JPH02235456A - Lan equipment for token passing bus system - Google Patents

Abstract

PURPOSE:To solve a problem attended with discrimination of an end point of a refresh cycle, to improve the capability cf control function and to prevent mis-discrimination of the end of one cycle by managing the end of the refresh cycle with a specific equipment. CONSTITUTION:A management equipment 18 starts the operation to send a data. A token rotation timer is started to transfer a token(TK) to a controller 11. When the controller 11 receives the TK, a data stored in a blackboard type memory 4 of its own equipment is transferred to all other stations via a bus 3. Then the TK is sent to a next controller 12. When simultaneous multi ple address of data comes from other controller, the data is sent to all other controllers and a management equipment in terms of multiple address. The operation above is repeated, the controller 17 completes the simultaneous multi ple address, receives the management, equipment 18 and sends the end of one cycle in multiple address. Then the data is transferred momentarily to a user memory 7 by a DMA 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a local area network (hereinafter referred to as LAN) device using a token bathing bus method, and particularly has a blackboard type memory used for the purpose of exchanging information between each device. This relates to LAN devices.

[Conventional technology]

BACKGROUND ART Conventionally, in fields such as factory automation, a plurality of control devices are arranged separately, and these control devices are connected through buses and communication channels to operate a production line. A LAN device is known that has a so-called blackboard type memory for coordinating such control devices (Japanese Patent Application Laid-open No. 254545/1982). Kurosaka memory is a memory that is provided in each control device and has an area that holds information output by all the control devices connected to the bus, and the information sent from each control device is stored in this memory. 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 bus-connected LAN devices with blackboard memory, each control device sequentially transmits its own information in the form of a broadcast, and the other control devices receive this information and store it in their memory. This operation is performed sequentially, and the time when all the control devices finish broadcasting at once is defined as one cycle, and by repeating this cycle, the blackboard memory of each device is refreshed. 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, each control device determines whether refreshing of the blackboard memory has been completed by detecting the end point of the last control device's simultaneous broadcast.

[Problem to be solved by the invention]

However, a LAN with such conventional blackboard memory
In the apparatus, each control device separately detects the end point of memory refresh. Therefore, each control device requires a circuit and software to determine the end of one cycle, which has the disadvantage of complicating the structure and increasing the load on the CPU. Another disadvantage is that if noise is added to the last control device's simultaneous notification, some control devices may not be able to determine whether the refresh cycle is over or not.

The present invention provides a LAN using such conventional blackboard memory.
This was done in view of the problems with the device, and the technical issue is to solve the problem associated with determining the end point of the refresh cycle by managing the end of the refresh cycle with a specific device. .

[Means to solve the problem]

The present invention is a token passing bus type LAN device in which a plurality of control devices 1 and a management device 2 are connected to a bus 3, and as shown in FIG. After receiving the token from the preceding device of the token logic ring, a blackboard type memory 4 having an area for holding data transmitted from each device is sent to another control device connected to the bus corresponding to the own device of the blackboard type memory. data sending means 5 for transmitting data to be sent and sending tokens to subsequent control devices, and data receiving means 5 for receiving tokens and data given from other control devices and writing them into corresponding areas of the blackboard memory. 6, and a user memory 7 that holds the data in the blackboard memory when the end of the cycle is notified from the data receiving means, and the management device monitors the end of the refresh cycle based on token reception. The refresh cycle is characterized by comprising an end monitoring means 8 and a cycle end transmitting means 9 which transmits the end of the refresh cycle to a connected control device after detecting the end of the cycle.

[Effect]

According to the present invention having such features, refreshing of the blackboard memory of each control device connected to a LAN device is started by sending a token from the management device, and when the token is returned, the memory is refreshed. Assuming that the refresh has been completed, a cycle end transmission means sends a completion signal to each control device at once. In this way, each control device takes in the data from the blackboard memory into the user memory within a certain period of time, and uses the data after refreshing to perform its respective control.

〔Effect of the invention〕

Therefore, according to the present invention, there is no need for each control device to determine whether the blackboard type memory paste cycle has ended, and a circuit for this purpose is no longer necessary. Additionally, there is no need for software to detect the end of refresh, which reduces the software load and improves the ability of the original control function. Furthermore, since the end of one cycle is determined by one control device, there is less risk of each control device incorrectly determining the end of one cycle, and all control devices maintain stable and constant periodicity. This will be obtained. Furthermore, since the data in the blackboard memory is loaded into the user memory after the refresh is completed, application programs for each control device can be easily created, and malfunctions in each control device can be prevented.

[Explanation of Examples]

Figure 2 is a block diagram showing the configuration of the control device and management device;
FIG. 3 is a diagram showing a logical ring of a token passing bus type LAN device according to an embodiment of the present invention. In these figures, control devices 11 to 17 and a management device 18 are commonly connected to the bus 3. Since the control devices 11-17 and the area device 18 have the same configuration, the structure of the control device 1l 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.
A protocol handler 22 is connected to an internal bus line 23. Each control device has a central processing unit (hereinafter referred to as CPU) 24, and the bus line 23 has the aforementioned blackboard type memory 4 and direct memory access (hereinafter referred to as DMA).
) 25 is connected, and further a user memory 7 for application execution is connected. As mentioned above, the blackboard type memory 4 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 portion is sent from the own device. Showing information.

Each control device transfers the contents of the memory to the user memory 7 by the DMA 25 when the refresh of the blackboard type memory 4 is completed. Each control device executes various applications based on data in the user memory 7.

The control devices 11 to 17 and the management device l8 are commonly connected to the bus 3 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 to the control device 11-
17 is a diagram of a logical ring showing a state in which a token is given to a controller l7 and returned from a control device l7 to a management device l8. The control devices 11 to 17 and the management device 18 hold the addresses of the preceding device to which a token is given and the succeeding device to which the token is sent.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG. 4.5 and the time chart of FIG. 6.

First, when the management device starts operating at time t on the first day, it transmits data from its own device (step 31). Then, a token rotation timer is started and the token is transferred to the next control device, ie, control device 1l (steps 32 and 33).

Then, in steps 34 to 3G, it is checked whether the token has been returned, whether the token rotation timer has timed up, and whether simultaneous notifications have been received from other devices.

On the other hand, in a normal control device, step 4 is performed as shown in Fig. 5.
1 to 43, or the management device 1
It is checked whether or not there has been a simultaneous notification from other control devices and management devices other than 8.

For example, when the fiJ control device 1l receives a token, it proceeds to step 44 and transfers the data held in its own blackboard memory 4 to the bus 3, as shown in FIG. 6(b).
and simultaneously transmits it to all other stations. The process then proceeds to step 45 and sends the token to the next device, in this embodiment the control device 1.2 (time t3). If there is a simultaneous broadcast of data from another control device, the process advances from step 42 to step 46, transfers the sent data to the area of the blackboard memory corresponding to that station, and returns to the loop of steps 41 to 43. . In this way, as shown in FIG. 6 (al to Cd), the tokens will be sequentially received and the data of the own device will be sent to all other control devices and management devices at once, and the blackboard memory 4 of each station will be refreshed. It happens. Now, at time t, when the control device 17 finishes broadcasting and sends a token to the management device 18, the management device 18 receives the token in step 34. and step 38
1 as shown in Figure 6 (time t?~1 of al.
Broadcast the end of the cycle. And blackboard memory 4
The data is instantly transferred to the user memory 7 by DMA (step 39). This time period t, ~t1. During this period, access to the user memory 7 from the application program created by the user is prohibited, as shown in FIG. 6(e). At this time, new data may be simultaneously written into the area of the blackboard memory 4 corresponding to the next station. Here, the management device 18 achieves the function of the cycle end monitoring means 8 that detects the end of a cycle in steps 32 to 35, and achieves the function of the cycle end transmitting means 9 that transmits the end of one cycle in step 38. There is.

Then, in step 40, the timer waits for the timer to expire, and in the next cycle, the process returns to step 31 and transmits the data from the local station.

Further, in each of the control devices 11 to 17, if there is a simultaneous notification from the management device 18, the process proceeds from step 43 to step 47, and in the same manner, data is transferred from the blackboard type memory 4 to the user memory 7 by DMA.
Transfer to. Then, the process returns to the loop from steps 41 to 43 and repeats the same process.

In this embodiment, the management device 18 itself also has a blackboard type memory,
The management device is also configured to execute a specific application program, but the management device sends out a token, detects only the completion of memory refresh, and broadcasts the completion to other control devices. You can also. Further, in this embodiment, each control device has a blackboard type memory and a user memory for executing an application. In this way, the user memory can be freely accessed from the user program at all other times, except for a certain period of time immediately after the end of the fresh cycle.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a token passing bus type LAN device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a management device and each control device, and FIG. 3 is a diagram showing the present embodiment. FIG. 4 is a flowchart showing the operation of the management device; FIG. 5 is a flow chart showing the operation of the management device.
The figure is a flow chart showing the operation of another control device, and FIG. 6 is a time chart showing the operation. 1.11-17---Control device 2.18--
- Management device 3 - Bus 4 - Blackboard type memory 5 - Data sending means 6 ----
--Data receiving means 7---User memory 8
−・−・−Cycle end monitoring means 9−・−・−
Cycle end transmission means patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Yoshiki Okamoto (and 1 other person) Jll Figure Figure Figure Figure Figure Figure T9 T10

Claims (1)

[Claims] (1) A token passing bus type LAN device in which multiple control devices and management devices are connected to a bus, and each control device holds data transmitted from all devices connected to the bus. After receiving the token from the preceding device of the token logic ring, a blackboard memory having a region transmits data corresponding to the own device of the blackboard memory to another control device connected to the bus, and transmits data corresponding to the own device of the blackboard memory to the subsequent control device. data sending means for sending out a token; data receiving means for receiving tokens and data given from another control device and writing them into the corresponding area of the blackboard memory; and when the end of a cycle is notified from the data receiving means. and a user memory that retains the data of the blackboard memory, and the management device is connected to cycle end monitoring means that monitors the end of the refresh cycle based on token reception, and a user memory that is connected after detecting the end of the cycle. cycle end transmitting means for transmitting the end of the refresh cycle to the controller in the control device;
1. A token passing bus type LAN device characterized by having: