JPS6019814B2 - automatic switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides, for example, in an online real-time system centered on a computer, a plurality of terminal devices provided in parallel to a central device, and a system that indicates the normality or abnormality of each terminal device. The present invention relates to an automatic switching device for selectively switching connections based on a status signal.

Conventionally, there has been an automatic switching device of this type as shown in FIG.

In the figure, the central device 10 includes two terminal devices 12a,
12b is connected to operate as one system, and the terminal devices 12a and 12b are multiplexed parallel devices that back up each other in order to increase the reliability of the system. It is a part. The automatic switching device 14 is a terminal T to which the central device 10 is connected. and,
The two terminal devices 12a and 12b have terminals Ta and Tb to which they are connected, respectively, and the terminals Ta and Tb are connected to the terminals 12a and 12b, respectively.
A switch 16 for switching connection is provided. The terminal devices 12a and 12b each have an abnormality detection function, and status signals Sa and 12b, respectively, indicate whether or not the device can operate normally.
Output Sb respectively. On the other hand, the automatic switching device 14 has input terminals ta to which the signal lines of the status signals Sa and Sb are connected, respectively, and the signals applied to the terminals ta and melon are input to the switching control circuit 18. . This switching control circuit 1
8 controls the switch 16 as follows based on the input status signals Sa and Sb. In other words, the state signals Sa and S
b are compared, and if one is found to be "normal" and the other is "abnormal", the switch 16 is controlled to connect the terminal device on the normal side to the central device 101. Further, if the status signals Sa and Sb are both "normal" or both "abnormal", the current state is maintained without changing the connection state of the switch 16. For example, if the terminal device 12a becomes abnormal in a state where both the terminal devices 12a and 12b are normal and the terminal device 12a and the central device 10 are connected and operating, the switching control circuit 18 switches the switch 16, Terminal device 12a
Instead, a terminal device 12b is coupled to the central device 10 to maintain the operating state of the system. However, in the conventional automatic switching device configured as above,
The drawback is that there is no flexibility at all with respect to specification changes that increase the multiplicity of terminal devices.

In other words, in a system where three or more terminal devices are installed and one normal terminal is connected to the central device (multiplicity is 3 or more), the automatic The switching device 14 could not be used, and the switching device 16 and switching control circuit 18 had to be reconfigured. The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide an automatic switching device that can cope with increasing the multiplicity of the system by adding devices with the same configuration. be.

In order to achieve the above object, the automatic switching device of the present invention includes:
A switching device that selectively connects connection terminals of a plurality of terminal devices to a connection terminal of a central device; and a switching control that controls the switching device based on status signals applied to each of the plurality of status signal input terminals. In addition to the circuit, a state signal selection circuit is provided which selects a state signal representing normality from among the state signals applied to each of the plurality of state signal input terminals and outputs the selected state signal to the state signal output terminal. . Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

In FIG. 2, reference numeral 14 denotes an automatic switching device according to the present invention, which similarly to the conventional device shown in FIG.
a switch 16 that switches and connects terminals Ta and Tb to which terminals b are connected, respectively; and a terminal device 12 to which an input terminal cat is applied.
The switching device 1
6 as described above.

Further, in addition to the above, the automatic switching device 14 of the present invention has state signals Sa, S applied to the input terminals ``N'' and ``tb'', respectively.
A state signal selection circuit 20 is provided which selects a signal representing "normal" from among the signals b and outputs the selected signal to a state signal output terminal To. To be more specific, when the status signals Sa and Sb are binary signals corresponding to "normal" or "abnormal", the status signal selection circuit 20 calculates the logical sum of the input status signals Sa and Sb, and selects one of them. When the output terminal L is "normal", the output terminal L becomes an OR circuit that outputs a "normal" signal.

Further, when the status signals Sa and Sb are analog signals corresponding to the degree of normality, the status signal selection circuit 20 selects the status signals S and Sb. This is a signal selection circuit that compares the signals and outputs the signal with a higher degree of "normality" to the output terminal. This selection circuit 2 has no particular meaning in a system with a multiplicity of 2 using two terminal devices 12a and 12b as shown in Fig. 2, but when increasing the multiplicity to 3 or more, a large have meaning.

In FIG. 3, three automatic switching devices 14 of the present invention configured as shown in FIG.
Multiplicity 4 to alternatively combine normal ones of 12b
This shows the case where the system is configured. As shown in FIG. 3, the automatic switching device 14
b and the status signals Sa and Sb from these act to be selectively coupled to the terminal Ta of the automatic switching device 14Z, and the status signal S output from the output terminal to of this device 14X is It is applied to the input terminal ta of the duty switching device 14Z.

In the same machine, the automatic switching device 14Y is connected to the terminal devices 12c and 12.
d to the terminal Tb of the automatic switching device 14Z based on the status signals Sc and Sd from these, and this device automatically connects the status signal Scd output from the output terminals 14Y. It is applied to the input terminal of the switching device 14Z. The automatic switching device '4Z then acts to selectively couple the automatic switching devices 14x, 14Y to the central device 10' based on the future status signals Sab,S. As is clear from the above description, in FIG. 3, for example, the status signal is a binary signal, and only the status signal Sd of the terminal device 12d is "normal", and the other status signals Sa, Sb
, Sc becomes "abnormal", the automatic switching device 14
The current status signal Sab is "abnormal", and in the automatic switching device 14Y, the normal terminal device 12b is coupled to the terminal Tb of the automatic switching device 14Z, and the status signal S from now on is "normal". Become.

In response to this, the automatic switching device connects the normal automatic switching device 14Y to the central device. As a result, the central device 10 and the terminal device 14d are combined and operate as one system. In this way, the multiplicity is 4 by using the three automatic switching devices 14×, 14Y, and 14Z with the same configuration.
system can be configured. In the same way, it is of course possible to construct a system with a large degree of multiplicity by using a larger number of automatic switching devices 14. In the above embodiment, one automatic switching device is for multiplicity 2, but the present invention is not limited to this, and it is possible to operate a system with multiplicity 3 or higher from the beginning with one automatic switching device. It is also easy to configure.

Further, the signal line connecting the central device and the terminal device is generally a multi-core wire, and naturally the above-mentioned switch and each terminal are configured accordingly. Further, the terminals in this device include various connectors, and for example, the terminal Ta and the status signal input terminal N may constitute one connector.
Furthermore, central reloading may be multiplexed as a system. As explained in detail above, according to the automatic switching device according to the present invention, it is possible to increase the multiplicity of the system by using a plurality of automatic switching devices with the same configuration, so it is easy to change the specifications of the system, etc. This is a highly versatile device that can handle various situations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional automatic switching device, FIG. 2 is a block diagram of an automatic switching device according to an embodiment of the present invention,
FIG. 3 is a block diagram showing an application example using three automatic switching devices of the present invention. Identical parts in each figure are given the same reference numerals.
12a to 12d are terminal devices, 14 (14x to 14Z) are automatic switching devices; 16 is a switch; 18 is a switching control circuit;
Two rivers are the state signal selection circuit, and the ratio is the state signal input terminal.
to is the status signal output terminal. No.! Figure 2 Figure 3

Claims (1)

[Claims] 1. Automatic switching device for selectively switching and connecting a plurality of terminal devices provided in parallel to a central device based on a status signal indicating normality or abnormality of each terminal device. a switch that selectively connects connection terminals of a plurality of terminal devices to a connection terminal of a central device; and a switch based on the status signals applied to each of the plurality of status signal input terminals. and a state signal selection circuit that selects a state signal representing normality from among the state signals applied to each of the plurality of state signal input terminals and outputs the selected state signal to the state signal output terminal. Device. 2. In the automatic switching device according to claim 1, the status signal is a binary signal that distinguishes between normal and abnormal, and the status signal selection circuit detects when any one of the plurality of input status signals is a normal signal. Automatic switching device that is an OR circuit that outputs a normal signal. 3. In the automatic switching device according to claim 1, the status signal is an analog signal corresponding to the degree of normality, and the status signal selection circuit selects the signal with the highest degree of normality among the plurality of input status signals. Automatic switching device that is an analog signal selection circuit that selects and outputs.