JPH11265209A - Sequence control method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency and operability of system development by making the flow of the control of a producing equipment coincident with a ladder sequence. SOLUTION: A sequencer 3 for controlling each process of an equipment 1 through a sensor/actuator 2 is provided with a progress managing function 10 to be periodically activated, and an end condition or the like is defined for every step of each process by a controlling operation defining part 12. A step control processing part 11 which is flow-described fetches present progress information or an operation request from an operation managing part 13, and decides an execution step by judging the presence or absence of interruption or step end according to the defined condition, and turns on the execution register STP of a step register 9 pertinent to the execution step. A facility control sequence 8 ladder-describes an outputting part obtained combining the execution register STP with a controlling operation in the step in each step unit, and outputs a control command from the outputting part to the actuator 2 according to the turning on of the execution register on.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sequence control apparatus for production equipment, and more particularly to a sequence control method capable of facilitating monitoring and operation of control of equipment and improving the efficiency of sequence development and maintenance.

[0002]

2. Description of the Related Art A sequencer for automatically controlling production equipment such as food, chemicals, medicines, and general machines is equipped with one or a plurality of equipment control sequences that operate at a fixed period. Many of the equipment control sequences are described in a language called a ladder sequence program. Although the ladder sequence was developed for relay control circuits, it can be described using simple rules that describe the output when the input conditions are satisfied, so user needs are high and widely used for describing sequence control by computer. Have been.

However, the ladder sequence program has a problem that the order of controlling the production equipment and the description of the program do not match. In addition, as the production equipment to be controlled becomes larger and more complicated, the capacity of the ladder sequence program increases, and the description of the control conditions and output conditions becomes more complicated. For this reason, similar to a computer program based on a normal flow description method, a ladder sequence program is described by combining ladder sequences having a common function into one and the capacity of the program is reduced.
No. 814.

[0004]

In the above-mentioned prior art, the problem that the description of the control scheme and the description of the ladder sequence program do not match cannot be solved.

FIG. 11 is an explanatory diagram of equipment control and a ladder sequence. FIG. 1A shows an example of a tank facility used for manufacturing food products and chemical products, and shows a tank A and elements necessary for a cleaning process thereof. Inlet valve V of tank A
01 and the outlet valve V02 are opened, and the chemical liquid injection valve V11 is opened.
Or one of the water injection valves V12 is opened and the liquid feed pump P
When U01 is operated, a chemical or water flows into tank A. FIG. 4B shows an example of a control plan for the cleaning process of the tank A, which comprises the following steps.

[0006] Start conditions: "Press the start button", STEP1: "Open the inlet valve V01 and outlet valve V02 of the tank A", STEP2: "Open the chemical liquid injection valve V11. Operate the liquid feed pump PU01", "Send Liquid time 30 seconds "," 30
Closes the liquid injection valve V11 after elapse of seconds ", STEP3:" Opens the water injection valve V12 "," Sends liquid for 60 seconds "," Water injection valve V1 after elapse of 60 seconds "
2), end processing: "close the inlet valve V01 and the outlet valve V02 of the tank A".

FIG. 1C shows an example in which the control method shown in FIG. 1B is described in a ladder sequence. The left part describes a condition part, and the right part describes an output part.

When the start button is pressed, the contact X01 is turned on. When the contact X01 is turned on, the internal register R01 is turned on, and the fact that the start button is pressed is stored. This corresponds to the start condition of the control plan.

When the internal register R01 is turned on, the coils V01 and V02 are turned on, and an open request signal is output to the inlet valve V01 and the outlet valve V02 of the tank A. This corresponds to STEP 1 of the control scheme.

When the inlet valve V01 and the outlet valve V02 of the tank A are opened, the contacts V01 and V02 are turned on.
When the contacts V01 and V02 are turned on, the internal register R
02 turns ON. When the internal register R02 is turned on, the coil T01 is turned on, the 30-second timer starts counting, and the coil V11 is turned on to turn on the chemical liquid injection valve V11.
And the coil PU01 is turned on to output an operation request signal to the liquid sending pump PU01. After 30 seconds, the contact T01 turns on and the internal register R03 turns on. When the internal register R03 is turned on, the internal register R
02 is turned off. When the internal register R02 is turned off, the coil V11 is turned off, and the chemical liquid injection valve V11 is closed. This corresponds to STEP 2 of the control scheme.

When the internal register R03 is turned on, the coil T02 is turned on, the 60-second timer starts counting, and the coil V12 is turned on to output an open request signal to the water injection valve V12. After 60 seconds, the contact T02 turns on and the one-shot register U01 turns on. When the one-shot register U01 turns on, the internal registers R01 and R03 turn off. When the internal registers R01 and R03 are turned off, the coils V01, V02 and V12 are turned off, and the inlet valve V01, the outlet valve V02 and the water injection valve V12 of the tank A are turned off.
Closes. When the inlet valve V01 and the water injection valve V12 of the tank A are closed, the contacts V01 and V12 are turned off. When the contacts V01 and V12 are turned off, the coil P
U01 turns off, and the liquid sending pump PU01 stops. The above corresponds to STEP 3 and the end processing of the control plan.

As described above, decoding the ladder sequence of (c) and associating it with the control scheme of (b) is a difficult task even for a small facility as in (a). For example, if the chemical solution runs short during the injection of the chemical solution in the control plan STEP2, it is necessary to take measures to temporarily stop or end in STEP2. Specifically, if the contact R02 in the ladder sequence of (c) is turned off, Good. However, accurate judgment in an emergency is not easy even for those familiar with the ladder sequence, and the more complicated the ladder sequence, the more difficult it becomes. Moreover, it is almost impossible for an operator with insufficient knowledge of the ladder sequence.

As described above, the fact that the description of the ladder sequence program does not match the control plan of the production equipment requires a large amount of time to develop the ladder sequence as the equipment to be controlled becomes larger and more complicated. The maintainability of the program is also poor. In addition, it is difficult to grasp the operation state of the equipment, and it is difficult for an operator to respond to the equipment control operation at the time of an abnormality.

In view of the problems of the prior art, an object of the present invention is to improve efficiency and operability of system development by using a ladder sequence in accordance with the flow of control of production equipment without impairing the advantages of a ladder sequence program. An object of the present invention is to provide a sequence control method and apparatus that can be improved.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to separate a condition part and an output part of a conventional ladder sequence, and to judge a condition part which determines a control flow according to a control plan. This is achieved by performing the processing in a flow description manner and performing the output unit for controlling the equipment in a ladder description manner.

That is, the progress of the execution step is managed from the step-by-step control operation definition of the control plan and the current progress state, and an ON signal is sent from the start or execution of the control step (execution step) to the corresponding execution register. The present invention is characterized in that a step control process for outputting is performed, and an equipment sequence is controlled for each control step in which an execution register and an output unit are described in ladder. The output unit includes a combination of a minimum necessary output operation for each control step, and further includes the output operation and an interlock condition in the step.

More specifically, a step end condition and a next step are defined in advance in the order of a process start condition and a control step for each process, and the process is started periodically, and the process start condition is determined based on the operation state of the equipment. It is determined whether or not there is an execution step for the process that satisfies, and if there is an execution step, it is determined whether or not the end condition is satisfied, and if so, the execution step is updated to the next step and managed. Output an OFF signal of the execution step before the update and an ON signal of the execution step after the update, and further repeat the series of processes described above for the next step, and execute the control step for each step according to the ON signal or the OFF signal. Each time the control logic describing the relationship between the execution step and the output unit in ladder is executed or stopped.

If the end condition is not satisfied, the next control cycle is continued without updating the execution step.
The step end conditions include "unconditional" and "time up".

In addition, the presence / absence of an interrupt process due to an operation request is determined preferentially. If there is an interrupt, the execution step is interrupted.
It is characterized by branching at different interrupt levels due to restart, stop, JUMP, etc., and executing step control processing according to the request content. As described above, since the step control based on the condition determination is performed by the flow description, the interrupt processing is facilitated.

The present invention further comprises a monitoring / operation screen editing function for identifying and displaying a step in execution of a series of control steps and / or its current progress status. An instruction button is provided.

As described above, the present invention is based on the equipment control sequence in which the output unit combining the minimum control operations in units of steps is described in ladder, and the step control in which the condition determination is described in flow order in the order of the control plan. It is possible to overcome the drawback of the conventional ladder sequence in which it is difficult to grasp the control flow of the equipment, and to facilitate operations such as monitoring the operation state of the equipment and intervening. Further, the ladder sequence describes only the conventional output unit, so that it is greatly simplified, and the development and maintenance work can be made more efficient.

Further, since the steps of the process being executed and the progress status thereof are identified and displayed on the monitoring screen, the operator can grasp the operation status at a glance, and manual intervention in the event of an abnormality or the like can be performed without decoding the ladder sequence. The operability has been remarkably improved, for example, it is possible with one touch.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same elements, the solid arrows in the drawings indicate the flow of processing, and the broken lines indicate the flow of data.

FIG. 1 is a system configuration showing a sequence control device according to one embodiment. A production facility 1, a sensor / actuator 2 for detecting its state and instructing a state change;
The sequencer 3 is configured to receive a signal from the sensor 2 and output an operation command to the equipment 1 through the actuator 2, and an input / output device 4 for transmitting an input from an operator to the sequencer and notifying the operator of the operation status of the sequencer 3.

The sequencer 3 includes an input / output register 6 for inputting / outputting to / from the sensor / actuator 2, an equipment control sequence 8 (8a-8n) for creating an operation command in the input / output register 6 in accordance with a ladder sequence (control logic), and an equipment control sequence. A sequence control mechanism 7 for managing the periodic operation of the equipment 8, a progress management mechanism 10 for managing the progress (step) of the equipment control sequence 8, and a step register 9 for instructing the progress control mechanism 10 to turn on / off the equipment control sequence 8. Consists of

The equipment control sequence 8 of this embodiment is described by a ladder sequence in which the minimum control operation combination is a unit step for each control unit. The step register 9 corresponds to the step numbers (00 to nn) of the facility control sequence 8 for each process, and has 1-bit execution registers STP1 to STPn.

The progress management mechanism 10 includes a control operation definition unit 12 for defining a progress condition of a process, an operation management unit 13 for storing a current progress status, and a progress condition of the defined process and step and a current progress status. A step control processing unit 11 for controlling the progress of the equipment control sequence 8 via a step register 9, and a working memory 1 for its internal processing.
5, a screen display editing unit 14 that edits information of the step register 9, the control operation definition unit 12, and the operation management unit 13 and outputs the information to the input / output device 4.

FIG. 2 is an explanatory diagram showing a processing flow of the sequence control device. In the present embodiment, in a plurality of processes of the production facility, a group of processes that operate simultaneously is sequentially activated within one cycle. The equipment control sequence 8 is composed of a plurality of control steps, each unit having a minimum required combination of control operations as a unit step, so that the execution of one control step is completed and the next control step is performed. doing.

The sequence control mechanism 7 starts the step control processing section 11 periodically, and starts the equipment control sequence 8 after the end of the step control processing section 11. The step control processing unit 11 fetches operation management information such as the current progress status of the equipment control sequence 8 from the operation management unit 13, and executes the control operation definition (step start condition, step end condition) defined in the operation definition unit 12. , Next step, etc.), it is determined whether or not the equipment control sequence 8 configured for each process and each step can be executed in units of steps, and the execution register STP of the step register 9 is turned on / off. In the equipment control sequence 8, the ladder sequence of the corresponding step is operated by the ON signal of the step register 9, and a control command is set in the input / output register 6 for operating the actuator 2 according to the control logic.

The screen display editing unit 14 is provided with a step register 9
The information of the control operation definition unit 12 and the operation management unit 13 is edited and output to the input / output device 4. The operator knows the status of the equipment control sequence 8 from the status displayed on the input / output device 4.

The operation request of the operator is stored in the operation management unit 13 via the input / output device 4. Upon receiving the operation request from the operator, the step control processing unit 11 controls the operation of the equipment control sequence 8 in accordance with the control operation definition for the interrupt processing. Although the present embodiment is configured by a single sequencer, it may be distributed to a plurality of sequencers depending on the scale of equipment and the like.

FIG. 3 shows the file structure of the control operation definition unit and the operation management unit. (A) shows a control operation definition unit 12, which stores tables 12a and 12 storing operation conditions for each process.
.., 12n. In the table 12, the "step name (number)", the "execution register number" of the corresponding step register 9, the "step end condition", and the next step are executed in the order of the step start condition and steps 01 to nn in the step. A “next step” which is a step number is defined.

(B) shows an operation management unit 13, which stores tables 13a, 13b,.
Consists of The table 13 includes “execution status”, “step start time”, “executing step (initial value 0)”, “interruption level (initial value 0)”, “JUMP” for managing whether the execution step is normal or interrupted. Previous step (initial value 0) "is stored.

Next, the processing operation of the sequence control device according to this embodiment will be described in detail. FIG. 4 shows an example of the monitoring / operation screen. Data displayed on the screen of the input / output device 4 is edited by the screen display editing unit 14.

The monitor / operation screen displays the progress status of the equipment control sequence 8 in units of steps based on the display of the currently executed process and its execution status (waiting, normal operation, interruption, etc.). It comprises a unit 4a, a display unit 4b for displaying detailed information of each step, and an operation unit 4c for the operator to operate the progress of the process. The operation unit 4c suspends / resumes,
It has function keys such as STEP end and JUMP, and instructs an operation request from the operator to the step control processing unit 11 via the operation management unit 13.

The display section 4a shows the exemplary raw material melting steps in the order of step numbers, and defaults to the currently executed step 10. The display unit 4b displays the elapsed time of step 10 (heating) and the operation status of the equipment in the ladder sequence 8 (8
j) Shown above. By the way, the displayed ladder sequence is the timer coil TC000 when STEP10 is turned on.
1 turns ON and starts counting the set time, and the valve V0
The output of the open request signal to 100 is indicated by an ON display color (green). Further, PU001 is activated,
The operation is continued until the time of TC0001 is up.

Here, the valve V0100 and the pump PU0
The ladder sequence of 01 constitutes an interlock logic for preventing a pump hammer, and indicates that the PU001 is activated after the release of V0100 is confirmed. Since there is a time lag from the command to the completion of opening of the valve V0100, the pump PU001 is still in this cycle.
Are not issued, and are shown in the OFF display color (white).

The present invention is characterized in that the condition part of the conventional ladder sequence is transferred to a flow description, and the execution register and the output part corresponding to the control step are configured by ladder description, as shown in FIG. May include a ladder description including interlock conditions. However, the conditions for describing the ladder are limited to the control conditions in the step,
The control of the step progress is not affected, and the characteristics as the ladder sequence according to the control order of the equipment are maintained.

FIG. 5 is a flowchart showing an outline of the step control processing. When activated by the sequence control mechanism 7 at a predetermined cycle, the step control processing section 11 takes in information from the input / output register 6 and the operation management section 13 and determines the start of the process according to the definition of the control operation definition section 12. The pre-processing 11a is performed.

Next, an interrupt determination 11b based on the presence or absence of an operation instruction from the operator, an operation status determination 11c determining whether the execution status of the equipment control sequence 8 is "normal" or "interrupted" due to an interrupt, an equipment control sequence 8, a step end determination 11d for judging the end of the execution step, an execution step update 11e for executing the next step when the step end condition is satisfied, an interruption processing 11g for processing an operation instruction from an operator as an interruption, It comprises an all-process loop 11f that repeats the processes 11a to 11g for all the processes registered in the control operation definition unit 12. Note that a “waiting” state at the start of the process may be added to the determination of the execution status, and in the case of “waiting”, the process of the step control may be shifted to the next process. Note that the execution status determination 11c can be omitted.

FIG. 6 is a flowchart showing the step control processing when there is no interruption.
a, step end determination 11d, execution step update 11e
And details of the entire process loop 11f.

When the pre-execution process 11a is started periodically, the first process 1 is executed, and after that, steps 2, 3,. . . Are executed in the order of First, the operation management unit 13
The value (initial value 0) of the “executing step” of the process 1 is read from, and it is determined whether or not there is an executing step (11a1).

If there is no step being executed (0), the process start condition of the process 1, for example, the signal x01: ON is read from the control operation definition unit 12 (11a2), and the state of the signal x01 is read by the input / output register 6 and the working state. The data is fetched from the memory 15 (11a3). Incidentally, the signal x01 and the like by the start button in FIG. Then, it is determined according to the definition logic whether the process start condition is satisfied (11a4), and the determination result is stored in the “operation state” of the operation management unit 13 (11a5). If the condition is satisfied, the status is "normal", and if not, the status is "waiting". The “interruption” of the operation state will be described later.
Next, in accordance with the result of the determination of the process start condition, a branching process is performed depending on whether or not the process 1 can be executed (11a6).

If the process start condition is satisfied and execution is possible,
The process proceeds to the step end condition (11d) through an interruption determination (11b) ⇒ “none” and an operation state determination (11c) ⇒ “normal” (not shown). It should be noted that, in the case where the execution step is present (1 or more) in the determination of the process 11a1, the process shifts similarly. First, a step end condition, for example, T01: UP is read from the operation definition unit 12 (11d
1), the state (count time) of the timer T01 is fetched (11d2) and temporarily stored in the working memory 15 (1d).
1d3), T01: It is determined whether or not the condition of UP is satisfied (11d4), and a branch is made according to the result (end / unfinished), and the process proceeds to the step update process (11e).

The judgment result of the step end condition is "not completed".
If so, it is determined whether the execution step is "0 (initial value)" (11e1). If "0", the execution step is set to 1 (11e2). Continues from the previous cycle). Next, the value of the step in execution of the operation management unit 13 and the start time of the step are stored (11e7), and the execution register number of the step in execution is read from the operation definition unit 12 (11e7). Turn on the register STP (1
1e9). Thereby, the logic of the equipment control sequence 8 connected to the execution register STP is executed, and a control signal for turning on the corresponding actuator 2 is output.

On the other hand, if the determination result of the step end condition is ended, the execution register STP of the step register 9 is turned off (11e3), and a control signal for turning off the actuator 2 is output. Next, the value of “next step” is read from the operation definition unit 12 (11e4), and it is determined whether there is a subsequent step (11e5). If there is, the execution step is incremented by 1 (11e6). The “executing step” and the “start time” are stored (11e7), and a signal for turning on the corresponding STP of the step register 9 is output (11e7).
e9).

When the execution step update processing (11e) is completed, the value of the next step is read from the operation definition section 12, the step number is updated (11f1), and the processing returns to step 11a to repeat the above processing. If the processing of all the steps has been completed (f2), the step control processing in this cycle ends.

The next cycle also starts from step 1. The “executing step” of the operation management unit 13 includes step 1 in the previous cycle.
Is stored, so there is a step during execution (11a
It is determined as 1), and the process proceeds to step end condition determination (11d). If the step end condition is, for example, "time set by a timer", ON / OFF of a time-up flag is read to determine end. If it is ON, the step is updated (11e), and the step 2 of the process 1 is executed. O
If it is FF, Step 1 of Process 1 is continuously executed. Therefore, in this embodiment, there is always one control step executed in the same cycle for each process. The same applies to other steps.

FIG. 7 is a processing flow of the interrupt processing 11g. The process is started when it is determined that the interrupt is present in the interrupt determination 11b in FIG. 5, and first, the interrupt level is determined (11g).
1) If the interrupt level is 1 (interruption / resume), the execution status of the execution step of the equipment control sequence 8 is determined (11g2). If the execution status is "normal", an OFF signal is output to the corresponding execution register of the step register 9 (11g3), and the execution status is updated from normal to suspended (11g4).

On the other hand, when the execution status is "interrupted", an ON signal is detected in the corresponding execution register of the step register 9 (11g5), and the execution status is updated to "normal" (11g).
g6). After that, interrupt level = 0 (11g11), J
The UMP destination step is initialized to 0 (11g12), and the interrupt processing 11g ends.

When the interrupt level is 2 (step end), the corresponding execution register is turned off (11g7), the execution step is updated to the next step (11g8), and the execution status is updated normally (11g9). The execution register corresponding to the updated execution step is turned on (11g10). When the interrupt level is 3 (JUMP), the corresponding execution register is turned off (11g13), and the execution step is set to JUMP.
The process is updated to the previous step (11g14), and thereafter, the process is the same as the above process 11g9.

FIG. 8 is an explanatory diagram of a specific operation when an interruption request is made for the step control processing. When the suspend / resume button is operated from the input / output device 4, the interrupt level = 1 is stored in the operation management unit 13.

The step control processing 11 operating in response to the start signal from the sequence control mechanism 7 includes a level determination 11
When an interrupt of level = 1 is confirmed in g1, the operation management unit 1
3 to read the “execution status” and determine the execution status (1
1g2) If “normal”, an interrupt request is recognized, and the control operation definition unit 12 executes the execution register number of the currently executing step x =
9x is read, and an OFF signal is output to the execution register 9x (11g3). As a result, the execution register 9x of the step register 9 is turned off, and the sequence control mechanism 7
The execution of the equipment control sequence 8x started from is stopped. In addition, the “execution status” of the operation management unit 13 indicates “interrupted”.
Is stored (11g5), and the interrupt level is initialized (= 0) (11g11).

On the other hand, when the facility control sequence 8x whose execution status is "interrupted" is to be resumed, the key operation of interruption / resumption is executed from the input / output device 4. When the interrupt level = 1 is input, the execution status determination 11g2 recognizes the request as a restart and turns on the execution register 9x of the interrupted execution step x.
Then, the equipment control sequence 8x returns to operation.

FIG. 9 is an explanatory diagram of a specific operation when a step end request is made for the step control processing. When a step end request is made from the input / output device 4, the interrupt level = 2 is stored in the operation management unit 13. The level determination 11g1 confirms that the request is a step end request, obtains the execution register number 9x of the step x from the control operation definition unit 12 (11g6), and turns off the execution register 9x of the step register 9 (11g7).

Next, the control operation definition section 12 sends a message to step x
, The step in execution of the operation management unit 13 is updated to y (11g8), and the execution status is “normal”.
Is stored (11g9). The execution register number of step y is fetched, and the execution register of step y of step register 9 is turned on (11g10). As a result, the equipment control sequence 8x started from the sequence control mechanism 7
Is stopped, and the equipment control sequence 8y which is the next step of the equipment control sequence 8x operates.

FIG. 10 is a flowchart showing the step control processing performed by the JU.
FIG. 9 is an explanatory diagram of a specific operation when an MP request is made.
When a JUMP request is made from the input / output device 4, the interrupt level = 3 is stored in the operation management unit 13. Subsequent operations are executed in the same manner as the operation described with reference to FIG. 9, the execution of the equipment control sequence 8x started by the sequence control mechanism 7 stops, and the equipment control sequence 8z corresponding to the step z of the JUMP destination operates. .

FIG. 12 is an explanatory diagram of equipment control and ladder sequence to which the sequence control of this embodiment is applied. As shown in FIGS. 11 (a) and 11 (b), the same equipment and control scheme as in FIG. FIG. 12C shows an example of the control operation definition according to the present embodiment, and FIG. 12D shows a description example of a ladder sequence.

When the start button of the cleaning process is pressed, the step control processing section 11 of this embodiment repeats steps 1 to 3 according to the control operation definition of (c) in response to a start signal from the sequence control mechanism 7. Repeatedly.

When step 1 is executed, the step register 9
Is turned on. As shown in (d),
When STP1 is turned on, the ladder sequence of the equipment control sequence 8 turns on the coils V01 and V02. Since step 1 ends unconditionally, the process moves to step 2 which is the next step in the next cycle. It is also possible to confirm that the valves V01 and V02 of the tank A are open and proceed to the next step.

When step 2 is executed, the step register STP1 in step 1 which is the previous step is turned off, but the execution register STP2 in step 2 is turned on instead.
Therefore, V01 and V02 are continuously turned on. Further, coil V11, coil T01, and coil PU01 are
N. When the coil T01 is turned on, a 30-second timer starts. When the time is up, Step 2 ends, and the process proceeds to the next step, Step 3.

When step 3 is executed, the execution register STP3 of step 3 is turned on, and the coil V01, the coil V0
2. While continuing to turn on PU01, coil V1
2. Turn on the coil T02. When the coil T02 is turned on, a 60-second timer starts, and when the time is up, Step 3 ends. At the end of step 3, the next step has not been defined, and thus ends. At the end, the step register 3 is turned off, and all the coils are turned off by the ladder sequence (d).

As described above, the control operation definition of this embodiment is divided into control step units of the control plan, and the progress of the control steps is controlled by the program of the flow description.
The step control process performed while determining the step end condition and the control step of the facility based on the ladder description match.
That is, the disadvantage of the conventional ladder sequence, that is, the mismatch between the control sequence of the production equipment and the ladder sequence can be solved.

According to this, not only the operation can be monitored, but also manual intervention in an emergency can be easily performed. For example, if the chemical solution is insufficient during the injection of the chemical solution in the control scheme STEP2 described in the section of the prior art, in this embodiment, if the step 2 of the step control process is temporarily interrupted by an interrupt or the end of the step 2 is instructed. Good. This instruction may be made by selecting a function key such as suspend / resume or STEP termination on the operation unit 4c of the monitoring / operation screen in FIG. Since the operation status of the step corresponding to the control plan is clearly displayed on the monitoring / operation screen, the operator can easily operate the ladder sequence even if he is not familiar with the ladder sequence.

Further, the ladder sequence of this embodiment is basically only a conventional output unit, and the description is greatly simplified. Therefore, the efficiency of the development and maintenance of the ladder sequence in complicated facilities can be improved. Program capacity can also be reduced.

[0066]

According to the present invention, the condition determination of the control plan is performed by the step control described in flow order in the step order, and the equipment control is performed by the equipment sequence of only the output unit described in ladder for each step. A sequence can be configured, and operations such as monitoring of the operation state of equipment and intervention can be facilitated.

Further, since the steps of the process being executed and the progress thereof are identified and displayed on the monitor screen, the operator can grasp the operation state at a glance, and manual intervention in the event of an abnormality or the like can be performed without decoding the ladder sequence. Operability can be remarkably improved, for example, with one touch.

Further, the ladder sequence only describes the conventional output unit, so that it is greatly simplified, and the development and maintenance work can be made more efficient.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing one embodiment of a sequence control device of the present invention.

FIG. 2 is an explanatory diagram showing a control flow of the sequence control device of FIG. 1;

FIG. 3 is an explanatory diagram showing a file configuration of a control operation definition unit and an operation management unit.

FIG. 4 is a screen configuration diagram showing one embodiment of a monitoring / operation screen.

FIG. 5 is a processing flowchart showing a procedure according to an embodiment of the sequence control method of the present invention.

FIG. 6 is a flowchart showing a detailed procedure in the case of no interruption in the sequence control of FIG. 5;

FIG. 7 is a processing flowchart showing details of the interrupt processing of FIG. 5;

FIG. 8 is an explanatory diagram showing a processing procedure and a data flow in response to an interruption request in the interrupt processing of FIG. 7;

FIG. 9 is an explanatory diagram showing a processing procedure and a data flow in response to a step end request in the interrupt processing of FIG. 7;

FIG. 10 is an explanatory diagram showing a processing procedure and a data flow according to a JUMP request in the interrupt processing of FIG. 7;

FIG. 11 shows an example of application of conventional sequence control, and is an explanatory diagram comprising an example of equipment, a control plan, and a ladder sequence program.

FIG. 12 is an explanatory diagram showing an application example of the sequence control of the present invention, which includes the same equipment and control plan as in FIG. 11, a control operation definition, and a ladder sequence program.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Facility, 2 ... Sensor / actuator, 3 ... Sequencer, 4 ... Input / output device, 6 ... Input / output register, 7 ... Sequence control mechanism, 8 ... Facility control sequence, 9 ... Step register, 10 ... Progress management mechanism, 11 ... Step control processing unit, 12 ... Control operation definition unit, 13 ... Operation management unit, 14
... Screen display editing unit, 15 ... Working memory.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FIG05B 19/05 L (72) Inventor Satoshi Oishi 5-2-1 Omikacho, Hitachi City, Ibaraki Pref. Hitachi, Ltd. Omika Plant

Claims (10)

[Claims] When a unit process of a production facility is divided into a plurality of control steps, a sequence control for periodically operating a control logic combining control operations in step units to control an operation state of the production facility. In the method, a step end condition and a next step are defined in advance for each of the control steps, and are periodically activated, and when a control step being executed (hereinafter, an execution step) satisfies the end condition, Updates and manages the execution step to the next step, outputs an ON signal of the updated execution step, and executes the control logic describing the relationship between the execution step and the output unit in ladder according to the ON signal. And outputting a control command. 2. When a plurality of processes of a production facility are divided into a plurality of control steps for each process, an operation state of the production facility or the like is periodically detected, and control is performed by executing control logic for each step. In the sequence control method of outputting a command and controlling the operation state of the production equipment, a step end condition and a next step are defined in advance in the order of a process start condition and a control step for each of the processes, and the process is started periodically. From the operation state, it is determined whether or not there is an execution step for a process that satisfies the process start condition. If there is an execution step, it is determined whether the end condition is satisfied. While updating and managing the steps, outputting an OFF signal of the execution step before the update and an ON signal of the execution step after the update,
Further, the above-described series of processing is repeated for the next step, and the control logic that describes the relationship between the execution step and the output unit in each step and each control step is executed in ladder according to the ON signal or the OFF signal. Or a sequence control method characterized by stopping. 3. The sequence control method according to claim 1, wherein when the termination condition is not satisfied, the execution step is not updated, and is continued in the next control cycle. 4. The method according to claim 1, 2 or 3, wherein the presence or absence of an interrupt due to an operation request is preferentially determined, and if there is an interrupt, an interrupt process corresponding to an interrupt level that differs depending on the request content is executed. A sequence control method, comprising: 5. The execution method according to claim 4, wherein if the request content is an interruption of the execution step, an OFF signal of the execution step is output while the execution step being managed is maintained, and the execution state of the execution step is “interrupted”. If the request content is a resumption of the suspended execution step, an ON signal is output to the managed execution step, and the execution status is updated to “normal”. If the request content is the end of the execution step, an OFF signal of the execution step is output, and the execution step is updated to the next step to output an ON signal. If the request content is JUMP, the execution step is turned off. A step of outputting a signal, updating the execution step to the JUMP destination step, outputting an ON signal, and performing step control according to the operation request. Nsu control method. 6. A sensor for detecting an operation state of a production facility, an actuator for changing an operation state of the production facility, and equipment control for receiving an operation state from the sensor and outputting a control command to the actuator according to a control logic. A sequence control device comprising a sequence and a sequence control mechanism for periodically outputting a start signal, wherein the equipment control sequence is divided into a plurality of control steps for each process, and an execution register and a control operation output unit are provided for each control step. The control logic is configured by a ladder description program that combines the above, and the progress of the control step is controlled according to a control operation condition, and the execution logic is configured by a flow description program to determine an execution register corresponding to the execution step. Characterized by the provision of a progress management mechanism Sequence control device. 7. The sequence according to claim 6, wherein the output unit includes a combination of a minimum necessary output operation for each control step, and further includes the output operation and an interlock condition in a step. Control device. 8. The control operation definition unit according to claim 6, wherein the progress management mechanism defines a process start condition and a step end condition, an execution register number, and a next step name for each control step. The execution of the equipment control sequence which has an operation management unit which manages the name of the step being executed, the interrupt level, etc. for each process, and is composed of a plurality of execution registers assigned with the execution register number, and which is connected by the ladder description. And a step register for turning on / off the execution register defined by the execution step updated by the progress management mechanism, and executing a corresponding equipment control sequence. Control device. 9. The input / output device according to claim 8, further comprising an input / output device having a plurality of operation keys for inputting an external operation request for the execution step by changing the interrupt level, wherein the progress management mechanism is configured to execute the interrupt. A sequence control device having an interrupt processing program corresponding to a level, wherein an execution step can be interrupted, restarted, stopped, JUMP, or the like in response to an input operation request. 10. A screen display editing unit according to claim 8, wherein the control step being executed and the operation state of the control step being executed on the ladder sequence are displayed on the screen of the input / output device. A sequence control device.