US 5,528,409 AGranted

Fiber-optic interface system

AssigneeNT International, Inc.

InventorsGerald R. Cucci, Peter Stasz, Paul E. Bjork

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Abstract

A fiber-optic data-link used to interface a remote process variable sensor/transmitter to a local process control system includes a local light source module and a remote interface module interconnected by one or more optical fibers. Energy for operating the remote interface module and its associated process variable sensor/transmitter is provided by light energy transmitted from the local site to the remote site and converted at the remote site to an electrical signal. The local light source module and the remote interface module each may include a microcontroller. The controllers not only control the flow of status messages in either analog or digital or analog and digital form simultaneously from the remote site to the local site, but also insure the integrity of the system and minimizes the amount of optical power delivered to the remote site to that which is required to electrically power the remote interface module and the process variable sensor/transmitter, thus extending the useful life of the light source. The system is also arranged to check the integrity of the optical fibers to ensure that the light intensity is always below a minimum eye-safe value whenever the optical fiber is not correctly connected between the local light source module and the remote interface module.

Claims23

Dependent claims

An optically-powered, fiber-optical data-link for interfacing a remote process variable transmitter to a local control system, comprising;

(a) a first controller means for controllably applying light energy to a first output terminal and for receiving digitally encoded, optically transmitted messages at a first input terminal;
(b) transmitter means electrically connected to said first controller means for transmitting information to said local control system based upon said messages received at said first input terminal;
(c) a second controller means having input and output terminals, the second controller means being located remotely from said first controller means for receiving both analog and digital signal components defining the state of a process variable sensed by said remote process variable transmitter and delivering optically encoded digital messages and status information relating to the performance of said second controller means as a message packet to a output terminal of said second controller means, said optically encoded digital message information being based upon the analog and digital signal components defining the state of a process variable sensed by said remote process variable transmitter, said second controller means including a power supply means comprising an optical-to-electrical power converter connected to a power supply converter means for the second controller means and an output conductor, said output conductor being connected to a power supply converter means for supplying electrical power to a remote microcontroller means and said remote process variable transmitter;
(d) at least one optical fiber optically coupled between said first output terminal of the first controller means, said input terminal of said second controller means, said output terminal of the second controller means and said first input terminal of the first controller means;
and
(e) means coupled to said first controller means at said local site for reconstructing the optically encoded digital message information in said message packet into tis analog and digital components prior to being sent to the local control system.

3 more elements

An optically-powered, fiber-optic data-link for interfacing a remote process variable transmitter to a local control system, comprising:

(a) a first controller means for controllably applying light energy to a first output terminal and for receiving digitally encoded optically transmitted information at a first input terminal;
(b) analog transmitter means electrically connected to said first controller means adapted for transmitting analog information to said local control system;
(c) a second controller means having input and output terminals, the second controller means being located remotely from said first controller means for receiving signals defining the state of a process variable sensed by said remote process variable transmitter and delivering optically encoded status information to the output terminal of the second controller means and including
(i) a power supply means comprising an optical-to-electrical power converter connected to said input terminal of the second controller means and an output conductor, said output conductor being connected to a power supply converter means for supplying electrical power to a remote microcontroller means and said remote process variable transmitter;
(d) a first optical fiber coupled between said first output terminal of the first controller means and said input terminal of the second controller means;
(e) a second optical fiber coupled between said output terminal of the second controller means and said first input terminal of the first controller means;
and
(f) means including said first controller means for initially applying said light energy to said first output terminal at a standard, accepted eye-safe low light energy value, said second controller means being responsive to receipt of said standard, accepted eye-safe low light energy value over said first optical fiber for transmitting a power-up command to said first controller means over said second optical fiber, whereby additional light energy above said standard accepted eye-safe light energy value is applied to said first optical fiber only if said power up command is received indicating that said first and second optical fibers are properly connected between their respective output and input terminals.

5 more elements

An optically-powered, fiber-optic data-link for interfacing a remote process variable transmitter to a local control system, comprising:

(a) a first con, roller means for controllably applying light energy to a first output terminal and for receiving digitally encoded optically transmitted information at a first input terminal;
(b) analog transmitter means electrically connected to said first controller means adapted for transmitting analog information to said local control system;
(c) a second con,roller means having input and output terminals, the second controller means being located remotely from said first controller means for receiving signals defining the state of a process variable sensed by said remote process variable transmitter and delivering optically encoded status information to said output terminal of the second controller means and including
(i) a power supply means comprising an optical-to-electrical power converter connected to said input terminal of the second controller means and an output conductor, said output conduct or being connected to a power supply converter means for supplying electrical power to a remote microcontroller means and said remote process variable transmitter, said second controller means includes means for measuring and digitising electrical power delivered from said power supply means to said romote process variable transmitter and for digitizing the said signals defining the state of a process variable;
(d) a first optical fiber coupled between said first output terminal of the first means and said input terminal of the second controller means;
(e) a second optical fiber coupled between said output terminal of the second controller means and said first input terminal of the first controller means;
and
(f) means including said first controller means for initially applying said light energy to said first output terminal at a standard, accepted eye-safe low light energy value, said second controller means being responsive to receipt of said standard, accepted eye-safe low light energy value over said first optical fiber for transmitting a power-up command to said first controller means over said second optical fiber, whereby additional light energy above said standard accepted eye-safe light energy value is applied to said first optical fiber only if said power up command is received indicating that said first and second optical fibers are properly connected between their respective output and input terminals.

5 more elements

An optically-powered, fiber-optical data-link for interfacing a remote process variable transmitter to a local control system, system, comprising:

(a) a first controller means for controllably applying light energy from a light source to a first output terminal and for receiving digitally encoded, optically transmitted messages at a first input terminal;
(b) input/output means electrically coupled to said first controller means for applying at least one of digital and analog information corresponding to said messages received at said first input terminal to said local control system;
(c) a second controller means having input and output terminals the second means being located remotely from said first controller means for receiving at least one of analog and digital signal components defining the state of a process variable sensed by said remote process variable transmitter and delivering message packets including optically encoded digital status information based upon said at least one of analog and digital signal components to the output terminal of the second controller means at periodic intervals to indicate proper operation of said second controller means, and said remote process variable transmitter to the first controller means;
(d) a power supply means comprising an optical-to-electrical power converter connected to said input terminal of the second controller means and an output conductor, said output conductor being connected to a power supply converter means for supplying electrical power to a remote microcontroller means and said remote process variable transmitter;
and
(e) at least one optical fiber coupled between said first output terminal and said input terminal of the second controller means and between said output terminal of the second controller means and said first input terminal, respectively, said status information in said message packet sent from said output terminal of the second controller means to said first input terminal being indicative of the level of power produced by said power supply means.

3 more elements

An optically-powered, fiber-optical data-link for interfacing a remote process variable transmitter to a local control system, comprising:

(a) a first controller means for controllably applying light energy from a light source to a first output terminal and for receiving digitally encoded, optically transmitted messages at a first input terminal;
(b) input/output means electrically coupled to said first controller means for applying at least one of digital and analog information corresponding to said messages received at said first input terminal to said local control system;
(c) a second controller means having input and output terminals, the second controller means being located remotely from said first controller means for receiving at least one of analog and digital signal components defining the state of a process variable sensed by said remote process variable transmitter and delivering message packets including optically encoded digital status information based upon said at least one of analog and digital signal components to the output terminal of the second controller means at periodic intervals to indicate proper operation of said second controller means, and said remote process variable transmitter to the first controller means;
(d) a power supply means comprising an optical-to-electrical power converter connected to said input terminal of the second controller means and an output conductor, said output conductor being connected to a power supply converter means for supplying electrical power to a remote microcontroller means and said remote process variable transmitter;
and
(e) at least one optical fiber coupled between said first output terminal and said input terminal of the second controller means and between said output terminal of the second controller means and said first input terminal, respectively, said status information in said message packet sent from said output terminal of the second controller means to said first input terminal being indicative of the level of power produced by said power supply means;
and
(f) alarm means in said first controller means for indicating when the status information indicates a level of power produced by said power supply means is outside of predetermined upper and lower limits.

5 more elements

Dependencies are inferred from the claim text.