Electrical/optical interface coupler

What is claimed is:

1. A removable coupler inter-connectable between an electrical interface of an analog signal generating device and an optical interface of an optical signal receiving device and comprising:

an elongated flexible cable having electrical and optical ends and including an electrical conductor housed therein and leading from said electrical end;

an electrical connector attached to said cable at said electrical end for being releasably connected to said analog signal generating device;

an optical interface housing attached to said cable at said optical end, said housing including a releasable connector for releasably connecting said housing to said optical signal receiving device, and a circuit for receiving an analog signal generated from said analog signal generating device and converting said analog signal to a digital signal; and

an optical emitter mounted in said optical interface housing and electrically connected to said circuit and responsive to said digital signal from said circuit to generate a corresponding optical signal for transmission to said optical signal receiving device.

2. A removable coupler as set forth in claim 1 wherein:

said lead includes an intermedially disposed separable fuse housing for carrying a fuse therein.

3. A removable coupler as set forth in claim 1 wherein:

said connector of said optical interface housing includes at least one releasable fastener to securely engage said optical signal receiving device.

4. A removable coupler as set forth in claim 3 wherein:

said optical signal receiving device includes a housing formed with at least one elongated slot for engagement to at least one respective said fastener.

5. A removable coupler as set forth in claim 1 wherein:

said optical interface housing includes a transparent optical signal transmission window and said optical signal receiving device includes a transparent optical signal receiving window.

6. A removable coupler as set forth in claim 5 wherein:

said optical signal receiving device includes a housing formed with at least one alignment hole, said optical interface connector includes a confronting surface including at least one alignment pin for respective receipt in said hole, said hole and said alignment pin operable to align said optical signal transmission window with said optical signal receiving window.

7. A removable coupler as set forth in claim 1 wherein:

said optical interface housing includes an optical detector for receiving optical prompt signals from said optical signal receiving device to prompt said optical transmitter to transmit said digital signal.

8. Electrical/optical converter cable apparatus for removably coupling between an electrical outlet of an electrical analyzer device generating an electrical signal and a portable data collector housed in an intrinsically safe housing formed with an optical interface having a predetermined configuration and including an optical sensor behind an optical window, said apparatus comprising:

an elongated, intrinsically safe flexible cable having first and second ends and including an electrical conductor housed therein and leading from said first end;

an electrical connector attached to said first end for connection to said electrical outlet;

a converter device carried from said second end and including a housing formed with an optical connector having an optically transparent window configured to complementarily mate with said optical interface and including an optical emitter electrically connected to said electrical connector and positioned to, when said converter device is mated with said optical interface, align in signal transmitting relation with said optical sensor; and

a releasable mechanical coupler for releasably coupling said converter device to said data collector with said transparent window complementarily mated with said optical interface whereby said electrical connector may be connected with said electrical outlet and said converter device coupled to said data collector without invading said intrinsically safe housing to thereby establish an intrinsically safe coupling between said analyzer device and data collector to provide for communication therebetween.

9. Electrical/optical converter cable apparatus as set forth in claim 8 for use with said data collector device that is portable and wherein:

said cable is elongated and flexible to allow for said data collector, while said electrical connector is connected to said outlet and said converter device coupled to said data collector, to be manipulated about relative to said first end.

10. Electrical/optical converter cable apparatus as set forth in claim 8 wherein:

said data collector device is portable and includes a bar code scanner to identify identification codes from different locations and a memory for storing said identification codes;

said cable includes a portable sensor for sensing predetermined conditions at the respective said locations and a communication line leading from said sensor to said analyzer device, said sensor being responsive to the sensing of said predetermined conditions at said locations to conduct said conditions to said analyzer device; and

said analyzer device is responsive to said conditions received from said communication line to generate a corresponding electrical signal transmitted along said conductor to said optical emitter.

11. Electrical/optical converter cable as set forth in claim 8 wherein:

said converter device includes an analog to digital converter electrically connected to said electrical conductor and optical emitter and responsive to an analog signal from said electrical conductor to generate a corresponding digital signal for transmission to said optical emitter.

12. A removable coupler inter-connectable between an electrical interface of an electrical signal transmitting device and an optical interface of an optical signal receiving and transmitting device including a first optical emitter and receiver, said apparatus comprising:

an elongated flexible cable having electrical and optical ends and including an electrical conductor housed therein and electrically connected to said electrical and optical ends;

an electrical connector attached to said cable at said electrical end for releasable connection to said electrical signal transmitting device for transmission of electrical signals generated by said electrical transmitting device along said conductor;

an optical interface housing attached to said cable at said optical end, said housing including a releasable connector for releasably connecting said housing to said optical signal receiving and transmitting device;

a second optical emitter mounted in said optical interface housing and disposed at a predetermined position therein to, when said optical interface housing is connected to said optical signal receiving and transmitting device, align with said first optical receiver;

a second optical receiver mounted in said optical interface housing and disposed at a predetermined position therein to, when said optical interface housing is connected to said optical signal receiving and transmitting device, align with said first optical emitter for receipt of an optical signal from said first optical emitter to generate a corresponding electrical prompt signal; and

an electrical circuit electrically connected to said second optical receiver, said second optical emitter, and to said conductor and responsive to said electrical prompt signal to transmit said electrical signals generated by said electrical signal generating device to said second optical emitter.

13. The coupler of claim 12 wherein:

said cable includes an intermedially disposed separable fuse housing for carrying a fuse therein.

14. The coupler of claim 12 wherein:

said connector of said optical interface housing includes at least one releasable fastener to securely connect said optical interface housing with said optical signal receiving and transmitting device.

15. The coupler of claim 12 wherein:

said optical interface housing includes an optically transparent signal transmission window and said optical signal receiving and transmitting device includes an optically transparent signal receiving window.

16. The coupler of claim 12 wherein:

said electrical signal transmitting device includes a signal generator for generating analog signals;

said circuit includes an analog to digital converter responsive to said analog signals to generate corresponding digital signals for transmission to said second optical emitter; and

said second optical emitter is responsive to said digital signals to generate corresponding optical signals for receipt by said first optical receiver.

17. The coupler of claim 16 wherein:

said electrical signal generating device includes a portable emissions sensor to sense the concentration of a gaseous emission and generate a corresponding analog sense signal representative thereof; and

said optical signal receiving and transmitting device includes a portable data collector including a memory tier receipt and storage of said optical signals.

18. A removable coupler and sensor assembly inter-connectable between an electrical interface and a sensor interface of an electrical signal transmitting device and an optical interface of an optical signal receiving device including an optical receiver, said apparatus comprising:

an elongated flexible cable having electrical and optical ends and including an electrical conductor housed therein and electrically connected to said electrical end;

an elongated sensor conduit connected to said cable and including a first end for releasable connection to said sensor interface and a free second end including a sensor for sensing a predetermined condition adjacent said sensor and for transmitting said condition through said conduit to said sensor interface of said electrical signal transmitting device;

an electrical connector attached to said cable at said electrical end for releasable connection to said electrical interface of said electrical signal transmitting device;

an optical interface housing attached to said cable at said optical end, said housing including a releasable connector for releasably connecting said housing to said optical interface; and

an optical emitter mounted in said optical interface housing, electrically connected to said electrical conductor and disposed at a predetermined position therein to, when said optical interface housing is connected to said optical signal receiving device, align with said optical receiver, said emitter being responsive to electrical signals conducted along said electrical conductor to generate corresponding optical signals for transmission to said optical receiver.

19. The coupler of claim 18 wherein:

said cable includes a medially disposed separable fuse housing for carrying a fuse therein.

20. The coupler of claim 18 wherein:

said connector of said optical interface housing includes at least one releasable fastener to securely connect said optical interface housing with said optical signal receiving and transmitting device.

21. The coupler of claim 18 wherein:

said optical interface housing includes an optically transparent signal transmission window and said optical signal receiving device includes an optically transparent signal receiving window.

22. The coupler of claim 18 wherein:

said electrical signal transmitting device includes a signal generator for generating analog signals and further including:

a converter circuit mounted in said optical interface housing and electrically connected to said conductor and responsive to said analog signals to generate a corresponding digital signal for transmission to said optical emitter and wherein:

said optical emitter is responsive to said digital signal to generate a corresponding optical signal for receipt by said optical receiver.

23. The coupler of claim 22 wherein:

said converter circuit includes an analog to digital converter responsive to said analog signal to generate said corresponding digital signal for transmission to said optical emitter.

24. The coupler of claim 18 wherein:

said electrical signal transmitting device includes a portable emissions sensor for sensing a gaseous emission and responsive to a condition thereof to generate a corresponding sense signal representative thereof; and

said optical signal receiving device includes a portable data collector including a memory for receipt and storage of said optical signals.

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to devices used to couple instruments together for data transmission therebetween and, more particularly to a device for coupling an instrument having an electrical interface and an instrument having an optical interface.

2. Description of the Prior Art

It is well known in the art that analytical instruments and the like are used to capture measurement data. Such data is represented by electrical signals which may easily be manipulated in desired formats. These electrical signals may be in either digital or analog form. Once this data is transformed into electrical signals, it is often desirable to transfer the electrical signals to cooperating instruments to trigger operations by those instruments or for data storage and data manipulation or the like. Such data may be transferred and received electrically by an electrical interface provided between the two instruments.

Some instruments are designed to communicate or otherwise transfer and receive data optically. It is well known in the art that electrical signals may be converted to optical signals and the data representative thereof transferred optically to cooperating instruments. These types of instruments generally communicate through optical interface ports.

Because instruments may have non-compatible communication interface ports, it becomes necessary to provide a communication link adapted for use between such non-compatible interfaces.

For example, such a dilemma has presented itself in the development of some portable gas monitoring systems. In this area of endeavor, federal, state, and local regulations have been implemented which require manufacturers or others handling hazardous materials to monitor potentially hazardous and/or explosive environments about their facilities. In particular, these regulations require periodic monitoring of potential release points such as valves, fittings or the like which pose a potentiality for leakage or emission of substances including toxic, hazardous and/or explosive material. Because some of these affected facilities include intricate piping systems having hundreds of potential release points, sampling of these points becomes quite time consuming and burdensome. As a result, portable monitoring systems have been developed which include a portable hazardous gas analyzer subsystem working in conjunction with a separate portable data collector/processor subsystem for storing data corresponding to concentration values of the hazardous constituents sensed by the gas analyzer at a release point. The data collector/processor subsystem may include a bar code reader to identify a potential release point and include a means of corresponding the identification data with sensed emissions data. A gas monitoring system of this nature is disclosed in U.S. Pat. No. 5,099,437 and is hereinafter incorporated by reference. The gas analyzer subsystem of this monitoring system has an electrical interface, such as a typical RS-232 connector, while the data collector/processor subsystem has an optical interface. Therefore, it becomes necessary to provide a coupling device to facilitate communication between the two instruments having these non-compatible interfaces.

In addition, since these instruments are utilized in potentially hazardous and/or explosive environments, the coupling device must be "intrinsically safe". National standards have been adapted in the United States for "intrinsically safe" equipment, as set forth in the National Electrical Code (NEC). For an instrument to be certified as intrinsically safe, it must be demonstrated that the equipment cannot produce a spark which could cause combustion or produce any other undesired effects in a potentially hazardous environment. An atmosphere having the presence of volatile gases, vapors or flammable liquids are examples of such a potentially hazardous environment. The electrical circuitry in these instruments must not be capable of producing a spark, even if failure of any of the electrical components in the circuitry occurs.

Hence, those skilled in the art have recognized the need to provide an intrinsically safe coupling device to facilitate communication between two instruments, wherein one such instrument has an optical interface and the other instrument has an electrical interface. Such a coupling device should be easily connectable, releasable and cost effective to produce. The present invention meets these needs and others.

SUMMARY OF THE INVENTION

The present invention is directed to a device for allowing communication between two instruments and specifically where one of such instruments has an electrical interface and the other such instrument has an optical interface. More particularly, the invention is embodied in a removable interface coupling, wherein the coupling itself converts electrical signals to optical signals and visa-versa.

The coupling device includes an electrical cable having first and second ends, one end attached to an electrical interface connector and the other end attached to an optical interface connector housing. The electrical interface connector is configured for releasable engagement with the instrument having the electrical interface. The optical interface connector housing includes a fastener configured for releasable engagement with the instrument having the optical interface. The fastener includes components which allow for secure engagement and accurate alignment of the connector housing with the optical interface for positive optical signal transmission therebetween. The optical interface connector housing of the coupler may receive electrical signals from the electrical signal interface and thereafter convert such electrical signal into an optical signal which subsequently is transmitted to the optical signal interface. Alternatively, or in combination with the aforementioned, the housing connector may receive optical signals from the optical interface and convert such optical signal to an electrical signal for receipt by the electrical interface.

In a more particular aspect of the invention, the foregoing coupling device is used to interconnect two subsystems of a portable gas detection system, one such subsystem having an electrical interface and the other subsystem having an optical interface. As such, the coupling is formed in combination with transportation tube.

Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate by way of example the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrical/optical interface coupler embodying the present invention;

FIG. 2 is a broken bottom view, in enlarged scale, of a second embodiment of the electrical/optical interface coupler embodying the present invention;

FIG. 3 is a broken top plan view, in enlarged scale, of the coupler shown in FIG. 1;

FIG. 4 is a bottom view, in enlarged scale, of an optical signal generating and receiving instrument included in the electrical/optical interface coupler shown in FIG. 1;

FIG. 5 is a side view, in enlarged scale, of an optical interface connector housing included in the electrical/optical interface coupler shown in FIG. 1;

FIG. 6 is a sectional view taken along the line 6--6 of FIG. 2;

FIG. 7 is a block diagram of one embodiment depicting operation of the electrical/optical interface coupler shown in FIG. 1;

FIG. 8 is a block diagram of another embodiment depicting operation of the electrical/optical interface coupler shown in FIG. 1; and

FIG. 9 is a schematic diagram of the electrical circuit included in the coupler embodiment shown in FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the drawings for purposes of illustration, the invention is embodied in a removable coupling inter-connectable between two analytical instruments and more particularly with one such instrument having an optical communications interface and the other instrument having an electrical communications interface.

Analytical instruments are used to capture and manipulate measurement data. To add to the overall capability, it is desirable that such instruments be adapted for downloading and transferring of data to other instruments. For communication between two instruments to occur, a communications link must be provided, the link generally facilitated by respective communications interface ports on each instrument. However, communication between instruments having non-compatible communication interfaces creates a problem. For instance, some devices communicate through electrical interfaces while other instruments communicate through optical interfaces. In particular, some portable gas monitoring systems include a portable hazardous gas analyzer subsystem having an electrical interface working in communication with a portable data collector/processor subsystem having an optical interface. To provide communication between the two non-compatible interfaces, a conversion must be made.

A convenient inexpensive solution is to provide a coupling device including the interface conversion therein which will facilitate communication between the two gas monitoring subsystems. So that a coupling device of this nature may be utilized in potentially hazardous and/or explosive environments, the coupling should be certified as "intrinsically safe" thereby demonstrating that it cannot produce any undesired effects that could cause combustion in a potentially hazardous environment.

Referring to FIG. 1, a combination coupler of the preferred embodiment of the invention is shown for use with a portable hazardous emissions monitoring and detection system as described above. A potential emissions release point is depicted as a flanged fitting 26 connecting two lengths of a hazardous materials transportation pipe. The flanged fitting has been tagged with a bar code 28 for ease of identification. The portable hazardous emissions detection system includes a gas analyzer, generally shown at 10, a portable data collector/processor, shown generally at 20, and the combination coupler of the invention, shown generally at 30. The portable data collector/processor has a sealed housing formed in its rear portion with a downwardly facing transparent optical transmission window 106 (FIG. 4) defining an optical interface. The gas analyzer is manufactured to be intrinsically safe and has an electrical receptacle 12, defining an electrical interface, and a gas sample inlet port 14. The gas analyzer receives a sample of air taken at the release point, analyzes such sample, and generates an electrical signal representative of a concentration of hazardous constituents present in the air sample. Typically, the electrical signal generated by the gas analyzer is an analog signal, but it is to be appreciated that such electrical signal may be digital in form.

The combination coupler 30 is releasably connectable between the aforementioned gas analyzer 10 and portable data collector/processor 20. The combination coupler, in general, includes a gas sample tube 38 integrally formed with an electrical/optical interface coupling 35. The interface coupling has an optical interface housing connector 52 for releasable connection to the optical interface of the portable data collector/processor 20 and an electrical interface connector or electrical plug, generally designated 46, connectable to the electrical receptacle 12 of the gas analyzer 10. The gas sample tube 38 includes a gas port connector 80 that is releasably connectable to the inlet sample port 14 of the gas analyzer. At the opposite end thereof, a sample wand 86 may be releasably attached to the body of the portable data collector/processor 20 using a hook and loop type velcro strip or the like.

Carried on a pistol grip handle 24, the portable data collector/processor 20 is generally box shaped and includes a forwardly facing bar code window 21 for transmission of optical signals to an internal bar code reader arranged to read a bar code at potential release points such as the bar code 28 shown disposed at the potential release point 26. The portable data collector includes an internal processor for processing data received from the gas analyzer 10 and further includes a memory in which to store such analyzer data and identification signals representative of indicia on such bar codes corresponding to emissions samples taken at the tagged release points. The portable data collector/processor also includes a manual input circuit for receiving control signals from an upwardly facing keypad 22 for manual data input which may supplement data pertaining to a particular release point.

It is a characteristic of commercially available collector/processors 20, such as those available on the market from Symbol Technologies, Inc., that the housing 21 and components thereof are intrinsically safe for use in hazardous gaseous atmospheres and the like. This feature is maintained so long as the housing is not penetrated or the integrity thereof otherwise violated. One of the objects of the present invention is to communicate data to and from such data processor without disturbing the integrity of its intrinsically safe character. To this end, advantage is taken of the optical interface provided by the optical interface window 106 of the data collector/processor 20 overlying an optical-to-electrical transducer, such as an optical detector 101 (FIG. 4) and an electrical-to-optical transducer such as an optical transmitter 103 (FIG. 4). The optical detector 101 may be a photo transistor or a photo diode, and the optical transmitter 103 may be a light emitting diode (LED) or an infrared emitter. Electronic circuitry is employed within the data collector/processor to receive data from the gas analyzer 10 via the optical detector.

As shown in FIG. 4, the underside of the portable data collector/processor housing is formed with a flat raised central surface 108 having a recessed border 90 about the periphery thereof to form, at the rear end thereof, a lateral projecting lip 105. Incorporated on the underside of such data collector/processor is a pair of laterally spaced apart, longitudinally extending, parallel retainer slots 100, each formed on their laterally inner sides with laterally outwardly opening grooves 102 to define upwardly facing retainer shoulders. A pair of small downwardly opening locator bores 104 are spaced longitudinally apart on the underside of such data collector on opposite sides of the window 106.

With particular reference to FIG. 3, the combination coupler 30 is hereafter described in detail. The combination coupler integrally combines the electrical/optical interface coupling 35 having an elongated electrical cable 36 with a gas sample tube 38. The combination coupler is elongated to form first and second ends, generally shown respectively at 32 and 34. An elongated tubular sheath 40 encases the central portion of the electrical cable 36 and gas sample tube 38 to gather the cable and tube along an intermediate length thereof. Respective first and second splitters 42 and 44 are disposed at either end of the sheath to transition the electrical cable and gas sample tube to their respective separated first and second ends 32 and 34. A first stainless steel tether cable 82 is attached to the first splitter 42 at one end and includes a first releasable clasp 84 attached to the opposite end thereof. Likewise, a second stainless steel tether cable 88 is attached to the second splitter 44 at one end and includes a second releasable clasp 90 attached to its opposite end thereof. The first clasp 84 may be attached to a hook (not shown) disposed on the gas analyzer 10 (FIG. 1) and the second clasp 90 attached to a hook (not shown) on the portable data collector/processor 20. When the clasps are attached, the respective tethers prevent the transfer of undue tension to the combination coupler assembly preventing damage to end connectors and/or to the integrity of the combination coupler itself. The electrical cable 36 consists of a plurality of electrically conductive wires surrounded by a protective insulation coating. The electrical/optical interface coupler 35, at the first end thereof, includes a fuse housing 45 that houses two 1/16 amp fuses therein. The fuse housing is separable for fuse replacement. At the free extremity of the electrical cable is an electrical plug, indicated generally at 46. The plug includes a plurality of electrical conductive pins 50 (shown here as three) connected to the respective aforementioned plurality of wires which are receivable in a receptacle 12 (not shown) of the gas analyzer 10. The plug 46 includes a twist-lock fitting 48 rotatable with respect to the plug which securely yet releasably engages the electrical interface 12. The second end of the electrical cable 36 is attached to the optical interface housing, the housing generally indicated at 52.

The first end of the gas sample tube 38 carries a gas sample port connector 80 including a snap locking mechanism to securely fit over and releasably engage the inlet gas sample port 14 of the gas analyzer 10. The second end 34 of the gas sample tube 38 is attached at the extremity thereof to one end of a cylindrical gas sample wand, generally designated 86, having an axial bore therethrough. The cylindrical wand is of a diameter which may be conveniently grasped in the hand of a workman taking gas samples in the field. The sample tube is attached to the bore of the wand at the bottom end thereof using a compression fitting 96 or the like. A removable stainless steel gas sample tube extension tip 94 is detachably connectable to the top end of the bore. The extension tip may be useful to detect emissions at potential release points in confined or restricted areas inaccessible by the wand. The tip may be removed and a wand cap 98 screwed over the tip of the wand to protect the gas sample tube and gas analyzer 10 from infiltration of extraneous particulates when the gas analyzer is not in use. A releasable fastener, such as a velcro hook-type strip 87 may be secured to the wand along the length thereof, allowing the workman to attach the wand conveniently to a respective velcro loop-type strip (not shown) on the side of the portable data collector/processor 20.

Since it is desirable to have flexibility in using the combination coupler 30 in potentially hazardous and/or explosive environments, the coupler is constructed to be "intrinsically safe". As mentioned above in the Background, a United States "intrinsically safe" rating applies to a classification of equipment which has been shown to meet the applicable standards as set forth in the National Electrical Code (NEC). For equipment to qualify as intrinsically safe, it must be constructed so that it will not produce a spark or any other undesired effects that could cause combustion in a potentially hazardous environment. The circuitry in such equipment must be selected to resist producing a spark, even if an electrical component contained in the circuitry should fail. Taken with this in mind, the combination coupler 30 and particularly the electrical/optical interface coupling 35 incorporates safety features and electronic design methodology to achieve an intrinsically safe designation. In addition to the selection of components forming the optical interface housing 52 (described hereafter) and the selection of particular electrical components housed therein, the electrical cable 36 includes features facilitating an intrinsically safe device. For instance, as described above, the electrical cable incorporates a plurality of independently insulated conductive wires all encased in a protective insulation coating and at the first end thereof includes a fuse housing 45 which houses two 1/16 amp fuses.

In another embodiment, the electrical/optical interface coupler 35 is constructed without the gas sample tube 38 in combination therewith. In referring particularly to FIG. 2, the optical interface housing 52, included in both this and the combination coupler embodiments, can be further described hereinafter. The housing 52 is rectangular shaped and formed on its bottom side with a raised limit lip 55 (FIG. 5) at the rear end thereof and a flush mounted housing window 54 disposed centrally thereon. Such window 54 is transparent and is disposed in close spaced relationship over an electrical-to-optical transducer or optical transmitter 56, such as a light emitting diode (LED) or an infrared emitter. Spaced laterally apart therefrom is an optical-to-electrical transducer or optical detector 57 such as a photo diode or photo transmitter. The optical transmitter 56 and optical detector 57 respectively transmit and receive optical signals. The optical window is formed of a transparent shock resistant material, such as high impact hard plastic, to protect the optical transmitter and detector from incidental impact.

A releasable connector device is provided to securely engage the optical interface housing 52 to the optical interface windows 106 of the portable data collector/processor 20. Such connector is in the form of a pair of pivotal fastener plates, generally indicated at 60, positioned in a parallel relationship on either side of the optical interface housing 52 for selective engagement in the fastener slots 100 (FIG. 4) on the underside of the data collector/processor 20. In addition, a pair of small diameter locator pins 58 protrude from the top surface of the housi