JP4845779B2 - DC output circuit with failure detection function - Google Patents

Description

  The present invention relates to a DC output circuit having a failure detection function for safely controlling field equipment in a railway security device.

  In railway security equipment that controls switchboards and signal lights, equipment failures can lead to serious accidents. Therefore, a fail-safe configuration for controlling the entire apparatus to the safe side is indispensable in the railway security apparatus even when the apparatus fails.

  In the DC output circuit that is a component of the railroad safety device and drives field equipment such as a switch and a signal light, an erroneous output that erroneously switches the switch or erroneously lights the signal light is a dangerous failure. Is a safe failure.

  In order to realize a fail-safe DC output circuit, a configuration in which two switches are connected in series between a load driving power source and a load may be used. In this configuration, even if one of the switches is on-failed, the DC output circuit does not erroneously output.

  However, if the on failure of the switch cannot be detected promptly, an erroneous output will occur if the other switch is on, resulting in a dangerous failure. For this reason, a system is generally used in which a voltage sensor is connected to the output side of each switch to detect a switch failure.

  However, in the above-described configuration, if the switch on the power supply side is turned on as part of the operation for detecting the switch failure in a state in which the on failure of the switch on the load side is latent, an error is output. For this reason, the execution of the failure detection operation needs to be prevented from causing a problem even if an erroneous output occurs.

For example, a method as disclosed in Patent Document 1 has been proposed for the above-described problem. Patent Document 1 discloses an abnormality detection device that detects failure of each switching element and improves fail-safety in a load driving device that drives a load through two switching elements connected in series. ing.
JP 2001-236871 A

  An object of the present invention is to provide a DC output circuit described in the background art that reliably detects on failure of a switch and prevents erroneous output.

The DC output circuit of the present invention has a function of detecting a switch failure by connecting a plurality of switches including a 1-system switch and a 2-system switch in series and connecting a voltage sensor to the output side of each switch. A common system switch is connected to the negative side output of the DC output circuit, and a plurality of switches including the first system switch and the second system switch and the initial state of the common system switch are all turned off. The response of the on / off operation is detected by a first voltage sensor to detect a failure of the common system switch. After executing the failure detection operation of the common system switch, the common system switch is then turned off. The response of the on / off operation of the 1-system switch is detected by a second voltage sensor, the failure of the 1-system switch is detected, and the failure detection operation of the 1-system switch is detected. After the operation is performed, the first system switch is in an on state, the common system switch is in an off state, and a response to the on / off operation of the second system switch is detected by a third voltage sensor to detect a fault in the second system switch. In the same manner, the response of the on / off operation is sequentially detected by the voltage sensor connected to the output side of each switch to detect the failure of each switch. It is characterized in that it does not cause an erroneous output and can reliably detect a failed switch.

  According to the present invention, by connecting a switch to the negative output of the DC output circuit and executing a specific procedure, the above problem can be solved, the switch on failure is reliably detected, and erroneous output is prevented. The DC output circuit can be configured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a DC output circuit using the present invention.
A load driving power source 1 and a load 5 driven by the load driving power source 1 are provided, and the load driving power source 1 is connected to the sensor 2 and the 1-system switch 6 via the wiring 9. The first system switch 6 is connected to the sensor 3 and the second system switch 7 via the wiring 10. The 2 system switch 7 is connected to the sensor 4 and the load 5 through the wiring 11. The load 5 is connected to the sensor 2 and the common system switch 8 via the wiring 13. The common system switch 8 is connected to the load driving power source 1, the sensor 3, and the sensor 4 through the wiring 12.

  Further, the 1-system switch 6 and the 2-system switch 7 are controlled by the CPU section 20 by the 1-system switch control signal 15 and the 2-system switch control signal 17, respectively. Each sensor informs the CPU 20 that a specified voltage has been applied as a common system switch failure detection result 14, a system 1 switch failure detection result 16, and a system 2 switch failure detection result 18.

  The failure detection of the 1-system switch 6, the 2-system switch 7, and the common system switch 8 can be performed by executing the flowchart of FIG.

  The initial state of the 1 system switch 6, 2 system switch 7, and common system switch 8 are all off, and the failure detection of the common system switch 8 is performed by detecting the response of the on / off operation of the common system switch 8 using the sensor 2 and the CPU 20 To tell. Thereby, failure detection of the common system switch 8 becomes possible.

  After the failure detection operation of the common system switch 8 is executed, the failure detection operation of the system 1 switch 6 is executed next. When failure detection of the 1-system switch 6 is performed, the common system switch 8 is turned off, and the response of the on / off operation of the 1-system switch 6 is transmitted to the CPU unit 20 by the sensor 3.

  At this time, since the failure of the common system switch 8 is detected, the off state of the common system switch 8 is guaranteed, and even if the second system switch 8 is on, the load 5 is not driven due to an erroneous output. . Thereby, failure detection of the 1-system switch 6 becomes possible.

  After executing the failure detection operation of the 1-system switch 6, the failure detection operation of the 2-system switch 7 is performed. When the failure detection of the 2 system switch 7 is performed, the 1 system switch 7 is in the ON state, the common system switch 8 is in the OFF state, and the response of the ON / OFF operation of the 2 system switch 8 is transmitted to the CPU unit 20 by the sensor 4.

  At this time, the failure detection of the 1-system switch 6 and the common system switch 8 is performed in the same manner as the detection of the failure of the 1-system switch 6, so that the on-state of the 1-system switch 8 and the off-state of the common system switch 8 are guaranteed. The load 5 is not driven by an erroneous output. Thereby, failure detection of the 2 system switch 7 is attained.

  Furthermore, according to the present invention, even when the switches connected in series have two or more stages (3-system, 4-system, 5-system,...), The switch failure can be detected by the same method.

  In railway safety devices such as railway traffic lights, it is necessary to reliably prevent erroneous output due to component failure or the like. For this reason, in addition to the control circuit for the relay drive output signal, a redundant circuit for detecting failure of the 1-system switch, 2-system switch, and common system switch is added, so that the configuration ensures safety. It becomes a structure like 1.

FIG. 3 shows a plurality of DC output circuits according to the second embodiment of the present invention.
The configuration of FIG. 3 is a circuit in the case where one DC output circuit shown in FIG. 1 is configured by a plurality of points. Since the wiring connected to the load drive power supply and the negative electrode side of the load is common to the output circuit having a plurality of points, there is one common system switch. Further, the load drive power supply is also configured to drive a plurality of loads with one system.

  As for the failure detection method, the basic method is the same as the flow chart of FIG. 2, but since the common system switch is a common switch for each output circuit, after the failure detection of the common system switch, 1/2 Failure detection of all points of the system output circuit must be performed.

  FIG. 4 shows a flowchart of the multipoint DC output circuit (the flowchart of FIG. 2 is omitted). After detecting the failure of the common system switch, a loop corresponding to the number of output circuits is added in order to detect the failure of the 1/2 system switch of all output circuits with the common system switch turned off.

FIG. 5 shows a double DC output circuit according to Embodiment 3 of the present invention.
In the configurations of the first and second embodiments, one load is driven using one DC output circuit. In the configurations of the first and second embodiments, the on / off failure detection can be performed by executing the procedures of the flowcharts of FIGS. 2 and 4 in the output stop state.

  However, in the output state (load drive state), when detecting an on-failure, it is necessary to turn off the switch, so the output must be stopped, which affects the load state. . A configuration for avoiding this is shown in FIG.

  In the dual system DC output circuit of the third embodiment in FIG. 5, a reverse system diode 47 is inserted in the configuration shown in FIG. One load is driven.

  In the normal operation state, both systems operate in exactly the same way. In the output state that is the problem, during the failure detection operation, the failure detection operation is performed with only one system, and the other systems are in the output state.

  After completion of the failure detection operation, the system that has been in the output state performs the failure detection operation, and the system that has been performing the failure detection operation is in the output state. As a result, failure detection can be performed without affecting the load.

1 is a configuration diagram of a single-point DC output circuit according to Embodiment 1 of the present invention. FIG. It is a flowchart of the DC output circuit failure detection of the single point of this invention. It is a DC output circuit block diagram of multiple points of Example 2 of the present invention. It is a flowchart of the DC output circuit failure detection of multiple points of the present invention. FIG. 6 is a configuration diagram of a double DC output circuit according to a third embodiment of the present invention.

Explanation of symbols

1 Load drive power supply 2 Sensor (Common system switch failure detection circuit)
3 Sensor (1 system switch failure detection circuit)
4 Sensor (2 system switch failure detection circuit)
5 Load 6 1 system switch 7 2 system switch 8 Common system switch 9-13 Wiring 14 Common system switch failure detection result 15 1 system switch control signal 16 1 system switch failure detection result 17 2 system switch control signal 18 2 system switch failure detection Result 19 Common system switch control signal 20 CPU unit 21 Common system switch on 22, 25 Common system switch failure detection result fetching 23, 26, 29, 32, 36, 39 Load drive power supply voltage presence / absence determination 24 Common system switch off 27, 33 1-system switch on 28, 31 1-system switch failure detection result capture 30, 40 1-system switch off 34 2-system switch on 35, 38 2-system switch failure detection result capture 37 2-system switch off 41 Initial value setting 42 Common System switch on / off failure detection (flow charts 21-26)
43 X point 1 system switch on / off failure detection (flow charts 27 to 32)
44 Increment of set value 45 X point 2 system switch on / off failure detection (flow chart of 33 to 40)
46 Judgment of loop count 47 Reverse current prevention diode

Claims (4)

In a DC output circuit having a function of detecting a switch failure by connecting a plurality of switches including a 1-system switch and a 2-system switch in series and connecting a voltage sensor to the output side of each switch,
A common system switch is connected to the negative output of the DC output circuit, and a plurality of switches including the first system switch and the second system switch and the initial state of the common system switch are all off.
Detecting a response of an ON / OFF operation of the common system switch by a first voltage sensor to detect a failure of the common system switch;
After executing the failure detection operation of the common system switch, the common system switch is turned off, and the response of the on / off operation of the first system switch is detected by a second voltage sensor. Detect failure,
After executing the failure detection operation of the system 1 switch, the system 1 switch is in an on state, the system switch is in an off state, and a response of an on / off operation of the system 2 switch is detected by a third voltage sensor, The failure detection of the 2 system switch is performed, and thereafter, similarly, the response of the on / off operation is sequentially detected by the voltage sensor connected to the output side of each switch to detect the failure of each switch.
A DC output circuit characterized in that even if one switch fails, it does not erroneously output and can detect the failed switch reliably. The DC output circuit according to claim 1,
2. The DC output circuit according to claim 1, wherein the plurality of switches are two switches. The DC output circuit according to claim 1,
A plurality of series including a plurality of switches including the first system switch and the second system switch are connected in series and connected to a load, and a voltage sensor is connected to the output side of each switch to detect a switch failure. And
One common system switch common to the series of the plurality of points is connected to the negative side output of the DC output circuit, and the common one common system switch , the 1 system switch and the 2 system in the plurality of series For multiple switches including switches, detect the failure of each switch in the same way,
A DC output circuit characterized in that even if a switch connected in series in the series of the plurality of points fails, no erroneous output is performed and the failed switch can be detected reliably. The DC output circuit according to claim 1,
A plurality of switches having a function of detecting a switch failure by connecting a plurality of switches in series, connecting a voltage sensor to the output side of each switch, and connecting a common system switch to the negative side output of the DC output circuit Are connected to one load,
A DC output circuit characterized in that, when each switch of the plurality of systems fails, a failure detection operation is performed in only one system, and the other system is in an output state.

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