Method for supplying fieldbus communication and power from a handheld maintenance tool in a hazardous area using a single lead set

Patent metadata

Field	Value
Publication number	US-9709602-B2
Application number	US-201514682714-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	Apr 9, 2015
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A connector assembly for a portable field device testing includes a two-wire communication line to provide communication between a handheld maintenance tool and a field device, a first two-prong plug to provide power and communication signals to the field device and a shunt plug to provide power to the field device using the two-wire communication line.

First claim

What is claimed is:

1. A method of switching power to a field device under testing conditions using a two-prong plug with first and second prongs, a shunt plug, and a two-wire communication line having a first terminal pair of wires at a first end connectable to the field device and removable therefrom and a second terminal pair of wires at a second end that terminates at the two-prong plug and a first wire of the second pair is connected to one of the first and second prong and a second wire connected to the other of the first and second prong of the two-prong plug, the method comprising:
connecting the two-wire communication line between a handheld maintenance tool and the field device to electrically couple the two-wire communication line with the handheld maintenance tool; and
inserting the shunt plug having a first prong and a second prong into the handheld maintenance tool and into the two-prong plug, such that the second prong of the shunt plug is inserted into a power jack of the handheld maintenance tool so that the shunt plug connects the second prong of the two-prong plug and the second prong of the shunt plug to apply a voltage of the handheld maintenance tool across the two-wire communication line to power the field device.

2. The method of claim 1 , including measuring a voltage on the two-wire communication line before the shunt plug is inserted into the handheld maintenance tool and applying a power voltage on the two-wire communication line between the handheld maintenance tool and the field device after the shunt plug is inserted into the handheld maintenance tool and the two-prong plug.

3. The method of claim 1 , including electrically connecting the first and second prongs of the shunt plug with the second prong of the two-prong plug via a circuit of the shunt plug that electrically connects the first and the second prongs of the shunt plug.

4. The method of claim 3 , wherein inserting the shunt plug comprises electrically connecting the first prong of the shunt plug to one of a one-jack receptacle of the two-prong plug and a predetermined jack receptacle of the handheld maintenance tool and electrically connecting the second prong of the shunt plug to the other of the one-jack receptacle and the predetermined jack receptacle of the handheld maintenance tool.

5. The method of claim 1 , further including operating the handheld maintenance tool to provide a time-varying signal voltage across a first jack and a second jack and to provide a constant power voltage to a third jack that is higher in voltage than the signal voltage.

6. The method of claim 1 , further including receiving an indicator from the handheld maintenance tool that the field device is unpowered and prompting a user to insert the shunt plug into the handheld maintenance tool and the two-prong plug into the handheld maintenance tool and the two-prong plug.

7. The method of claim 1 , including operating the handheld maintenance tool to apply the voltage to a third jack of the handheld maintenance tool when the handheld maintenance tool has power.

8. The method of claim 1 , including automatically decoupling the shunt plug from the two-wire communication power line when the voltage is turned off from the two-wire communication line.

9. The method of claim 8 , further including implementing a manual reset by removing the shunt plug from the two-prong plug and the handheld maintenance device and re-inserting the shunt plug into the two-prong plug and the handheld maintenance device after the shunt plug decouples from the two-wire communication power line.

10. The method of claim 1 , further including providing a DC voltage for powering the field device and a signal voltage for communicating with the field device across the two-wire communication line after inserting the shunt plug.

11. An electrical connector assembly for selectively coupling a power voltage to a communication line comprising:
a two-prong plug including a first prong, a second prong, and a one-jack receptacle;
a two-wire communication line including a first terminal pair of wires of a first end of the two-wire communication line and a second terminal pair of wires of a second end of the two-wire communication line;
a shunt plug including a first and a second prong and a circuit that electrically connects the first and second prongs to each other,
wherein the first terminal pair of the first end of the two-wire communication line is connectable to a pair of terminals of a field device and removable therefrom, and the second terminal pair of the second end terminates at the two-prong plug wherein a first wire of the second terminal end is connected to one of the first prong and the second prong of the two-prong plug and a second wire of the second terminal end is connected to the other of the first prong and the second prong of the two-prong plug;
wherein the two-prong plug is configured to insert into a first jack and a second jack of a three jack receptacle of a handheld maintenance tool; and
wherein the one-jack receptacle of the two-prong plug is electrically coupled to the second prong of the two-prong plug and the second prong of the shunt plug when the shunt plug is inserted into the two-prong plug.

12. The electrical connector assembly of claim 11 , wherein the shunt plug is configured to insert into the two-prong plug and a third jack of the three jack receptacle of the handheld maintenance device in a single orientation with respect to the two-prong plug.

13. The electrical connector assembly of claim 12 , wherein the shunt plug further includes a diode as part of the circuit to block a reverse current.

14. The electrical connector assembly of claim 12 , wherein the shunt plug and the two-prong plug are linearly oriented to align with a linear three jack receptacle of a handheld maintenance device.

15. The electrical connector assembly of claim 12 , wherein the shunt plug and the two-prong plug are arranged in a triangular orientation to align with a three jack receptacle of a handheld maintenance.

16. The electrical connector assembly of claim 11 , wherein the two-wire communication line is adapted to carry a power sufficient to power at least two field devices within intrinsic safety guidelines.

17. The electrical connector assembly of claim 11 , wherein the shunt plug further comprises a body, wherein the body includes ribs.

18. The electrical connector assembly of claim 11 , wherein the shunt plug further comprises a body, and wherein the body includes a recessed area.

19. The electrical connector assembly of claim 18 , wherein the recessed area of the body of the shunt plug is flat.

20. A portable device assembly for communicating with a field device of a process control network, the assembly comprising:
a handheld maintenance tool including a three jack receptacle;
a two-prong plug including a first prong, a second prong, and a one-jack receptacle;
a shunt plug that includes a first prong, a second prong, and a circuit that electrically connects the first prong and second prong to each other;
a two-wire communication line including a first terminal pair of wires of a first end of the two-wire communication line and a second terminal pair of wires of a second end of the two-wire communication line, the two-wire communication line electrically and communicatively coupling the handheld maintenance tool to the field device;
wherein the first terminal pair of wires of the first end of the two-wire communication line is connectable to a pair of terminals of a field

Assignees

• Fisher Rosemount Systems Inc

Inventors

• Dewey Alan Roger
• Russell Iii Alden C
• Benson Roger
• Ferguson Anthony
• Toepke Todd M

Classifications

• G01R31/2834

  Automated test systems [ATE]; using microprocessors or computers (G01R31/317 takes precedence; ATE for detection of defective computer hardware G06F11/2736) · CPC title

• G01R31/2851

  Testing of integrated circuits [IC] (G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801) · CPC title

• H01R13/68

  with built-in fuse · CPC title

• G01R1/206 Primary

  Switches for connection of measuring instruments or electric motors to measuring loads (switches in general H01H) · CPC title

• H01R31/08 Primary

  Short-circuiting members for bridging contacts in a counterpart · CPC title