Field device calibration

• US 20080091376A1
• Filed: 10/12/2007
• Published: 04/17/2008
• Est. Priority Date: 10/13/2006
• Status: Active Grant

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Russell, Alden C., Dewey, Alan R.
• Granted Patent: US 8,364,431 B2
• Time in Patent Office: Days
• US Class Current: 702/107
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G05B 2219/25428 Field device
• CPC Class Codes: G05B 2219/31181 Controller and device have several formats and protocols, select common one
• CPC Class Codes: G05B 2219/33331 Test, diagnostic of field device for correct device, correct parameters

Abstract

A calibrator for field devices is provided. In one aspect, the calibrator has the ability to communicate in accordance with at least two process communication protocols, and tests an attached process connection before engaging communication. In another aspect, the calibrator includes isolation circuitry to facilitate compliance with at least one intrinsic safety requirement, while communicating with field devices using an all-digital process communication protocol. In another aspect, a method of calibrating field devices is provided which accesses device descriptions of the field devices to generate calibration tasks.

Claims

1. A field device calibrator comprising:

a calibration source for generating a known input to the field device;

a first loop communication module operably coupleable to a process communication loop, the first loop communication module being configured to communicate completely digitally;

a second loop communication module operably coupled to the process communication loop;

detection circuitry operably coupleable to the process communication loop; and

a controller coupled to the first and second loop communication modules and the detection circuitry, the controller being configured to test the type of the process communication prior to calibration using the detection circuitry and to communicate with and calibrate the field device using the loop communication module that matches the type of process communication detected.

2. The field device calibrator of claim 1, wherein the calibration source is disposed within the calibrator.

3. The field device calibrator of claim 1, wherein the calibration source includes measurement circuitry within the calibrator that measures a relatively unknown input to the field device, and provides a calibration traceable representation of the input.

4. The field device calibrator of claim 1, wherein the calibrator is intrinsically safe.

5. A calibrator for calibrating a field device that only communicates digitally, the calibrator comprising:

a calibration source for generating a known input to the field device;

isolation circuitry operably coupleable to the field device;

a loop communication module coupled to the isolation circuitry, the loop communication module being configured to communicate with the field device; and

a controller coupled to the loop communication module, the controller being configured to communicate with and calibrate the field device.

6. The calibrator of claim 5, wherein the calibrator is intrinsically safe.

7. A system for calibrating a field device, the system comprising:

a calibrator including;

a first loop communication module configured to communicate in accordance with a first all-digital process industry standard communication protocol;

a controller operably coupled to the first loop communication module;

memory coupled to the controller and configured to store information relative to at least one calibration;

short range wireless input/output communication circuitry; and

a first universal source including;

short range wireless input/output communication circuitry configured to communicate with the short range input/output communication circuitry of the calibrator;

a controller coupled to the short range input/output communication circuitry; and

an output control module coupled to the controller and configured to generate a physical output signal to the field based on an instruction from the controller.

8. The system of claim 7, and further comprising a second universal source.

9. A method of calibrating a field device, the method comprising:

coupling a calibrator to the field device accessing a device description of the field device;

generating at least one calibration task based upon the device description of the field device;

executing the at least one calibration task by generating a known input to the field device;

communicating with the field device to determine the field device'"'"'s measurement corresponding to the known input; and

determining if the field device'"'"'s measurement is sufficiently close to the known value of the input.

10. The method of claim 9, wherein the device description is loaded into the calibrator prior to coupling the calibrator to the field device.

11. The method of claim 9, wherein the device description is an EDDL description.

12. The method of claim 9, wherein communicating with the field device is done completely digitally.