JPH03147002A - Majority logic circuit - Google Patents

Abstract

PURPOSE:To output alternating signals as output when there are alternating signals in more than two systems by combining the outputs for triple systems in a comparison part when a real speed and an allowable speed are compared so as to adopt majority logic. CONSTITUTION:Speed checking parts 1-3 comparing the real speed with the allowable speed are constituted in such a way that they output the alternating signals at the time of detecting a safety-side, and a direct current at the time of detecting a danger-side. When the outputs are inputted to majority logic 4 and when there are the alternating signals of more than two systems, the alternating signals are outputted and only an alternating component is amplified by an AC amplifier 5, Ryo is driven and Ryo is picked up by signifying that it detects the safety-side as the triple system. Pulse generation circuits detecting 41, 42 and 43 detect the edge of the change of an input signal and generate pulses, and they generate pulse strings (d)-(f) when there are input signals (a)-(c).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic train control system, and particularly to a logical configuration method for combining multiple system outputs into one.

[Conventional technology]

The automatic train control device transmits the train's permissible speed signal, which is determined in relation to the position of the preceding train, from the ground to the onboard train.The onboard system detects the train's actual speed, compares it with the above permissible speed signal, and determines the actual speed. This system automatically applies the brakes when the speed exceeds the allowable speed. The on-board device compares the allowable speed and the actual speed as described above, but most of them have a triple system configuration for safety. , the output of each prefecture is used as the relay output, and as shown in FIG. 4, two or more systems are configured so that the output coincides with the final output. This is because although the overall configuration is basically a triple system, only the part that outputs the final output is a single system, so we take advantage of the asymmetry in the incidence of relay failure modes.

The final output part is made fail-safe.

However, a relay with large asymmetry must have a large return spring force, and therefore the excitation coil must also be large, so ultra-small relays cannot be used, and a relay of a certain size is required. I have no choice but to do so.

[Problem to be solved by the invention]

As mentioned above, the conventional technology inevitably results in a large size and weight.

The present invention provides a configuration method in which this final output portion is made into an electronic circuit and has a high fail-safe property.

[Means to solve the problem]

In order to achieve the above purpose, the part that compares the allowable speed and the actual speed, that is, the output of the speed checking section, is not used as a relay output as in the conventional case, but on the safe side, that is, when the actual speed is less than the allowable speed, the output is digitally turned ON.

In the dangerous case of an alternating signal that repeats an OFF value, that is, when the actual speed exceeds the allowable speed, it is defined and output as a partial level of DC, that is, digital ON or OFF, and these output triple system components are assembled. In addition, if there is an alternating signal in two or more systems, the alternating signal is output as an output.

[Effect]

In the case of electronic circuits, when a failure occurs, switching of internal elements becomes impossible and the output is often fixed at a specific level. Therefore, by setting the output to the safe side when an alternating signal is generated as described above, the failure mode can be avoided. The occurrence rate is highly asymmetric, and high fail-safety can be ensured.

〔Example〕

FIG. 1 shows a block diagram of the automatic train control system according to the present invention.As shown in FIG. It is configured to output an alternating signal when the sensor is detected, and output a DC signal when detecting a dangerous situation.

These outputs are input to the majority logic 4, and when there is an alternating signal from two or more systems, an alternating signal is output, and only this alternating current component is amplified by the AC amplifier 5 to drive Ryo, resulting in safe detection as a triple system. The configuration is such that it picks up Ryo in the sense that it is doing so.

FIG. 2 shows the majority logic according to the present invention shown in FIG. 1. Further, FIG. 3 shows the operating waveforms of the numbered part in the second figure.

41, 42, and 43 in Figure 2 are pulse generation circuits that detect edges of changes in the input signal and generate pulses, and Figure 3a
When there is an input signal like -c, pulse trains like d to f are generated. These pulse trains are processed by OR circuits 44 to 46
Thus, a combination of two systems of pulse trains is generated, and the pulse train of g=i in FIG. 3 is generated. These pulse trains are
The signal is input to a trigger input of an alternating signal transmission circuit constituted by edge trigger type latch circuits 47, 48, and 49. On the other hand, a second alternating signal whose frequency is more than half lower than that of the first alternating signal generated by the speed verification units (1) to (3) is input to the first data input terminal of this alternating signal. . Therefore, the second alternating signal is transmitted to the subsequent stage only when there is a pulse at the trigger terminals 47-49.

As shown in Figure 3, two systems of the outputs of each speed checking section are connected to one trigger terminal system, so if two or more systems output an alternating signal, the latch circuits 47 to 49 will be connected to the input signal. Second
The alternating signal is transmitted to the output of the final stage, and the alternating signal can be output as the final output.

When this signal is output, an alternating signal is input to the AC amplifier shown in FIG. 1, and the output Ryo is driven.

〔Effect of the invention〕

Since the present invention is constructed as described above, if a part of the constituent circuits stops functioning, the output alternating signal acts in a direction that makes it impossible to output, and unless a failure such as a short circuit between the input and output occurs, the speed check will continue. When two or more systems are outputting DC output, the alternating output will not be output as the final output.

In other words, even in the event of a failure, no alternating signal is erroneously output, and fail-safe properties can be easily maintained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an automatic train control device according to an embodiment of the present invention, Fig. 2 is a fail-safe majority logic circuit diagram of the present invention, Fig. 3 is an operation explanatory diagram of the fail-safe majority logic circuit, and Fig. 4 shows a block diagram of an automatic train control device using conventional majority logic. 1.2.3...Speed check section, 4...Majority logic section,
5... AC amplifier section, 41, 42.43... Pulse generation circuit, 44, 45.46... OR circuit. No. 2

Claims (1)

[Claims] 1. Monitors the state of the object to be controlled, detects when the state of the object has become dangerous beyond a predetermined state, and outputs an alternating signal to the output if it is on the safe side. In this case, input the first detector that outputs a logic value of a certain level of DC, the second and third detectors that have the same function, and the outputs of the first to third detectors, When an alternating signal is input to each input, a pulse generating circuit detects the changing edge thereof and outputs a pulse, and an alternating frequency having a frequency of 1/2 or less of the frequency of the alternating signal is input, A combination of an alternating signal transmission circuit in which multiple stages of edge trigger type latch circuits are connected in series and the above-mentioned pulse generation circuit are input to the trigger terminal of this latch circuit, and the safe side is achieved only when there is an alternating signal at the output of the alternating signal transmission circuit. A majority logic circuit that outputs an output indicating that it has detected.