DE2901123A1 - CONTROL SYSTEM - Google Patents

Description

The Bendix Corporation

Executive offices

Bendix Center January 11, 19 79

Southfield, Mich. 48076, U.S. Attorney File M-4803

Tax system

The invention relates to a control system according to the preamble of the main claim.

Control systems contain processing units and analog and discrete input and output signal channels associated with the processing units. The control systems respond to signals from external signal sources, which are often exchange units (LRU ¹ s). When systems of this type are used for flight control purposes, it is necessary to take protective measures against faults on critical wires which are in the wiring and which connect the signal sources to the system. Additionally, to reduce re-equipment costs, it should not be necessary to disconnect all wiring when re-equipping the aircraft. Maintenance costs should be reduced by reducing the amount of on-floor troubleshooting of the wiring, as well as by

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Integration with existing flight surveillance equipment. Also must Appropriate means must be provided to ensure the validity of critical wires after the LRU replacement, thereby reducing the Maintenance time reduced and administrative approval, e.g. approval by the Federal Aviation Administration (FAA), and other approvals required for flight control systems is obtained. In the past, the functions mentioned could only go through extensive test work is carried out on the ground, which is costly and time consuming.

The object of the present invention is to provide a control system of the initially mentioned to create said type, in which a test device for the wiring interface is included, which critical wires tests that connect external signal sources to the system.

This task is described in the characterizing part of the main claim Invention solved; advantageous developments are given in the subclaims.

The control system according to the invention includes a built-in test facility for the wiring interface, which is a high frequency sine wave oscillator used. The output of the oscillator is routed through a decoupling network that acts as a DC resistor circuit and a tracking signal of known impedance supplies. The decoupling network applies the tracking signal to a first multiplexer. The multiplexer is used by the system processing unit controlled to provide multiple tracking signals and each of those signals to a particular wire applies. A second multiplexer is used by the processing unit

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controlled in such a way that he first verifies that this is due to the particular There is a wired signal on this wire; then it checks that the signal is not on another wire. He delivers a verification signal applied to a frequency detector will. The detector is designed so that its output will be "FALSE" when it detects a high frequency signal and a "RIGHT" if he doesn't. The system is therefore fail-safe. The output signal of the frequency detector is sent to the Processing unit created and controls its control functions. The system of the invention can be used as part of built-in soil verification test equipment (BITE) can be used in flight as a landing test or coupled with flight monitoring systems. the Validation of critical wires after the LRU replacement can be performed more cheaply than before.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing; show it

Figure T is a block diagram used for purposes of illustration

represents a digital control system such that the system according to the invention for testing the wiring interface can use;

Fig. 2 is a schematic electrical block diagram showing the system according to the invention for testing the Wiring interface together with certain components of a digital control system as shown in Fig. 1 shows.

The invention is described in terms of a digital control system; however, it can also be used in analog systems. A typical

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digital control system contains, as shown, a (free) addressable read-write memory (RAM) 2 and a read-only memory (ROM) 4. The RAM 2 sets a variable memory content and the ROM 4 sets a programmed memory content to a processing unit 6 (control device) via a memory-data-and-address! 8. A real-time clock 10 supplies a signal which is applied to the processing unit 6 and which determines the speed of the arithmetic sampling in the digital control system.

An analog input signal channel, generally identified by the reference number 12 is characterized, an analog output signal channel, which is indicated overall by the reference number 14, a discrete input signal channel, generally identified by the reference number 16, and a discrete output signal channel, generally identified by the reference number 18, are via an input / output data and addressing rail 20 is connected to the processing unit 6.

The analog input signal channel 12 receives a plurality of analog input signals from signal sources, for example the sensors 13, which are to Explanatory gyroscopes or other sensors for flight conditions, that are in a digital flight control system. The analog signals are sent to appropriate differential amplifiers / demodulators / filters laid, which are provided overall with the reference number 22, and passed from these to a multiplexer 24. The multiplexer 24 supplies a signal which is applied to an analog / digital converter 26 and from there via the input / output data and address rail 20 to the processing unit 6.

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The analog output signal channel 14 contains a digital / analog converter 28, which is connected to the processing unit via the rail 20 and generates an analog signal which is sent to a demultiplexer 30 is placed. The demultiplexer 30 supplies several signals which are applied to appropriate "sample and hold" circuits, which are identified as a whole by the reference number 32 and deliver several analog output signals. The analog output signals are, for example, placed on servo systems or the like, which are identified as a whole by the reference number 15 and the control surfaces move an aircraft.

The discrete input signal channel 16 receives multiple discrete input signals, generated on an operator operated system control panel 17. For illustration purposes you can these signals are valid signals, i.e. a logic "HIGH" or a logic "LOW", corresponding to the analog signals which are supplied by the sensors 13. The discrete input signals are applied to the corresponding level translators, the total are identified by the reference number 34, and from there to a multiplexer 36, which is connected via the input / output data and address rail 20 is connected to the processing unit 6.

The discrete output channel 18 contains a demultiplexer 38, the is connected to the processing unit 6 via the rail 20. The demultiplexer 38 provides several signals to corresponding Registers are placed, which are identified as a whole by the reference number 40 and a corresponding plurality of discrete output signals deliver. These operate display devices or the like, which are identified as a whole with the reference number 19 and the Gül-

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Indicate whether or not the analog input signals are valid.

As previously mentioned, the one described with reference to FIG. 1 is digital Control system of a known type, such as used for flight control purposes; only as much of the system as for What is needed to explain the present invention has been illustrated and described.

Fig. 2 shows an embodiment of the test system for the wiring Interface; the analog input signal channel 12 and the discrete input signal channel 16 are shown. Contains for illustration purposes the channel 12 shown has two sensors 13A and 13B, of which each provides corresponding system input signals. The channel 16 contains the control panel 17 which has a single system input signal supplies. These input signals are passed through the arrangement according to the invention. It goes without saying that other, appropriate Input signals can be routed through similar configurations to achieve a corresponding purpose.

The sensor 13A of the sensors 13 (Fig. 1) provides two analog input signals on conductors 50 and 52, which can represent the "HIGH" and "LOW" signal levels. The conductor 50 is over one Resistor 54 connected to an inverting input 56 of a differential amplifier 58; the conductor 52 is grounded and via a Resistor 59 to the non-inverting input 60 of the differential amplifier 58 connected. The non-inverting input 60 is grounded via a resistor 62. An output terminal 63 of the differential amplifier 58 is connected to the inverting input 56 via a resistor 64 is connected. The differential amplifier 58 and the

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-, IP assigned Resistors are in a particular differential amplifier / demodulator / filter 22A of differential amplifiers / demodulators / filters 22 (Fig. 1).

The particular sensor 13B of sensors 13 (Fig. 1) provides two analog ones Input signals on conductors 66 and 68 representing the signal levels Can represent "HIGH" and "LOW". The conductor 66 is via a coil 70 and a resistor 72 with an inverting input 74 connected to a differential amplifier 76, while the conductor 68 is grounded and through a resistor 78 to a non-inverting Input 80 of amplifier 76 is connected. The non-inverting input 80 is grounded via a resistor 82. A Output terminal 83 of differential amplifier 76 is through a resistor 84 connected to the inverting input 74 of the amplifier 76. The amplifier 76 and its associated resistors are included in a particular differential amplifier / demodulator / filter 22B of the differential amplifier / demodulator / filter 22 (Fig. 1).

For purposes of illustration, the control panel 17 shown provides a single discrete input signal on conductor 86. The conductor 86 is via a coil 88 and a resistor 89 with a certain level translator 34A of the level translators 34 (Fig. 1) tied together.

In connection with the coils 70 and 88 it should be noted that the signals from the sensor 13B and the control panel 17 signals with can be low impedance and the coils impart a known impedance to the signals for the proper functioning of the system, such as

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hereafter becomes clear.

-74

The conductors 50, 52, 66, 68 and 86 are part of the wiring that connects the sensors 13A and 13B and the control panel 17 to the control system connects as is known.

The outputs of differential amplifiers / demodulators / filters 22A and 22B are applied to the multiplexer 24 and from there to the analog / digital converter 26, as shown in FIG. The exit of the level translator 34A is connected to the multiplexer 36 and from there to the I / O rail 20, as is also shown in FIG.

A high frequency oscillator 90 generates a sine wave output signal, which is connected to a decoupling network 92. The decoupling network 92 generates a tracking signal with a specific one Impedance.

The tracking signal is applied to a tracking _{signal injection multiplexer 94 which supplies a plurality of signals labeled T 1} , T ″ and T ″. The multiplexer 94 is controlled by the processing unit 6 and applies these signals to appropriate wires which connect the sensors 13A, 13B and the control panel 17 to the digital control system.

Thus, the signal T _{1 is applied} to the conductor 86, which leads from the control panel 17 via the coil 88 and the resistor 89. The signal T2 is applied to the conductor 66, which leads from the sensor 13B via the coil 70 and the resistor 72. The signal T is applied to the conductor 50, which from the sensor 13A via the sensor output and the

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Resistance 54 leads.

The signals T .., T ", T from the tracking signal injection multiplexer are applied to a tracking signal detection multiplexer 96, which is controlled by the processing unit 6 and first verifies that each injection signal from the tracking signal injection multiplexer 94 appears on the correct wire 86,66 or 50; after that he checks that the signal is not on another Wire lies; The tracking signal detection multiplexer 96 provides a verification signal which is sent to a frequency detection circuit 104 is placed. The arrangement is such that the output of the detection circuit 104 is "FALSE" when a high frequency signal is detected and a "RIGHT" if the high frequency signal is not detected. The system is therefore fail-safe. The output signal of the frequency detector 104 is sent to the processing unit 6 and controls the processing unit when the control signals are applied to the multiplexers 94 and 96.

From the above description with reference to the drawing it can be seen that the above-mentioned object has been achieved. A tax system becomes provided with a test device for the wiring interface, which connects critical, external signal sources with the system Wires tests. The test facility makes it easy to reconnect and validate critical wires after the LRU swap. The test system can be integrated with other monitoring devices, thereby reducing maintenance costs and making LRU interchangeability promoted as is desirable to maintain the certification of flight control systems.

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Claims (5)

29 011 The Bendix Corporation Executive Offices Bendix Center Jan. 11, 19 79 Southfield, Mich. 48076, U.S. Attorney File M-4803 Claims 1. / Control system with built-in test device, which is responsive to a plurality of signals from external signal sources and performs a control function, with wiring comprising a plurality of wires which feed the plurality of signals to the control system; with a processing unit, characterized in that there are provided: means (90, 92) which generate a tracking signal; a first device (94) which is connected to the tracking signal device (90,92), is responsive to the tracking signal and thereafter a plurality of tracking signals (T ₁ , ^, T _n ) is generated and connected to the processing unit (6) and from it is controlled to apply each of the plurality of tracking signals (Τ., Τ ^, Τ) to a particular one of the plurality of wires (50,52,66,68,86) in the wiring; a second device (96), which is connected to the first device (9 4), which _{supplies a plurality of tracking signals (T .., T ", T N} ) and which receives these signals ORIGINAL INSPECTED and is connected to and from the processing unit (6) is controlled to verify that each of the plurality of tracking signals (T .., T ", T) is applied only to the particular wire and provides a verification frequency signal; An institution (104), which is applied to the second device (96) and detects the frequency of the verification signal and a corresponding one Output signal supplies. 2. Control system according to claim 1, characterized in that the means (90,92) which supplies the tracking signal includes: means (90) for generating a radio frequency signal; means (92) responsive to the radio frequency signal responds and generates the tracking signal with a certain impedance. 3. Control system according to claim 1, characterized in that the processing unit (6) generates first and second control signals; in that the first device (9 4) is controlled by the first signal to apply each of the plurality of tracking signals (T ₁ → T n, T) to a particular one of the plurality of wires (50-86) in the wiring; that the second device (96) is controlled by the second signal so that it verifies that each of the plurality of tracking signals (Τ., Τ-, Τ) is only applied to the particular wire. 4. Control system according to claim 1, characterized in that the device (104) which is connected to the second device (96) and the frequency of the verification signal is detected and a corresponding output signal is generated, an output signal 909831/0609 generated in the "FALSE" state when the verification signal is high Frequency, and an output signal in the "TRUE" state if the verification signal is not a high frequency. 5. Control system according to claim 1, characterized in that the device (104) which is connected to the second device (96) and the frequency of the verification signal is detected and a corresponding output signal is generated with the processing unit (6) is connected, and that the processing unit (6) in the control of the first and the second device (94,96) is controlled in accordance with this output signal. 9 0 9 B 3 1/0 RQ 9