JPH02228143A - Lan device for token passing bus system - Google Patents

Abstract

PURPOSE:To hold a refresh cycle in a prescribed time by providing a logical ring inverting means for inverting a preceding station and a succeeding station of a token. CONSTITUTION:Controllers 11-17 and a managing device 18 are connected in common to a bus, a token from the device 18 is given successively to 11-17 or 17-11, the token is returned to the device 18 and token logical rings are formed alternately in the A and B directions. The controller 11 consists of a cycle data sending-out means 4 for transmitting the data corresponding to its own device to a blackboard type memory 3, an event information sending-out means 5 for sending out event data after sending out data, and also, stepping its counter, and a logical ring inverting means 6 for holding addresses of a preceding station and a succeeding station of the token, and inverting the preceding station and the succeeding station after sending out the token. In such a way, the event data can be sent out equally and a refresh cycle can be held in a prescribed time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a token passing bus type local area network (hereinafter referred to as LAN) device, and particularly to a LAN having a blackboard type memory used for the purpose of exchanging information between each device. It is related to the device.

[Conventional technology]

BACKGROUND ART Conventionally, in fields such as factory automation, a plurality of control devices are distributed and arranged, and these control devices are connected through buses and communication channels to operate a manufacturing line. A LAN device having a so-called blackboard type memory is known to achieve coordination among such control devices (Japanese Patent Laid-Open No. 62-254545). Blackboard memory is a memory that is provided in each control device and has an area that holds information output from all control devices connected to the bus. By holding the information in an area corresponding to each device, any control device can obtain the necessary information of all the control devices when needed. In this way, in a bus-connected LAN device with blackboard memory,
Each control device sequentially transmits its own information in the form of a simultaneous broadcast, and the other control devices receive this information and store it in their memory, until all control devices have completed the simultaneous broadcast. The blackboard memory of each device is refreshed by repeating this cycle, with each point in time as one cycle. Each control device needs to detect the end point in order to perform various controls using the refreshed data in the blackboard memory. In conventional LAN devices,
By detecting the end point of the last control device's simultaneous notification, each control device determines whether refreshing of the blackboard memory has been completed.

[Problem to be solved by the invention]

However, a LAN with such conventional blackboard memory
In the device, the timing at which data to be transmitted to another control device is to be transmitted is determined in advance in the refresh cycle, and cannot be transmitted at any other time. However, in addition to this information, information to be transmitted to a specific device (hereinafter referred to as event data) occurs irregularly, so event data must also be transmitted. It is required to realize this in one network. However, when this LAN device is used for FA, it is necessary to keep the refresh period of cyclic transmission constant.

The present invention provides a LAN using such conventional blackboard memory.
This was done in view of the problems with the device, and when performing cyclic transmission and event transmission at the same time, it ensures that cyclic transmission is performed at a constant cycle, and
The technical problem is to enable each control device to transmit events almost equally.

[Means to solve the problem]

The present invention is a token passing bus type LAN device in which a plurality of control devices I are connected to a bus 2, and as shown in FIG. After receiving a token including an event tolerance counter from the preceding device of the token logic ring, the blackboard memory 3 has an area for holding the data to be stored, respectively, and a token is sent to the blackboard memory to another control device connected to the bus. Cyclic data sending means 4 for transmitting corresponding data
and an event information sending means 5 which sends event data and increments the counter when the sending of event data is permitted by an event permission counter after sending out the cyclic data by the cyclic data sending means.
and logical ring reversal means 6 which holds the addresses of the preceding station and the succeeding set of tokens and reverses the preceding station and the succeeding set after sending out the token.

[Effect]

According to the present invention having such characteristics, refreshing of the blackboard memory of each control unit connected to the LAN device is initiated by sending a refresh transmission and a token at the specific control unit. At the same time as the token is sent, the logical ring is changed. Each controller changes the addresses of the predecessor and successor sets of the token logic ring held in its respective memory. At the same time, if there is event data, the event data is sent out and an event tolerance counter is incremented. Therefore, when the refresh of the blackboard memory in a certain logical ring is completed, the direction of the logical ring is automatically reversed.

〔Effect of the invention〕

Therefore, according to the present invention, the order of the logical rings formed by the control devices connected to the bus can be reversed each time the blackboard memory is refreshed. Then, since the token is sent with the permissible number of event data sending capacity numbers attached, each control device sends cyclic data when receiving the token, and also sends event information as necessary. be able to. Since the event data is sequentially changed in the logical ring, it becomes possible for all the control devices to send out the event data almost equally, and it is possible to maintain the refresh cycle at a constant time.

[Explanation of Examples]

FIG. 2 is a diagram showing a connection state of a token passing bus type LAN device according to an embodiment of the present invention, and FIG. 3 is a diagram showing a logical ring. In these figures, control device 1
1 to 17 and a management device 18 are commonly connected to the bus 2. Since the control devices 11 to 17 and the management device 18 have the same configuration, the structure of the control device 11 will be explained in more detail. In FIG. 2, the control device 11 has a driver/receiver 21 and a protocol handler 22 that checks the validity of a given transmission frame and controls the communication protocol. Connected. Furthermore, each control device has a central processing unit (hereinafter referred to as CPU) 24, a blackboard type memory 3 and a direct memory access (hereinafter referred to as DMA) 25 are connected to the pass line 23, and a user memory for executing applications. 26 are connected.

The blackboard type memory 3 is a blackboard type memory having an area for holding information obtained from the own device and other control devices connected to this LAN, and the shaded area indicates information sent from the own device. There is. The contents of the memory 26 are transferred to the user memory 26 by the DMA 25 when the refresh of the blackboard memory 3 is completed, and various applications are executed based on the data in the user memory 26. The user memory 26 has an area for holding event data that occurs irregularly and an area for holding the addresses of the preceding station and the succeeding station of the token logical ring.

The control devices 11 to 17 and the management device 18 are commonly connected to the bus 2 as shown in FIG. 1, and the token transmission order is determined as shown in FIG. 3. FIG. 3 shows that tokens sent from the management device 18 are sequentially sent from the control device 11 to
17 or 17-11, and the control device 17 or 11
2 is a diagram of a logical ring illustrating a state in which a token is returned from to a management device 18. FIG. In this way, token logical rings are formed alternately in the arrow entry direction and the arrow B direction.

FIG. 4 is a diagram showing token frames sent between the management device 18 and the control devices 11 to 17. Is the token a preamble (P) followed by a start delimiter (SD) and a frame system? Areas are provided for an event tolerance counter (1llCFC) and an event tolerance counter, as well as destination address (DA), source address (SA), and frame check sequence (FCFC).
S) followed by an end delimiter (ED). The event tolerance counter determines whether each control device can send event data when it has event data, and when event data is sent, the count value of this counter is decremented and transmitted to the next control device. .

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG. 5.6. First, when the management device 18 starts operating, it starts a token rotation timer (step 31). The process then proceeds to step 32 and transmits the cyclic data from the own device (step 3
2). Thereafter, the process proceeds to step 33, where it is checked whether there is any event data to be sent to another control device.

If there is event data, the process proceeds to step 34, where the event allowance counter of the token is checked to see if event data can be sent. If the event data can be sent, the process proceeds to steps 35 and 36, where the event data is sent with an address for the specific control device and the event acceptance counter is decremented. Thereafter, the process proceeds to step 37, where the event allowance counter is set to a predetermined value and the token is sent to the next station.

Furthermore, the logical ring is changed by exchanging the addresses of the preceding station and the succeeding station of each control device (step 38). Then, proceed to steps 39 to 42 and receive a token from another station.
Checks whether the token rotation timer has timed up or whether simultaneous broadcasts and event data from other stations have been received.

On the other hand, in a normal control device, as shown in FIG.
1 to 54, the token is received or received by the management device 1.
It is checked whether there has been a simultaneous notification from other control devices or management devices other than 8, and whether event data has been received. For example, when the control device 11 receives a token, the process proceeds to step 55 and sends out the cyclic data held in the blackboard memory 3 of its own station onto the bus 2 to all other stations at the same time. Transmit. The process then proceeds to step 56 to check for the presence or absence of event data. If there is event data, it is checked whether the event data can be sent based on the event acceptance counter of the received token. If the event data can be sent, the process proceeds to step 58, where the event data is sent from the user memory 26 and the event tolerance counter is decremented (step 59). Then, the process proceeds to step 60, where the token is sent to the next succeeding station, and the process proceeds to step 61, where the addresses of the preceding station and the succeeding station are exchanged, the logical ring is changed in the direction of arrow B, and the process returns to the loop of steps 51-54. If there is a simultaneous broadcast of data from another control device, the process advances from step 52 to step 62, transfers the data sent to the area of the blackboard memory corresponding to that station, and returns to the loop of steps ~54. .

If event data is received in step 54, the process proceeds to step 63, transmits the received event data to the user memory 26, and returns to the loop of steps 51-54.

In this way, it will receive the tokens sequentially and broadcast the data of its own device to all other control devices and management devices at the same time.
If necessary, event information can be transmitted to a control device that is permitted by the event permission counter. Here, the management device 18 performs step 32. The control device performs step 51.
At step 55, after receiving the token from the preceding device, the function of the cyclic data sending means 4 is achieved, which transmits the data of the own device in the blackboard type memory to another control device connected to the bus. Further, in steps 33 to 36 and 56 to 59, the function of the event information sending means 5 for sending event data is achieved when sending of event data is permitted. Furthermore, the management device performs step 38. The control device fulfills the function of the logical ring reversing means 6 in step 61, which reverses the addresses of the preceding station and the succeeding station after sending out the token.

Now, if the management unit W18 receives a simultaneous broadcast from another station, it proceeds to steps 41 to 43, transmits the data to the blackboard type memory 3, and returns to the loop of steps 39 to 42. When the control device 17 finishes broadcasting and sends the token to the management device 18, the management device 18 receives the token in step 39. The process then proceeds to step 44, where the end of one cycle is broadcast all at once. Then, data is instantaneously transferred from the blackboard memory 3 to the user memory 26 by DMA (step 45). During step 45, data is stored in the user memory 2 from the application program created by the user.
Access to 6 is prohibited. At this time, new data may be written in the area of the blackboard memory 3 corresponding to the own station. When event data from another station is received, the process proceeds from step 42 to step 46, where it is held in the user memory 26 and returns to the loop of steps 39-42. When one refresh cycle is completed, the process advances to step 47 and waits to see if a certain time has elapsed. If the time has elapsed, the process returns to step 31 and repeats the same process. In this way, as shown in FIG. 3, when the tokens are transmitted in the order of the arrow A direction and the refresh cycle ends, the preceding station and the succeeding station will be rewritten in each control device and management device, so the logical ring is changed, and in the next refresh cycle, tokens are sent in the direction shown by arrow B in FIG.

Therefore, in the logic ring in the direction of arrow A, for example the control device 16
Alternatively, in case 17, there is a possibility that the event acceptance counter counts up and the event data cannot be transmitted, but the event data can be transmitted in the logical ring in the direction of arrow B. In this way, compared to the case where the token ring is only in a predetermined direction, all control devices can have almost equal opportunities to transmit event data.

In this embodiment, the management device 18 itself also has a blackboard type memory,
Although the management device is also configured to execute a specific application program, the management device is not necessarily necessary, and each control device may independently detect the end of a refresh cycle.

[Brief explanation of the drawing]

Figure 1 shows the L of the token passing bus system according to the present invention.
FIG. 2 is a block diagram showing the configuration of a management device and each control device according to an embodiment of the present invention; FIG. 3 is a diagram showing the logical ring of tokens of the LAN device according to the present embodiment. 4 is a diagram showing the configuration of a token to be transmitted, FIG. 5 is a flowchart showing the operation of the management device according to this embodiment, and FIG. 6 is a flowchart showing the operation of another control device. 3--Blackboard memory 4--Cyclic data sending means 5--Event information sending means 6--Logic ring reversing means 18--
・-Management device patent applicant Tateishi Denki Co., Ltd. agent Patent attorney Yoshiki Okaki (and 1 other person) 1.11-17--・--Control device 2--
・Bus Figure 1 Figure 2 Figure 2 Figure 3

Claims (1)

[Claims] (1) A token-passing bus type LAN device in which multiple control devices are connected to a bus, and each control device has a blackboard that has an area for holding data transmitted from all devices connected to the bus. and a cyclic data sending means for transmitting data corresponding to the own device of the blackboard type memory to another control device connected to the bus after receiving a token including an event tolerance counter from a preceding device of the token logic ring. and an event information sending unit that sends event data and increments the counter when sending of the event data is permitted by an event permission counter after the cyclic data sending unit sends the cyclic data, and a token preceding station. and logical ring reversal means for holding the address of the succeeding station and reversing the positions of the preceding station and the succeeding station after sending the token.