Open circuit diagnostic for pulsed solenoid I/P

Patent metadata

Field	Value
Publication number	US-11525523-B2
Application number	US-202016779409-A
Country	US
Kind code	B2
Filing date	Jan 31, 2020
Priority date	Jan 31, 2020
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Techniques for diagnosing failures in a digital solenoid I/P converter are provided herein. A controller of the I/P converter may apply a fixed voltage to an I/P coil of the I/P converter, causing an armature to move from an off-position to an on-position in a properly-functioning I/P converter. The controller may receive an indication of whether a digital logic line trip has occurred, indicating that a current for the I/P coil has reached a desired maximum current level. The controller may remove the fixed voltage applied to the I/P coil when the maximum current level is reached or when a threshold period of time has elapsed from the application of the fixed voltage to the I/P coil. The controller may diagnose, based on whether the digital logic line trip occurred prior to removing the fixed voltage, a failure in the I/P converter.

First claim

What is claimed is:

1. A method for diagnosing failures in a digital solenoid I/P converter of a field device in a process control system, wherein the digital solenoid I/P converter includes an I/P coil and drive circuitry, and wherein the digital solenoid I/P converter, when actuated, causes an armature to move from an off-position to an on-position, the method comprising:
establishing that a fixed voltage has been applied to the I/P coil at a first time;
establishing that the fixed voltage was removed from the I/P coil at a second time;
receiving, from a current sensor, an indication of a current level associated with the I/P coil;
performing a first comparison of the indication of the current level associated with the I/P coil and a desired maximum current level;
causing, based on the comparison, a digital logic line to trip when the current level associated with the I/P coil reaches the desired maximum current level;
performing a second comparison of whether the digital logic line trips before the second time;
determining, based on the second comparison, whether the I/P coil and drive circuitry are properly functioning or whether one or more of the I/P coil or the drive circuitry has failed; and
causing a controller to take a control action changing an operation of the process control system based on determining that one or more of the I/P coil or the drive circuitry has failed, wherein the control action includes switching from using the field device in the process control system to using a second, redundant field device in the process control system.

2. The method of claim 1 , wherein determining whether the I/P coil and drive circuitry are properly functioning or whether one or more of the I/P coil or the drive circuitry has failed further comprises:
determining, based on the digital logic line tripping before the second time, that the I/P coil and drive circuitry are properly functioning.

3. The method of claim 1 , wherein determining whether the I/P coil and drive circuitry are properly functioning or whether one or more of the I/P coil or the drive circuitry has failed:
determining, based on the digital logic line not tripping before the second time, that one or more of the I/P coil or the drive circuitry has failed.

4. The method of claim 3 , further comprising determining, based on the digital logic line not tripping before the second time, that one or more of the I/P coil or the drive circuitry has failed due to an open circuit in one or more of the I/P coil or the drive circuitry.

5. The method of claim 3 , further comprising:
generating an alert based on determining that one or more of the I/P coil or the drive circuitry has failed.

6. A system for diagnosing failures in a digital solenoid I/P converter in a process control system, the system comprising:
a digital solenoid I/P converter of a field device of the process control system, including an I/P coil and drive circuitry, the digital solenoid I/P converter being configured to cause an armature to move from an off-position to an on-position when actuated;
a controller configured to cause a fixed voltage to be applied to the I/P coil at a first time and to remove the fixed voltage applied to the I/P coil at a second time, when the first of the following occurs: (i) the I/P coil reaches the desired maximum current level; or (ii) a threshold period of time has elapsed from the first time;
a current sensor configured to sense an amount of current associated with the I/P coil; and
a diagnostic circuit configured to:
perform a first comparison of the sensed amount of current associated with the I/P coil and a maximum desired current level;
cause, based on the first comparison, a digital logic line to trip when the sensed amount of current associated with the I/P coil reaches the maximum desired current level;
perform a second comparison of whether the digital logic line has tripped after the first time;
determine, based on the second comparison, whether the I/P coil and drive circuitry are properly functioning or whether one or more of the I/P coil or the drive circuitry has failed; and
cause the controller to take a control action changing an operation of the process control system based on determining that one or more of the I/P coil or the drive circuitry has failed, wherein the control action includes switching from using the field device in the process control system to using a second, redundant field device in the process control system.

7. The system of claim 6 , wherein the diagnostic circuit is configured to determine, based on the digital logic line tripping before the second time, that the I/P coil and drive circuitry are properly functioning.

8. The system of claim 6 , wherein the diagnostic circuit is configured to determine, based on the digital logic line not tripping before the second time, that one or more of the I/P coil or the drive circuitry has failed.

9. The system of claim 8 , wherein the diagnostic circuit is configured to determine, based on the digital logic line not tripping before the second time, that one or more of the I/P coil or the drive circuitry has failed due to an open circuit in one or more of the I/P coil or the drive circuitry.

10. The system of claim 8 , wherein the diagnostic circuit is further configured to generate an alert based on determining that one or more of the I/P coil or the drive circuitry has failed.

Assignees

• Fisher Controls Int Llc

Inventors

• Fontaine Michael R
• Nicholas Davin S
• Bulleit Gregory R
• Arnold Christopher C
• Smid David L

Classifications

• F16K31/423

  the actuated members consisting of multiple way valves · CPC title

• F16K31/0675

  Electromagnet aspects, e.g. electric supply therefor · CPC title

• F16K31/0606 Primary

  fluid passing through the solenoid coil · CPC title

• F16K31/0658 Primary

  Armature and valve member being one single element · CPC title

• F16K27/0263

  multiple way valves · CPC title