JPS62295102A - Output selection logic circuit for multiplex controller - Google Patents

Abstract

PURPOSE:To improve the reliability and availability of a control system by providing a specific switching circuit so as to add a fail safe function and switching a switching circuit corresponding to a troubled controller if said controller is excluded from the control system. CONSTITUTION:An output selection logic circuit is constituted of 1st-3rd controllers 1-3 forming a triple system, a 213 logic circuit 4 which judges signals a1-a3 by majority decision and preferentially outputs a corresponding signal, a maintenance output switching circuit 5, 1st-3rd inner switching circuits 7-9 forming an output signal switching circuit 6 and a controller output signal dissidence detection circuit 10. In addition to a majority decision function, multifunctional selection among OR, AND as a duplicated system and 'fail as is' can be made. In case the controller is troubled, the switching circuit corresponding to said controller is switched to exclude it from the system. Simultaneously the system is continuously controlled by the normal controller.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention relates to an output selection logic circuit for a multiplexed controller that requires a high degree of reliability as a control system.

(Prior Art) Generally, in a control system, a multiplexed controller system consisting of a plurality of controllers for one controlled device is often employed in order to achieve higher control reliability and safety.

In this multiplexed controller system, it is necessary to combine the outputs of each controller into one and send it to the controlled device.
For this reason, an output selection logic circuit is provided between each controller on the control side and the controlled device.

A specific example of this output selection logic circuit is a logical sum (hereinafter referred to as
OR) circuit, AND circuit (hereinafter referred to as AND),
There are circuits that hold the old output when the controller outputs do not match (hereinafter referred to as fail-as-is), majority logic circuits, etc.

Which circuit to adopt among these depends on the safety philosophy of the entire system, taking into consideration the characteristics of the W device to be controlled and the influence on other devices.For example, if you want to proactively control when a discrepancy occurs between each controller. For example, an OR circuit is used as an output selection logic circuit, and an AND circuit is used for passive control.

(The problem to be solved by the invention) If each of these output selection logic circuits were to be made on a dedicated board, it would be necessary to prepare as many boards as there are possible output selection logic circuits, and the manufacturing process and management becomes complicated. Also,
When replacing a board due to a change in the selection logic of a multiplexed controller system, incorrect board insertion may occur, the board itself may be damaged, or a failure may occur, resulting in a decrease in reliability.

On the other hand, the method of manufacturing a plurality of output selection logic circuits on a single board and switching each circuit results in unused circuits being distributed on the board, resulting in a large number of parts and high costs.

Furthermore, when removing a faulty controller, the control output must also be temporarily stopped, which poses problems such as straining the control system.

Therefore, the present invention realizes a compact and inexpensive output selection logic circuit with a small number of parts and few unused circuits by configuring each selection logic function on the same board. It is possible to implement this without affecting the control system.
An object of the present invention is to provide an output selection logic circuit for a multiplexed controller with a high j-rate.

[Structure of the Invention] (Means for Solving the Problems) The present invention uses a 2 out of 3 (hereinafter referred to as 2/3) logic circuit to provide a majority voting function as a triplex system as well as a dual system. Based on a circuit that can perform multi-functional selection of OR, AND, and fail-as-is, a switching circuit is provided that can output an externally set logic signal regardless of the input signal from each controller. A fail-safe function is added that outputs an external setting input signal when a mismatch occurs in the signals of the controllers, and furthermore, between the input signals from each controller and the 2/3 logic circuit, there is a fail-safe function that outputs the external setting input signal. A switching circuit is provided that can switch and output the input signals of each controller, and when the controller is normal, the input signal from each controller is output, and when a controller malfunctions and that controller is removed from the control system, it is handled accordingly. The switching circuit is switched, the failed controller is removed from the system, and the system itself can continue to be controlled by the normal controller.

(Function) As a result, each output selection logic circuit, which was conventionally provided exclusively for each, becomes a single circuit that is inexpensive and compact, with no waste, and output selection logic can be easily selected, and maintenance is avoided in the event of a controller failure. In this case, the output selection logic circuit of the multiplexed controller can be provided which can be continuously controlled by only the normal controller during maintenance, without stopping the control system, and which has high reliability and high availability.

(Example) FIG. 1 is a configuration diagram showing an embodiment according to the present invention.

L, 2.3 are respectively 1st and 2nd in the triplex system. The third controller (hereinafter each controller 1
．． Controller 2. Each controller outputs a digital signal of #JOII or '1''. 4 is the first from each controller
゜Second. Third signals as, a2+a3 (hereinafter referred to as signals al, respectively).

Signal a2. 2/3 inputs a signal (referred to as signal a3), performs majority decision, and outputs the signal corresponding to the input from the majority side with priority.
It is a logic circuit. The output of the 2/3 logic circuit 4 is sent to the controlled device through the maintenance output switching circuit 5.

6 is an output signal switching circuit, and an internal first switching circuit 7 (
Hereinafter, simply referred to as switching circuit 7), second switching circuit 8 (hereinafter, simply referred to as switching circuit 8), and third switching circuit 9 (hereinafter, simply referred to as switching circuit 9) respectively receive the first switching signal b1 (hereinafter, simply referred to as switching circuit 9). The switching is performed by a signal bl), a second switching signal bz (hereinafter simply referred to as switching signal b2), and a third switching signal b3 (hereinafter simply referred to as switching signal b3).

The switching circuit 7 normally sends the signal a input from the controller 1 to the 2/3 logic circuit 4, and when the switching signal b1 is input, sends the signal a2 input from the controller 2 to the 273 logic circuit. Can be switched. The switching circuit 8 normally sends the fi signal a2 input from the controller 2 to the 2/3 logic circuit 4, and when the switching signal b2 is input, sends the signal al input from the controller 1 to the 2/3 logic circuit 4. It can be switched as follows.

The switching circuit 9 normally sends the signals at and a2 input from the controllers 1 and 2 to the 2/3 logic circuit 4, but when a third switching signal b3 (hereinafter simply referred to as switching signal b3) is input, , the signal al182 is cut off, and a fourth signal a4 (hereinafter referred to as external setting signal a4), which is preset to "0" or 1"' according to the controlled device, is sent to the logic circuit 213. Can be switched.

lO is a controller output signal lower coincidence detection circuit for detecting a mismatch of output signals from each controller,
When the signals of each controller do not match, a controller output rate match signal C is output.

Reference numeral 11 denotes an output selection 53 consisting of a controller, an output signal switching circuit 6, and a controller power signal mismatch detection circuit 10.
1 logic circuit, and is housed in a case as shown in FIG. Reference numeral 12 denotes a socket board, on which a safety side output setting device 13 for maintenance is provided. During maintenance, when pulling out the output selection logic circuit body 11 from the socket part 12, the maintenance output switching circuit 5 is switched to the terminal on the maintenance safety output setter 13 side, and the control signal to the controlled device is set to the safety side. I'll do it later.

With the above configuration, various output selection logic functions can be realized by appropriately setting the switching states and input/output signals of each switching circuit. Below, various functions that can be realized by the output selection logic circuit will be explained in order.

First, an example in which this embodiment is applied to a duplex system will be described.

Three input terminals 11A of the output selection logic circuit main body 11.

11B, IIC has three controllers 1,
2. Connect 3. Also, the switching circuit in the output signal switching circuit 6? , 8.9 are shown in the non-operating state. Furthermore, an external setting signal a4 is applied to the input terminal 110.

As a result, the output selection logic circuit body 11 receives the signals al+a2.3 input from the controllers 1, 2.3. This becomes a majority logic circuit in which a3 is directly used as each input of the 2/3 logic circuit 4. At the same time, by providing the match detection circuit 10 under controller input, a fail-safe function is also realized.

That is, the signal at input from the controllers 1, 2.3.

When a2 and 83 match, the output selection logic circuit main body 11 outputs the match signal via the 2/3 logic circuit 4. In this state, if any one input signal does not match, the output selection logic circuit main body 11 outputs a correct input signal in which the two signals match via the 2/3 logic circuit 4.

At this time, the controller input match detection circuit IO monitors each output signal of the controllers 1, 2, and 3, and outputs the first mismatch occurrence signal c1 to the outside when a mismatch occurs. As a result, it is possible to output a warning of controller abnormality and take measures such as excluding the controller that has become inconsistent. The controller input match detection circuit 10 further monitors the remaining two normal controller outputs, and when a mismatch occurs between the two signals, outputs a second mismatch occurrence signal c2 to the outside. By inputting the switching signal b3 from the input terminal 11G in response to the output of the signal C2 and switching the switching circuit 9, the external setting signal a4 set to the safe side is outputted from the 273 logic circuit 4. Fail-safe can be achieved.

Next, an example in which the output selection logic circuit according to this embodiment is applied to a duplex system will be described.

Two controllers 1 and 2 are connected to input terminals 11A and IIB, and a signal representing logic "1" is input to input terminal 11C. As a result, the output selection logic circuit main body 11 is an OR circuit in which the 2/3 logic circuit 4 outputs '1'' when either the signal a1 from the controller 1 or the signal a2 from the controller 2 becomes II II II. becomes.

Also, by inputting a signal representing logic "0" to the input terminal 11C, the output selection logic circuit main body 11 outputs the signal a1 inputted from the controller 1 and the signal a2 inputted from the controller 2, if both become II 111. This becomes an AND circuit in which the output from the 2/3 logic circuit 4 cannot become "1".

Next, by inputting the output signal of the 273 logic circuit 4 to the input terminal 11C, if the controller 1.2 is normal, it will output a normal controller signal, and if one of the controllers is abnormal, the signals al, a2 When a mismatch occurs, a fail-as-is function is realized in which the output signal before the mismatch is maintained.

Furthermore, if either of the controllers 1 or 2 fails and a mismatch occurs, the controller input match detection circuit 10 detects the mismatch and outputs the controller input match signal c2 in the same manner as explained above for the triplex system. By inputting the switching signal b3 from the input terminal 11G and at the same time inputting the external setting signal a4, which is set on the safe side for the controlled device, to the input terminal 110, the fail-safe function of the redundant system is realized. Can be done.

As described above, majority logic as a triple system, fail-safe, OR, AN as a redundant system
A large number of output selection logic functions such as D, fail-as-is, and fail-safe can be realized.

Next, maintenance when a controller failure occurs will be explained.

As mentioned above, the controller input matching detection circuit lO
monitors the output of each controller and outputs a mismatch occurrence signal C when a mismatch occurs.

This discrepancy occurrence signal C is received and diagnosed by a controller abnormality diagnosis circuit (not shown). If it is determined that the controller 1 is malfunctioning, the switching signal b1 is inputted from the input terminal 11B to the output signal switching circuit 6, and the switching is performed. Switch circuit 7. As a result, the switching circuit 7 outputs the signal a2 from the controller 2 instead of the signal a1. As a result, 2
The output signal of the /3 logic circuit becomes the signal a2 from the normal controller 2, and the faulty controller 1 is connected to the input terminal 11A.
It can be removed and repaired. Further, during this period, the controlled device can be continuously controlled by the normal controller 2.

Similarly, when the controller 2 fails, by inputting the switching signal b2 to the input terminal 11F and switching the switching circuit 8, control by the normal controller 1 can be continued while the failed controller 2 is being repaired.

Next, maintenance of the output selection logic circuit main body 11 will be explained.

When removing the output selection logic circuit body 11 from the socket 12, the maintenance output switching circuit 5 is switched to the maintenance safety output setter 13 side, and the control signal to the controlled device is set to the safety side. As a result, the controlled device can obtain a safe control signal, and the output selection logic circuit main body 11 can be removed without adversely affecting the controlled device. The handling procedure during the above maintenance will be explained with reference to the drawings.

FIG. 2 shows an external view of the output selection logic circuit, and the same parts as in FIG. 1 are given the same numbers. In this figure, 5 is an output switching circuit for maintenance, and by sliding it in the direction of the arrow, the output signal to the controlled device is changed to the output of the 2/3 logic circuit 4 or the output of the safety output setting device 13 for maintenance. Switch. 11 is the main body of the output selection logic circuit.

12 is a socket portion. 14 is a safety side output selection pin during maintenance, and by inserting it into the socket part 12,
A digital output signal of II O#l or '1'' from the external power supply can be obtained as the output of the maintenance safety output setting device 13. 15 is a signal between the external power supply and the maintenance safety output setting device 13 or the main body. 11, each controller, a controlled device, and each input signal.

Now, the procedure for removing the main body 11 from the socket part 12 is as follows.
First, by inserting and removing the maintenance safe output selection pin 14, the safe side for the controlled equipment is selected as the maintenance setting output from either ``0'''' or re 1 u. Next, the maintenance output switching circuit 5 is slid to switch between the high-strength terminal of the 2/3 logic circuit 4 and the output terminal of the maintenance safety output setting device 13. As a result, the output set on the safe side will be sent to the controlled device. In this way, the main body 11 removed from the control system is removed from the socket portion 12. Conversely, when attaching the main body 11 to the socket, after attaching the main body 11 and stabilizing the control output, slide the maintenance output switching circuit 5 to change the output to the controlled system to the maintenance safety output setting device. 13 to the main body 11. This allows the original control system to be restored.

By the above procedure, maintenance of the output selection logic circuit main body 11 can be performed while keeping the controlled equipment safe.

As described above, according to this embodiment, a multifunctional output selection logic circuit can be obtained on a single board, a faulty controller can be maintained without stopping control, and the output selection logic circuit itself can be maintained. It is possible to obtain an output selection logic circuit that is safe, highly reliable, and has a high operating rate without adversely affecting the controlled equipment during maintenance.

In the above embodiments, each switching circuit is implemented using relay contacts, but it goes without saying that the present invention can also be implemented using semiconductor elements or the like.

In addition, in the above embodiment, a third switching circuit for switching to an external setting signal is provided on the input side of the 2/3 logic circuit, and switches with a signal from another controller, but on the output side of the 2/3 logic circuit. Even if a third switching circuit is provided to switch between the output signal of the 2/3 logic circuit and the external setting signal, it is possible to implement a fail-safe function of outputting the external setting signal when the controller outputs match.

In addition, the fail-safe feature of the output selection circuit in the above embodiment is that when the controller input signals do not match, the external setting signal a
4, but if it is possible to instantly determine which controller is faulty when the input signals do not match, the switching circuit 7 or 8 can be switched by inputting the switching signal bl or b2 to the output signal switching circuit 6. It is also possible to switch to a control system using only the normal controller.

[Effects of the Invention] As described above, according to the present invention, a multifunctional output selection logic circuit can be obtained with one circuit.

Moreover, since the controller to be maintained can be removed during maintenance without affecting the control system, it is extremely effective in improving the reliability and operation rate of the control system.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an output selection logic circuit in a multiplexing system according to one implementation side of the present invention, and FIG.
FIG. 2 is an external view showing the structure of a force selection logic circuit. DESCRIPTION OF SYMBOLS 1... First controller, 2... Second controller, 3... Third controller, 4... 2/3 logic circuit, 5... Output switching circuit for maintenance, 6... - Output signal switching circuit, 7... First switching circuit, 8... Second switching circuit, 9... Third switching circuit, 10... Controller output signal mismatch detection circuit, 11...・Output selection logic circuit body. 12...Socket part, 13...Safety side output setting device for maintenance, 14...Safety side output selection bin for maintenance, 15...
・Screw for fixing the power supply. Figure 1

Claims (5)

[Claims] (1) First, second, third, and fourth input terminals into which the first, second, third, and fourth signals are respectively input;
, a first switching circuit connected to the third and fourth input terminals to normally select the first signal and select the second signal upon input of a first switching signal; and the first and second input terminals. a second switching circuit that is connected to and normally selects the second signal, and selects and outputs the first signal by inputting a second switching signal; A third input terminal is connected to the fourth input terminal and normally selects each output signal of the first and second switching circuits, and selects each of the fourth signals by inputting the third switching signal to output two signals. a switching circuit; and a 2-out-of-3 logic circuit inputting three signals, the two signals outputted from the third switching circuit and the third signal, and outputting two or more matching signals; , the output signals of the first and second controllers multiplexed as the first and second signals are inputted to the second input terminal, and the output signals of the third controller are inputted as the third signal to the third input terminal. the output signal, the predetermined logic signal and the 2o
Input one of the output signals of the ut of3 logic circuit,
An output selection logic circuit for a multiplexing controller, wherein an external setting logic signal is input as a fourth signal to the fourth input terminal. (2) The multiplexed controller according to claim 1, further comprising a controller output mismatch detection circuit that monitors at least the first and second signals to detect a mismatch in the outputs of the multiplexed controller. output selection logic circuit. (3) In claim 1, when the controller connected to the first input terminal becomes abnormal, inputting the first switching signal to switch the first switching circuit; An output selection logic circuit for a multiplexed controller, characterized in that when a controller connected to an input terminal becomes abnormal, the second switching signal is inputted to switch the second switching circuit. (4) In claim 1, the first,
An output selection logic circuit for a multiplexed controller, characterized in that when the outputs of the multiplexed controllers connected to the second input terminals do not match, the third switching signal is inputted to switch the third switching circuit. (5) In claim 1, the 2ou
An output selection logic circuit for a multiplexed controller, characterized in that it is provided with a switching circuit that switches between the output of a to of3 logic circuit and a safety output for maintenance.