JP3305202B2 - Network system for redundant controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system for a controller which is duplicated for improving the reliability of a controller system, and more particularly, to transmitting data of a controller of a local station in a programmable controller system or the like at regular intervals. The present invention relates to an inter-controller network system that performs cyclic transmission, which is a transmission method for exchanging data with another station controller.

[0002]

2. Description of the Related Art FIG. 15 shows a basic system configuration of a conventional network between programmable controllers.
The network system between programmable controllers has network interface units (hereinafter, referred to as NET units) 1M, 1N for each programmable controller (hereinafter, abbreviated as PC) 2, and the NET units 1M, 1N,. It is connected to the.

[0003] Each PC 2 transmits a signal from the outside to the PC.
2, an input / output unit (hereinafter, referred to as an I / O unit) 3 for outputting a result processed by the PC 2 to the outside is connected.

The NET units 1M, 1N,... Are assigned unique station numbers different from each other, such as 1, 2,. In the network between PCs, data transmission / reception processing is performed based on this station number, so that the same station number is not allowed in one network.

As shown in FIG. 16, the NET units 1M, 1N,... Have network devices that can be commonly used by stations in the network in order to mutually transmit data. It can be assigned to each station. In the example of FIG. 16, two devices having names “A” and “B” are assigned to each station. The parameter for allocating this device to each station is called "allocation parameter".

[0006] The user can select each NET unit 1M, 1N ...
In order to allocate devices A and B to the PC and to access them by the control program of each PC 2, an allocation parameter table as shown in FIG.
Register with M. Each of the NET units 1M, 1N,... Is classified into a management station 1M that manages allocation parameters and a normal station 1N other than the management station 1M.

[0007] As shown in FIG. 18, a NET unit 1 has a memory unit 1031A for storing a device A inside the unit, a memory unit 1031B for storing a device B inside the unit, and a NET unit 1 for cyclic transmission. Parameter storage unit 1 for storing a series of parameters to be used
031C and communication means 10 for performing communication processing with each NET
31D, and the device A memory unit 1031A, the device B memory unit 1031B, and the communication unit 1031C are mutually connected by the internal bus 1031E.

[0008] As shown in FIG.
Are a control program storage unit 1032A for storing a program for performing I / O control, a transmission processing program storage unit 1032B for storing a program for performing transmission processing, and a reception processing program storage unit 1032C for storing a program for performing reception processing. Which are interconnected by an internal bus 1032E.

The device A memory unit 1 of the NET unit 1
031A and device B memory section 1031B and PC2
The transmission processing program storage unit 1032B and the reception processing program storage unit 1032C are interconnected by an external bus 1032F.

FIGS. 19 and 20 show device A and device B.
The memory space of FIG. For example, it is assumed that device A is a bit device and device B is a word device, and both have device numbers from 0 to FFF. As a notation method, the device number 7 of the device A is “device A-7”, and the device B has the same notation method.

FIGS. 21 and 22 show a device A memory unit 1.
031A and the address map when the head address in the device B memory unit 1031B is set to “0” and the address of each device is allocated in units of 1 byte. The addresses 0 to 0 indicate addresses that are actually accessed inside each NET unit.

[0012] The management station 1M, based on the set allocation parameter table (FIG. 17) according to the allocation information table creation rules shown in FIG. 23, each station device allocation information table (hereinafter, referred to as FIG. 24).
(Referred to as an allocation information table). The allocation parameter table and the allocation information table are stored in the parameter storage unit 1031C.

[0013] allocation information table generating rules shown in FIG. 23, a start mark assignment information table (PARATB L_ START), a memory unit of the device A whole network uses 1031A, leading in the memory portion 1031B of the device B The address and size (hereinafter referred to as overall allocation information), the start address and size (hereinafter referred to as each station allocation information) in the memory section 1031A of the device A and the memory section 1031B of the device B to be transmitted for each station, and the end mark (PA
RATBL_END).

The contents of the allocation information table will be described taking one station as an example. According to the allocation parameter table shown in FIG.
00-00F ”and“ 000-00F ”for device B.
F ". The head address of device A transmitted by one station is" 000 ", and the size of device A transmitted by one station is one word (16 bits) because device A is a bit device. Similarly, the head address of the device B transmitted by one station is “000” and the device B is a word device, so the size of the device B transmitted by one station is 10 words.

[0015] For the entire network, both devices A and B use "000-05F". That is, the start address of device A in the entire network is “00”.
0 ", and the size of device A in the entire network is 6 words. Similarly, device B in the entire network
Is "000", and the size of device B in the entire network is 60 words (see FIG. 24).

Next, a procedure for creating an allocation information table will be described with reference to FIG. First, an initial value “1” is set in a counter inside the NET unit (step S
100). Although not shown, the counter is a temporary storage memory used when executing the allocation information table creation processing in the NET unit, and indicates a station number.

Next, the parameter of the station number (1 station) indicated by the counter is read from the allocation parameter table (step S110), and the head addresses and sizes of the devices A and B used by the station number indicated by the counter are calculated from the parameters (step S110). (S120), these are stored in the assignment information column of the corresponding station number in the assignment information table (step S130).

Next, the counter is updated (here, it becomes 2) (step S140), and it is confirmed whether or not the setting for all stations has been completed based on the updated count value (step S150). If it is not completed, the process returns to step S1 1 0, repeatedly executes steps S1 1 0~S140.

On the other hand, if completed, the head addresses and sizes of the devices A and B used in the entire network are calculated from the read parameters (step S).
160), and store these in the allocation information column of the entire network in the allocation information table (step S17).
0).

As shown in FIG. 26, the management station 1M
Transmits the allocation information table to each normal station 1N in the network, and notifies each station of the allocation contents (thin line in FIG. 26).

When each of the normal stations 1N receives the allocation information table from the management station 1M, the management station 1M “receives” the information.
Is returned (dotted line in FIG. 26). The management station 1M starts cyclic transmission after receiving this response.

FIGS. 27 and 28 show the allocation ranges of devices A and B in which the allocation information table is developed. 27 and 28, “● (black circle)” indicates the transmission range of each station. Hereinafter, FIGS. 29 to 3
By repeating the data transmission operation of No. 4 sequentially, the data of the own station can be refreshed to other stations at high speed.

In this data transmission, assuming that the same transmission range is allocated to one and two stations, two stations transmit data immediately after one station transmits data, and two stations transmit data to the data area transmitted by one station. Will be overwritten. FIGS. 35 and 36 show how data is overwritten for each of device A and device B.

Therefore, in the conventional inter-PC network system, devices having the same transmission range cannot be allocated to stations having different station numbers.

In the conventional inter-PC network system based on the cyclic transmission method described above, devices having the same communication range cannot be allocated to stations having different station numbers. Therefore, in order to improve the reliability of the system, the PC and NE are required.
Duplication of the T unit has already been proposed.

As shown by reference numerals 300 and 301 in FIG. 37, the PCs are duplicated, and one PC of the NET unit and five PCs of the NET unit are respectively connected to a control system PC (working PC), two NET units and six NET units. The PC is set to the role of the standby PC.

The control system PC is a PC in charge of control among the duplicated PCs, and the standby system PC is the other PC.
If the control PC is abnormal and the control PC cannot be continued due to an abnormality, the control is performed instead. However, when the control PC is normal, the PC is on standby. In this case, since the control system PC and the standby system PC are of course duplicated, programs having the same control contents are registered in advance.

The control system PC always transmits and receives data using the connected NET units. If a failure such that control cannot be continued in the control system PC occurs due to some factor, the standby system PC switches the control system PC to the control system PC. The control is executed in place of the PC. Therefore, since the standby PC does not normally perform control, the standby PC is provided so as to perform only data reception and control at any time instead of the control PC.

[0029]

In the conventional cyclic transmission system, if the station number is different, the transmission range of the assigned device is also different. In the case of transmission, the program of the control part of the control system PC and the control part of the standby system PC is different. Regarding the data receiving portion even if they can be the same, for example, the usable device range of the station number 1 is 000 to 00F, and the station number 2 is 010 to 01F.
Therefore, it is necessary to change it according to the assigned device number.

Accordingly, as shown in FIG. 38, the reception processing program in this case first checks whether the control PC is operating normally (step S200). reading a transmission allocation range data (step S201), if the abnormal contrast, reads the transmission assignment range data of station 2 instead of to read out the transmission assignment range data of station 1 (step S2
02), and thereafter, a control process is executed (step S20).
3) It becomes complicated.

The present invention has been made in order to solve the above-described problems, and has as its object to provide a network system capable of easily creating a reception processing program for cyclic transmission in a network system for a redundant controller. In particular, by enabling the standby PC to take over the transmission range of the control PC as it is, the reception processing program of each PC reads out the transmission allocation range data of one station number and executes the control processing. It can be as simple as it is, and it can be executed by a combination of multiple devices and multiple stations, making it easy to program a redundant system,
Further, it is an object of the present invention to obtain a network system for a redundant controller that can easily construct a redundant system itself.

[0032]

In order to achieve the above-mentioned object, a network system for a redundant controller according to the present invention has a network interface unit provided with a unique station number for each of the redundant controllers. The network interface units are communicably connected to each other by a network cable, and the network interface unit comprises:
It has a network device that can be assigned for each station number to exchange various information with other network interface units in the same network, and by transmitting data of the assigned network device at regular intervals. In a redundant controller network system that cyclically transmits data held by the controller to another network interface unit, the same network device number is assigned to two network interface units that are paired according to the redundancy of the controller. Each of the two allocated and paired network interface units has a controller for storing information indicating whether the own station controller is a control system or a standby system. Has a state storage unit, only the network interface unit local station controller is a control system based on the information stored in the controller state storage unit is one that is configured to perform data transmission.

It should be noted that, due to the exclusive control of the duplicated controller, the two paired network interface units do not simultaneously become a control system.

In the network system for a redundant controller according to the present invention, it is possible to assign the same number to a network device regardless of different station numbers in the network, and two network interfaces paired according to the redundant controller. The unit is assigned the same number of the network device, and the paired two network interface units transmit data only when the local controller is the control system based on the information stored in the controller status storage unit. Therefore, even if the same transmission range is assigned to two paired network interface units, data is not overwritten.

In the network system for a redundant controller according to the next invention, in the above-described network system for a redundant controller, a plurality of pairs of network interface units are set in accordance with the number of the duplexed controllers. It is configured such that the same number of the network device can be assigned to each of the network interface units.

In the network system for a redundant controller according to the present invention, it is possible to set a plurality of combinations in which the same number of the network device can be assigned irrespective of the different station numbers in the network, and according to the number of the redundant controller sets. A plurality of pairs of network interface units are set, and the same number of the network device is assigned to each of the two network interface units in each pair.

In the network system for a redundant controller according to the next invention, in the network system for a redundant controller described above, the same number of a network device can be assigned to two paired network interface units by a plurality of network device types. It is configured.

In the network system for a redundant controller according to the present invention, the same number of network devices can be assigned to a plurality of types of network devices regardless of different station numbers in the network.
With respect to the two paired network interface units, the same number of the network device is assigned by a plurality of network device types.

A network system for a redundant controller according to the next invention is the network system for a redundant controller described above, wherein the controller is a programmable controller, and one of the two programmable controllers is an input / output unit by a bus switching unit. Is connected to the control system programmable controller, the programmable controller not connected to the I / O unit forms a standby system, and the network interface unit only outputs data when the local station programmable controller is the control system that controls the I / O unit. It is configured to perform transmission.

In the network system for a redundant controller according to the present invention, the exclusive control of the two redundant programmable controllers becomes the control system programmable controller by connecting only one of them to the input / output unit by the bus switching unit. The network interface unit transmits data only when the local station programmable controller is a control system for controlling the input / output unit.

[0041]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, the same components as those of the above-described conventional example are denoted by the same reference numerals as those of the above-described conventional example, and description thereof will be omitted.

[First Embodiment] FIG. 1 shows a first embodiment of a network system for a redundant controller according to the present invention. The duplicated PC device 7 includes two PCs 2 and two Ns having different station numbers.
Separately from the ET unit, I / O via connection cable 6
It has a bus switching unit 5 to which the unit 3 is connected.

The bus switching unit 5 performs switching control of selectively connecting one of the two PCs in the single redundant PC device 7 to the I / O unit 3.

FIG. 2 shows the internal configuration of the redundant PC device 7. Here, two PCs 2 are referred to as A for convenience.
In order to distinguish between the system and the B system, A is added to the end of the code for the A system, for example, PC2A, and is added to the end of the code, for example, PC2B for the B system. To B.

Since the NET unit is classified into a management station and a normal station, the NET unit 1MA is used for the management station A, the NET unit 1NA is used for the normal station, and the management station is used for the B system. The NET unit is 1 MB, and the NET unit is 1NB for a normal station.

Here, the A system is a control system (active system),
The B system is assumed to be a standby system that takes over the control in place of the control system when an abnormality occurs in the control system, and waits while the control system is normal.

As another example, of the A system and the B system,
The one started first may be the control system, and the one started later may be the standby system. However, here, it is assumed that the system A is always the control system and the system B is always the standby system.

Since the present invention does not relate to the setting method of which of the A system and the B system is used as the control system and which is used as the standby system, the switching system and the setting system of the control system / standby system are not described. Is not described here.

The bus switching unit 5 includes PCs 2A, 2
B of any of the control system signals to the I / O unit 3
It has an I / O control unit 8 for inputting / outputting data to / from.

[0050] PC 2A, 2B are each normal self PC, and the PC itself abnormality detecting circuit 9 to determine the abnormal, self PC of the control system, it is determined from the information of the information of the standby system host PC abnormality detecting circuit 9 Last A state determination circuit 10 for determining whether the own PC is a control system or a standby system, and these are connected by internal buses 14 and 16.

The state discrimination circuit 10 responds to the possibility that an abnormality may occur in the A-system PC on the way even if the A-system is operated as the control system and the B-system is operated as the standby system as described above. ing.

The NET units 1MB and 1NB are connected to the state discriminating circuit 10 and the internal bus 15 to store the contents of the discrimination of the state discriminating circuit 10 on the NET unit side. And a parameter storage unit 12 for storing PCs and Ns of a control system and a standby system.
It includes a pairing setting storage unit 13 for storing the setting status of the combination (pairing) of the ET units. Here, it is assumed that “0” is stored in the own station PC status storage unit 11 if the own PC is a control system, and “1” is stored if the own PC is a standby system.

FIG. 3 shows an outline of the operation of the redundant PC apparatus when an abnormality has occurred in the own PC or the partner PC according to the state of the own PC. In the table of FIG. 3, the own PC status is set to “row”, and the occurrence event of the abnormality is set to “column”. Own P
If an abnormality occurs in the own PC when C is the control system, the state of the own PC is shifted to the standby system, and the own NET unit is notified. Also, when an error occurs in the partner PC when the own PC is in the standby system, the own PC needs to control the I / O unit 3 instead of the partner PC.
C is transferred to the control system to notify the own station NET unit.

FIGS. 4 and 5 show the contents of the pairing setting for setting the setting status of the pair of the control system and the standby system. As shown in FIG. 5, when a certain bit is set to "1", it means "the station is paired with the previous station number". In the example shown in FIG. 5, pair setting is performed for two stations and six stations from FIG. This indicates that there is a pair of 1 and 2 stations and a pair of 5 and 6 stations. That is, when the duplex system configuration of FIG. 1 is constructed, the pairing setting is performed as shown in FIG.
become that way.

FIG. 6 shows a network device allocation parameter table for the duplex system configuration of FIG. The setting of the station number 2 is invalidated by the pairing setting in FIG. In order to solve the problem that “when the station number 1 and the station number 2 are duplicated, the receiving side program such as the station number 3 and the station number 4 becomes complicated”, “the station number 1 and the station number 2 are the same. It must be within the device allocation range. "

Next, a procedure for creating the assignment information table shown in FIG. 7 from the pairing shown in FIG. 5 and the assignment parameter table shown in FIG. 6 will be described with reference to FIG.

First, "1" indicating station number 1 is stored in the counter (step S100). Next, in the pairing setting of FIG. 5, it is confirmed whether or not the station indicated by the counter has been paired (step S102). Because if the pairing setting is not made to perform a conventional example exactly same processing (Step S1 1 0 to 170), description thereof will be omitted.

If the pairing is set, the station assignment information whose station number is indicated by [(counter value) -1] is stored in the station assignment information column of the station number whose counter value is the counter value (step S104), and the process proceeds to step S140. Jump.

As an example, when (counter value) = 2, when the pairing setting of two stations is confirmed, [(counter value) −
1] = 1 is copied to two stations of (counter value) = 2.

Next, the counter is updated (step S14).
0), it is checked whether the processing for all stations has been completed (step S150), and if not, the process returns to step S102 to repeat a series of processing. If it is determined that the processing for all stations has been completed, step S
160 and S170 and subsequent steps are performed to create allocation information for the entire network.

That is, the assignment information table creation rule
The concept of pairing setting shown in FIGS. 4 and 5 is newly introduced without any change, and the flow chart of the conventional example shown in FIG. 25 includes steps S102 and S1 shown in FIG.
By simply adding the process 04, it is possible to assign the same number to the network device despite the different station numbers in the network.

Similarly, the pairing setting can be performed for the station numbers 5 and 6, and the fact that the contents of the station numbers 5 and 6 are the same in the allocation parameter table of FIG. 7 is different from other pair setting stations. It is also possible for a pair setting station. In other words, it is possible to set a plurality of combinations in which the same number can be assigned to the network device regardless of different station numbers in the network.

Although the allocation information table of FIG. 7 is created for only two device types, network device A and device B, as in the conventional example, the concept is the same even if the device types are increased. It is obvious that the same station number can be divided into a plurality of device types for each station number in the network.

Next, the transmission process will be described with reference to FIG.

First, the pairing setting is read from the pairing setting storage unit 13, and it is checked whether the pairing setting has been made for the own station (steps S10 and S11).

If the pairing has been set, the own station is constructing a duplex system. Therefore, the contents of the own station PC status storage unit 11 are checked, and whether the own PC is a control system is determined. It is determined whether it is a standby system (step S1).
2). If it is a control system, data transmission is performed (step S
13) If it is a standby system, no data transmission is performed (step S14).

If it is determined in step S11 that the own station has no pairing setting, it is checked whether the (own station number + 1) station has a pairing setting (step S1).
5) If there is no pairing setting, the process proceeds to step S13 to perform data transmission.

On the other hand, if there is a pairing setting, the station itself is constructing a duplex system.
Proceeding to step S12, it is determined whether the own station PC is a control system or a standby system, and data transmission is performed in response to the determination.
Judge whether to do.

That is, according to this transmission processing flow, it is possible to realize exclusive control in which data transmission is performed only when the local controller becomes a control system.

FIGS. 10 to 13 show the status of transmission / reception processing of each station. 10 and 11, device A and device B are transmitted by station numbers 1 and 5, respectively, which are control system stations. FIGS. 12 and 13 similarly show a state in which the devices A and B are performing data transmission with the control system station becoming abnormal and the standby system station being switched.

That is, the operation state originally intended when the PC and the NET unit are duplicated in order to improve the reliability of the system is shown.

In this case, it is possible for the standby PC to perform data transmission while taking over the transmission range of the control PC as it is, and the reception processing program of each PC is shown in FIG.
As shown in (1), the transmission allocation range data of the station number 1 is read (step S20), and the control processing is executed (step S21).

The same effects can be obtained even if the above embodiments are implemented by an FA controller, a personal computer, or the like.

[0074]

As can be understood from the above description, in the network system for a redundant controller according to the present invention, data transmission is performed only in the paired network interface unit whose own controller is the control system. Therefore, it is possible to assign the same number to network devices regardless of different station numbers in the network, and even if the controllers in the network are duplicated as a control system controller and a standby system controller, the data reception side Is effective in that a program for duplication can be easily created in a conventional programming style without being conscious of duplication of stations.

In the network system for a redundant controller according to the next invention, it is possible to set a plurality of combinations in which the same number of the network device can be assigned irrespective of a different station number in the network. However, the control program on the data receiving side can be easily created in the conventional programming style without having to be aware of the station duplication even if the program is duplicated as a control system controller and a standby system controller. And the construction of the duplex system itself becomes easy.

In the network system for a redundant controller according to the next invention, the same number of network devices can be assigned to a plurality of network device types regardless of different station numbers in the network. Even if the system controller and the standby controller are duplicated, the effect is that the control program on the data receiving side can easily create a program for duplication in the conventional programming style without being aware of the duplication of the station.

In the network system for a redundant controller according to the next invention, exclusive control of the two redundant programmable controllers becomes a control system programmable controller by connecting only one of them to the input / output unit by the bus switching unit. The network interface unit performs data transmission only when its own programmable controller is a control system that controls the input / output unit, so the same number is assigned to the network device regardless of the different station number in the network. A plurality of combinations that can be set can be set, and a plurality of programmable controllers in the network can be used as the control system PC and standby system P
Even if the program is duplicated as C, the effect is obtained that the control program on the data receiving side can easily create a program for duplication in the conventional programming style without being aware of the duplication of the station.

[Brief description of the drawings]

FIG. 1 is an overall view of a system configuration showing a first embodiment of a network system for a redundant controller according to the present invention.

FIG. 2 is an internal block diagram showing a redundant system configuration in a redundant controller network system according to the present invention.

FIG. 3 is an explanatory diagram showing an outline of an operation in a case where an abnormality has occurred in one's own or the other's PC according to the own PC's state.

FIG. 4 is an explanatory diagram showing the contents of a pairing setting for setting a setting status of a pair of a control system and a standby system.

FIG. 5 is an explanatory diagram showing the contents of a pairing setting between a control system and a standby system in the system configuration shown in FIG. 1;

FIG. 6 is an explanatory diagram showing a network device allocation parameter table in the system configuration shown in FIG. 1;

7 is an explanatory diagram showing an assignment information table created according to an assignment parameter table creation rule based on the assignment parameter table shown in FIG. 6 as in the conventional example.

FIG. 8 is a flowchart showing a procedure for creating an assignment information table in the network system for a redundant controller according to the present invention.

FIG. 9 is a flowchart showing a transmission processing routine in the redundant controller network system according to the present invention.

FIG. 10 is an explanatory diagram showing an operation state of transmission / reception processing of the device A of each station in a state where the first and fifth stations are control system PCs.

FIG. 11 is an explanatory diagram showing an operation state of transmission / reception processing of device B of each station in a state where one and five stations are control system PCs.

FIG. 12 is an explanatory diagram showing an operation state of a transmission / reception process of the device A of each station in a state where two stations and six stations are control PCs.

FIG. 13 is an explanatory diagram showing an operation state of transmission / reception processing of the device B of each station in a state where two stations and six stations are control PCs.

14 is a flow <br/> chart showing a reception processing routine in the network system for redundant controller according to the present invention.

FIG. 15 is a configuration diagram showing a basic system of a conventional inter-PC network.

FIG. 16 is an explanatory diagram showing a state where network devices are allocated to each station in the system configuration shown in FIG.

FIG. 17 is an explanatory diagram showing an example of allocation parameters of a basic system configuration of a conventional inter-PC network.

FIG. 18 is an internal block diagram of a conventional PC and NET unit.

FIG. 19 is an explanatory diagram showing a map of a network device A.

20 is an explanatory diagram showing a map of the network device 2. FIG.

21 is an explanatory diagram showing an address map of a network device A in byte units. FIG.

FIG. 22 is an explanatory diagram showing an address map of the network device 2 in byte units.

FIG. 23 is an explanatory diagram showing an allocation parameter table creation rule for an inter-PC network in a conventional example.

FIG. 24 is an explanatory diagram showing a state in which allocation parameters are developed in an allocation parameter table according to an allocation parameter table creation rule.

FIG. 25 is a flowchart showing a procedure for creating an allocation parameter table in a conventional example.

FIG. 26 is an explanatory diagram showing a state in which a parameter table allocated to each normal station in the network is transmitted and the allocation range of each station is notified.

FIG. 27 is an explanatory diagram showing an allocation range of a device A in which an allocation information table is developed.

FIG. 28 is an explanatory diagram showing an allocation range of a device B in which an allocation information table is developed.

FIG. 29 is an explanatory diagram showing a data transmission operation of one station in a conventional example.

FIG. 30 is an explanatory diagram showing a data transmission operation of two stations in a conventional example.

FIG. 31 is an explanatory diagram showing a data transmission operation of three stations in a conventional example.

FIG. 32 is an explanatory diagram showing a data transmission operation of four stations in a conventional example.

FIG. 33 is an explanatory diagram showing a data transmission operation of five stations in a conventional example.

FIG. 34 is an explanatory diagram showing a data transmission operation of six stations in a conventional example.

FIG. 35 is an explanatory diagram showing the transmission status of device A when the transmission ranges of the first and second stations, the fifth station, and the sixth station are the same.

FIG. 36 is an explanatory diagram showing the transmission status of device B when the transmission ranges of the first and second stations, the fifth station, and the sixth station are the same.

FIG. 37 is a configuration diagram showing a basic system configuration of a redundant PC / NET unit of a conventional example.

FIG. 38 is a flowchart showing a reception processing routine in a conventional example.

[Explanation of symbols]

1 NET unit, 2 PC, 3 I / O unit,
4 network cable, 5 bus switching unit, 6 connection cable, 7 redundant PC device, 8 I / O
Control unit, 9 own PC abnormality detection circuit, 10 state discrimination circuit, 11 own PC state storage unit, 12 parameter storage unit, 13 pairing setting storage unit, 14, 15, 16
Internal bus

Continuation of the front page (56) References JP-A-5-153114 (JP, A) JP-A-58-124350 (JP, A) JP-A-8-65331 (JP, A) JP-A-4-238437 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04L 12/42-12/437 H04L 12/00-12/26 H04L 12/50-12/66

Claims (4)

(57) [Claims] A network interface unit having a unique station number is connected to each of the duplicated controllers, and the network interface units are communicably connected to each other by a network cable.
It has a network device that can be assigned for each station number to exchange various information with other network interface units in the same network, and by transmitting data of the assigned network device at regular intervals. In a network system for a redundant controller that cyclically transmits data held by the controller to another network interface unit, the same network device number is assigned to two network interface units that are paired according to the redundancy of the controller. Each of the two allocated and paired network interface units is a controller that stores information indicating whether the local controller is a control system or a standby system. A duplex storage controller having a status storage unit, wherein only the network interface unit in which the own station controller is a control system performs data transmission based on the information stored in the controller status storage unit. Network system. 2. A duplex controller network system according to claim 1, Netw pairing network interface unit is a plurality of sets set in accordance with the number of sets of duplicated controllers, two network interfaces in each set A network system for a redundant controller, wherein each unit is configured to be assigned the same number of a network device. 3. The network system for a redundant controller according to claim 1, wherein the paired two network interface units are configured so that the same network device number can be assigned to a plurality of network device types. A network system for a redundant controller. 4. The network system for a redundant controller according to claim 1, wherein the controller is a programmable controller, and one of the two redundant programmable controllers is an input / output unit by a bus switching unit. Is connected to the control system programmable controller, the programmable controller not connected to the I / O unit forms a standby system, and the network interface unit only outputs data when the local station programmable controller is the control system that controls the I / O unit. A network system for a redundant controller configured to perform transmission.