Two-wire process variable indicator with microencapsulated electrophoretic display

• US 9,429,462 B2
• Filed: 12/21/2012
• Issued: 08/30/2016
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Schumacher, Mark S.
• Primary Examiner(s): Lieu, Julie
• Application Number:
  US13/724,548
• Publication Number:
  US 20130162439A1
• Time in Patent Office: 1,348 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01F 15/068 with electrical means G01F15/063 takes precedence
• CPC Class Codes: G01F 23/00 Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G08B 5/36 using visible light sources

Abstract

A two-wire process variable indicator includes a housing having a plurality of terminals disposed therein. The terminals are coupleable to a two-wire process control loop. A power module is coupled to the plurality of terminals to receive current flow from the process control loop. Driver circuitry is coupled to the power module and a microencapsulated electrophoretic display is coupled to the driver circuitry.

Claims

1. A two-wire process variable indicator comprising:

a housing;

a plurality of terminals disposed within the housing and being coupleable to a two-wire process control loop which carries at least one of an analog and a digital signal representative of information related to a process variable wherein the terminals are configured to receive the information from the two-wire process control loop related to the process variable;

a power module coupled to the plurality of terminals to receive current flow from the process control loop;

driver circuitry coupled to the power module; and

a microencapsulated electrophoretic display coupled to the driver circuitry and configured to display information related to the process variable received from two-wire process control loop;

wherein the driver circuitry and the microencapsulated electrophoretic display are wholly powered with power from the two-wire process control loop.

2. The two-wire process variable indicator of claim 1, wherein each location of the display changes reflectivity based on charge applied by the driver circuitry to electrophoretic microcapsules disposed within the microencapsulated electrophoretic display.

3. The two-wire process variable indicator of claim 1, wherein the microencapsulated display is disposed within the housing.

4. The two-wire process variable indicator of claim 1, wherein the display is larger than the housing.

5. The two-wire process variable indicator of claim 1, wherein the process variable is a level of material in a container, and wherein the microencapsulated electrophoretic display is mounted to the container.

6. The two-wire process variable indicator of claim 5, wherein the material is a solid.

7. The two-wire process variable indicator of claim 1, wherein the current flow varies between 4 and 20 milliamps to indicate a process variable.

8. The two-wire process variable indicator of claim 1, wherein display provides information relative to a plurality of process variables.

9. The two-wire process variable indicator of claim 1, wherein the display provides diagnostic information.

10. The two-wire process variable indicator of claim 1, wherein the display indicates an alarm condition.

11. The two-wire process variable indicator of claim 1, wherein the indicator is mechanically attached to a process material container.

12. The two-wire process variable indicator of claim 11, wherein the indicator is clamped to the process material container.

13. The two-wire process variable indicator of claim 11, wherein the indicator is magnetically coupled to the process material container.

14. The two-wire process variable indicator of claim 1, wherein the housing is explosion-proof.

15. The two-wire process variable indicator of claim 1, wherein the power module and driver circuitry are intrinsically safe.

16. A process variable indicator comprising:

a housing;

a plurality of terminals disposed within the housing and being coupleable to a process control loop which carries at least one of an analog and a digital signal representative of information related to a process variable wherein the terminals are configured to receive the information from the process control loop related to the process variable;

a power module coupled to the plurality of terminals and configured to power the process variable indicator from the process control loop;

driver circuitry coupled to the power module; and

a microencapsulated electrophoretic display coupled to the driver circuitry to display an indication of the process variable received from the process control loop;

wherein the driver circuitry and the microencapsulated electrophoretic display are wholly powered with power from the process control loop.