to claim 2, wherein:

the bulk supply comprises a capacitor having an associated time constant; and

the impedance regulator controls the time constant based on the unused portion of the power.

6. The device according to claim 1, wherein the bulk supply comprises a battery.

7. The device according to claim 1, further comprising a comparator having a charge output indicating an electrical charge of the bulk supply, wherein a controller of the device circuitry controls an activation of the supplemental circuit based on the charge output.

8. The device according to claim 1, further comprising at least one of:

a sensor configured to sense a process parameter; and

a control element configured to control a process.

9. The device according to claim 8, wherein the device circuitry comprises at least one of:

measurement circuitry configured to process an output from the sensor indicative of the process parameter; and

control circuitry configured to control the control element.

10. The device according to claim 1, wherein the supplemental circuit is configured to communicate data to an external device.

11. The device according to claim 10, wherein the supplemental circuit is configured to communicate data to the external device in accordance with a Bluetooth communication protocol.

12. A method of operating a field device for an industrial process, the field device including device circuitry, a shunt circuit, a bulk supply, a charging power regulator, and a supplemental circuit, the method comprising:

receiving power and communicating data over a two-wire process control loop using the device circuitry;

shunting an unused portion of the power to an electrical ground using the shunt circuit;

regulating an excess portion of the power to charge the bulk supply based on a magnitude of the unused portion using the charging power regulator; and

powering the supplemental circuit using the bulk supply.

13. The method according to claim 12, wherein:

the charging power regulator comprises;

a variable impedance connecting a supply voltage to the bulk supply, wherein the excess portion of the power delivered to the bulk supply varies based on the variable impedance; and

an impedance regulator; and

regulating the excess portion of the power comprises adjusting the variable impedance using the impedance regulator based on the unused portion of the power.

14. The method according to claim 13, wherein:

the shunt circuit comprises a resistance; and

the method includes sensing the unused portion of the power comprising sensing a voltage drop across the resistance; and

adjusting the variable impedance comprises adjusting the variable impedance based the sensed voltage drop.

15. The method according to claim 14, wherein:

outputting a control signal using the impedance regulator based on the sensed voltage drop; and

adjusting the variable impedance comprises;

communicating the control signal to a transistor of the variable impedance; and

adjusting the variable impedance based on the control signal.

16. The method according to claim 13, wherein:

the bulk supply comprises a capacitor having an associated time constant; and

regulating the excess portion of the power comprises controlling the time constant using the impedance regulator based on the unused portion of the power.

17. The method according to claim 12, further comprising:

sensing an electrical charge of the bulk supply; and

controlling an activation of the supplemental circuit based on the sensed electrical charge using a controller of the device circuitry.

18. The method according to claim 12, further comprising performing at least one of:

sensing a process parameter using a sensor; and

controlling a process using a control element.

19. The method according to claim 12, further comprising communicating data to an external device using the supplemental circuit.

20. The method according to claim 18, wherein communicating data to the external device comprises communicating data to the external device in accordance with a Bluetooth communication protocol.