Startup control for multi-drop transmitters powered by current limited power supplies

Patent metadata

Field	Value
Publication number	US-2018150094-A1
Application number	US-201615365197-A
Country	US
Kind code	A1
Filing date	Nov 30, 2016
Priority date	Nov 30, 2016
Publication date	May 31, 2018
Grant date	—

Abstract

A method of operating process variable transmitters configured for sensing within an industrial processing facility connected in parallel to a current loop that receives power from a common power supply. The transmitters include a power accumulator module including an energy storage device including at least one capacitor or a rechargeable battery and a sensor module including a transceiver coupled to a processor having an associated memory that stores a startup sequencing algorithm. After a fixed period of time following a startup, an initial node voltage is measured across the energy storage device. The initial node voltage is compared to a predetermined voltage, and the transmitter is placed in a low power mode when the initial node voltage is <the predetermined voltage, an at least partially random low power state time for the transmitter is set, and startup sequencing algorithm is restarted after the low power time.

First claim

1 . A method of operating process variable transmitters, comprising:
providing a plurality of process variable transmitters configured for sensing a process variable within an industrial processing facility each connected in parallel to a current loop that receives power from by a common power supply driving said current loop, said process variable transmitters each including a power accumulator module comprising an energy storage device that includes at least one capacitor or a rechargeable battery and a sensor module including a transceiver coupled to a processor having an associated memory that stores a startup sequencing algorithm; after a fixed period of time following a startup, measuring a parameter relating to an input current charging said energy storage device received from said current loop; comparing said parameter to a reference level for said parameter; placing said process variable transmitter in a low power mode based on results of said comparing; setting an at least partially random low power state time for said process variable transmitter, and restarting said startup sequencing algorithm after said low power state time.

2 . The method of claim 1 , wherein said parameter comprises an initial node voltage across said energy storage device, said startup sequencing algorithm comparing comprises comparing said initial node voltage to a predetermined voltage level, and wherein said placing comprises placing said process variable transmitter in said low power mode when said initial node voltage is less than said predetermined voltage level.

3 . The method of claim 1 , wherein said process variable transmitters further comprise a terminal module for connecting to said current loop and providing power to said sensor module.

4 . The method of claim 1 , further comprising using a current drawn by said process variable transmitters from said current loop while in said low power mode to replenish and store energy.

5 . The method of claim 1 , wherein said setting said at least partially random low power state time comprises calculating times from a function seeded with a value from a noise source.

6 . The method of claim 1 , wherein said setting said at least partially random low power state time comprises generating times based on an assigned device identification number.

7 . The method of claim 1 , wherein said process variable transmitters comprise Guided Wave Radar (GWR) transmitters.

8 . A process variable transmitter for sensing a parameter within an industrial processing facility, comprising:
a terminal module for connecting to a current loop that receives power from a power supply driving said current loop; a sensor module receiving power through said terminal module including a power accumulator module comprising an energy storage device that includes at least one capacitor or a rechargeable battery and a sensor module including a transceiver coupled to a processor having an associated memory that stores a startup sequencing algorithm; said sensor module implementing a method comprising:
after a fixed period of time following a startup comparing a parameter relating to an input current charging said energy storage device received from said current loop to a reference level for said parameter;
placing said process variable transmitter in a low power mode based on results of said comparing;
setting an at least partially random low power state time for said process variable transmitter, and
restarting said startup sequencing algorithm after said low power state time.

9 . The process variable transmitter of claim 8 , wherein said setting said at least partially random low power state time comprises calculating times from a function seeded with a value from a noise source.

10 . The process variable transmitter of claim 8 , wherein said setting said at least partially random low power state time comprises generating times based on an assigned device identification number.

11 . The process variable transmitter of claim 8 , wherein said process variable transmitter further comprises said terminal module for connecting to said current loop and providing power to said sensor module.

12 . The process variable transmitter of claim 8 , wherein said startup sequencing algorithm implements said comparing.

13 . The process variable transmitter of claim 8 , wherein said energy storage device comprises a plurality of said capacitors arranged in a capacitor bank.

14 . The process variable transmitter of claim 8 , wherein said process variable transmitters comprise Guided Wave Radar (GWR) transmitters.

15 . The process variable transmitter of claim 8 , wherein said parameter comprises an initial node voltage across said energy storage device, said startup sequencing algorithm comparing comprises comparing said initial node voltage to a predetermined voltage level, and wherein said placing comprises placing said process variable transmitter in said low power mode when said initial node voltage is less than said predetermined voltage level.

Assignees

• Honeywell Int Inc

Inventors

• Conroy Michael
• Andronic Cristian

Classifications

• G05F1/66 Primary

  Regulating electric power · CPC title

• G05B15/02

  electric · CPC title