JP3465798B2 - Distributed control system - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to FA (factory
The present invention relates to a distributed control system applied to a LAN (Local Area Network) between programmable control devices used in the field of manufacturing industries such as automation.

[0002]

2. Description of the Related Art Conventionally, programmable controllers and series
Control between control devices such as sequencer, inverter drive device, etc.
When sending and receiving control signals and status information, master on the transmission line
By setting a station, other devices become slaves, and polling is performed.
The method of cyclically exchanging information and each control device
Have equal transmission rights, such as token passing
All control devices are controlled in sequence while controlling the transmission right by the stage.
Broadcasting is performed and output signals are transmitted, and the output of each control device
The force signal is distributed to the memory area in each device for each control device.
By opening it, the execution control unit in each control device does not
Professionals as if all devices were sharing the same information.
So-called virtual shared memory that can be programmed
Any of the methods (see, for example, JP-A-5-342171)
Was the mainstream. Other transmission methods include cyclo
Required by control programming without licking transmission
Message transmission method to instruct message transmission according to
Although it is possible, transmission overhead is generally large.
In addition, since the processing load on the execution control unit also increases,
I haven't been able to endure. Of these, the large
Centralized control for each control device from the programmable controller
In a system configuration that controls the
A polling method is generally used because no mutual information exchange is required.
Was taken. On the other hand, each is a sufficient programming machine
Generally, the control operations are performed independently between the control devices that have the function.
In the distributed control system form, some signals are
Operates in cooperation with each other while referring to the operating status of the control device
Therefore, the virtual shared memory transmission method is
It was common.

Further, as shown in FIG. 9, a system developed from the virtual shared memory system is "SYSMAC LIN".
Development of K system "(OMRON TECHNICS
Vol. 1 No. 3 (1991)) has been proposed. In this conventional example, in order to save the virtual shared memory area, information about the output data amount of each control device and information about the station number of the control device to be expanded in the virtual shared memory area are used for each control device for each station. The output signal of is selected arbitrarily. A conceptual block diagram in the control device of this system is considered to be as shown in FIG. FIG. 10 is a block diagram example relating to the node 2 (# 2 station) control device in FIG. In FIG. 10, the virtual shared memory area 4 is managed in each control device 10 (each node 2, node 5, node 6, node 8 in FIG. 9) that is distributed and arranged on a common transmission path. In the figure, the transmission control unit 2 selects and stores / updates only the output data from the control device having the station number registered in the LR register configuration information 5'in the virtual shared memory area 4, so in the example of the figure #
Only the data of 2 stations, # 5 station, and # 6 station are stored, and the data of other stations are not saved. Virtual shared memory area 4
Is copied based on the LR register ← → DM register copy information 6 ', and the other node reception area 7', own node transmission area 8'and virtual shared memory area 4 on the DM register are stored in the same memory image. Is dripping As a result, the control programs P1 and P2 in the control device 10 are
Of the output data transmitted from each station on the transmission line 1, only the data of the station having the station number necessary for the processing of the control program can be referred to and updated on the DM register.

[0004]

In the conventional general virtual shared memory system, the output signal is issued when the output signal of each control device is expanded in the virtual shared memory area in the transmission control section of each control device. Since the same output signal is copied in the order of the station number on the control device's transmission line, if the system configuration is changed, the relative address of the control device output signal on the virtual shared memory will change, and such output The control program of the execution control unit, which refers to and updates the signal, must be modified in accordance with the change in the relative address, which lowers the program development efficiency. Also, for the same reason, for the control program in the control device that shares similar functions in other similar systems, the reference address of the output signal must be changed according to the system configuration, and the program can be reused. Was difficult.

Further, although the developed system of the virtual shared memory system described in the above document is effective in saving the memory area, the expansion of the output data to the memory area is performed in ascending order of station numbers in units of control devices. The output word and bit required by the control program are extracted from the output signals from other stations, and the output word and bit required by the control program are extracted in word and bit units at the address referenced on the control program. Since it is impossible to rearrange them, it has no effect on the above problem. Therefore, the problem to be solved by the present invention is to provide a distributed control system in which control programs can be made common regardless of the difference in system configuration.

[0006]

In order to solve the above-mentioned problems, a distributed control system of the present invention is a distributed control system for transmitting and receiving a signal between a plurality of control devices via a common transmission line. An execution control unit that holds and executes a control program in each of the control devices; a transmission control unit that manages communication procedures; a virtual shared memory area that holds and manages output signals of all control devices; In, an input signal register for a control program to refer to an output signal from another control device, an output signal register for the control program to notify a signal to another control device in the execution control unit, and all control devices and Input / output showing the correspondence between the virtual shared memory area configuration information based on the number of output signals, each output signal of each control device on the virtual shared memory area, and the input signal register. Conversion information, and the transmission control unit transmits the information of the output signal register to all the other control devices through a transmission path, and the information of the output signal register of all the control devices is the virtual shared memory. In a distributed control system having a configuration in which an image of a virtual shared memory area among all control devices is commonly managed by storing it in a virtual shared memory area within its own device based on area configuration information, the transmission control unit further comprises: Means for arbitrarily allocating an arbitrary output signal of an arbitrary control device in the virtual shared memory area to an input signal register of its own control device on the basis of the input output conversion information, and in the control program of the execution control unit, It has a step of referring to and updating the input signal register and the output signal register. The input / output conversion information includes data type, input bit position, and output bit position information. When bit data is designated as data to be updated by the transmission control unit, the data in the virtual shared memory area is output as output bits. It is possible to determine only the bit information indicated by the position and update only the bit indicated by the input bit position in the corresponding word of the input signal register to be written.

[0007]

According to the above means, the "transmission control section" transmits the data of the "output signal register" to all the other "control apparatuses" via the "transmission path" when the transmission right of the output signal of the own station is obtained. At the same time, the own station “output signal” update location of the “virtual shared memory area” in the own device is updated based on the “virtual shared memory configuration information”. Further, in the “transmission control unit”, when the “output signal” of the other station “control device” is received via the “transmission path”, first, based on the “virtual shared memory configuration information”,
The relevant station part of the "virtual shared memory area" is updated, and based on the "input / output conversion information", the "input signal register"
The corresponding data in the "virtual shared memory area" corresponding to is extracted and the information in this "input signal register" is updated. As a result, in the "control program" executed by the "execution control unit", reading is done by the "input signal register" without directly accessing the "virtual shared memory area".
For output to other stations "control device", it is sufficient to update the "output control register". Therefore, set "virtual shared memory configuration information" and "input / output conversion information" according to the relevant system configuration. Then, even if the system configuration is different, the program can be constructed by using the same "input signal register" address or the same "output signal register" address in the control program.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a conceptual block diagram of a control device according to a first embodiment, FIG. 2 is a system configuration diagram, FIG. 3 is a schematic flow diagram of a transmission control unit, and FIGS. 4, 5 and 6 are detailed partial flow diagrams thereof. Is. Looking at the entire system as shown in the figure,
A plurality of control devices 10a, 10b, ...
.., 10c are distributed, and virtual shared memory areas 4a, 4b, ..., 4c are managed in each control device. In these virtual shared memory areas, #
The output signal transmitted from the 1st station controller 4a is transmitted to each station of the # 2 station controller 4b, ..., #n station controller 4c and written at the head of the virtual shared memory. The output signal transmitted from the # 2 station control device 4b is the # 1 station control device 4a, ...
, Is transmitted to each station of the #n station control device 4c and written in an area following the output signal of the # 1 station control device 4a. Similarly, the output signal transmitted from the #n station control device 4c is #
It is transmitted to each station of the 1-station control device 4a, # 2 station control device 4b, ... And written to the end of the virtual shared memory, these operations are cyclically executed, and the virtual shared memory of each station becomes the same memory image. It is kept.

As shown in FIG. 1, a transmission control unit 2 and an execution control unit 3 are provided inside each control device, and a virtual shared memory area 4, virtual shared memory configuration information 5, and input / output conversion are provided in the memory. There are information 6, an input signal register 7, an output signal register 8, and control programs P1 and P2. It is assumed that the control program is programmed by the system user to execute the control peculiar to the control device, and is executed by the execution control unit 3 as a task / process. In the present invention, when referring to the output signal of another control device in these control programs, the output signal is read through the input signal register 7, and when there is an output signal to be notified to the other control device, it is written through the output signal register 8. Is programmed to On the other hand, in the transmission control unit 2, the processing is performed according to the flow shown in FIG. 3, whereby the virtual shared memory area is updated, the input signal register is updated, and the output signal register is transmitted to the transmission path through virtual sharing. It is executed based on the memory configuration information 5 and the input / output conversion information 6.

FIG. 3 shows an example of a processing flow of the transmission control unit 2 when the transmission right is controlled by token passing. According to this, the transmission control unit 2 normally waits for data reception (20). When data is received, it is judged whether or not it is a token addressed to the own station (21), and it is true. For example, since the transmission right has been acquired, the data transmission process (22) shown in FIG. 4 is executed, and after passing the token to the next station (23), if it is the update timing of the input signal register (24), it is shown in FIG. Executes input signal register update processing. If the data received in the determination process (21) is the information of the output signal transmitted by #i (i = 1 to n) (26), the #i station output signal reception process (2) shown in FIG.
7) is executed and the process proceeds to the judgment process (24). Judgment process (2
The update timing of the input signal register in 4) may be various depending on the characteristics of the control device, but as a typical example, it may be every time after the #i station output signal receiving process of the process (27), but the execution control It is a predetermined execution cycle of the unit or a timeout of a periodic timer.

The data transmission process (22) is shown in FIG.
According to this, the output signal register is first read and transmitted to all the control devices (30), and then based on the virtual shared memory configuration information 5, the local station in the virtual shared memory area is read. The storage address of the output signal is obtained (31), and the same information of the own station output signal register that was transmitted in the processing (30) is written in the corresponding area (3).
2). Regarding the #i station output signal reception processing (27), a detailed flow is shown in FIG. 5. According to this,
First, hold the received data in a temporary buffer (4
0), the storage address of the received data on the virtual shared memory is obtained based on the virtual shared memory configuration information 5 (41), and the buffered output signal of the #i station controller is written (42).

Regarding the update processing of the input signal register,
As shown in FIG. 6, the input / output conversion information 6 shown in FIG.
Based on the correspondence information between the input signal register inside and the offset value of the output signal register designated by the expanded designated station, corresponding information is read from the virtual shared memory and written in the input signal register. First, the processing INDEX value: x in the input / output conversion information 6 is initialized (50),
As the x-th processing, the x-th information of the input / output conversion information 6 is taken out (53), and the output station number [x-1] in this is extracted.
Based on the virtual shared memory configuration information 5, the storage start address of the output signal information corresponding to the same station in the virtual shared memory is obtained (54), and this address (output register [x-
1] -1), the same output signal information of the same station on the virtual shared memory at the address added is taken out and stored in the input signal register indicated by the input register [x-1]. This x
While sequentially updating (52) until the end of all cases (5
1) Input / output conversion information is processed as described above.

FIG. 7 shows another embodiment of the input / output conversion information. In the second embodiment, the information of the data type, the input bit position, and the output bit position is the first as the input / output conversion information.
It is added to the input / output conversion information 6 in the embodiment. Here, when word data (16 bits): "W" is selected as the data type, the operation is exactly the same as in the first embodiment, but when the bit data is "B",
Process 55 in the input / output signal register update flow of FIG.
A difference occurs in the processing of storing in the input signal register in. The flow in this case is shown in FIG. As shown in the figure,
In the second embodiment, the data on the virtual shared memory is judged only for the bit information 0/1 indicated by the output bit position (60).
Then, only the bit indicated by the input bit position in the corresponding word of the input signal register to be written is updated (6
0,61). At this time, bit operation is performed so that other bits in the same word are not affected at all (57,
58, 59, 61, 62). This realizes signal rearrangement in bit units.

[0014]

As described above, according to the present invention, the control program programmed by the system user reads through the input signal register when referring to the output signals of other control devices, and If there is an output signal to be notified to the control device, it can be programmed to write through the output signal register, so that the system configuration differs by setting the virtual shared memory configuration information and the input / output conversion information according to the relevant system configuration. Even if the same "input signal register" in the control program
The program can be constructed using the address or the same "output signal register" address. Furthermore, even if the configuration of the constructed system is changed and the station number is changed or the control device is deleted or added, the control program can be changed by simply changing the virtual shared memory configuration information and input / output conversion information. Since it is not necessary to modify the address of the input / output signal register coded inside, it is necessary to commonly design control programs of similar functions in such a distributed control system regardless of the difference in system configuration of the system. Is possible.

According to the second aspect of the invention, since the output signals of other stations can be rearranged in bit units and extracted into the input signal register, signals from discrete input devices such as operation switches in the system can be extracted. Can be rearranged, and a common design of control programs can be realized regardless of the difference in the connection configuration of these devices.

[Brief description of drawings]

FIG. 1 is a conceptual block diagram in a control device showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a virtual shared memory type distributed control system according to a first embodiment.

FIG. 3 is a schematic flowchart of a transmission control unit of the first embodiment.

FIG. 4 is a data transmission flow chart in the transmission control unit of the first embodiment.

FIG. 5 is an output signal reception flow chart of the #i station control device of the first embodiment.

FIG. 6 is an input signal register update flow chart according to the first embodiment.

FIG. 7 is a configuration diagram of input / output conversion information showing a second embodiment.

FIG. 8 is an input signal register update flowchart in the second embodiment.

FIG. 9 is an expanded block diagram of a virtual shared memory system showing a conventional example.

FIG. 10 is a conceptual block diagram in the control device in the conventional example of FIG.

[Explanation of symbols]

1 transmission path, 2 transmission control unit, 3 execution control unit, 4 virtual shared memory area, 5 virtual shared memory configuration information, 6
Input / output conversion information, 7 input signal register, 8 output signal register, 10 control device, P1, P2 control program

Continuation of the front page (56) Reference JP-A-60-110072 (JP, A) JP-A-3-129456 (JP, A) JP-A-3-129457 (JP, A) JP-A-6-19867 (JP , A) JP-A-1-287768 (JP, A) JP-A-5-342171 (JP, A) Hiroaki Takemura Shinji Murayama Naoaki Ikeno, Development of SY SMAC LINK system, OMRON TECHNICS, September 15, 1991 Sun, Vol. 31, No. 3, Volume 99, p. 207-212 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06F 13/00 G06F 15/16

Claims (2)

(57) [Claims] 1. A distributed control system for transmitting and receiving signals between a plurality of control devices 10 via a common transmission line 1, wherein an execution control unit holds and executes a control program in each of the control devices 10. 3, a transmission control unit 2 that manages communication procedures, a virtual shared memory area 4 that holds and manages output signals of all control devices, and a control program in the execution control unit 3 that output signals from other control devices. , An output signal register 8 for the control program in the execution control unit 2 to notify other control devices of signals, and a virtual sharing based on all control devices and the number of output signals thereof. The transmission control is provided with memory area configuration information 5, input / output conversion information 6 showing correspondence between each output signal of each control device on the virtual shared memory area 4 and the input signal register 7. The section 2 transmits the information of the output signal register 8 to all the other control devices through the transmission line 1, and the information of the output signal register 8 of all the control devices based on the virtual shared memory area configuration information 5 In the distributed control system configured to commonly manage the image of the virtual shared memory area 4 among all the control devices by storing it in the virtual shared memory area 4 in the transmission control unit 2, the transmission control unit 2 further includes the input / output conversion information. 6 is provided with means for arbitrarily allocating an arbitrary output signal of an arbitrary control device in the virtual shared memory area 4 to the input signal register 7 of the own control device, and in the control program of the execution control unit 3, A distributed control system comprising a step of referring to and updating the input signal register 7 and the output signal register 8. 2. The virtual shared memory area, which has information of a data type, an input bit position, and an output bit position as the input / output conversion information 6, and when bit data is designated as data to be updated by the transmission control unit 2. Output the data on 4 and determine only the bit information indicated by the bit position,
2. The distributed control system according to claim 1, further comprising means for updating only the bit indicated by the input bit position in the corresponding word of the input signal register 7 to be written.