Patent EP0437162A2 successfully refreshed from Google Patents.
EP0437162A2
Expired / Lapsed
EP
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Optical fiber link control safety system
Assignee: International Business Machines Corp
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Filing: 1990-11-27
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Granted: —
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Expires: 2010-11-27
Abstract
Abstract A fully redundant safety interlock system is provided comprising, means for detecting the loss of light on a fiber optic link; controller means, coupled to said means for detecting, for determining the safety condition of the link based on the output of said means for detecting, and for controlling the radiant energy output of an optical transmitter, based on the determined safety condition, via redundant output control signals; and means, coupled to said controller means, responsive to said redundant control signals, for interconnecting the output of said controller means to transmitter drive circuitry to thereby adjust the radiant energy output by the transmitter. According to a preferred embodiment of the invention, the controller means includes an electronic implementation of two independent state machines, each of which redundantly determines the connection state of the optical link between two optical link cards. The output from the state machines is used to adjust (for example, turn on and turn off) the drive circuitry for the transmitter via fully redundant paths which carry the redundant control signals.
Inventors
- 👤 Gerald Michael Heiling
- 👤 David Ardel Knodel
- 👤 Michael Joseph Peterson
- 👤 Brian Andrew Schuelke
- 👤 David Warren Siljenberg
- 👤 Ronald Lee Soderstrom
- 👤 John Thomas Trnka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 07:48
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/07; H04B10/075; H04B10/077; H04B10/079; H04B10/0795; H04B10/07955; H04B10/25; H04B10/2589
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
69 words
A fully redundant safety interlock for a fiber optic link, comprising : (a) means for detecting loss of light on said link, including means for outputting at least two independent Loss of Light signals; and (b) controller means, coupled to said means for detecting, for controlling the radiant energy output by an optical transmitter, based at least in part on the values of said independent loss of light signals.
Claim 2
Dependent Claim
52 words
Apparatus as set forth in claim 1 wherein said controller means is operative to cause the radiant energy output by said optical transmitter to be limited or shut off whenever said transmitter is continuously outputting radiant energy and any of said Loss of Light signals indicate loss of light on the link.
Claim 3
Dependent Claim
153 words
Apparatus as set forth in claim 1 wherein said controller means further comprises : (a) means for determining the safety condition of said link, in terms of whether or not the link is closed and contains functioning safety apparatus at the opposite end of the link, including means for outputting at least two separate signals indicative of said safety condition; and (b) output means, coupled to said means for determining, for outputting redundant signals in response to said separate signals, wherein said redundant signals may be used to control the radiant energy output by said transmitter, and wherein said means for determining further comprises a plurality of state machines, the states of which are used, together with said independent Loss of Light signals, to determine the safety condition of said link, and said means for detecting further comprises a plurality of timers, each associated associated with one of said plurality of state machines.
Claim 4
Dependent Claim
48 words
Apparatus as set forth in claim 3 further comprising interconnect means, coupled to said output means, for interconnecting said redundant signals to transmitter drive circuitry, and wherein said interconnect means comprises a redundant laser switch that requires redundant signal inputs of opposite polarity to continuously activate said transmitter.
Claim 5
Dependent Claim
52 words
Apparatus as set forth in any one of claims 1 to 4 wherein said means for detecting further comprises at least two independent light sensors, at least one of said light sensors being an AC coupled light detector and at least one of said light sensors being a DC coupled light detector.
Claim 6
Dependent Claim
31 words
Apparatus as set forth in any one of claims 1 to 5 wherein said controller means further comprises means for powering down said transmitter in response to user input control signals.
Claim 7
Dependent Claim
27 words
Apparatus as set forth in any one of claims 1 to 6 wherein said controller means further comprises means for signalling inactive link status to a user.
Claim 8
Dependent Claim
45 words
Apparatus as set forth in any one of claims 1 to 7 wherein said controller means is responsive to user generated power on reset signals and, in response thereto, first determines the safety condition of said link before permitting the transmitter to be continuously activated.
Claim 9
Dependent Claim
61 words
Apparatus as set forth in any one of claims 3 to 8 wherein said state machines each include at least a check state, corresponding to an inactive mode of said transmitter; an active state, corresponding to an active mode of said transmitter; and both a stop state and a connect state, which exist when said transmitter is in a connect mode.
Claim 10
Dependent Claim
33 words
Apparatus as set forth in claim 9 wherein the redundant signals output by said controller means are operative to cause said transmitter to be pulsed at a predetermined frequency during said inactive mode.
Claim 11
Dependent Claim
106 words
Apparatus as set forth in claim 9 wherein the redundant signals output by said controller means are operative to cause reconnection handshake signals to be output by said transmitter during said connect mode, to enable said controller means to determine if said link is closed and that functioning safety apparatus exists at the opposite end of the link, and wherein said redundant signals output by said controller means are operative to inhibit continuous power from being provided to said transmitter unless said controller means determines during said connect mode that said link is closed and contains functioning safety apparatus at the opposite end of the link.
Claim 12
Dependent Claim
29 words
Apparatus as set forth in claim 9 wherein the redundant signals output by said controller means are operative to provide continuous power to said transmitter during said active mode.
Claim 13
Dependent Claim
72 words
A fully redundant safety interlock for a fiber optic link, comprising : (a) means for sensing a fiber disconnect as a function of at least two independent signals which each indicate the presence or absence of light on said link; (b) controller means, coupled to said means for sensing, operative to cause the radiant energy output by an optical transmitter to be limited or shut off whenever a fiber disconnect is sensed.
Claim 14
Dependent Claim
120 words
Apparatus as set forth in claim 13 wherein said controller means further comprises means for periodically causing said transmitter to emit pulses used to determine if said fiber has been reconnected, wherein said controller means further comprises means for causing reconnect handshake signals to be output by said transmitter, to enable said controllers means to determine if said link is closed and that functioning safety apparatus exists at the opposite end of the link, and wherein said controller means further comprises means for causing the restoration of continuous radiant energy output by said transmitter whenever said fiber has been reconnected, so long as said reconnect handshake signals indicate that functioning safety apparatus exists at the opposite end of the link.
Claim 15
Dependent Claim
151 words
An open fiber link safety system for providing a fully redundant safety interlock for a fiber optic link, wherein said link includes first and second optical link cards, each of which is capable of transmitting and receiving data over said link, and further wherein said first card includes a first optical transmitter, driver means for said first transmitter, and first receiver/amplifier means; and further wherein said second card includes a second optical transmitter, driver means for said second transmitter, and second receiver/amplifier means, comprising : (a) first safety means, coupled between said driver means for said first optical transmitter and said first receiver/amplifier means; (b) second safety means, coupled between said driver means for said second optical transmitter and said second receiver/amplifier means; wherein said first and second safety means are each operative to power down the respective transmitters to which they are coupled upon detecting a break in said link.
Claim 16
Dependent Claim
212 words
Apparatus as set forth in claim 15 wherein each of said safety means further comprises; (a) means for detecting loss of light on said link, including means for outputting at least two independent Loss of Light signals; and (b) controller means, coupled to said means for detecting, for controlling the radiant energy output by an optical transmitter, based at least in part on the values of said independent loss of light signals, each of said safety means being further operative to cause continuous radiant energy output by said first and second optical-transmitters, when a link is being initialized or reconnected, only if each safety means is able to verify the existence of the other safety means as part of the link, and each of said controller means further comprising : (a) means for determining the safety condition of said link, in terms of whether or not the link is closed and contains functioning safety apparatus at the opposite end of the link, including means for outputting at least two separate signals indicative of said safety condition; and (b) output means, coupled to said means for determining, for outputting redundant signals in response to said separate signals, wherein said redundant signals may be used to control the radiant energy output by said transmitter.
Claim 17
Dependent Claim
63 words
Apparatus as set forth in claim 16 wherein said means for determining further comprises a plurality of state machines, the states of which are used, together with said independent Loss of Light signals, to determine the safety condition of said link, and wherein said means for detecting further comprises a plurality of timers, each associated with one of said plurality of state machines.
Claim 18
Independent Claim
358 words
A method for providing a fully redundant safety interlock for a fiber optic link, wherein said link includes a first optical fiber, a second optical fiber, first and second optical link cards, each of which is capable of transmitting and receiving data over said link, and further wherein said first card includes a first optical transmitter for transmitting optical signals between said first card and said second card via said first fiber, first receiver/amplifier means, first safety control means and first timer means; and further wherein said second card includes a second optical transmitter for transmitting optical signals between said second card and said first card via said second fiber, second receiver/amplifier means, second safety control means and second timer means, comprising the steps of: (a) disabling said first and second optical transmit ters whenever said first optical fiber is discon nected by : (a1) generating a first Loss of Light signal via said second receiver/amplifier means, for use by said second safety control means whenever said first fiber is disconnected from the link; (a2) powering down said second optical transmitter, via said second safety control means, in response to said first Loss of Light signal; (a3) starting a timer, maintained by said second timer means, via said second safety control means; (a4) generating a second Loss of Light signal, via said first receiver/amplifier means, as a result of said second optical transmitter being powered down; and (a5) powering down said first optical transmit ter, via said first safety control means, in response to said second loss of light signal, to thereby create a safe condition with respect to the open link created by the disconnection of said first optical fiber; (b) starting a timer, maintained by said second timer means, when said second optical transmitter is powered down according to step (a2); (c) starting a timer, maintained by said first timer means, when said first optical transmitter is powered down according to step (a5); and (d) powering up each of said first and second optical transmitters after a time period T, for a smaller time period t, in a synchronous fashion, in order to check link status.
Claim 19
Dependent Claim
134 words
A method as set forth in claim 18 further comprising the step of generating reconnect handshake signals via said first and second safety control means to verify closed link status and verify that a functioning safety device exists at both ends of the link, the step of permitting continuous radiant energy to be output by both said first and second optical transmitters in the event both closed link status and the existence of a functioning safety device at both ends of the link are verified via said handshake signals, and the step of powering down said first and second optical transmitters for time period T and repeating step (d) if said handshake signal fails to verify both closed link status and the existence of a functioning safety device at both ends of the link.
Claim 20
Independent Claim
357 words
A method for providing a fully redundant safety interlock for a fiber optic link, wherein said link includes a first optical fiber, a second optical fiber, first and second optical link cards, each of which is capable of transmitting and receiving data over said link, and further wherein said first card includes a first optical transmitter for transmitting optical signals between said first card and said second card via said first fiber, first receiver/amplifier means, first safety control means and first timer means; and further wherein said second card includes a second optical transmitter for transmitting optical signals between said second card and said first card via said second fiber, second receiver/amplifier means, second safety control means and second timer means, comprising the steps of : (a) disabling said first and second optical transmitters whenever said second optical fiber is disconnected by : (a1) generating a first Loss of Light signal via said first receiver/amplifier means, for use by said first safety control means whenever said second fiber is disconnected from the link; (a2) powering down said first optical transmitter, via said first safety control means, in response to said first Loss of Light signal; (a3) starting a timer, maintained by said first timer means, via said first safety control means; (a4) generating a second Loss of Light signal, via said second receiver/amplifier means, as a result of said first optical transmitter being powered down; and (a5) powering down said second optical transmit ter, via said second safety control means, in response to said second loss of light signal, to thereby create a safe condition with respect to the open link created by the disconnection of said second optical fiber; (b) starting a timer, maintained by said first timer means, when said first optical transmitter is powered down according to step (a2); (c) starting a timer, maintained by said second timer means, when said second optical transmitter is powered down according to step (a5); and (d) powering up each of said first and second optical transmitters after a time period T, for a smaller time period t, in a synchronous fashion, in order to check link status.
References Cited (Backward Citations)
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