JP2020144581A - Signal changeover apparatus - Google Patents

Abstract

To obtain a signal changeover apparatus capable of preventing a false detection such that a disconnection occurs when a signal is changed over.SOLUTION: A signal changeover apparatus includes: a first signal changeover device (2) which selects either one of input signals from two controllers (51 and 52), respectively, on the basis of an external changeover signal, and which outputs the selected input signal to a process; and a second signal changeover device (3) that forms a return circuit so as not to form an open circuit for the other input signal not selected by the first signal changeover device in the input signals from the two controllers, respectively, on the basis of the changeover signal.SELECTED DRAWING: Figure 1

Description

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

The signal switching device is used at the time of controller renewal work, and realizes that one signal is output simultaneously in two directions or two signals are output in any one direction in terms of hardware. By using a signal switching device equipped with such a function, the sequencer and the dedicated program installed in the sequencer, which have been conventionally required for signal switching, are no longer required, the cost of renewal work is reduced, and the renewal work is highly efficient. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-115805

In recent years, such a function is required not only to be applied to controller renewal work but also to be applied as a signal switching device in a duplicated controller input / output unit configuration. In particular, recent controllers that emphasize system reliability have been commercialized with a duplicated input / output section and a function to detect disconnection of the signal transmission path from the input / output section to the process. ing.

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

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

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a signal switching device capable of preventing erroneous detection that a disconnection has occurred during signal switching. ..

The signal switching device according to the present invention selects one of the input signals from each of the two controllers based on the switching signal from the outside, and outputs the selected input signal to the process. With respect to the input signal from one signal switching device and the input signal from each of the two controllers based on the switching signal, the other input signal not selected by the first signal switching device is folded back so as not to open the circuit. It includes a second signal switching device that forms a circuit.

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

It is an internal block diagram of the digital output signal switching device which is an example of the signal switching device which concerns on Embodiment 1 of this invention. It is an internal block diagram of the digital output signal switching device which is an example of the signal switching device which concerns on Embodiment 2 of this invention. It is an internal block diagram of the digital output signal switching device which is an example of the signal switching device which concerns on Embodiment 3 of this invention. FIG. 5 is an external structural diagram showing a case where a signal input from a switching signal output device is used as a driving signal for a DO signal switching device 2 in the first to third embodiments of the present invention. FIG. 5 is an external structural diagram showing a case where a signal input from a switch with a connector capable of manual operation is used as a driving signal for a DO signal switching device in the fourth embodiment of the present invention. It is an internal block diagram of the digital output signal switching device which is an example of the conventional signal switching device. It is an internal block diagram of the digital output signal switching device which is an example of the 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.
Before explaining the configuration of the present invention, the configuration of the conventional signal switching device, which causes a problem of erroneously detecting a disconnection abnormality, will be described with reference to FIGS. 6 and 7. 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 a circuit diagram per point of the digital output signal.

In FIG. 6, the conventional digital output signal switching device 100 includes a DO signal switching device 2 inside. Further, outside the digital output signal switching device 100, 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 are connected.

The DO signal from the DO card 51 of the controller (A) is connected to the b contact 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 a contact 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 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, and the loop shown by the broken line L1 in FIG. 6 is formed.

On the other hand, since the a contact of the DO signal line from the DO card 52 of the controller (B) is in the OFF state, the signal line to the process 54 is an open circuit. This state is shown in FIG. The 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 part marked with x in FIG. 7.

When such an open circuit state occurs, the controller having the disconnection detection function erroneously detects the open circuit state as "disconnection occurrence". Therefore, the signal switching device according to the first embodiment having a configuration capable of preventing such false 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 the signal switching device according to the first embodiment of the present invention. In FIG. 1, a circuit diagram per point of a digital output signal is shown.

In FIG. 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 inside. Here, the DO signal switching device 2 corresponds to a first signal switching device that performs a switching operation based on a switching signal from the outside. Further, the return signal switching device 3 corresponds to a second signal switching device that performs a switching operation based on a switching signal from the outside.

Further, outside the digital output signal switching device 1, 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 are connected.

Therefore, the digital output signal switching device 1 according to the first embodiment is among the input signals from the two controllers (A) and (B) based on the switching signal from the switching signal output device 53. , One of them is selected, and the input signal of the selected one is output 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 return signal switching device 3 and a resistor 4. The point is different.

The DO signal from the DO card 51 of the controller (A) is the b contact of the DO signal switching device 2 and the a contact of the return signal switching device 3 as one input signal to the digital output signal switching device 1. Is connected to. On the other hand, the DO signal from the DO card 52 of the controller (B) is the a contact of the DO signal switching device 2 and the b contact of the return signal switching device 3 as the other input signal to the digital output signal switching device 1. Is 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 a contact is in the OFF state. The operations up to this point are the same as those of the prior art shown in FIGS. 6 and 7.

However, in the first embodiment, the DO signal from the DO card 52 of the controller (B) is connected to the b contact of the return signal switching device 3. Therefore, when the switching signal of the switching signal output device 53 is OFF, the loop shown by the 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 no longer an open circuit, and even when a controller having a disconnection detection function is connected, the disconnection is not detected during the signal switching operation, and the disconnection occurs. It will not be erroneously detected as. At this time, the resistor 4 may be set to an arbitrary value that can secure the minimum current required 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, and the same applies to the DO from the DO card 51 of the controller (A). The signal is not open circuit. Therefore, even in this case, since the disconnection is not detected during the switching operation, it is not erroneously detected as the disconnection occurs.

Further, FIG. 1 is merely an example showing a circuit configuration, and if the same effect can be obtained, each contact, relay, power supply, etc. can use a member instead of the member.

Further, in order to simplify the explanation, only one circuit is described in FIG. 1, but by increasing the number of circuits according to the application, the specifications can be made suitable for the system.

Embodiment 2.
In the first embodiment, the case where the digital output signal switching device corresponding to the disconnection detection function of the controller is provided with a circuit configuration for preventing erroneous detection that a disconnection has occurred during the switching operation has been described. However, such a circuit configuration is unnecessary for a controller that does not have a disconnection detection function.

Therefore, 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 folding signal switching device 3 and the resistor 4 will be described. To do. In the signal switching device according to the second embodiment having such a circuit configuration, the first part and the second part are combined or the second part is removed according to the presence or absence of the disconnection detection function of the controller. It is possible to realize a structure in which only the first part can be selected.

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 the second embodiment of the present invention. FIG. 2 shows a circuit diagram per point of the digital output signal. In FIG. 2, the digital output signal switching device 1 has a structure separated into a signal switching unit 11 corresponding to the first portion and a signal folding portion 21 corresponding to the second portion.

Here, the signal switching unit 11 is internally equipped with the connector 12 together with the DO signal switching device 2. On the other hand, the signal folding section 21 is equipped with a connector 22 together with a signal switching device 3 and a resistor 4 for folding.

The connection methods 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, which are connected to the outside of the digital output signal switching device 1, are described above. It is the same as the first embodiment.

The signal switching unit 11 and the signal folding unit 21 have a structure in which they can be combined with each other or individually removed by the connector 12 and the connector 22. When the signal switching unit 11 and the signal folding unit 21 are combined, it 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 unit 21 is removed and only the signal switching unit 11 is configured, 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 configurations can be physically reduced according to the specifications of the controller to be connected. As a result, it is possible to reduce the cost.

Since the circuit operation of the signal switching device according to the second embodiment is the same as that of the first embodiment, the description thereof will be omitted. Further, the connector 12 and the connector 22 may have any shape as long as they can exchange signals.

Embodiment 3.
In the second embodiment, the configuration in which the signal is transferred between the signal switching unit 11 and the signal folding unit 21 is described via the connector 12 and the connector 22. By adopting 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 folding portion 21 can be physically removed, and the member We were able to reduce the number and reduce costs.

On the other hand, in the third embodiment, a case where a configuration in which the presence / absence of signal transfer is controlled by a relay contact or the like is adopted instead of the connector configuration will be described. 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 the third embodiment of the present invention. In FIG. 3, a circuit diagram per point of the digital output signal is shown.

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 equipped with both functions of the signal switching unit 11 and the signal folding unit 21. It is composed of. Further, the signal switching unit 31 with a disconnection erroneous detection prevention function is further equipped with a turn-back setting circuit 33 having a relay 32 and a disconnection erroneous detection prevention function presence / absence selection switch 34.

The folding back setting circuit 33 having the relay 32 and the disconnection erroneous detection function presence / absence selection switch 34 have a configuration that replaces the connector 12 and the connector 22 in the second embodiment. That is, the turn-back 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 turn-back unit 21.

Here, the return setting circuit 33 corresponds to a relay circuit that can switch between a connected state and a non-connected state by the operation of the relay 32. Further, the disconnection erroneous 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 return signal switching device 3 can be selected as either a connected state or a non-connected state according to the selection switch input. There is.

The connection methods 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, which are connected to the outside of the digital output signal switching device 1, are described above. It 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 turn-back setting circuit 33 are turned off. Therefore, the signal switching unit 11 and the signal folding unit 21 are electrically separated from each other, and the disconnection erroneous 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 erroneous detection prevention function presence / absence selection switch 34 is turned on. To do. As a result, the relay 32 is turned on, and all the contacts of the return setting circuit 33 are turned on. Therefore, the signal switching unit 11 and the signal folding unit 21 are electrically connected to each other, and the disconnection erroneous detection prevention function is effective.

As described above, by providing the configuration shown in FIG. 3, the signal folding unit 21 can be directly attached to and detached from the signal switching unit 11 by simply operating the switch without having to make the signal folding unit 21 physically removable. The signal folding section 21 can be electrically connected or disconnected. As a result, regardless of the presence or absence of the disconnection detection function of the controller, one type of signal switching device can be used, and the manufacturing cost and the product management cost can be reduced.

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 immediately switches to both controllers only by operating a switch. It becomes possible to correspond to. Therefore, the efficiency of the update work can be improved.

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

Further, for the sake of simplification of the explanation, only one circuit is described in FIG. 3, but the specifications can be made suitable for the system by increasing the number of circuits according to the application. That is, the folding back setting circuit 33 may be similarly installed corresponding to each of the plurality of circuits, and further, the plurality of circuits may be applied to be controlled collectively.

Embodiment 4.
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 in which a drive signal of the DO signal switching device 2 can be input by using a switch contact that can be manually operated at an arbitrary timing will be described.

The signal switching device 1 also has different structural and operational aspects depending on whether it is used in controller renewal work or in a redundant system configuration of a controller input / output unit.

When the signal switching device 1 is used for controller renewal work, it is necessary for the worker to switch the signal at an arbitrary timing. Therefore, it is required to mount a switch on the main body of the device to enable manual switching operation.

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

Conventionally, it is necessary to prepare signal switching devices 1 having different structures depending on the application, and there is a problem that an increase in members due to an increase in a product lineup leads to an increase in cost. Therefore, in the fourth embodiment, a countermeasure for such a problem will be described.

FIG. 4 is an external structural diagram showing a case where the signal input from the switching signal output device 53 is used as a driving signal for 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 diagram showing a case where the signal input from the switch 42 with a connector that can be manually operated is used as a drive signal for the DO signal switching device 2 in the fourth embodiment of the present invention. In FIG. 5, the switch 42 with a connector has a configuration in which a manual switch 43 is mounted on a changeover signal input connector (plug side) 41.

As shown in FIGS. 4 and 5, by adopting a connector structure using a switching signal input connector (receptacle side) 40 in order to capture a switching signal from the outside, the digital output signal switching device 1 Without changing the structure, automatic switching by the switching signal output device 53 and manual switching by operating the switch 42 with a connector are possible. Therefore, as the signal switching device 1, those having the same specifications can be used, and it is not necessary to prepare different products for each application.

Although the switch 42 with a connector has been described with reference to FIG. 5 showing a toggle switch, the same effect can be obtained with switches having different structures. Further, FIG. 5 showing an integrated structure of the changeover signal input connector (plug side) 41 and the manual switch 43 is only an example, and the switch 42 with a connector has a structure different from such an integrated structure. May be.

Further, the case where the switch 42 with the connector in the fourth embodiment is connected to the digital output signal switching device 1 has been described. However, the switch 42 with a connector is not limited to this, and can be applied to a digital input, an analog output, an analog input, or other devices whose main purpose is signal switching, which requires an external switching signal to be input. Is.

1 Digital output signal switching device (signal switching device), 2 DO signal switching device (first signal switching device), 3 folding signal switching device (second signal switching device), 4 resistor, 11 signal switching unit , 12 connector, 21 signal folding part, 22 connector, 31 signal switching unit with disconnection false detection prevention function, 32 relay, 33 folding setting circuit, 34 disconnection false detection prevention function presence / absence selection switch, 40 switching signal input connector (receptacle) Side), 41 Changeover signal input connector (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 the switching signal from the outside and outputs the selected input signal to the process.
Based on the switching signal, a folding circuit is formed so as not to open a circuit for the other input signal not selected by the first signal switching device among the input signals from each of the two controllers. A signal switching device including a second signal switching device. The first aspect of claim 1, wherein the second signal switching device is connected to the first signal switching device via a connector and has a structure that can be attached and detached according to the specifications of the two 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 connected state and a non-connected state according to a selection switch input, and the two devices. The signal switching device according to claim 1, which has a structure in which either the connected state or the non-connected state can be selected with respect to the first signal switching device according to the specifications of the controller. The signal switching device according to any one of claims 1 to 3, further comprising a connector structure for capturing a switching signal from the outside.

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