I / O unit and communication system

Abstract

This invention relates to an input / output unit and a communication system. The input / output unit (14) includes: a plurality of front-side terminals (30) for connection to a main unit (12) or other input / output units (14); a plurality of rear-side terminals (32) for connection to other input / output units (14) and connected to different front-side terminals (30); and a slave processing circuit (26) connected to one of the plurality of front-side terminals (30) and the rear-side terminal (32) connected to this one front-side terminal (30) to perform signal processing.

Description

[Technical Field]

[0001] The present invention relates to an input / output unit (I / O unit) for connecting a main unit to a device and transmitting signals between the main unit and the device, and a communication system having a plurality of such input / output units. [Previous Technology]

[0002] Japanese Patent Application Publication No. 2016-110460 discloses a programmable logic controller system. This programmable logic controller system includes a basic unit (master unit) and multiple expansion units (slave units). The basic unit and the multiple expansion units are connected in a daisy chain, with the master unit as the head. Each of the multiple expansion units is, for example, an input / output unit (I / O unit). The basic unit sends or receives signals to or from the controlled device via the multiple expansion units. The controlled device is, for example, a sensor or an actuator. [Summary of the Invention]

[0003] The main unit and the multiple input / output units are arranged in a predetermined direction, with the main unit as the first. The terminals of adjacent main units are connected to the terminals of the input / output units. In addition, the terminals of adjacent input / output units are interconnected. In this way, the main unit and the multiple input / output units are connected in a communicative manner without the need for additional cables. In the following description, the block consisting of the main unit and the multiple input / output units connected in a communicative manner is also referred to as a "station". The station, as described above, is constructed without the use of cables. Therefore, the wiring around the station is less likely to become complicated. In addition, cable misconnections are prevented.

[0004] The main unit has a predetermined processing circuit (main processing circuit). The main processing circuit is the circuit that performs signal processing in communication with the input / output units. However, the number of input / output units that can be connected to the main processing circuit is limited by the design.

[0005] Therefore, if the number of input / output units to be used exceeds the limit of the number of input / output units that the main processing circuit can connect to, the operator must set up a separate station.

[0006] The purpose of this invention is to solve the above-mentioned problems.

[0007] A first embodiment of the present invention is an input / output unit that connects a main unit to a device and transmits signals between the main unit and the device; the input / output unit includes: a plurality of front-side terminals for connecting to the main unit disposed in the front section or other input / output units disposed in the front section; a plurality of rear-side terminals for connecting to other input / output units disposed in the rear section and connected to front-side terminals that are different from each other; and a slave processing circuit connected to one of the plurality of front-side terminals and the rear-side terminal connected to this one front-side terminal to perform signal processing.

[0008] A second embodiment of the present invention is a communication system comprising a main unit and a plurality of input / output units connected to the main unit for transmitting signals between the main unit and a device; the main unit comprises: a plurality of main processing circuits for performing signal processing; and a plurality of branch terminals for connecting to different main processing circuits; each of the plurality of input / output units comprises: a plurality of front-end terminals for connecting to the main unit disposed in the front end or other input / output units disposed in the front end; and a plurality of rear-end terminals for connecting to the main unit disposed in the front end or other input / output units disposed in the front end. The input / output units are connected to other input / output units in the rear section and connected to front-side terminals that are different from each other; and a slave processing circuit is connected to one of the plurality of front-side terminals and to the rear-side terminal connected to this one front-side terminal to perform signal processing; the plurality of input / output units include: a plurality of first input / output units that connect the slave processing circuit to a first main processing circuit; and a plurality of second input / output units that connect the slave processing circuit to a second main processing circuit that is different from the first main processing circuit.

[0009] According to the present invention, an input / output unit that can be easily added to a station and a communication system having a plurality of the input / output units are provided.

[0010] The above-mentioned objectives, features and advantages should be easily understood from the description of the following embodiments with reference to the accompanying drawings.

Implementation Method

[0017] A preferred embodiment of the input / output unit and communication system of the present invention is disclosed below with reference to the accompanying drawings.

[0018] [Embodiment] FIG1 is a diagram showing a communication system 100 of a reference example of the present invention.

[0019] The communication system 100 is a system for transmitting signals between the control device 102 and the equipment 104. The equipment 104 is installed in a mechanical device. The mechanical device may be, for example, a work machine or a workman. The equipment 104 includes an output device 104a and an input device 104b. The output device 104a may be, for example, an actuator such as a switch. When the control device 102 drives the output device 104a, it sends a control signal to the output device 104a via the communication system 100. The input device 104b may be, for example, a sensor that detects pressure, voltage, or current. The control device 102 receives detection signals from the input device 104b via the communication system 100.

[0020] The communication system 100 includes a complex number of communication coupling units 106 (106a, 106b) and a complex number of input / output units 108. The complex number of input / output units 108 is composed of complex number of input / output units 108a and complex number of input / output units 108b.

[0021] The control device 102, communication coupling unit 106a, and communication coupling unit 106b are connected sequentially in the order described above. This forms a communication path (mainstream line La) that sequentially passes through the control device 102, communication coupling unit 106a, and communication coupling unit 106b. The connection between the control device 102 and the communication coupling unit 106a is made using a cable. Furthermore, the connection between the communication coupling unit 106a and the communication coupling unit 106b is made using other cables. The operator prepares the cables.

[0022] Complex input / output units 108a are sequentially connected to the downstream end of communication coupling unit 106a. This allows communication coupling unit 106a and complex input / output units 108a to form a station. Furthermore, a communication path (branch line Lb1) is formed that sequentially passes through communication coupling unit 106a and complex input / output units 108a.

[0023] Complex input / output units 108b are sequentially connected to the downstream end of communication coupling unit 106b. This allows communication coupling unit 106b and complex input / output units 108b to form a station. Furthermore, a communication path (branch line Lb2) is formed that sequentially passes through communication coupling unit 106b and complex input / output units 108b.

[0024] The complex input / output unit 108 is connected to the complex device 104. The complex input / output unit 108 of FIG1 is connected to different devices 104. However, a single input / output unit 108 can also be connected to a single complex device 104.

[0025] Communication coupling units 106a and 106b each have a main processing circuit 16. Input / output units 108a and 108b each have a slave processing circuit 26 and an interface 28. The slave processing circuit 26 is a circuit that performs signal input / output with the main processing circuit 16. The main processing circuit 16 and the slave processing circuit 26 may each include a CPU (Central Processing Unit). However, the main processing circuit 16 and the slave processing circuit 26 may also each include an ASIC (Application-Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field-Programmable Gate Array). The interface 28 is hardware (circuit, electronic components) that transmits signals between the slave processing circuit 26 and the device 104. The interface 28 connects the slave processing circuit 26 to the device 104, enabling the slave processing circuit 26 to perform signal input / output with the device 104. Furthermore, the specific configuration of interface 28 varies depending on the type of device 104.

[0026] The main processing circuit 16 of the communication coupling unit 106a and the main processing circuit 16 of the communication coupling unit 106b are daisy-chained together via the main line La, with the control device 102 as the first connection. Furthermore, the slave processing circuit 26 of the complex input / output unit 108a is daisy-chained together via the branch line Lb1, with the main processing circuit 16 of the communication coupling unit 106a as the first connection. Further, the slave processing circuit 26 of the complex input / output unit 108b is daisy-chained together via the branch line Lb2, with the main processing circuit 16 of the communication coupling unit 106b as the first connection.

[0027] When the control device 102 sends a control signal to the device 104, the control device 102 outputs a control signal to the communication coupling unit 106a connected to the first segment (first one) from its own perspective. This control signal includes address information of the input / output unit 108 connected to the target device 104. The main processing circuit 16 of the communication coupling unit 106a determines whether the address information contained in the control signal displays any of the multiple input / output units 108a. If the address information does not display any of the multiple input / output units 108a, the main processing circuit 16 of the communication coupling unit 106a outputs a control signal to the main processing circuit 16 of the communication coupling unit 106b. If the address information displays any of the multiple input / output units 108a, the main processing circuit 16 of the communication coupling unit 106a outputs a control signal to the input / output unit 108a of its subsequent segment. The slave processing circuit 26 of the input / output unit 108a, which receives the control signal from the front end, determines whether the address information contained in the input control signal displays itself. Here, if the address information displays itself, the slave processing circuit 26 of the input / output unit 108a outputs a control signal to the device 104 connected to it. This causes the device 104 to operate. On the other hand, if the address information contained in the input control signal does not display itself, the input / output unit 108a outputs a control signal to its downstream input / output unit 108a. Additionally, the input / output unit 108 can also output a control signal to its downstream input / output unit 108 if the address information contained in the control signal displays itself. Furthermore, the communication coupling unit 106 can also output a control signal to its downstream communication coupling unit 106 if the address information contained in the control signal displays the address information of its connected input / output unit 108.

[0028] There is a case where device 104 outputs a signal to control device 102. In this case, the signal from device 104 is input to the slave processing circuit 26 of the input / output unit 108 to which device 104 is connected. The slave processing circuit 26 sends the signal input from device 104 connected to it to control device 102. In this case, the slave processing circuit 26 outputs a signal to the input / output unit 108 or the communication coupling unit 106 connected to its front end. Here, the slave processing circuit 26 includes the content output by device 104 and the address information of the input / output unit 108 that outputs the signal in the output signal. The input / output of signals between communication coupling unit 106 and input / output unit 108 is known technology, so further explanation is omitted.

[0029] In the reference example, as described above, a station is constructed with communication coupling unit 106a as the head and a station is constructed with communication coupling unit 106b as the head.

[0030] As explained above, the number of input / output units (slave processing circuits 26) 108 that can be connected as slaves to the main processing circuit 16 has been limited. Therefore, if the number of input / output units 108 exceeds the above-mentioned limit, the operator has to set up multiple stations and connect them using separately prepared cables.

[0031] However, for the operator, it is advisable to set up the communication coupling unit 106 and the necessary input / output units 108 together as much as possible.

[0032] In view of the above explanation, the embodiments will be described in the following content. In addition, for constituent elements that are the same as those described in the reference example, the same reference numerals are given and their descriptions are omitted, and the description will focus on the parts that are different from those in the reference example.

[0033] FIG2 is a diagram showing a communication system 10 according to an embodiment of the present invention. The communication system 10 includes a communication coupling unit 12 and a complex input / output unit 14. The complex input / output unit 14 is sequentially connected to the rear end of the communication coupling unit 12.

[0034] The communication coupling unit 12 includes multiple main processing circuits 16, a power supply 18, two connectors 20 (20a, 20b), multiple branch terminals 22, and a housing 24. The multiple main processing circuits 16, the power supply 18, the two connectors 20 (20a, 20b), and the multiple branch terminals 22 are housed in the housing 24.

[0035] The communication coupling unit 12 includes two main processing circuits 16 (16a, 16b). However, the communication coupling unit 12 may also include three or more main processing circuits 16. Furthermore, one of the two main processing circuits 16 included in the same communication coupling unit 12, main processing circuit 16a, is also referred to as the first main processing circuit 16a in the following description. Conversely, the other main processing circuit 16b is also referred to as the second main processing circuit 16b in the following description.

[0036] Power supply 18 supplies power to the two main processing circuits 16. In addition, power supply 18 can also supply power to at least one of the slave processing circuits 26 and interface 28 of input / output unit 14.

[0037] Connector 20a is used to connect to a device that has the main line La located at the front end of the communication coupling unit 12. For example, a control device 102 (refer to FIG. 2) has the main line La located at the front end of the communication coupling unit 12. The connection between connector 20a and control device 102 is, as before, via a cable. However, connector 20a can also be connected to other communication coupling units 12 or communication coupling units 106 that have the main line La located at the front end of the communication coupling unit 12. Connector 20b is used to connect to other communication coupling units 12 or communication coupling units 106 that have the main line La located at the rear end of the communication coupling unit 12. However, connector 20b is open in the example of FIG. 2. Assuming that other communication coupling units 12 are located at the rear end of the communication coupling unit 12 for the main line La, connector 20b of the communication coupling unit 12 is connected to connector 20a of other communication coupling units 12 via a cable.

[0038] Connector 20a is connected to main processing circuit 16a. Furthermore, main processing circuit 16a is connected to main processing circuit 16b. Therefore, control device 102 is daisy-chained with main processing circuits 16a and 16b on the main line La.

[0039] Each of the plurality of branch terminals 22 is a terminal used to connect to the input / output unit 14 disposed at the rear end of the communication coupling unit 12. The number of branch terminals 22 disposed in the communication coupling unit 12 is the same as the number of main processing circuits 16 provided in the communication coupling unit 12. That is, the communication coupling unit 12 has two branch terminals 22. One of these two branch terminals 22 is also referred to as branch terminal 22a in the following description. In contrast, the other branch terminal 22 is also referred to as branch terminal 22b.

[0040] Branch terminal 22a is connected to main processing circuit 16a. Branch terminal 22b is connected to main processing circuit 16b. That is, multiple branch terminals 22 are connected to different main processing circuits 16.

[0041] The multiple input / output units 14 each have a slave processing circuit 26, an interface 28, multiple front-end terminals 30, multiple rear-end terminals 32, and a housing 38. The slave processing circuit 26, the interface 28, the multiple front-end terminals 30, and the multiple rear-end terminals 32 are housed in the housing 38.

[0042] Each of the plurality of front-side terminals 30 is a terminal used to connect to the communication coupling unit 12 disposed on the front end or other input / output unit 14 disposed on the front end. The number of front-side terminals 30 is the same as the number of branch terminals 22 provided by the communication coupling unit 12. That is, the input / output unit 14 has two front-side terminals 30. One of these two front-side terminals 30 is also referred to as front-side terminal 30a in the following description. In contrast, the other front-side terminal 30 is also referred to as front-side terminal 30b.

[0043] Each of the plurality of rear-side terminals 32 is a terminal used to connect to other input / output units 14 disposed in the rear section. The number of rear-side terminals 32 is the same as the number of front-side terminals 30 provided by the input / output unit 14. That is, the input / output unit 14 has two rear-side terminals 32. One of these two rear-side terminals 32 is also referred to as rear-side terminal 32a in the following description. In contrast, the other rear-side terminal 32 is also referred to as rear-side terminal 32b in the following description.

[0044] The front-side terminal 30a is connected to the rear-side terminal 32a via the first signal line 34. Furthermore, the front-side terminal 30b is connected to the rear-side terminal 32b via the second signal line 36. That is, for each input / output unit 14, a plurality of front-side terminals 30 are connected to different rear-side terminals 32.

[0045] When a communication coupling unit 12 is provided at the front end of the input / output unit 14, the front end terminal 30a is connected to the branch terminal 22a of the communication coupling unit 12. Furthermore, the front end terminal 30b is connected to the branch terminal 22b of the communication coupling unit 12. On the other hand, when other input / output units 14 are provided at the front end of the input / output unit 14, the front end terminal 30a of the input / output unit 14 is connected to the rear end terminal 32a of the other input / output unit 14. Furthermore, the front end terminal 30b of the input / output unit 14 is connected to the rear end terminal 32b of the other input / output unit 14.

[0046] Each slave processing circuit 26 of the multiple input / output units 14 is connected to one of the multiple front-side terminals 30 and to a rear-side terminal 32 connected to the front-side terminal 30. For example, the slave processing circuit 26 is connected to the front-side terminal 30a and the rear-side terminal 32a. However, the slave processing circuit 26 may also be connected to the front-side terminal 30b and the rear-side terminal 32b.

[0047] The complex input / output unit 14 is classified into a first input / output unit 14A and a second input / output unit 14B. The first input / output unit 14A is an input / output unit 14 with a slave processing circuit 26 installed on the first signal line 34. The second input / output unit 14B is an input / output unit 14 with a slave processing circuit 26 installed on the second signal line 36. The slave processing circuit 26 (26a) of the first input / output unit 14A is connected to the main processing circuit 16a on the branch line Lb1. On the other hand, the slave processing circuit 26 (26b) of the second input / output unit 14B is connected to the main processing circuit 16b on the branch line Lb2.

[0048] Signals input to and output to the front-side terminal 30b and rear-side terminal 32b of the first input / output unit 14A pass through the first input / output unit 14A via the second signal line 36. On the other hand, signals input to and output to the front-side terminal 30a and rear-side terminal 32a of the second input / output unit 14B pass through the second input / output unit 14B via the first signal line 34.

[0049] According to this embodiment, the first input / output unit 14A operates as a slave to the main processing circuit 16a. Furthermore, the second input / output unit 14B operates as a slave to the main processing circuit 16b. The first input / output unit 14A and the second input / output unit 14B are arranged in a row within one station. If the operator needs more input / output units 14 than the limit set by the main processing circuit 16a, the excess units can be set as slaves of the main processing circuit 16b.

[0050] Thus, according to this embodiment, an input / output unit 14 that can be easily added to a station and a communication system 10 having a plurality of the input / output units 14 are provided.

[0051] Furthermore, in the example of FIG2, the plurality of first input / output units 14A are positioned further forward than the plurality of second input / output units 14B. The communication system 10 is not limited to this configuration. For example, the plurality of second input / output units 14B may also be arranged further forward than the plurality of first input / output units 14A. In addition, the plurality of first input / output units 14A and the plurality of second input / output units 14B may also be arranged in a mixed manner.

[0052] [Modifications] The above description illustrates an embodiment of the present invention as an example. Various modifications or improvements can be made to the above-described embodiment. Furthermore, it is clear from the contents of the claims that the technical scope of the present invention may include embodiments with such modifications or improvements.

[0053] Hereinafter, variations of the above embodiments will be described. However, in the following description, explanations that are repeated with the above embodiments will be omitted as much as possible. Unless otherwise stated, the constituent elements that have been described in the above embodiments will be given the same reference numerals as those in the above embodiments.

[0054] (Modification 1) Figure 3A shows the input / output unit 14' (14) of Modification 1.

[0055] The input / output unit 14' not only includes the constituent elements of the input / output unit 14 (see also FIG. 2), but also further includes a selection circuit 40. The selection circuit 40 is a circuit that selects the combination of a plurality of front-side terminals 30 and a plurality of rear-side terminals 32 connected to each other. In addition, the input / output unit 14' has two front-side terminals 30 and two rear-side terminals 32. In this case, the selection circuit 40 selects the connection relationship between the two front-side terminals 30 and the two rear-side terminals 32 from the next first connection relationship and the second connection relationship.

[0056] Figure 3B is a diagram showing the input / output unit 14' when the first connection relationship is selected.

[0057] For example, as shown in FIG3B, when selecting the first connection relationship, the front end terminal 30a is connected to the rear end terminal 32a, and the front end terminal 30b is connected to the rear end terminal 32b.

[0058] Figure 3C shows the input / output unit 14' when the second connection relationship is selected.

[0059] Furthermore, as shown in FIG3C, for example, when selecting the second connection relationship, the selection circuit 40 connects the front end terminal 30a to the rear end terminal 32b and connects the front end terminal 30b to the rear end terminal 32a.

[0060] The selection circuit 40 may be appropriately configured, for example, using mechanical switches, electrical switches, semiconductor switches, or other switches and conductors. Alternatively, the selection circuit 40 may also be configured as part of other circuits. For example, the selection circuit 40 may also be configured as part of an ASIC.

[0061] According to this modified example, the connection relationship between the two front-side terminals 30 and the two rear-side terminals 32 of the input / output unit 14' can be easily changed by the selection circuit 40. Furthermore, the differences between the first input / output unit 14A and the second input / output unit 14B are integrated within the selection circuit 40. That is, the configurations of the first input / output unit 14A and the second input / output unit 14B are made common. The selection of the connection relationship does not need to be constant; for example, it can be selected only during the assembly of the input / output unit 14.

[0062] In the examples of Figures 3A to 3C, the selection circuit 40 is arranged between the slave processing circuit 26 and one of the two rear-side terminals 32. In this case, the selection circuit 40 becomes the main processing circuit 16 to which the slave processing circuit 26 of the other input / output unit 14 located in the rear section of the input / output unit 14 is connected.

[0063] Figure 4 is a diagram showing the input / output unit 14' of the configuration of the change selection circuit 40.

[0064] As shown in FIG4, the selection circuit 40 may also be configured such that it is sandwiched between the slave processing circuit 26 and one of the two front-end terminals 30. In this case, the selection circuit 40 becomes the main processing circuit 16 to which it is connected, instead of the slave processing circuit 26, which is the same as its own input / output unit 14.

[0065] Thus, the selection circuit 40 functions differently depending on whether the slave processing circuit 26 is located on the rear-side terminal 32 side or on the front-side terminal 30 side. In view of the above, the input / output unit 14' may also include a selection circuit 40 located closer to the rear-side terminal 32 side than the slave processing circuit 26, and other selection circuits 40 located closer to the front-side terminal 30 side than the slave processing circuit 26.

[0066] (Modification 2) Figure 5 is a diagram showing the input / output unit 14'' (14) of Modification 2.

[0067] The input / output unit 14'' has four front-side terminals 30, four rear-side terminals 32, and a selection circuit 40'.

[0068] The selection circuit 40', similar to that in Modification 1, appropriately includes various switches, etc. The selection circuit 40' selects a combination of multiple front-side terminals 30 and multiple rear-side terminals 32 connected to each other from a first connection relationship (solid line in FIG. 5) and a second connection relationship (dashed line in FIG. 5). The first connection relationship is a connection in which each of the multiple front-side terminals 30 is connected to one of two predetermined rear-side terminals 32. The second connection relationship is a connection in which each of the multiple front-side terminals 30 is connected to the other of the aforementioned two predetermined rear-side terminals 32. In either the first or second connection relationship, the multiple front-side terminals 30 are connected to different rear-side terminals 32.

[0069] The selection circuit 40' may also be located in the input / output unit 14'' closer to the rear terminal 32 than the subordinate processing circuit 26. In this case, the selection circuit 40' becomes the main processing circuit 16 connected to the subordinate processing circuit 26 of another input / output unit 14 in the rear of the input / output unit 14''. Furthermore, the selection circuit 40' may also be located in the input / output unit 14'' closer to the front terminal 30 than the subordinate processing circuit 26. In this case, the selection circuit 40' becomes the main processing circuit 16 connected to the subordinate processing circuit 26 of its own input / output unit 14''.

[0070] Figure 6 is a diagram showing the communication system 10' having the input / output unit 14'' of Modified Example 2. In Figure 6, the numbers 1 to 4 assigned to the four main processing circuits 16 and the numbers 1 to 4 assigned to the four slave processing circuits 26 respectively show the correspondence between the main processing circuits 16 and the slave processing circuits 26 connected to the main processing circuits 16.

[0071] According to this modified example, as shown in FIG6, the entire configuration of the input / output unit 14'' is made common. Furthermore, by only changing (selecting) a portion of the selection circuit 40', multiple slave processing circuits 26 can be connected to different main processing circuits 16.

[0072] (Modification 3) In the case where the communication coupling unit 12 has two or more main processing circuits 16, one of the two main processing circuits 16 can also be a redundant circuit of the other. In this way, the security and reliability of the communication system 10 become better.

[0073] [Inventions that can be obtained from the embodiments] Inventions that can be obtained from the above embodiments and variations are described below.

[0074] <First Invention> The first invention is an input / output unit (14) that connects a main unit (12) to a device (104) and transmits signals between the main unit and the device; the input / output unit (14) includes: a plurality of front-side terminals (30) for connecting to the main unit or other input / output units provided in the front section; a plurality of rear-side terminals (32) provided for connecting to other input / output units provided in the rear section and connected to front-side terminals that are different from each other; and a subordinate processing circuit (26) connected to one of the plurality of front-side terminals and the rear-side terminal connected to this one front-side terminal to perform signal processing.

[0075] This provides an input / output unit that can be easily added within the station.

[0076] The first invention may also include a selection circuit (40) that selects a combination of a plurality of the front-side terminals and a plurality of the rear-side terminals that are connected to each other. In this way, the overall configuration of the input / output unit can be maintained, and the combination of a plurality of the front-side terminals and a plurality of the rear-side terminals can be changed by only changing a part of the selection circuit.

[0077] This main unit may also have multiple main processing circuits (16); multiple front-side terminals are connected to different main processing circuits. In this way, signals are input to the input / output unit from the multiple main processing circuits. The signal of one of the multiple main processing circuits is processed by a slave processing circuit, so that the signals of the other main processing circuits pass through to the rear-side.

[0078] The front-side terminal and the rear-side terminal connected to the slave processing circuit can also be connected to each other via the slave processing circuit. In this way, multiple slave processing circuits are connected in a daisy chain manner by sequentially connecting multiple input / output units.

[0079] The first invention may further include an interface (28) that connects the slave processing circuit to the device to enable the slave processing circuit to perform signal input and output with the device.

[0080] <Second Invention> The second invention is a communication system (10) comprising a main unit (12) and a plurality of input / output units (14) connected to the main unit for transmitting signals between the main unit and a device (104); the main unit comprises: a plurality of main processing circuits (16) for performing signal processing; and a plurality of branch terminals (22) for connecting to different main processing circuits; each of the plurality of input / output units comprises: a plurality of front-end terminals (30) for connecting to the main unit disposed in the front end or other input / output units disposed in the front end; and a plurality of rear-end terminals (32) for... The input / output unit is configured to connect to other input / output units located in the rear section and to the front section terminals that are different from each other; and a slave processing circuit (26) is connected to one of the plurality of front section terminals and to the rear section terminal connected to this one front section terminal to perform signal processing; the plurality of input / output units includes: a plurality of first input / output units (14A) that connect the slave processing circuit to a first main processing circuit; and a plurality of second input / output units (14B) that connect the slave processing circuit to a second main processing circuit that is different from the first main processing circuit.

[0081] This provides a communication system that allows for easy addition of input / output units within the station.

[0082] The first main processing circuit can also be a redundant circuit of the second main processing circuit. In this way, the security and reliability of the communication system are improved.

[0083] Each of the input / output units may further have an interface (28) to connect the slave processing circuit to the device, so as to enable the slave processing circuit to perform signal input / output with the device. [Simplified Explanation of the Diagram]

[0011] FIG1 is a diagram showing a communication system according to a reference example of the present invention.

[0012] Figure 2 is a diagram showing a communication system according to an embodiment of the present invention.

[0013] Figure 3A shows the input / output unit of Modified Example 1. Figure 3B shows the input / output unit with the first connection relationship selected. Figure 3C shows the input / output unit with the second connection relationship selected.

[0014] Figure 4 is a diagram showing the input / output unit of the change selection circuit configuration.

[0015] Figure 5 is a diagram showing the input / output unit of Modified Example 2.

[0016] Figure 6 is a diagram showing a communication system having the input / output unit of Modified Example 2.

Claims

1. An input / output unit (14) for connecting a main unit (12) having a main processing circuit to a device (104) and transmitting signals between the main unit and the device; the input / output unit includes: a plurality of front-side terminals (30) for connecting to the main unit disposed in the front section or other input / output units disposed in the front section; a plurality of rear-side terminals (32) for connecting to other input / output units disposed in the rear section and connected to different front-side terminals; and a subordinate processing circuit (26) connected to one of the plurality of front-side terminals and the rear-side terminal connected to the one front-side terminal, for performing signal processing; the one front-side terminal and the other front-side terminals of the plurality of front-side terminals are connected to different main processing circuits.

2. As in the input / output unit of request item 1, wherein, Includes a selection circuit (40) that selects a combination of the front-side terminals and the rear-side terminals that are connected to each other.

3. As in request item 1 or 2, the input / output unit, wherein, The main unit includes a plurality of main processing circuits (16); a plurality of the front-side terminals are connected to different main processing circuits.

4. As in request item 3, the input / output unit, wherein, The front-side terminal and the rear-side terminal connected to the slave processing circuit are connected to each other via the slave processing circuit.

5. The input / output unit as requested in item 1 or 2, wherein, It also includes an interface (28) that connects the slave processing circuit to the device and enables the slave processing circuit to perform signal input and output with the device.

6. A communication system (10) comprising a main unit (12) and a plurality of input / output units (14) connected to the main unit for transmitting signals between the main unit and a device (104); the main unit comprising: a plurality of main processing circuits (16) for performing signal processing; and a plurality of branch terminals (22) connected to different main processing circuits; each of the plurality of input / output units comprising: a plurality of front-end terminals (30) for connecting to the main unit disposed in the front end or other input / output units disposed in the front end; a plurality of rear-end terminals (32) for connecting to other input / output units disposed in the rear end and connected to different front-end terminals; and a subordinate processing circuit (26) connected to one of the plurality of front-end terminals and to a rear-end terminal connected to this one front-end terminal for performing signal processing; the plurality of input / output units comprising: The first input / output unit (14A) connects the slave processing circuit to the first master processing circuit; And a second input / output unit (14B) connects the slave processing circuit to a second main processing circuit that is different from the first main processing circuit.

7. The communication system as described in request item 6, wherein, The first main processing circuit is a redundant circuit of the second main processing circuit.

8. The communication system as described in request item 6 or 7, wherein, Each of the input / output units further includes an interface (28) that connects the slave processing circuit to the device to enable the slave processing circuit to perform signal input / output with the device.

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