JPH11178067A - Network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inform a manager or a worker of the existence of a slave station with duplicate addresses by having the operation of the slave station stopped with the duplicated addresses. SOLUTION: A host station 11 and a master station 11 are connected to a wired communication LAN and the master station 11, and plural slave stations (12) are interconnected by a radio communication LAN. The master station 11 sends to the slave station 12 a duplicated registration check polling frame that has a destination address set by the user and that has each unique address of each slave station 12 in capable of being set by the user. Receiving the duplicate registration check polling frame, the slave station 12 reads the destination address and the unique addresses in the duplicate registration check polling frame. When the destination address is the same but the unique addresses are different, the slave station 12 stops its operation, regarding the addresses of its own station as being a duplicate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a network system in which a host station and a master station are connected to a wired communication LAN, and the master station and a plurality of slave stations are connected by a wireless communication LAN.

[0002]

2. Description of the Related Art Conventionally, a wireless communication LAN is a wired communication LA.
N, the reliability of data communication is lower than that of N, so that it can be used for simple data transmission but has not been used for data transmission between control devices requiring high reliability.

[0003] However, in recent years, the reliability of data transmission has been remarkably improved due to advances in wireless technologies such as a spread spectrum system and an error correction technology, and a network system using a wireless communication LAN has been developed at a manufacturing site for the following reasons. It has been introduced and spread.

[0004] The total lead time is reduced. Reduce construction costs. Reduce costs associated with frequent line layout changes. Since there are restrictions on the moving body, the rotating body, the operation, and the like, it is difficult to lay communication cables.

For example, a network system as shown in FIG. 11 has been introduced at a manufacturing site and is becoming popular.

[0006] This network system uses a remote I
Programmable controller (PL
C) A wired communication LAN including a remote I / O network 60 to which the master station 51 is connected, and a wireless communication LAN for wirelessly transmitting and receiving data between the master station 51 and the slave station 52.

[0007] In addition, the wireless communication LAN and the wired communication LAN require a programmable controller 50 to repeat cyclic processing within a predetermined time as a communication method to be adopted, so that a communication cycle can be defined and data transmission can be performed. The polling / selecting method that can guarantee the time or the token passing is adopted.

When transmitting / receiving data to / from the slave station 52, the master station 51 pre-joins the network to the slave station 52.
After confirming the above, data such as control information is transmitted and received.

[0009]

However, in a network system having a wireless communication LAN which has been introduced and spread at a manufacturing site, the slave station 5 which the master station 51 receives is not used.
Since only the data with the highest radio wave intensity is received as data from 1, it was virtually impossible to detect duplication of addresses.

[0010] For this reason, the above-described network system which has been introduced and spread at the manufacturing site operates in a state having an overlapping address.
The data transmitted from the master station 51 controls the device.
In the case of / O data, not only does the production line not operate normally, but also there is a problem that a serious accident may be caused due to a runaway of the equipment.

Here, in the wireless communication LAN, the fact that it is practically impossible to detect an address duplication is considered, for example, because the address is set so that the child station 52 of A and the child station 52 of B are duplicated. The following is an example of the case.

If the response frame to the polling frame transmitted by the master station 51 is assumed to have a stronger radio field intensity than the response frame received from the slave station 52 of B, the response frame received from the slave station 52 of A is assumed. First, the master station 51 receives the radio wave of the response frame transmitted by the slave station 52 of A, and as a result, recognizes that a normal response frame has been transmitted in response to the previously transmitted polling frame. This makes it virtually impossible to detect duplicate addresses.

Therefore, when the master station 51 subsequently transmits valid data to the slave station 51 at the corresponding address, the slave station 52 of A and the slave station 52 of B receive the data. .

In a wired communication LAN, wireless communication LA
It will be described that unlike the N system, a duplicate address can be easily detected.

For example, a slave station whose address is duplicated with respect to a polling frame from the master station transmits a response frame to the master station almost simultaneously with the polling frame from the master station. In the response frame to be transmitted, data is overlapped by the response frame transmitted by each slave station, and the bit information is destroyed.

As a result, the master station determines that there is no response to the transmitted polling frame, and receives only the response frame as an error frame even if the polling frame is retransmitted many times, and cannot receive a normal response frame. .

Therefore, in a wired network system,
It can be detected that the address is duplicated in the corresponding address.

In view of the above-mentioned problem, by stopping the operation of the slave station having the duplicate address,
It is an object of the present invention to provide a network system that informs an administrator or an operator of having a child station having a duplicate address.

[0019]

According to a first aspect of the present invention, there is provided a network system including a master station and a slave station, wherein the master station has a destination address set by a user. When the user cannot set and transmits a duplicate registration check polling frame having a unique address unique to each slave station, and the slave station receives the duplicate registration check polling frame, The transmission destination address and the unique address are read, and when the transmission address is the same but the unique address is different, the operation is stopped assuming that the address of the own station is duplicated.

According to a second aspect of the present invention, in the first aspect of the present invention, a network table for storing subscription information indicating whether the master station has joined or left the network, and A unique address information table for storing unique address information serving as the unique address for the sub-station subscribed to, and based on the network table and the unique address information table, the duplicate registration check polling frame. To be transmitted to the slave station.

The third aspect of the present invention is the first or second aspect.
In the described invention, when the duplicate registration check polling sequence ends, the master station performs an operation such as addition or subtraction of a predetermined number to an address set by the user to set the address outside the user setting range, and transmits the address. The transmission frame having the destination address is transmitted to the slave station.

According to a fourth aspect of the present invention, in the first aspect of the invention, when the slave station receives the duplicate registration inspection polling frame from the master station, the slave station stores polling confirmation information indicating the fact. Information transmission / reception means, and when a transmission frame having no unique address is received after the duplicate registration check polling sequence, even if the transmission address is the same as the own station, polling confirmation is performed. If the polling confirmation information is not stored in the information storage unit, the operation is stopped assuming that the address of the own station is duplicated.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the master station refers to the unique address information table to join the slave station that has left, with the unique address. A confirmation polling frame is transmitted, and the slave station recognizes that the same address is present when the destination address of the received subscription confirmation polling frame is the same as that of the own station but the unique address is different. To stop the operation.

According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, the duplicate registration check polling frame transmitted by the master station to stop the operation of the slave station in which the duplicate address is registered, and When a child station leaves the network after subscribing, only the subscription confirmation polling frame sent by the master station to the slave station has the destination address set by the user and the slave station that cannot be set by the user. A transmission frame having a unique address having
In other transmission frames, the transmission frame does not have the unique address.

According to the present invention, when the slave station receives the double registration check polling frame, the slave station reads the destination address and the unique address in the duplicate registration check polling frame. , The operation stops assuming that the address of the own station is duplicated.

When the slave station receives a transmission frame having no unique address after the duplicate registration check polling sequence, even if the transmission address is the same as that of the own station, the slave station stores the polling confirmation information. If the polling confirmation information is not stored in the server, the operation is stopped assuming that the address of the own station is duplicated.

Further, when the destination address of the received subscription confirmation polling frame is the same as that of the own station, but the unique address is different, the slave station recognizes that the same address exists and stops operation. I do.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A network system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of a network system according to an embodiment of the present invention.

The network system of this embodiment is
As shown in FIG. 1, a programmable controller 10 as a host station, a # 1 master station having a use band of channel CH1, and a # 2 master station 11 having a use band of channel CH2 include a remote I / O network 20. And the master stations 11 of # 1 and # 2 are connected to a plurality of slave stations 12 by a wireless communication LAN, and polling is performed as a communication method of the wired communication LAN and the wireless communication LAN. -It is configured by adopting the selecting method.

Further, the network system of this embodiment polls the slave stations 12 under the control of the master stations 11 of # 1 and # 2, and performs one communication cycle until polling is performed again as shown in FIG. A cyclic communication phase for periodically polling the slave station 12,
There is a peripheral process, for example, a notification phase for performing a process of displaying the radio wave reception status in each slave station 12 on a monitor device (not shown).

In the cyclic phase, the master station 11 transmits a subscription confirmation polling frame, an idle polling frame, an initial data frame, and a cyclic data frame as I / O data to the slave station 12.

Here, the join confirmation polling frame is a frame for requesting a response to the slave station 12 as to whether or not to join the wireless communication LAN. The initial data frame is transmitted to the slave station 12 requesting the join. On the other hand, it is a frame having setting data such as communication parameters necessary for network operation.

Here, a transmission frame used in the network system of this embodiment will be described.

As shown in FIG. 3A, the transmission frame used for the wireless communication LAN constituting the network system of this embodiment includes a first transmission frame 70 having no unique address area and a transmission frame 70 shown in FIG. b), a second transmission frame 80 having a unique address area.

The first transmission frame 70 having no unique address area is used as a subscription confirmation polling frame, a response frame for the subscription confirmation polling frame, and a response frame for initial data.

The first transmission frame 70 has a synchronization flag (SYN) area 70a having a 1-byte length having a synchronization flag for designating the head of the frame, and a transmission destination area having a 1-byte length having an address of the transmission destination. An address (DA) area 70b, and 1 having a source address
Source address (SA) area 70c consisting of byte length
A 2-byte length control code (CF) area 70e having information for identifying the type of the frame, and a 4-byte length data area 70f having I / O data, call code (CallSign) data, and the like. 1 having a flag check sequence area 70g having a 2-byte length and a synchronization flag designating the end position of the frame
And a synchronization flag (SYN) area 70h having a byte length.

The second transmission frame 80 having the unique address area is used for a subscription confirmation polling frame transmitted to confirm the departure at the time of the previous departure and now departure, and a duplicate registration check polling frame.

The frame 80 has a synchronization flag (SYN) area 80a having a 1-byte length having a synchronization flag designating the head of the frame, and a destination address (1-byte length) having a destination address. D
A) an area 80b, a 1-byte source address (SA) area 80c having a source address,
A unique address area 80d having a 5-byte length having a call code (CallSign) of the slave station 12, a control code (CF) area 80e having a 2-byte length having information for identifying the type of frame, I / O data, A 4-byte data area 80f having call code (CallSign) data and the like, a 1-byte synchronization flag having a flag check sequence area 80g having a 2-byte length and a synchronization flag designating a frame end point ( SYN) area 80h.

The second frame 80 shown in FIG.
Indicates that there is no unique address (SN) area 80d 12
1.4 (17/1) compared to the first frame of byte length
2) It has twice the length.

The host PLC 10 controls devices to be controlled such as sensors and motors.

The # 1 master station 11 employs a spread spectrum system as a communication system executed with the slave station 12.
"W" as an ID for specifying a channel group to be used
GID ”has“ 1 ”and the master station 11 of # 2
Has a “WGID” of “2”.

Also, the master stations 11 of # 1 and # 2 respectively
It has a network table to be described later, and based on this network table, transmits a subscription confirmation polling frame (to be described later), a duplicate registration check polling frame (to be described later), and the like to the slave station 12.

Each of the # 1 and # 2 master stations 11 has a unique data storage table (described later), and a call code (CallSign) (unique data) stored in the unique data storage table. ) Is used as a unique address, and a duplicate registration inspection polling frame and an initial data frame are transmitted to the slave station 12.

Here, the reason why the calling code is used as the unique address is that the calling code is unique data for identifying the own station to be transmitted when performing wireless communication in Japan (based on the law). .

Next, the network table and the unique data storage table will be described.

As shown in FIG. 4, the network table 111 includes a WNID area 111a having a WNID as an ID for specifying the slave station 12, and whether the slave station 12 specified by the WNID has joined the wireless communication LAN system. Subscription flag area 111 having a flag indicating whether or not
b.

The WNID is a serial number such as 1, 2, 3,..., N. When the join flag is “1”, the corresponding slave station 12 joins the wireless communication LAN. In the case of "0", it indicates that the corresponding slave station 12 has left the wireless communication LAN.

As shown in FIG. 5, the unique data storage table 112 stores a WN as an ID for designating the slave station 12.
A WNID area 112a having an ID, and a call code area 112b having a call code included in a response frame transmitted from the slave station 12 to join the wireless communication LAN after performing a polling confirmation to the slave station 12. It is composed of

Incidentally, the WNID area 112 denoted by A
The calling code of “a” is “CallSign-1”.

The slave station 12, like the master station 11, has "WGID" as an ID for designating a channel group to be used, and has a slave station 12 using the same channel.
"WNID" as an ID for specifying

By the way, the slave station 12 indicated by A in the figure is:
The slave station 12 has “2” as “WGID” and “1” as “WGID”.
It has “2” as “WGID” and “2” as “WGID”.

When the slave station 12 receives the subscription confirmation polling frame from the master station 11, it sends a response frame to the master station 11 when joining the wireless communication LAN.

When the slave station 12 receives the duplicate registration check polling frame from the master station 11, it sends a response frame to the master station 11 in response to the polling frame.
And a response signal notifying that the setting corresponding to the initial data frame has been completed is received from the master station 11.
To be sent to.

Further, when the slave station 12 receives the subscription confirmation polling frame or the duplicate registration examination polling frame from the master station 11, the slave station 12 stores "1" in the polling confirmation area formed in the work area of the RAM (not shown).
(Polling confirmation flag).

When no response frame to the subscription confirmation polling frame or the duplicate registration inspection polling frame is transmitted to the master station 11, the flag of the polling confirmation area is "0".

Next, the operation of this network system will be described with reference to the sequence diagram of FIG.

After the power is turned on or at a predetermined time interval, the master station 11 sends a subscription confirmation polling frame for inquiring whether or not the slave station 12 joins the wireless communication LAN. WNID is "n" from station 12
Are sequentially transmitted to the slave stations 12 of FIG.
, E).

When the slave station 12 receives the join confirmation polling frame from the master station 11, it sets "1" in the polling confirmation area.
The calling code (CallS) is stored in the data area 70f of the frame.
(i.g., (ign.)) to the master station 11 (see f in FIG. 6). On the other hand, when not joining the wireless communication LAN, nothing is sent to the master station 11.

When the master station 11 receives a response frame corresponding to the join confirmation polling frame from the slave station 12, the slave station 12
Is stored (see g in FIG. 6).

Here, the master station 11 may not be able to transmit the transmitted subscription confirmation polling frame to the child station 12 due to fading or the like, or may transmit the subscription confirmation polling frame from the child station 12 even if the transmission is successful. When it is not possible to receive the response frame of
Even when the slave station 12 has a request to join the wireless communication LAN, the slave station 12 is disconnected.

Then, the corresponding slave station 1 that should operate normally
The control device connected to 2 will not operate, causing a serious failure.

Therefore, a. When transmitting the subscription confirmation polling frame at power-on to the slave station 12, the master station 11 transmits a subscription confirmation polling frame having no unique address a predetermined number of times (see FIG. 6).
Try to prevent withdrawal.

As a result, when the master station 11 does not receive a response frame corresponding to the join confirmation polling frame from the slave station 12 (see FIG. 6), the master station 11 sets the location of the corresponding slave station 12 in the network table 111 to “ 0 ", and detaches the slave station 12 from the wireless communication LAN (see FIG. 6).

On the other hand, upon receiving a response frame to the subscription confirmation polling frame from the slave station 12, the master station 11 registers the calling code of the slave station 12 at the corresponding location.

B. The master station 11 transmits the join confirmation polling frame (see FIG. 6), and when there is no response frame corresponding thereto (see FIG. 6),
If the destination slave station 12 has previously subscribed to the wireless communication LAN, a subscribe confirmation polling frame having a unique address consisting of a call code is transmitted a predetermined number of times with reference to the call table 112 (FIG. 6). A, b in).

As a result, when the master station 11 does not receive a response frame to the join confirmation polling frame from the slave station 12 (see c in FIG. 6), the master station 11 determines the location of the corresponding slave station 12 in the network table 111. "1" is changed to "0", and this slave station 12
Release from AN (see d in FIG. 6).

On the other hand, upon receiving a response frame to the join confirmation polling frame from the slave station 12, the master station 11 updates and registers the call code of the slave station 12 at the corresponding location in the unique data storage table.

The master station 11 is a slave station 12 whose WNID is “n”.
When the above-described processing for the subscription confirmation polling is completed, with reference to the unique data storage table 112, a duplicate registration inspection polling frame having a unique address consisting of a call code is transmitted from the slave station 12 having a WNID of "1" to a WNID having a The data is sequentially transmitted to the slave stations 12 of “n” (see h, k, and p in FIG. 6).

The slave station 12 that has received the duplicate registration inspection polling frame transmits a response frame corresponding thereto to the master station 1.
1 (see i and q in FIG. 6).

When the master station 11 receives the response frame for the duplicate registration check polling frame from the slave station 12, the master station 11 transmits the response frame to the corresponding station of the network table 111 in order to join the slave station 12 to the wireless communication LAN. The joining flag is set to "1" (see j and r in FIG. 6).

On the other hand, even if the master station 11 outputs the duplicate registration check polling frame to the slave station 12 a predetermined number of times (see l in FIG. 6), it does not receive a response frame corresponding thereto (see FIG. 6). ), The slave station 12 that has transmitted the duplicate registration inspection polling frame recognizes that it does not join the wireless communication LAN, and the unique data storage table 1
At the same time, the calling code of the corresponding portion of the block 12 is deleted (see n in FIG. 6), and the joining flag of the corresponding portion of the network table 111 is set to “0” (see o in FIG. 6).

The master station 11 is a slave station 12 whose WNID is “n”.
When the above-described processing for the duplicate registration check polling for the slave station 12 is completed, the initial data frame is sequentially transmitted from the slave station 12 whose WNID is "1" to the slave station 12 whose WNID is "n" with reference to the network table 111. Is transmitted (see s and u in FIG. 6).

The master station 11 that has received the initial data frame reads the setting data such as the communication parameters necessary for the network operation described in the frame, sets the read communication parameters and the like, and notifies that the setting is completed. The response frame is output to the master station 12 (see t and v in FIG. 6).

The master station 11 is a slave station 12 whose WNID is “n”.
When the above-described processing for the initial data corresponding to is completed, the subscription confirmation processing in the wireless communication LAN ends.

Subsequently, the slave station 12 for which the dual address has been set
The process of stopping the operation of the server will be described separately for the following cases.

(1) When the master station 11 starts up, the slave station 11
FIG. 7 is a sequence diagram for stopping the operation of the slave station having the registered duplicate address when the master station starts up.

The master station 11 starts up by turning on the power supply, and transmits a subscription confirmation polling frame to the slave station 12.

The # 1 slave station 12 and the # 2 slave station 12
Upon receiving a subscription confirmation poll from the master station 11 (see, FIG. 7), “1” is set in the polling confirmation area, and a response frame is transmitted to the master station 11 (FIG. 7).
Inside, see).

Since the received signal strength of the slave station 12 of # 1 is stronger than the received signal strength of the slave station 12 of # 2, the master station 11
Receive the response frame of the slave station 12 of the slave station # 1 in the unique address area 80d.
Is transmitted (refer to FIG. 7).

Upon receiving the duplicate registration check poll from the master station 11, the slave station # 1 refers to the destination address area 80c and the unique address area 80d in the duplicate registration check poll frame and transmits the same to its own station. It recognizes that the frame has been sent, and outputs a response frame (see FIG. 7).

On the other hand, when receiving the duplicate registration check poll from the master station 11, the slave station # 2 refers to the destination address area 80c and the unique address area 80d in the duplicate registration check poll frame, Although the destination address in the address area 80c is the same, but the unique address in the unique address area 80d does not have the calling code of its own station,
It recognizes that it has a duplicate address and stops operation (see FIG. 7).

As described above, the local station 12 is connected from the wireless communication LAN.
When the operation of the server is stopped, the worker or the administrator can indirectly recognize that there is a duplicate registration in the network system.

(2) When subscribing to the wireless network last time and leaving the wireless network this time,
FIG. 8 is a sequence diagram for stopping the operation of the slave station having the duplicate address registered when the mobile station has joined the wireless network last time and has left the wireless network this time.

As described above, when the slave station 12 leaves the wireless network, the slave station 12 does not transmit a response frame for subscription confirmation polling because it really needs to leave, or the slave station 12 transmits a subscription confirmation polling frame. But the master station 1 due to fading etc.
In order to confirm whether or not the number has reached 1, a process of transmitting a subscription confirmation polling frame a predetermined number of times is performed (see FIG. 6).

At this time, for example, when a slave station 12 having the same address (destination address) enters the communication area from outside the communication area, or when the slave station 12 having the same address turns on the power, This is because when these slave stations 12 receive the join confirmation polling frame, they do not transmit a response frame to the master station 11 and stop the operation of the slave stations 12 having this duplicate address.

The parent station 11 refers to the unique data storage table 112 (see FIG. 8), and leaves the child station 1 to leave.
2, a subscription confirmation polling frame having a unique address consisting of a call code is transmitted (see FIG. 8).

Then, as described above, the # 2 slave station 12 having the same address as the # 1 slave station 12 entering the communication area from outside the communication area is transmitted by the master station 11. Upon receipt of the join confirmation polling frame, "1" is set in the polling confirmation area.

Then, the slave station 12 of # 2 has the same destination address of the received frame as its own station.
If the unique addresses are different, the operation is stopped by recognizing that the same address exists in the wireless network system (see FIG. 8).

(3) The case where a command frame such as initial data is transmitted to the wireless slave station 12 having an overlapping address in the communication area of the wireless network, that is, the wireless slave station having the overlapping address described so far. Is performed in the subscription confirmation polling sequence and the duplicate registration inspection polling sequence. The subscription confirmation polling sequence and the duplicate registration inspection polling sequence are completed, and the subscription confirmation polling sequence is transmitted again. For example, a description will be given of a process of stopping the operation of a wireless slave station having an overlapping address when, for example, an initial data frame is transmitted.

FIG. 9 is a sequence diagram showing an operation for stopping the operation of the overlapping wireless slave station when a command frame such as initial data is transmitted.

The radio base station 11 sets the “WNID” set by the user to 80H (H, for example) until the subscription confirmation polling sequence and the duplicate registration inspection polling sequence are completed and the subscription confirmation polling sequence is transmitted again.
"WNID + 80"
An initial data frame or the like having a destination address that has transitioned to H ”(an address that cannot be set by the user with the address setting switch) is transmitted (see FIG. 9).

Then, both the # 1 wireless slave station 12 and the # 2 wireless slave station receive the initial data frame.

Since the polling confirmation flag in the polling confirmation area is “0”, the wireless slave station # 2 enters the communication area from outside the communication area after the subscription confirmation polling sequence and the duplicate registration inspection polling sequence. Or, it is recognized that the power supply has been turned on and the own station has not joined the wireless network, and the operation is stopped.

Since the # 1 wireless slave station 12 has passed through the join confirmation polling sequence and the duplicate registration check poll sequence, the polling progress flag is "1", so that the own station joins the wireless network. I understand that there is.

In the network system of this embodiment, when the slave station 12 receives the double registration check polling frame, the slave station 12 reads the destination address and the unique address in the double registration check polling frame, and the transmission address is the same. If the unique addresses are different, the operation is stopped assuming that the address of the own station is duplicated.

Further, when the slave station 12 receives a transmission frame having no unique address after the duplicate registration check poll sequence, even if the transmission address is the same as that of the own station, the slave station 12 stores the polling confirmation information. If the polling confirmation information is not stored in the means, the operation is stopped assuming that the address of the own station is duplicated.

Further, when the destination address of the received subscription confirmation polling frame is the same as that of the own station, but the unique address is different, the slave station recognizes that the same address exists and stops operation. I do.

As described above, by stopping the operation of the slave station 11 having the duplicate address, it is possible to notify the manager or the operator that the slave station 12 has the duplicate address.

In the network system of this embodiment, of the frames to be transmitted, the duplicate registration inspection polling frame transmitted by the master station 11 to stop the operation of the slave station 12 in which the duplicate address has been registered has been previously joined. When the slave station 12 leaves the wireless communication LAN this time, only the subscription confirmation polling frame transmitted by the master station 11 to the slave station includes the destination address set by the user and the slave station 12 which cannot be set by the user. Is a second transmission frame 80 having a unique address that has its own unique address, and the other transmission frames are first transmission frames 70 having no unique address, so that wireless communication is performed without reducing transmission efficiency. be able to.

The network system of this embodiment is
The calling code is used as the unique address, but in other cases, the serial number of the product held by the master station 11 and the slave station 12 and the MAC address of the Ethernet may be used as the unique address. The generated random number may be used for the unique address.

Even when a random number is used, as shown in FIG. 10, the same processing as that for the call code used in the network of this embodiment is performed, and a detailed description of the processing will be omitted.

[0103]

As described above, according to the present invention, when the slave station receives the double registration check polling frame transmitted by the master station, the slave station reads the destination address and the unique address in the duplicate registration check polling frame. If the addresses are the same but the unique addresses are different, the operation can be stopped assuming that the address of the own station is duplicated.

In addition, even if the slave station receives a transmission frame having no unique address after the duplicate registration check polling sequence, even if the transmission address is the same as that of the own station, the slave station stores the polling confirmation information storage means. If the polling confirmation information is not stored in the server, the operation is stopped assuming that the address of the own station is duplicated.

Further, when the destination address of the received subscription confirmation polling frame is the same as that of the own station, but the unique address is different, the slave station recognizes that the same address exists and stops operation. I do.

As a result, it is possible to notify the manager or the operator that there is a slave station having a duplicate address, and it is possible to prevent a serious trouble in the system at the manufacturing site.

[0107] Of the frames to be transmitted, the duplicate registration check polling frame transmitted by the master station to stop the operation of the slave station in which the duplicate address has been registered is the same as the previously registered subscribed polling frame. When the station leaves, only the subscription confirmation polling frame transmitted by the master station to the slave station is a transmission frame having a destination address set by the user and a unique address that cannot be set by the user and has a unique address of each slave station. In other transmission frames, since the transmission frame does not have a unique address, wireless communication can be performed without reducing transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a network system according to the present invention.

FIG. 2 is an explanatory diagram illustrating processing contents of one communication cycle of the network system according to the embodiment;

FIG. 3 is a block diagram showing a configuration of a transmission frame used in the network system according to the embodiment;

FIG. 4 is a block diagram showing a configuration of an address table.

FIG. 5 is a block diagram showing a configuration of a unique data storage table.

FIG. 6 is an exemplary sequence diagram showing processing of the network system according to the embodiment;

FIG. 7 is a sequence diagram when a child station finds double registration in the processing of the network system according to the embodiment;

FIG. 8 is a sequence diagram when a child station finds double registration in the processing of the network system of the embodiment.

FIG. 9 is a sequence diagram when a child station finds double registration in the processing of the network system according to the embodiment;

FIG. 10 is a sequence diagram when a random number is used as unique data.

FIG. 11 is a schematic configuration diagram of an embodiment of a conventional network system.

[Explanation of symbols]

 Reference Signs List 10 programmable controller 11 master station 12 slave station 20 remote I / O network 111 address table 112 unique data storage table 70 first transmission frame 80 second transmission frame

Claims (6)

[Claims] 1. A network system including a master station and a slave station, wherein the master station has a destination registration address set by a user and a unique address that cannot be set by a user and has a unique address unique to each slave station. When the slave station receives the duplicate registration check polling frame, the slave station reads the destination address and the unique address in the duplicate registration check polling frame, and the transmission address is the same, but the unique address If the addresses are different, the operation of the network system is stopped assuming that the address of the own station is duplicated. 2. The master station comprises: a network table storing subscription information indicating whether the subscriber station has joined or left the network; and for the slave station subscribed to the network,
A unique address information table for storing unique address information serving as the unique address; forming the duplicate registration inspection polling frame based on the network table and the unique address information table; and transmitting the polling frame to the slave station. The network system according to claim 1, wherein 3. When the duplicate registration check polling sequence is completed, the master station adds or subtracts a predetermined number to an address set by the user to make the address outside the user set range, and transmits the address. 3. The network system according to claim 1, wherein a transmission frame having a destination address is transmitted to the slave station. 4. The slave station, when receiving the duplicate registration check polling frame from the master station, has polling confirmation information storage storage means for storing polling confirmation information indicating the reception of the duplicate registration check polling frame. After the polling sequence, if a transmission frame having no unique address is received, even if the transmission address is the same as the own station,
2. The network system according to claim 1, wherein if no polling confirmation information is stored in the polling confirmation information storage unit, the operation of the network is stopped assuming that the address of the own station is duplicated. 5. The master station refers to the unique address information table and transmits a join confirmation polling frame having the unique address to the leaving slave station. 5. The operation according to claim 1, wherein the transmission destination address of the confirmation polling frame is the same as that of the own station, but when the unique address is different, the operation is stopped by recognizing that the same address exists. Network system. 6. A duplicate registration check polling frame transmitted by the master station to stop the operation of a slave station in which a duplicate address is registered, and a master station transmits a duplicate registration check polling frame when the slave station has joined before and leaves the network this time. Only the subscription confirmation polling frame transmitted by the station to the slave station is a transmission frame having a destination address set by the user and a unique address that cannot be set by the user and has a unique address of each slave station. Wherein the transmission frame does not have the unique address.
6. The network system according to any one of claims 1 to 5.