The present invention relates generally to hardware/software interfaces for control and test of annunciators and loudspeaker devices in public address system equipment. More particularly, the present invention relates to an apparatus and method for testing distributed components of a public address system, and for adding more-refined controls to signal distribution.
In representative industrial and commercial audio announcing systems, loudspeakers and other audio output transducers are typically hard wired, either in parallel or in multiple branches, sometimes referred to as audio loops. These output devices can be driven all at once, or, where specialized or improvised control equipment is used, can be driven separately by audio loop. Such announcing systems can use available public address (PA) systems, annunciator control panels, or personal computer (PC)-based systems as the central control devices. Some PC-based systems may be managed using software controls such as Millennium Event Driver Interface (MEDI™) software. MEDI is an example of a software control that can assign groups of speakers to zones, and, if proper hardware is in place, can activate zones individually.
Some systems based on purpose-built control panels are capable of performing integrity checks, known as supervision, on one or more audio loops by applying a signal across each loop, provided the loop ends in a line termination resistor. If the loop, as tested by a circuit in the control panel, falls within an acceptable range, then the loop is presumed to be intact, whereas if the test result is out of range, the loop is likely shorted or has an open-circuit failure.
Some PC-based and other systems are not capable of performing integrity checks, whether because of added costs associated with hardware and control functions, or because the systems predate such features. Systems capable of detecting basic faults caused by wiring failures in the form of shorts and open circuits may nonetheless not detect faults with high precision. Limited fault detection capability can be further restricted in audio systems into which external amplifiers are incorporated, such as for signal boosting or for expansion of existing systems to support multiple zones. A fault in an external amplifier, for example, can render one or more entire audio loops beyond the amplifier inoperable without providing an operator with a failure report.
Accordingly, it is desirable to provide a method and apparatus that increase public address system controllability and integrity verification test capability.
The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect an apparatus is provided that in some embodiments provides a public address system in which an audio test signal at an inaudibly high frequency is transmitted through an amplifier and distributed to one or more addressable zone relay (AZR) devices in the public address system. Each appropriately equipped AZR device serves as a switch apparatus for signal routing and performs one or more tests, both to validate system integrity in part and to detect the test signal. The result of the integrity and signal distribution tests is subsequently returned from the AZR devices by polling to a central control device in the system. In the event that one or more failures are detected in the operation of system, as reported by the AZR device(s), the central control device decodes the polled failure indication(s) and uses one or more annunciatory functions such as graphical screen displays and audible signals to announce the failures.
In accordance with one embodiment of the present invention, an apparatus for generating audible signals from at least one audio transducer is presented. The apparatus includes an electrical load that includes at least one audio transducer, an audio amplifier configured to supply electrical signals having sufficient power to energize the at least one audio transducer, an addressable zone relay configured to control passage of audio information signals from the audio amplifier to the electrical load, an audio control subsystem configured to provide audio signals to the audio amplifier, and further configured to provide bidirectional control communication to and from the addressable zone relay, an audio control subsystem user interface configured to accept commands from a user and further configured to present system status information to a user, and a system monitor function whereby amplifier operability and audio transducer integrity verification functions are performed and presented as components of the system status information.
In accordance with another embodiment of the present invention, a method for generating audible signals from at least one audio transducer is presented. The method for generating audible signals includes generating at least one alternating-current electrical signal for informational message output, wherein the signal includes energy content in an audible frequency range, sensing electrical signal activity, whereby operability of an informational message signal source is confirmed, and redirecting an interconnection path that routes to an audio transducer load a signal, sourced from an amplifier, substituting therefor a test circuit, whereby a load status electrical state is determined at least in part by confirmation of a condition of electrical integrity of the path and the load.
In accordance with yet another embodiment of the present invention, an from at least one audio transducer is presented. The apparatus for generating audible signals includes means for generating at least one alternating-current electrical signal for informational message output, wherein the means for generating furnishes energy content in an audible frequency range, means for sensing electrical signal activity, whereby operability of the means for generating is confirmed, means for transducing an electrical signal into an audio signal, whereby information is broadcast, means for testing the means for transducing, and means for redirecting an interconnection path that routes to the means for transducing a signal, sourced from the means for generating, substituting therefor the means for testing, whereby a load status electrical state is determined at least in part by confirmation of a condition of electrical integrity of the interconnection path and the means for transducing.
There have thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments, and of being practiced and carried out in various ways. It is also to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description, and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention provides control and switch apparatus with test circuitry and associated operational and test support software, the combination of which can perform information signal routing and remote verification of wiring integrity within public address system elements not readily tested using previous apparatus and methods.
The invention presented herein includes, among other elements, a hardware apparatus referred to as an addressable zone relay (AZR). One or more AZRs can be used in conjunction with modified or unmodified millennium event driver interface (MEDI) software in a public address system. AZRs can direct audio signals carrying information such as tone signals, voice messages, radio program material, and the like from an amplifier into at least one output zone, can perform resistive integrity checks on the wiring and electronic devices connected to form the output zones, and can perform signal-detection integrity checks on incoming audio from the amplifier to the AZR. In the embodiments described in greatest detail herein, AZR output zones are tested while public address system signal outputs are disabled. The resistive integrity checks test the condition of end-of-line resistors (REOL) for load verification. The integrity of the audio input path coming into the AZR from the system master through various amplifiers is verified using pulsed audio tone supervision (PATS) software.
In the AZR applications disclosed herein, PATS-enhanced MEDI software performs control panel functions that cannot be performed from a PC-based or fixed function public address (PA) audio system. When controlled by PATS-enhanced MEDI software, an AZR provides real-time integrity diagnostics of its output zones and further supports real-time verification of audio signals detected on its input from the amplifier. This PATS technique can overcome a lack of built-in integrity checking in some audio amplifiers. Using PATS, integrity checking can be successfully performed on audio amplifiers used in public address and other audio systems.
In the PA system 30 shown, the serial port 36 provides, via a representative IEC-232-compatible cable 38, a bidirectional interface to an external IEC-232/IEC-485 bidirectional converter device 40, also referred to as a transmitter/receiver or transceiver. In some embodiments, it may be preferable to provide IEC-485 output directly from the PC 34, such as by using an add-in circuit board within the PC 34. While this may change the physical configuration, it can have negligible effect on system operation for some embodiments. Other communication methodologies may be preferable in some embodiments, including the use of bidirectional wireless links to distribute signals between parts of a PA system 30 for which direct wiring may be undesirable.
In addition to the IEC-232 serial port 36, the PC 34 preferably includes an audio output generator 42, which in some embodiments furnishes output at a low signal level, such as 1 VRMS maximum. In the embodiment shown, the PC audio generator 42 uses an external cable 44 to feed a low-level signal to an audio amplifier 46, external to the PC 34. As with the IEC-232/IEC-485 transceiver 40, the audio amplifier 46 may in some embodiments be incorporated within the PC 34. In other embodiments, one or both the audio and transceiver functions may be incorporated within a unit such as an annunciator control panel.
The audio amplifier 46 shown in
Instead of directly feeding loudspeakers, as in some prior PA systems, the audio amplifier 46 of
At the system configuration level, multiple AZRs can be wired in parallel, using, in some embodiments, control line taps 58 off common lines, as shown in
The MEDI control software 32 operates within the PC 34 to provide event data and control—that is, messages such as status inquiries, configuration instructions, activation commands or events, and the like—to PA system components including one or more AZRs 50. MEDI 32 incorporates the Pulsed Audio Tone Supervision (PATS) function 64 to perform integrity validation from the PC audio generator 42, through the audio amplifier 46, to a detector within the AZR 50. MEDI 32 further provides in a video screen display a text and/or graphical representation of system status, including fault conditions, and can additionally include capabilities such as audible signals and enhanced graphical indications to announce fault events, whereby prompt attention to faults can be sought.
In the embodiment shown, PATS 64 generates an ultrasonic signal—a tone at a frequency above the human audible range—with a specific envelope, using the PC 34 audio generator function 42. In some embodiments, a data file providing a point-by-point digitized voltage waveform is retrieved from system memory and sent to the PC audio generator 42, which converts the data file to an electrical signal having substantially the original frequency and having amplitude appropriate for input to an amplifier 46. If the tone so generated falls within the operating frequency range of typical audio amplifier apparatus, it can be amplified by the amplifier 46, propagated throughout the system, and sensed in one or more AZRs 50 to verify system integrity.
Because the PATS 64 signal is ultrasonic, the broadcast is not typically noticeable in locations where the usual audio output of the same PA system is readily heard. For example, a tone around 25 KHz, which is somewhat above the nominal human limit, may in some embodiments be somewhat distorted by an amplifier 46 and speakers 20, but typical distortion products are even higher in frequency, and thus further beyond the audible range. A typical PC audio generator 42 and a typical amplifier 46 may each exhibit rolloff above the audible range, so that the amplitude of a realized ultrasonic signal from a given computed waveform amplitude may be less than the realized amplitude of a comparable audible-range signal, but rolloff is in many cases sufficiently gradual to permit operation at desirable PATS 64 frequencies. If a PATS 64 signal at a frequency some octaves further above the audio range were used, such as 200 KHz, for example, output amplitude rolloff could be more affected by PC audio generator 42 characteristics and by a user's choice of amplifier 46.
In some embodiments, the amplitude of the PATS 64-generated signal can, if applied as a “boxcar” function, so that the signal amplitude slews at maximum rate from no output to full output and vice versa, cause a detectable “pop” sound at the beginning and end of an otherwise inaudible ultrasonic tone. Other waveform envelopes, such as a ramp up/hold/ramp down amplitude envelope, can allow the PATS 64 function to operate substantially free of audible artifacts.
A criterion of functionality is the active area bounded by the envelope—that is, the integral of signal power over time to yield the applied energy of the PATS 64 signal. This energy value determines in part the effectiveness of the detector circuit.
The PATS 64 ultrasonic signal can coincide with an audible event signal such as a tone or a voice announcement, but the effect of such an occurrence is largely unnoticeable in many embodiments. If transmitted during a period when the public address system is silent, the PATS 64 signal is substantially transparent to system function. For example, the PATS 64 signal may be in progress when, or may begin while, an event occurs. Typical audio devices such as an audio generator 42 within a PC 34 can support asynchronous application of multiple waveform data files, with the sound output circuit of the generator 42 summing the waveforms. The ultrasonic component of speaker 20 output can in general exhibit negligible effect on the perceived sound from an AZR-equipped PA system 30.
As many as sixty-four AZRs 50 are individually addressable in the embodiment shown. The signal strength fanout limitations of the IEC-485 standard reduce to thirty-two the maximum number of AZRs 50 in a fully compliant system in which no IEC-485 repeaters are used, so a maximized system could require at least one bidirectional IEC-485 data repeater 66. Excessive line lengths and the inclusion of other loads on the command bus 56 may similarly limit the maximum fanout under IEC-485.
The bidirectional IEC-232/IEC-485 converter 40 is used to convert between the IEC-232 single-ended serial communication on the PC 34 side and IEC-485 differential serial communication on the AZR 50 side. Each AZR 50 in embodiments such as those shown has an IEC-485 data port to allow the AZR 50 to receive commands from and transmit replies to the MEDI software 32. Events and polling commands are transmitted by the PC 34 using the existing MEDI 32 command structure, as described in detail in U.S. patent application Ser. No. 10/664,911, filed Sep. 22, 2003, and incorporated herein in its entirety by reference.
It is to be understood that the term “relay” as used herein refers to a monostable electromechanical switch device with a single electromagnetic actuator that can be caused to move to an active state with application of input power. When activated, the switch device changes the state of any component switch contacts from a deenergized state, in which any “normally closed” contacts are connected to “common” contacts, to an energized state, in which any “normally open” contacts are connected to the common contacts instead. Deenergizing such a device restores the original contact status, unlike magnetic latching relay types, which lack an intrinsic fail-safe characteristic. Relays used in electronic circuits can require drivers 82, which may be simple bipolar transistors, power field effect transistors (FETs), or other devices as determined by the power required to cause a particular style of relay to actuate. So-called solid state relays and devices such as FETs themselves can be used as isolated switch devices in place of electromechanical relays in some applications, and can exhibit fail-safe functionality in some embodiments.
A typical AZR 50 may be configured to accept a total of 250 watts of audio signal power, divided between two output speaker loops, so that 125 watts is available to each of two speaker loops. In some embodiments, the relays 84 and 86 can each carry the full 250 watts, so their need be no constraint on assigning loads to AZR 50 outputs. In other AZR 50 configurations, additional relays may be incorporated into the AZR 50, so that an increased number of branches may be provided, either by reducing the power to each branch or by increasing the amplifier 46 output capability.
Each relay output, shown deenergized, connects a signal from the common input to one of the AZR 50 outputs. When the relay coils 84 and 86 for relays K1 and K2, respectively, are energized, the input is disconnected from the outputs, while test circuits 108 and 110, respectively, apply an AZR 50 internally-regulated source voltage through the end-of-line resistors REOL 26 shown in
Control of the relays 84 and 86 in the embodiment shown is performed by the microcontroller 74, shown in
The audio detector circuit 122 in
In the embodiment shown, the AC_SUPRV signal 132 is applied to a digital input 78 of the microcontroller 74, shown in
In some embodiments, a unit response string after polling can employ the following format:
The STATUS character for any polled unit in a MEDI-controlled system, such as an AZR 50, originates from an eight-bit word within the unit, wherein each bit represents a datum. Not all characters returned are displayable, but all are readable by MEDI software 32. The bits defined in a preferred AZR 50 embodiment indicate the following:
The AZR builds a single eight-bit character and includes the character as the STATUS character within the return string of a poll command.
In the embodiment shown in
As discussed above, AZR 50 integrity data includes the state of the PATS signal detector circuit 120, shown in
If a scheduled event such as an audible tone or a voice message occurs during a PATS transmission 64 or a poll command 162, the activities can occur simultaneously, since the PATS 64 signal can be inaudible, the poll command 162 uses the IEC-485 lines, and the scheduled events are assigned to the audio lines.
The many features and advantages of the invention are apparent from the detailed specification, and, thus, it is intended by the appended claims to cover all such features and advantages of the invention that fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, that fall within the scope of the invention.
This application claims priority to U.S. non-provisional patent application entitled, “PROGRAMMABLE EVENT DRIVER/INTERFACE APPARATUS AND METHOD,” filed Sep. 22, 2003, having a Ser. No. 10/664,911, the disclosure of which is hereby incorporated by reference in its entirety. This application also claims priority to U.S. provisional patent application entitled, “ADDRESSABLE ZONE RELAY METHOD AND APPARATUS,” filed Feb. 16, 2005, having a Ser. No. 60/653,093, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60653093 | Feb 2005 | US |