JPH0324682B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a control system.

Conventional small sequencers have a large number of control input/output points for controlled devices, and if you want to control multiple controlled devices because one device is not enough, for example, you can use the limit switch signal X ₁ of the controlled device to If sequencers 1, 2, and 3 are used, the limit switch signal _X1 must be connected to the three input terminals of sequencers 1, 2, and 3. Also, when the calculation results of one sequencer are used by another sequencer, the calculation results are output to the output terminal,
Its output terminal must be connected to the input terminal of the sequencer that requires the operation result.

As described above, when a single piece of equipment is operated using a plurality of conventional small sequencers, there is a problem in that input and output usage efficiency becomes poor and scalability is lacking.

On the other hand, when controlling equipment with a single large sequencer, there are disadvantages in that if the control part breaks down, the entire equipment goes down, and the input/output signal lines to limit switches, solenoid valves, etc. must be pulled to one location. There must be. In addition, since it is large, it has disadvantages such as requiring a large space for installation.

Accordingly, an object of the present invention is to provide a control system that can shorten the wiring distance of input/output signal lines and increase reliability, has high input/output usage efficiency, and is highly expandable.

This invention enables multiple small sequencers with a small number of input/output points to mutually transmit their respective control data so that each sequencer can freely use the control data of other sequencers in its user program. Although it is a small sequencer, it is expandable enough to handle the same number of input/output points as a large sequencer, and by extending data transmission, it enables distributed processing and shortens the wiring distance of input/output signal lines. Furthermore, reliability is to be improved by using multiple small sequencers. To this end, in the control system of the present invention, each of the plurality of sequencers sequentially transmits its own control data including input data and output data to all other sequencers through a serial data transmission path, and also transmits its own control data and serial Control data from all other sequencers transmitted through the data transmission path is stored in corresponding locations in the control data memory, and the sequencer control section sends output data to the parallel data bus based on the contents of the control data memory. ing.

Embodiments of the present invention will be described below based on the drawings.

As shown in Figure 1, this control system consists of an optical signal output section OUT that converts serial data into an optical signal and sends it to the optical fiber OF, which is a serial data transmission path, and the serial data sent from the optical fiber OF. Optical signal input section that converts
Consists of multiple sequencers PC ₁ to PC _o with IN,
Optical signal output section of one sequencer, e.g. PC ₁
OUT and the optical signal input section IN of the next sequencer PC _o
Connect with the optical fiber OF, and connect the sequencer PC ₁ to
PC _o are connected in a ring with optical fiber OF. Each of the sequencers PC ₁ to _{PC o} has the number of sequencers shown in Fig. 2 corresponding to the number that can be connected to the serial data transmission system in the internal control data memory.
It has a control data area for PC ₁ to _{PC o} , and during actual operation, as shown in Figure 3, execution of the user program → output of calculation results → capture of input signals → control data for each sequencer PC ₁ to _{PC o} The steps of transmitting and receiving are repeated endlessly. In this case, the control data refers to signals used in the user's sequencer program, such as input signals, output signals, numerical data, etc. of each sequencer PC ₁ to _{PC o} .

Specifically, each of the sequencers PC ₁ to _{PC o} includes an optical signal input section IN, an optical signal output section OUT, a sequencer control section SC, an input signal conversion section CVI, and an output signal conversion section CVO, as shown in FIG. The basic sequencer unit _U1 consists of a data bus DB connecting these, read signals RD, RD', and write signals WT, WT', an input signal converter CVI' and an output signal converter CVO'. It is composed of a unit _U1 and a sequencer input/output expansion unit _U2 arranged close to each other, and although there is only one sequencer input/output expansion unit _U2 in the figure, a plurality of sequencer input/output expansion units U2 can be connected.

The optical signal input section IN and the optical signal output section OUT are as described above.

The sequencer control unit SC receives a serial data input signal from the optical signal input unit IN, outputs a serial data output signal to the optical signal output unit OUT, and also controls the user's sequence program for controlling external equipment and the sequencer itself. It has a memory for storing programs and control data for each sequencer _PC1 to _PCo shown in Figure 2, and is used to exchange control data with other sequencers, input signal converter CVI,
Controls data exchange with CVI′, output signal converter CVO, and CVO′.

The input signal converters CVI and CVI' convert multiple signals from external control devices placed in close proximity to internal IC signal levels and convert them into parallel data buses DB using read signals RD and RD' from the sequencer control unit SC.
Outputs signals from external control equipment on the top.

The output signal conversion unit CVO is the sequencer control unit SC
The contents on the parallel data bus DB are stored using the write signals WT and WT' from the IC, and the stored contents at the IC signal level are converted to a level that can control the loads of external control equipment to control multiple external loads.

Next, the operation of this control system is shown in Figure 5A.
An example of sequence control as shown in B will be explained.

The program shown in FIG. 5A is installed in the sequencer PC ₁ shown in FIG _{. 1 ,} and the input signal and connect the program as shown in Figure 5B to sequencer PC ₂ .
Input signal X ₁₀₀ and output signals Y ₁₀₁ and Y ₁₀₂ are connected to external equipment via input signal converter CVI and output signal converter CVO shown in FIG.

In this state, when operating as shown in Figure 3,
At timing T ₃ in Figure 3, sequencers PC ₁ and PC ₂
each receives a signal from an external device from the input signal converter CVI. Of course, the sequencer PC ₁ writes the input signal X ₁₀ , and the sequencer PC ₂ writes the input signal X ₁₀₀ into the respective control data areas shown in FIG. 2 of the sequencer control section SC.

Next, at timing T ₄ , each sequencer PC ₁ ~
PC _o sends out its own control data as shown in Figure 2. _For example _, the sequencer PC ₁ stores the memory contents of the control data area of the _{PC 1} in _{FIG .}
data) is converted into an optical signal and transmitted over an optical fiber.
Send it to OF. At this time, other sequencer PCs ₂ ~
PC _o writes the sent control data of sequencer PC ₁ into the PC ₁ control data area of the control data memory shown in FIG. 2, which each sequencer PC ₂ to _{PC o} has.

When the transmission of control data from sequencer PC ₁ is completed, transmission of the next control data from sequencer PC ₂ begins. In this case, the end of data transmission can be detected by sending an end command at the end of the transmission control data, or by transmitting the number of data to be transmitted before the start of transmission, and each receiving sequencer counts the number of data. There is a method to detect the end of transmission.

In this way, the sequencer PC ₂ also sends out its own control data from its own control data memory shown in FIG. 2 to the optical fiber OF. At this time, the other sequencers PC ₁ , PC ₃ to _{PC o} receive the control data (X ₁₀₀ , Y ₁₀₁ , Y ₁₀₂ ) of sequencer PC ₂ sent to the control data area of PC ₂ in their respective control data memories.
).

In this way, the control data transmission of each sequencer PC ₁ to _{PC o} is performed in order, and when it is completed, the contents of the control data memory of each sequencer shown in Fig. 2 will be the same, and the timing shown in Fig. 3 will be completed.
At _T1 , each of the sequencers _PC1 to _PCo executes the user program written in their respective program memories. When this is completed, the resulting output data is sent to each sequencer at timing _T2 in Figure 3.
Write to the output signal converter CVO of PC ₁ to _{PC o} through the parallel data bus DB to control external equipment.

At this timing _T1, the user programs shown in FIGS. 5A and 5B are executed by the sequencers _PC1 and _PC2 . In other words, in sequencer PC ₁ , the timing
Write the input signal X ₁₀ captured at T ₃ to the output signal Y ₁ . Sequencer PC ₂ takes in input signal X ₁₀₀ at timing T ₃ , input signal X 10 transmitted at timing T _{4 ,} and output signal Y ₁ written by the previous user program execution and transmitted at timing T ₄ . Execute _the user program shown in Figure 5B using _the input signal X ₁₀₀ captured at timing T ₃ and write the AND result of input signals X ₁₀ and
PC ₁ output signal Y ₁ to sequencer PC ₂ output signal
Write to Y ₁₀₂ .

When the execution of the user program is finished, the output signal is outputted from the output signal converter CVO to the outside at timing _T2 to control the external device. That is, sequencer PC ₁ outputs output signal Y 1 in response to input signal X ₁₀ , and sequencer PC ₂ outputs output signal Y ₁ in response to input signal X ₁₀ .
The AND result of and X ₁₀₀ outputs the output signal Y ₁₀₁ , and outputs the output signal Y ₁ as the output signal Y ₁₀₂ .

In this way, by cyclically executing each step as shown in Fig. 3 with the configuration shown in Fig. 1, the user can input and output signals connected to sequencer PC ₁ to sequencer PC ₂ . You can freely incorporate it into your program and use it. Of course, if timer and counter values and numerical data are also included in the control data and transmitted/received, they can be used freely by other sequencers.

In this example, the sequencer PC ₂
The control data of PC ₁ was only used, but the reverse is also possible. Furthermore, the sequencers PC ₁ to _{PC o} are not only connected to their own input signal converter CVI and output signal converter CVO, but also connect to other The control data of the sequencer written in the control data memory shown in Figure 2 can be freely used in the user program.
Programs can be assembled and executed as if they were a single sequencer.

The above operation explanation is an example in which input and output are expanded by mutually transmitting input and output signals using optical fiber OF.
Although it is possible to control external devices using only U ₁ , if the number of input/output points of the sequencer basic unit U ₁ is insufficient and the input/output lines can be routed close to the sequencer basic unit U ₁ , the sequencer input shown in Fig. 4 can be used. You can also connect the output expansion unit U ₂ to the sequencer basic unit U ₁ to increase the number of input/output points that can be handled, and connect input/output lines to it to control external equipment.

In this case, several more input/output signals can be read and written at the same time, and the sequencer basic unit U ₁
and sequencer input/output expansion unit U ₂ .
There is no need to transmit control data using serial data transmission, and a data bus DB is used between the sequencer input/output expansion unit U ₂ and the sequencer basic unit U ₁ .
This allows for a system that responds to input/output signals at a higher speed than when increasing the number of input/output points using serial data transmission, that is, when using other sequencers to make up for the shortfall in the number of input/output points.

This is for the following reasons. If you increase the number of input/output points by adding the sequencer input/output expansion unit U ₂ , if the number of input and output points is completed only by the input/output of the own sequencer, transmission between sequencers will not be used. It is now possible to operate (for example, standalone operation) in one control cycle (see Figure 3).
It becomes possible to omit _T4 cycles. Therefore, it is possible to respond to input signals and output signals faster than when using the input/output of a plurality of sequencers in serial data transmission.

Furthermore, even when serial transmission is used, information exchange with input/output can be performed using dedicated instructions or direct input/output control for parts that use their own input/output, even while the user program is running. Therefore, it can respond to input and output signals at high speed.

The response speed can also be selected by considering the appropriate use of increasing the number of input/output points due to serial transmission and increasing the number of input/output points of the unit itself due to unit expansion.

As a result of this configuration, the following effects can be obtained.

(A) Each small sequencer PC ₁ to PC _o has a small number of input/output points. By connecting them as shown in Figure 1 and transmitting signals between them, you can freely transmit the input/output signals and numerical values of other sequencers. Data, etc. can be used with just the optical fiber OF without increasing the number of input/output wiring, providing excellent input/output expandability.

(B) Since the execution of the user program is divided and executed simultaneously in parallel on each sequencer PC ₁ to _{PC o} , the user program execution time is faster than when controlled by one large sequencer.
The response to external equipment becomes faster, the reliability of the system becomes higher, and the input/output wiring distance can be shortened by enabling distributed processing.

(C) Because it can be expanded freely, the basic sequencer unit U ₁ can be small, and by connecting the basic sequencer unit U ₁ and the sequencer input/exit expansion unit U ₂ or the basic sequencer units U ₁ and U ₁ , one The sequencer model can control everything from small machines to large machines, making it versatile.

(D) Optical fiber OF is not a branch type, but each sequencer
Since the optical signal is regenerated by PC ₁ to PC _o , the attenuation of the optical signal does not change even if the number of consecutive sequencers PC ₁ to _{PC o} increases.

(E) Since the serial data transmission system is a closed loop, it is easy to check whether the transmitted data has been sent correctly.

(F) Since the connection is made using an optical fiber OF, data can be sent at high speed with high noise resistance, and there is no need to worry about electric shock or short circuit accidents as there can be a potential difference between the sequencers PC ₁ and PC _o .

(G) Expand input/output with serial data transmission,
Alternatively, you can increase the input/output response speed by expanding the input/output with a parallel data bus DB and considering the use of increasing the number of input/output points by serial data transmission and increasing the number of own input/output points by expanding the unit. You can configure a highly flexible system that you can freely choose from.

(H) Since the configuration is such that the control data of each of the multiple sequencers and the control data from all other sequencers are stored unconditionally in the corresponding location of the control data memory, the contents of the memory of all sequencers can be made the same, and even if the program of one sequencer is changed, there is no need to change the program of other sequencers, and the program of each sequencer can be easily changed.

Figure _5B shows _a program that _{realizes Y 101 =} As shown in _, if you want to change _{the program} to realize _{Y 101} = X ₁₂・_{X 100 +} Since the data is unconditionally transmitted to the sequencer PC ₂ , the sequencer
It is only necessary to make changes to PC ₂ , and there is no need to change the program of sequencer PC ₁ . As in the conventional example, ₁₀ inputs require ₂ sequencer PCs
Sequencer PC ₁ selects only the data and transfers it to sequencer PC _2.
In the case of a configuration where part of the program of sequencer PC ₂ is changed from formula (1) to formula (3), sequencer PC ₁ selects input X ₁₀ and sends it to sequencer PC _2. Input from program X ₁₂ , X ₁₃
must be changed to a program that selects and sends it to sequencer PC ₂ . This embodiment eliminates the need to change the program for data selection.

() Since the configuration is such that all transmitted data is stored unconditionally in memory, the user can handle information from other sequencers simply by using the necessary information in the program (ladder sequence, etc.). information from other sequencers can be easily used without the need for special operations or separate transmission control software for transmission reception selection.

In the embodiment, an optical fiber OF is used as the serial data transmission line, but an electric wire may also be used.
Furthermore, although the serial data transmission paths are connected in a loop, the configuration is not limited to a loop, and any configuration may be used as long as the sequencers PC ₁ to _{PC o} can mutually transmit signals.

As described above, the control system of the present invention can shorten the wiring distance of input/output signal lines, increase reliability, and increase the efficiency of input/output use to provide greater flexibility. In addition, since each of the sequencers is configured to store its own control data and all the control data from all other sequencers unconditionally in the corresponding location of the control data memory, the contents of the memory of all sequencers are the same. Even if the program of one sequencer is changed, there is no need to change the program of other sequencers, and the program of each sequencer can be easily changed.

In addition, since the configuration is such that all transmitted data is stored unconditionally in memory, the user can program the necessary information (such as a ladder sequence).
You can easily use the information of other sequencers by simply using it, and there is no need for special operations for transmission reception selection or separate transmission control software. can.

The second invention is further flexible because it is possible to select the input/output response speed by considering the use of increasing the number of input/output points by serial data transmission and increasing the number of input/output points by expanding the unit. can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control system according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the configuration of its control data memory, FIG. 3 is a schematic diagram showing the processing process of the sequencer, and FIG. 5 is a detailed block diagram showing the internal configuration of each sequencer, and FIGS. 5A, 5B, and 5C are configuration diagrams showing examples of the built-in programs of the sequencers. PC ₁ ~ PC _o ...Sequencer, IN...Optical signal input section, OUT...Optical signal output section, SC...Sequencer control section, CVI, CVI'...Input signal conversion section, CVO,
CVO′...Output signal converter, _U1 ...Sequencer basic unit, _U2 ...Sequencer input/output expansion unit, DB...Parallel data bus, OF...Optical fiber (serial data transmission line).

Claims (1)

[Scope of Claims] 1. A control system in which a plurality of sequencers are connected via a serial data transmission line, wherein each of the plurality of sequencers has a built-in control data memory for storing all control data of the plurality of sequencers. a sequencer control section, a parallel data bus connected to the sequencer control section, and an input signal conversion section that sends input data from an external device located nearby to the parallel data bus in response to a read signal from the sequencer control section. , an output signal conversion unit that sends output data from the parallel data bus to the external device in response to a write signal from the sequencer control unit, each of the plurality of sequencers sequentially converting the input data and output data. It transmits its own control data, including its own control data, to all other sequencers through the serial data transmission path, and also unconditionally transmits its own control data and control data from all other sequencers transmitted through the serial data transmission path. The control system stores the control data at a corresponding location in the control data memory, and the sequencer control unit sends output data to the parallel data bus based on the contents of the control data memory. 2. A control system in which a plurality of sequencers are connected via a serial data transmission line, wherein each of the plurality of sequencers has a built-in control data memory for storing all the control data of the plurality of sequencers, and a sequencer control section comprising: a parallel data bus connected to a sequencer control unit; and a first input signal conversion unit that sends input data from an external device located close to the parallel data bus in response to a first read signal from the sequencer control unit. , a sequencer basic unit comprising a first output signal converter that sends output data from the parallel data bus to the external device in response to a first write signal from the sequencer controller; a second input signal converter that sends input data to the parallel data bus in response to a second read signal from the sequencer controller;
A sequencer input/output unit, which is arranged close to the sequencer basic unit, and includes a second output signal conversion unit that sends output data from the parallel data bus to the external device in response to a second write signal from the sequencer control unit. Equipped with an expansion unit,
Each of the plurality of sequencers sequentially transmits its own control data including the input data and output data to all other sequencers through the serial data transmission path, and also transmits its own control data and its own control data through the serial data transmission path. All control data from all other sequencers are unconditionally stored in corresponding locations of the control data memory, and the sequencer control section sends output data to the parallel data bus based on the contents of the control data memory. control system.