JP6629474B1 - Signal switching device - Google Patents

Abstract

A signal switching device is provided that can prevent erroneous detection that a disconnection has occurred during signal switching. A signal switching device selects one of input signals from two controllers (51, 52) based on a switching signal from the outside, and selects one of the selected input signals. A first signal switching device (2) to be output to the process, and, based on the switching signal, the other input signal not selected by the first signal switching device among the input signals from each of the two controllers. And a second signal switching device (3) forming a folded circuit so as not to be an open circuit. [Selection diagram] Fig. 1

Description

  The present invention relates to a signal switching device that prevents erroneous detection of a disconnection point due to signal switching.

  The signal switching device is used at the time of controller renewal work, and realizes simultaneous output of one signal in two directions or output of two signals in any one direction in terms of hardware. The use of a signal switching device with such a function eliminates the need for a sequencer and dedicated programs that are conventionally required for signal switching, reducing the cost of updating work and increasing the efficiency of updating work. (For example, see Patent Document 1).

JP 2014-115805 A

  In recent years, such a function has been required to be applied not only to a controller update work but also to a signal switching device in a redundant configuration of controller input / output units. In particular, recent controllers that place emphasis on system reliability have commercialized products that have a dual input / output section and a function to detect the disconnection of the signal transmission path from the input / output section to the process. ing.

  Consider a case where a conventional signal switching device is applied to such a controller. For example, consider a case in which a digital output signal switching device selects one output from digital signals output from two controllers and outputs it to a process.

  In this case, the one output signal line on the non-selected side becomes an open circuit inside the digital output signal switching device. For this reason, the controller with the disconnection detecting function has a problem in that this open circuit state, which occurs as a normal state at the time of signal switching, is determined to be a disconnection, and a disconnection abnormality is erroneously detected.

  The present invention has been made in order to solve the above-described problem, and has as its object to provide a signal switching device that can prevent erroneous detection that a disconnection has occurred during signal switching. .

  A signal switching device according to the present invention selects one of input signals from each of two controllers based on an external switching signal, and outputs the selected one of the input signals to a process. One signal switching device and, based on the switching signal, of the input signals from each of the two controllers, the other input signal not selected by the first signal switching device is turned back so as not to be an open circuit. And a second signal switching device forming a circuit.

  According to the present invention, there is provided a configuration for preventing a circuit on an unselected side from becoming an open circuit at the time of signal switching. As a result, it is possible to obtain a signal switching device that can prevent erroneous detection that a disconnection has occurred during signal switching.

FIG. 2 is an internal block diagram of a digital output signal switching device, which is an example of the signal switching device according to Embodiment 1 of the present invention. FIG. 9 is an internal block diagram of a digital output signal switching device, which is an example of a signal switching device according to Embodiment 2 of the present invention. FIG. 9 is an internal block diagram of a digital output signal switching device, which is an example of a signal switching device according to Embodiment 3 of the present invention. FIG. 4 is an external structural diagram illustrating a case where a signal input from a switching signal output device is used as a drive signal of a DO signal switching device 2 in the first to third embodiments of the present invention. FIG. 17 is an external structural diagram illustrating a case where a signal input from a switch with a connector that can be manually operated is used as a drive signal for a DO signal switching device in a fourth embodiment of the present invention. FIG. 9 is an internal block diagram of a digital output signal switching device, which is an example of a conventional signal switching device. FIG. 9 is an internal block diagram of a digital output signal switching device, which is an example of a conventional signal switching device.

  Hereinafter, preferred embodiments of the signal switching device of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
Before describing the configuration of the present invention, a configuration of a conventional signal switching device in which a problem of erroneously detecting a disconnection abnormality occurs will be described with reference to FIGS. 6 and 7 are internal block diagrams of a digital output signal switching device, which is an example of a conventional signal switching device. 6 and 7 show circuit diagrams for one point of the digital output signal.

  In FIG. 6, a conventional digital output signal switching device 100 includes a DO signal switching device 2 therein. Outside the digital output signal switching device 100, a DO card 51 of the controller (A), a DO card 52 of the controller (B), a switching signal output device 53, and a process 54 are connected.

  The DO signal from the DO card 51 of the controller (A) is connected to the contact b of the DO signal switching device 2 as one input signal to the digital output signal switching device 100. On the other hand, the DO signal from the DO card 52 of the controller (B) is connected to the contact a of the DO signal switching device 2 as the other input signal to the digital output signal switching device 100.

  In this state, when the switching signal of the switching signal output device 53 is OFF, the contact b of the DO signal switching device 2 is ON and the contact a is OFF. In such a state, the DO signal from the DO card 51 of the controller (A) is selected and output to the process 54, and a loop indicated by a broken line L1 in FIG. 6 is formed.

  On the other hand, the DO signal line from the DO card 52 of the controller (B) has the contact a in the OFF state, so that the signal line to the process 54 is an open circuit. This state is shown in FIG. A broken line L2 in FIG. 7 is a loop of the DO signal from the DO card 52 of the controller (B). However, since the a-contact of the DO signal switching device 2 is currently in the OFF state, the DO signal line to the process 54 is an open circuit at the x mark in FIG.

  When such an open circuit state occurs, the controller having the disconnection detection function erroneously detects the open circuit state as “disconnection has occurred”. Therefore, a signal switching device according to the first embodiment having a configuration capable of preventing such erroneous detection will be described in detail below with reference to the drawings.

  FIG. 1 is an internal block diagram of a digital output signal switching device, which is an example of a signal switching device according to Embodiment 1 of the present invention. FIG. 1 shows a circuit diagram for one point of a digital output signal.

  1, the digital output signal switching device 1 according to the first embodiment includes a DO signal switching device 2, a return signal switching device 3, and a resistor 4 therein. Here, the DO signal switching device 2 corresponds to a first signal switching device that performs a switching operation based on an external switching signal. Further, the signal switching device 3 for loopback corresponds to a second signal switching device that performs a switching operation based on a switching signal from the outside.

  Outside the digital output signal switching device 1, a DO card 51 of the controller (A), a DO card 52 of the controller (B), a switching signal output device 53, and a process 54 are connected.

  Therefore, the switching device 1 for digital output signals according to the first embodiment outputs the switching signal from the switching signal output device 53 based on the switching signals from the two controllers (A) and (B). , And outputs one selected input signal to the process 54.

  Compared with the conventional signal switching device shown in FIGS. 6 and 7, the signal switching device according to the first embodiment shown in FIG. 1 further includes a folding signal switching device 3 and a resistor 4. Is different.

  The DO signal from the DO card 51 of the controller (A) is used as one input signal to the digital output signal switching device 1 as the b contact of the DO signal switching device 2 and the a contact of the return signal switching device 3. And connected to. On the other hand, the DO signal from the DO card 52 of the controller (B) is used as the other input signal to the digital output signal switching device 1 as an a contact of the DO signal switching device 2 and a b contact of the return signal switching device 3. And connected to.

  Next, the operation of the signal switching device 1 according to the first embodiment shown in FIG. 1 will be described. When the switching signal of the switching signal output device 53 is OFF, the b contact of the DO signal switching device 2 is in the ON state, and the a contact is in the OFF state. In such a state, the DO signal from the DO card 51 of the controller (A) is selected and output to the process 54.

  On the other hand, the DO signal line from the DO card 52 of the controller (B) is not output to the process 54 because the contact a is in the OFF state. The operation up to this point is the same as in the prior art shown in FIGS.

  However, in the first embodiment, the DO signal from the DO card 52 of the controller (B) is connected to the contact b of the return signal switching device 3. Therefore, when the switching signal of the switching signal output device 53 is OFF, a loop indicated by a broken line L3 is formed via the resistor 4.

  As a result, the output line from the DO card 52 of the controller (B) is not an open circuit, and even when a controller having a disconnection detection function is connected, disconnection is not detected at the time of signal switching operation, and disconnection occurs. Will not be erroneously detected. At this time, the resistor 4 may be set to any value that can secure the minimum current necessary for the disconnection detection function of the controller.

  In the above description, the case where the switching signal of the switching signal output device 53 is OFF and the DO signal from the DO card 51 of the controller (A) is selected has been described. However, the same applies to the case where the switching signal of the switching signal output device 53 is ON and the DO signal from the DO card 52 of the controller (B) is selected. The signal will not be an open circuit. Therefore, also in this case, since the disconnection is not detected during the switching operation, there is no possibility that the disconnection is erroneously detected.

  Further, FIG. 1 is merely an example showing a circuit configuration, and each contact, relay, power supply, and the like may use alternative members as long as equivalent effects can be obtained.

  Further, for simplicity of description, only one circuit is shown in FIG. 1; however, a specification suitable for the system can be obtained by increasing the number of circuits according to the application.

Embodiment 2 FIG.
In the first embodiment, a case has been described in which the switching device for digital output signals corresponding to the disconnection detection function of the controller has a circuit configuration for preventing erroneous detection that disconnection has occurred during the switching operation. However, such a circuit configuration is unnecessary for a controller having no disconnection detection function.

  In the second embodiment, a signal switching device having a circuit configuration that can be separated into a first portion including only the DO signal switching device 2 and a second portion including the return signal switching device 3 and the resistor 4 will be described. I do. The signal switching device according to the second embodiment having such a circuit configuration combines the first part and the second part or removes the second part according to the presence / absence of a disconnection detection function of the controller. Thus, it is possible to realize a structure that can select either the first part or the first part.

  FIG. 2 is an internal block diagram of a digital output signal switching device, which is an example of a signal switching device according to Embodiment 2 of the present invention. FIG. 2 shows a circuit diagram for one point of the digital output signal. 2, the digital output signal switching device 1 has a structure in which a signal switching unit 11 corresponding to a first portion and a signal folding unit 21 corresponding to a second portion are separated.

  Here, a connector 12 is mounted inside the signal switching unit 11 together with the DO signal switching device 2. On the other hand, a connector 22 is mounted on the signal return section 21 together with the return signal switching device 3 and the resistor 4.

  The connection method of the DO card 51 of the controller (A), the DO card 52 of the controller (B), the switching signal output device 53, and the process 54 connected to the outside of the digital output signal switching device 1 is as described above. This is the same as in the first embodiment.

  The signal switching unit 11 and the signal turn-back unit 21 have a structure that can be combined with each other or removed individually by the connector 12 and the connector 22. When the signal switching unit 11 and the signal folding unit 21 are combined, they can be used as a digital output signal switching device corresponding to the disconnection detection function of the controller.

  On the other hand, when the signal folding section 21 is removed and only the signal switching section 11 is used, it can be used as a digital output signal switching device corresponding to a controller having no disconnection detection function. By providing such a separable structure, unnecessary functional components can be physically reduced according to the specifications of the connected controller. As a result, it is possible to reduce costs.

  Note that the circuit operation of the signal switching device according to the second embodiment is the same as that of the first embodiment, and a description thereof will not be repeated. The shape of the connector 12 and the connector 22 is not limited as long as signals can be transferred.

Embodiment 3 FIG.
In the second embodiment, the configuration in which the signal is exchanged between the signal switching unit 11 and the signal turn-back unit 21 via the connector 12 and the connector 22 has been described. By employing such a connector configuration, when the signal switching device according to the second embodiment is used for a controller having no disconnection detection function, the signal turn-back portion 21 can be physically removed, The number was reduced and the cost was reduced.

  On the other hand, in the third embodiment, a case will be described in which, instead of the connector configuration, a configuration in which the presence or absence of signal transmission is controlled by a relay contact or the like is employed. FIG. 3 is an internal block diagram of a digital output signal switching device, which is an example of the signal switching device according to Embodiment 3 of the present invention. FIG. 3 shows a circuit diagram for one point of the digital output signal.

  The digital output signal switching device 1 according to the third embodiment shown in FIG. 3 includes a signal switching unit 31 with a disconnection error detection prevention function in which both functions of the signal switching unit 11 and the signal folding unit 21 are mounted. It is configured. The signal switching unit 31 with a disconnection error detection prevention function further includes a loopback setting circuit 33 having a relay 32 and a disconnection error detection prevention function presence / absence selection switch 34.

  The return setting circuit 33 having the relay 32 and the disconnection error detection prevention function presence / absence selection switch 34 are configured to replace the connector 12 and the connector 22 in the second embodiment. That is, the return setting circuit 33 having the relay 32 and the disconnection error detection prevention function presence / absence selection switch 34 are configured to combine or separate the signal switching unit 11 and the signal return unit 21.

  Here, the loop-back setting circuit 33 corresponds to a relay circuit that can switch between a connected state and a disconnected state by the operation of the relay 32. Further, the disconnection error detection prevention function presence / absence selection switch 34 corresponds to a switch that generates a selection switch input capable of switching the relay 32 to an on state or an off state. Therefore, the circuit configuration shown in FIG. 3 has a structure in which the DO signal switching device 2 and the turn-back signal switching device 3 can be selected in either the connection state or the non-connection state according to the selection switch input. I have.

  The connection method of the DO card 51 of the controller (A), the DO card 52 of the controller (B), the switching signal output device 53, and the process 54 connected to the outside of the digital output signal switching device 1 is as described above. This is the same as each of the first and second embodiments.

  Next, the operation of the signal switching device 1 according to the third embodiment shown in FIG. 3 will be described. When the signal switching device 1 according to the third embodiment is used as a digital output signal switching device for a controller having no disconnection detection function, the disconnection error detection prevention function presence / absence selection switch 34 is turned off. As a result, the relay 32 is turned off, and all the contacts of the loop-back setting circuit 33 are turned off. Therefore, the signal switching unit 11 and the signal turn-back unit 21 are electrically disconnected from each other, and the disconnection error detection prevention function is invalidated.

  On the other hand, when the signal switching device 1 according to the third embodiment is used as a digital output signal switching device for a controller having a disconnection detection function, the disconnection error detection prevention function presence / absence selection switch 34 is turned ON. I do. As a result, the relay 32 is turned on, and all the contacts of the return setting circuit 33 are turned on. For this reason, the signal switching unit 11 and the signal turn-back unit 21 are electrically connected, and the disconnection error detection prevention function is effective.

  In this way, by providing the configuration shown in FIG. 3, the signal switching unit 11 can be connected to the signal switching unit 11 only by operating the switch without having to physically detach the signal folding unit 21 from the signal switching unit 11. The signal folding section 21 can be electrically connected or disconnected. As a result, irrespective of the presence or absence of the disconnection detecting function of the controller, it is possible to cope with one type of signal switching device, and it is possible to reduce the manufacturing cost and the cost for product management.

  Further, when updating from a controller without a disconnection detection function to a controller with a disconnection detection function, or vice versa, the signal switching device 1 according to the third embodiment can immediately switch between the controllers by performing only switch operations. Can be handled. Therefore, the efficiency of the updating operation can be improved.

  In the third embodiment, the case where the relay 32 is used as the loop-back setting circuit 33 has been described. However, instead of the relay 32, a semiconductor relay or another component can also realize the same function as long as it has the same switch function and can perform ON / OFF control of a signal.

  Although only one circuit is shown in FIG. 3 for simplification of the description, the specifications suitable for the system can be obtained by increasing the number of circuits according to the application. That is, the loop-back setting circuit 33 may be provided for each of the plurality of circuits, or the circuit may be applied to control the plurality of circuits collectively.

Embodiment 4 FIG.
In the first to third embodiments, the case where the signal from the switching signal output device 53 is input as the driving signal of the DO signal switching device 2 has been described. On the other hand, in the fourth embodiment, a configuration will be described in which a drive signal of the DO signal switching device 2 can be input using a switch contact that can be manually operated at an arbitrary timing.

  The signal switching device 1 has different parts in terms of structure and operation between the case where the signal switching device 1 is used in a controller update work and the case where the signal switching device 1 is used in a redundant system configuration of controller input / output units.

  When the signal switching device 1 is used in a controller update work, an operator needs to switch signals at an arbitrary timing. For this reason, it is required that a switch be mounted on the apparatus main body to enable a manual switching operation.

  On the other hand, when the signal switching device is used in a redundant system configuration of the controller input / output unit, a switching signal input connector is mounted on the device main body, and a system error is detected by the switching signal input from the controller or other devices. Sometimes it is necessary to enable automatic signal switching.

  Conventionally, a signal switching device 1 having a different structure must be prepared for each application, and there has been a problem that costs increase due to an increase in members due to an increase in the product lineup. Therefore, in the fourth embodiment, measures for coping with such a problem will be described.

  FIG. 4 is an external structural view showing a case where a signal input from the switching signal output device 53 is used as a drive signal of the DO signal switching device 2 in the first to third embodiments of the present invention. In FIG. 4, a switching signal input connector (receptacle side) 40 is mounted on the front surface of the digital output signal switching device 1. The switching signal from the switching signal output device 53 is connected to the switching signal input connector (receptacle side) 40 via the switching signal input connector (plug side) 41.

  On the other hand, FIG. 5 is an external structural view showing a case where a signal input from the switch 42 with a connector which can be manually operated is used as a drive signal of the DO signal switching device 2 in the fourth embodiment of the present invention. In FIG. 5, the switch with connector 42 has a configuration in which a manual switch 43 is mounted on the switching signal input connector (plug side) 41.

  As shown in FIG. 4 and FIG. 5, by adopting a connector structure using a switching signal input connector (receptacle side) 40 to take in a switching signal from the outside, the digital output signal switching device 1 Automatic switching by the switching signal output device 53 and manual switching by operating the switch with connector 42 are possible without changing the structure. For this reason, the same signal switching device 1 can be used, and it is not necessary to prepare different products for each application.

  Although the connector-equipped switch 42 has been described with reference to FIG. 5 showing a toggle switch, a similar effect can be obtained with a switch having a different structure. FIG. 5 showing an integrated structure of the switching signal input connector (plug side) 41 and the manual switch 43 is merely an example, and the switch with connector 42 has a structure different from such an integrated structure. It may be.

  Further, the connection of the switch with connector 42 in the fourth embodiment has been described in the case where the switch 42 is connected to the digital output signal switching device 1. However, the present invention is not limited thereto, and the switch with connector 42 can be applied to a digital input, an analog output, an analog input, or any other device mainly for signal switching, which needs to input a switching signal from outside. It is.

  Reference Signs List 1 digital output signal switching device (signal switching device), 2 DO signal switching device (first signal switching device), 3 turn signal switching device (second signal switching device), 4 resistor, 11 signal switching unit , 12 connectors, 21 signal return section, 22 connector, 31 signal switching section with disconnection error detection prevention function, 32 relay, 33 return setting circuit, 34 disconnection error detection prevention function presence / absence selection switch, 40 switching signal input connector (receptacle Side), 41 Connector for switching signal input (plug side), 42 Switch with connector, 43 Manual switch.

Claims (4)

A first signal switching device that selects one of the input signals from each of the two controllers based on an external switching signal, and outputs the selected one of the input signals to a process;
A fold-back circuit is formed based on the switching signal so that the other input signal not selected by the first signal switching device among the input signals from each of the two controllers is not opened. And a second signal switching device. The said 2nd signal switching device is connected via a connector with respect to the said 1st signal switching device, and has a structure which can be attached or detached according to the specification of two said controllers. Signal switching device. The second signal switching device is connected to the first signal switching device via a relay circuit that can switch between a connection state and a non-connection state according to a selection switch input. The signal switching device according to claim 1, wherein the signal switching device has a structure capable of selecting one of the connection state and the non-connection state with respect to the first signal switching device according to the specification of the controller. The signal switching device according to any one of claims 1 to 3, further comprising a connector structure for receiving the switching signal from the outside.

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