Startup and operational techniques for a digital flowmeter

• US 8,483,979 B2
• Filed: 06/26/2012
• Issued: 07/09/2013
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: Schneider Electric Systems USA, Inc. (Schneider Electric SE)
• Original Assignee: Invensys Systems Incorporated (Invensys PLC)
• Inventors: Henry, Manus P., Zamora, Mayela E.
• Primary Examiner(s): Le, John H
• Application Number:
  US13/532,858
• Publication Number:
  US 20130000418A1
• Time in Patent Office: 378 Days
• Field of Search: 702 45- 47, 702/50, 702/54, 702/100, 702/104, 702/106, 702/137, 738/610.4, 738/611.2, 738/613.55, 738/613.56, 738/613.57
• US Class Current: 702/45
• CPC Class Codes: G01F 1/8427 detectors
• CPC Class Codes: G01F 1/8431 electronic circuits
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8486 with multiple measuring conduits
• CPC Class Codes: G01F 1/849 having straight measuring conduits
• CPC Class Codes: G01F 25/10 of flowmeters

Abstract

Startup and operational techniques for a digital flowmeter are described. For example, during a startup operation of the flowmeter, the mode of operation might include a random sequence mode, in which filtered, random frequencies are applied as a drive signal to a flowtube associated with the digital flowmeter. Once the flowtube reaches a resonant mode of vibration, the digital flowmeter may transition to a positive feedback mode, in which a sensor signal representing a motion of the flowtube is fed back to the flowtube as a drive signal. In a digital synthesis mode of operation, the analyzed sensor signals are used to synthesize the drive signal. The digital flowmeter may revert to a previous mode to regain stable and desired oscillation of the flowtube, such as might be required during a recovery operation associated with a disturbance to an operation of the digital flowmeter.

Claims

1. A flowmeter comprising:

a vibratable flowtube;

a driver connected to the flowtube and configured to impart motion to the flowtube;

a sensor connected to the flowtube and configured to sense the motion of the flowtube and generate a sensor signal; and

a controller to receive the sensor signal and configured to;

receive a first signal at the flowmeter, the first signal representing the motion of the flowtube;

generate a second signal based on the first signal, the second signal being compensated for a phase delay associated with an electronic element of the flowmeter,

the second signal having a predetermined amplitude when an amplitude of the first signal is less than a predetermined threshold; and

apply the second signal to the driver coupled to the flowtube and configured to impart motion to the flowtube.

2. The flowmeter of claim 1, wherein the generated second signal is substantially in phase with the first signal.

3. The flowmeter of claim 1, wherein the controller is further configured to multiply the generated second signal by a gain term prior to applying the second signal to the driver.