JP3471566B2 - Display method and apparatus for displaying sequence state transition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to sequence control,
Involved in a process control system consisting of a process control device for monitoring the process status and an operation console, especially CR
The present invention relates to a method of displaying a sequence state in a distributed control system suitable for plant automation, centering on T operation.

[0002]

2. Description of the Related Art A conventional method of displaying a sequence state in a process control system is, as shown in FIG. 6, roughly dividing a target sequence into several steps on an operation console of a process control device for performing sequence control. They are given names (preparation, temperature rise, reaction ...) To distinguish the process currently being executed from other processes and display them on the screen as a set of processes.

[0003] This display method is effective for steady-state operation in which the movement of the target sequence is roughly monitored in milestones, and the operator is informed of the sequence status for each target sequence. It is required to store in correspondence with some process names. To implement this display method, the process control apparatus provides several flags corresponding to individual steps for each sequence, sets the corresponding step flag in the logic of sequence control, and The flag is set so as to be reported to the processing unit of the operator console through the communication line at each process change.

Further, on the operation console, the names of all the steps of all sequences are stored in advance, and only the steps for which the flag is ON are emphasized more than other steps for the sequences called from the key input device. If you configure it to display,
The process currently being executed can be displayed separately from other processes.

[0005]

However, the above-mentioned conventional technique is only a rough process display method for displaying the execution status of sequence control, and therefore, in an emergency such as occurrence of a plant failure or at the time of maintenance of the plant. In the case where more detailed information is required, it is impossible to promptly obtain the necessary information.

Originally, the sequence control is composed of a combination of logics and is executed, so that it is difficult to visualize. For this reason, when the sequence control deviates from the normal operation, the operator or the like is often forced to investigate the logic for collecting the situation step by step. In the worst case, the difficult sequence control logic is used. In some cases, it is inevitable that the described drawings will be visually resolved.

In such a case, as in the prior art,
If you rely only on rough sequence control information, it will take much time to recover. That is, the conventional technique lacks the function of accurately displaying and transmitting the state of sequence control, which is mainly the present.

An object of the present invention is to display on a screen, in real time, accurate information on the current state in sequence control and accurate information on what condition is next satisfied to transition to the next state. It is to realize a display method and device of a sequence state transition to be displayed.

[0009]

[Means for Solving the Problems]

(1) The present invention is configured as follows to achieve the above object. That is, an operation console having a display means, a key input means and an operation console processing means, a process control means having a control processing means for executing sequence control on a process control target, and the operation console and the process control means. In a method of displaying a sequence state transition of a distributed control system including a communication line to be connected, the above-mentioned output from the time of changing the type of output signal output from the process control means to a control target to the next time of change in the process control means The signal status is held as a code, and the corresponding status code is communicated to the console via the communication line at each sampling cycle of the input signal from the sequence control target, and the process control is performed in the console processing means. Each time the type of output signal output from the control unit to the controlled object is changed, the ON / OFF state of all output signals is output in time-series order. And the display means for distinguishing the output signal matrix corresponding to the status code communicated from the process control means from the other groups in response to the call operation from the key input means. And the state transition diagram showing the progress of the sequence control executed by the process control means is displayed on the display means.

(2) Preferably, in the above (1),
The output signal type output from the process control means to the controlled object is changed, and the logic of the signal which is the condition for transitioning the signal output state is calculated by changing the output signal type every time the output signal type is changed. A logical expression based on a combination of the product element and the negation element is held in the console processing means, and the process control means is provided for each sampling cycle of the input signal from the sequence control target in response to the calling operation from the key input means. The logical expression corresponding to the status code transmitted from the device to the operator console via the communication line is displayed on the display means.

(3) Further, preferably, in the above (2), the process control means sets an ON / OFF state of an input signal which is a condition for transitioning a signal output state at each sampling cycle of the input signal, Each time the output signal type is changed, the logic of the signal, which is a condition for communicating with the operator console via the communication line and changing the signal output state in response to the calling operation from the key input means of the operator console, is performed. In the case of displaying, based on the ON / OFF state of the input signal communicated from the process control means, the terminals, elements, and signal paths in the above logical expressions are identified in the ON / OFF state by the display means. indicate.

(4) Also, in the above (2), preferably, in response to a calling operation from the key input means, the process control means displays the operation console via the communication line at every sampling cycle of the input signal. Based on the status code to be communicated, the candidate for the next transition signal output status is determined,
The logical expression that is a combination of the logical sum element, the logical product element, and the negation element of the input signal, which is the transition condition, is displayed on the display means together with the transition condition logical expression of the current signal output state.

(5) Further, an operation console having a display means, a key input means and an operation console processing means, a process control means having a control processing means for executing sequence control on a process control target, and the above-mentioned operation. In a display device for sequence state transition of a distributed control system comprising a desk and a communication line connecting process control means, the process control means is arranged to change the output signal type output from the process control means to a control target from the time of change to the next. Code holding means for holding the state of the output signal as a code up to the time of change, and for each sampling period of the input signal from the sequence control target, output the corresponding state code to the operator console via the communication line. The operation console is provided with a communication means, and the operation console outputs the full output every time the output signal type output from the process control means to the control target is changed. Matrix holding means for holding the on / off state of signals as an output signal matrix in chronological order is provided, and the console processing means controls the output signal matrix by the process control in response to a calling operation from the key input means. An output signal group corresponding to the status code communicated from the means is displayed on the display means in distinction from other groups, and a state transition diagram showing the progress of sequence control executed by the process control means is displayed on the display means. indicate.

(6) Preferably, in the above (5),
The console processing means changes the output signal type output from the process control means to the controlled object, and associates the logic of the signal which is a condition for transitioning the signal output state, every time the output signal type is changed. As a logical expression by a combination of a logical sum element, a logical product element and a negative element of the signals, the logical expression is held in the console processing means and sampling of the input signal from the sequence control target is performed in response to the calling operation from the key input means. For each cycle, the logical expression corresponding to the status code output from the process control means to the operator console via the communication line,
It is displayed on the display means.

(7) Further, preferably, in the above (6), the process control means sets an ON / OFF state of an input signal which is a condition for transitioning a signal output state at each sampling cycle of the input signal, Each time the output signal type is changed, the logic of the signal, which is a condition for outputting to the operator console via the communication line and changing the signal output state in response to a calling operation from the key input means of the operator console, is performed. In the case of displaying, based on the on / off state of the input signal output from the process control means, the terminals, elements, and signal paths in the above-mentioned logical expressions are identified in the display means by identifying their on / off states. indicate.

(8) Further, in the above (6), preferably, the console processing means is connected to the communication line from the process control means every sampling cycle of the input signal in response to a calling operation from the key input means. Based on the status code output to the console via the, the candidate of the signal output state to transit to next is determined, and the transition condition is the combination of the logical sum element, the logical product element and the negation element of the input signal. Is displayed on the display means together with the transition condition logical expression of the current signal output state.

The process control means turns on / off a signal associated with the status code of the current sequence and the logic which is a condition for transitioning the sequence to the next state via the communication line for each sampling control for the sequence control target. The off state is communicated to the console processing means.

In the console processing means in the console, the output signal group corresponding to the status code communicated from the process control means is emphasized in response to the calling operation from the key input means, in a time-series order of all output signals. The matrix and the logical expression that is the transition condition to the next state, in which the on / off states of the related signals communicated are reflected in the terminals, elements, and signal paths, are displayed. That is, the on / off state of all control output signals of the called sequence and the transition condition to the next state,
Also, a logic diagram representing the current state of the signal associated with the condition is displayed as a sequence state transition.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method and apparatus for displaying a sequence state transition according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an apparatus for carrying out a method for displaying a sequence state transition of the present invention, FIG. 2 is a sequence state transition diagram displayed by the above display method, and FIG.
4 is a block diagram of a synthesizing unit for synthesizing state transitions, FIG. 4 is an overall block diagram of a distributed control system, and FIG. 5 is a schematic block diagram of the inside of a processing device.

First, the overall configuration of the distributed control system will be described. In FIG. 4, the distributed control system is
Operator console 4-1, communication line 4-2, process control device 4-
It is composed of 3 etc. Then, the process control device 4-3
Is, for example, a PID obtained by fetching a flow rate signal from a flow rate detection unit 4-7 attached to the pipe 4-6 of the reaction can 4-4.
Calculation is performed and process control such as outputting the calculation result to the control valve 4-5 is performed.

This process control is often accompanied by sequence control such as closing the steam inflow valve when the temperature exceeds a target value, and so on. In the process control system, sequence state monitoring support is also important. It becomes a function. That is, the function of displaying the state of sequence control by the process control device 4-3 on the console 4-1 via the communication line 4-2 is important.

Next, FIG. 5 shows an operation console 4-1 of the process control system equipped with a display mechanism for a sequence state transition diagram.
And a schematic configuration of the process control device 4-3 and a transfer route of the communication text 5-9 necessary for displaying the state transition diagram.

In FIG. 5, in the processing device 1-16 in the process control device 4-3, the sequence control arithmetic unit 1
-18 determines the sequence state transition condition logic 5-14 (1-21, 1-22, 1-23) for each sampling cycle, and if the condition is satisfied, outputs the output value of the corresponding state as a sequence control signal. Time-sequential output pattern 5-13 (1
-19, 1-20) and output to the process through the output terminal 1-27.

In addition, a communication text 5-9 (1) in which the current status code and the current on / off status of the process input signal are lined up from the process control device 4-3 via the communication line 4-2 for each sampling period. -29, 1-30) is sent to the console 4-1. In the processing device 1-1 of the console 4-1 the content of the communication text 5-9 is fetched by the data receiving section 1-2.

In response to the operation of calling the sequence state transition diagram from the keyboard 1-15 by the operator, the state transition diagram editing section 5-6 (1-3 to 1-12) produces a time-series matrix of output signals. Extract the state transition logic diagram to the next state. Then, the state transition diagram editor 5-6 uses different colors in the output signal matrix to distinguish the output column corresponding to the state code from the other columns. The colors of the terminals, elements, and signal paths are changed according to the current on / off status, and a composite drawing of these is sent to the image output unit 1-13. The image output unit 1-13 outputs and displays the state transition diagram on the CRT display screen 1-14.

Next, FIG. 1 shows in detail the console and the internal mechanism of the process control device for displaying the sequence state transition diagram. In FIG. 1, in the processing device 1-16 in the process control device, the sequence control calculation unit 1-18 takes in an input signal from the outside through the process input signal taking-in terminal 1-17 every sampling cycle. And
The sequence control calculation unit 1-18 collates the input signal thus captured with the sequence state transition logic diagram group 1-20,
It is determined whether or not the condition for shifting from the current state to the next state is satisfied. If the condition for shifting to the next state is satisfied, the sequence control computing unit 1-18 outputs the output signal pattern (output signal pattern to the process control target) corresponding to the next state from the output signal matrix group 1-19. The data is taken out and supplied to the output pattern / state code setting unit 1-21.

Output pattern and status code setting section 1-2
In No. 1, the output pattern supplied from the sequence control calculation unit 1-18 is set in the output pattern holding unit 1-22. Further, the status code setting unit 1-21 fetches the current state of the input signal from the process input signal fetching terminal 1-17 and stores it in the state code holding unit 1-26. If there is a change, a new status code indicating the change is stored in the status code holding unit 1-25. Then, the status code setting unit 1-21 activates the communication data transmitting unit 1-24 every sampling cycle.

The process control signal output unit 1-23 takes out the output value from the output pattern holding unit 1-22 every sampling period and outputs it to the process control signal output terminal 1-27. A process control signal is output from the process control signal output terminal 1-27 to the outside.

In the communication data transmitting section 1-24, the status code and the current input signal are taken out from the status code holding section 1-25 and the input signal holding section 1-26 at every sampling cycle, and the status code 1-29 is output. The communication text 5-9 including the input signal 1-30 is sent to the communication data receiving section 1-2 of the processing device 1-1 in the operator console via the communication line 1-28 (4-2).

The communication data receiving section 1-2 sends the received data to the communication data analyzing section 1-3. The communication data analyzing unit 1-3 analyzes the data sent from the communication data receiving unit 1-2, and analyzes the analyzed data into the status code holding unit 1-4.
And the current input signal holding unit 1-5.

When the operator performs a sequence state transition diagram calling operation using the keyboard 1-15, the output signal matrix and state transition logic diagram extracting unit 1-6 is called from the output signal matrix group 1-7. The output signal corresponding to the sequence state is taken out. Then, the extraction unit 1-6, in the output signal matrix of the corresponding sequence, the column corresponding to the status code obtained from the status code holding unit 1-4 (the column indicating the output terminal as shown in FIG. 2).
The output signal matrix 1-11 is created by differentiating from the other columns in color.

Further, the take-out unit 1-6 takes out the state transition logic diagram of the next state to which the current state can be transferred from the state transition logic diagram group 1-8, and on the retrieved state transition logic diagram, The state transition logic diagram 1-12 in which the ON / OFF state of the signal obtained from the input signal holding unit 1-5 of FIG.

The sequence state transition logic diagram synthesizing unit 1-9 synthesizes the output signal matrix 1-11 created by the extracting unit 1-6 and the state transition logic diagram 1-12 to obtain the sequence state transition diagram. Create 1-10. The created sequence state transition diagram 1-10 shows the image output unit 1-
13 is supplied.

The sequence state transition diagram 1-10 supplied to the image output unit 1-13 is supplied from the image output unit 1-13 to the CRT display device 1-14, and the sequence is displayed on the CRT display device 1-14. The state transition diagram 1-10 is displayed on the screen.

FIG. 2 shows details of the sequence state transition diagram. In FIG. 2, the output signal matrix 1-11 and the state transition logic diagram 1-12 are superimposed and displayed on the cathode ray tube screen 2-2 of the console 4-1. On the output signal matrix 1-11, an output terminal arrangement 2-4 in which boxes with output terminal names are arranged on the vertical axis is arranged, and a state code arrangement 2-4 with boxes with status codes is arranged on the horizontal axis 2- 5 are arranged. The ON / OFF value of each output terminal is reflected as an element of the matrix for each column (01, 02, ... 64) of the status code.

That is, for each output terminal, the status code for turning on the terminal is displayed in a color different from other status codes. Therefore, by looking at the row of a certain output terminal, the on / off status of the output signal, that is, the time-series change status corresponding to each status code can be grasped.

Further, in the column corresponding to the current state code, that is, the column 2-6 of the current state in the example of FIG. 2, the on / off value of each element of the matrix is higher than the columns of other state codes, the brightness, etc. Is highlighted. As a result, it is possible to immediately grasp where the column corresponding to the current state is and what the on / off status of each output terminal is.

Further, the names of the output terminals arranged in the output terminal row 2-4 are also color-coded for the output terminals in the ON state in the column 2-6 in the current state from the output terminals in the OFF state. Is displayed. In the example of FIG. 2, v-101 and v-102 of the output terminal array 2-4 are displayed in different colors from the other output terminals. Therefore, it is possible to determine at a glance whether an output terminal is currently on or off.

In the state transition logic diagram 1-12 superimposed and displayed on the output signal matrix 1-11, there is an input terminal arrangement 2-8 at the left end, and input terminal named boxes 2-9 are arranged there. Has been. Also, the state transition logic diagram 1-
At the right end of 12, there is a state transition presence / absence reflecting terminal array 2-10, and there is a reflection terminal 2-11 indicating the presence / absence of transition to the next state.

The logical expression between each input terminal in the input terminal array 2-8 and the terminal for reflecting the presence / absence of transition to the next state 2-11 is the logical element 2-13 such as AND or OR and the inter-element path 2- It is displayed graphically in combination with 12 mag. The input terminal 2-9, the logic element 2-13, the inter-element path 2-12, and the state transition presence / absence reflection terminal 2-11 are displayed in different colors according to the current on / off status of the input terminal 2-9. .

That is, the input terminal 2-which is currently on
9 is emphasized and displayed from the input terminal 2-9 in the off state, and the inter-element path 2-12 at the “H” level is emphasized from the “L” level inter-element path 2-12. Will be displayed. The input signal or output of the logic element 2-13 and the state transition presence / absence reflection terminal 2-11 are also
For example, in the case of "H" level, it is displayed more emphasized than in the case of "L" level. Therefore, it becomes possible for the operator or the like to determine at a glance which input signal is turned on or off next and the sequence transitions to the next state.

FIG. 3 is a diagram showing a sequence state transition diagram synthesizing unit for creating a sequence state transition diagram, which is composed of an output signal matrix of a sequence and a state transition logic diagram. This sequence state transition diagram synthesis unit has an output pattern synthesis unit 3-1 and a state transition logic diagram synthesis unit 3-7.
These combining sections 3-1 and 3-7 are internal functional blocks of the output signal matrix and state transition logic diagram extracting section 1-6 of FIG.

In FIG. 3, first, the output pattern synthesizing section 3-1 generates the output pattern 3-4 (output signal matrix 1-11) by applying the corresponding output pattern element 3 to it.
-2 and the output terminal element 3-3 are fetched from the output signal matrix group 1-7. Then, the output pattern synthesis unit 3-
1 is the output pattern current status 3-6 in which the color of the column corresponding to the status code is changed, and the output terminal current status 3-6 in which the color corresponding to the ON / OFF value of the column corresponding to the status code is changed.
5 and 5 are arranged at predetermined positions in the output pattern 3-4.
Similarly, the output pattern synthesis unit 3-1 sequentially arranges the output pattern current situation 3-6 and the output terminal current situation 3-5 at predetermined positions of the output pattern 3-4, and outputs the output pattern 3- Create 4.

Next, the state transition logic diagram synthesizer 3-7 generates the state transition logic diagram by applying the corresponding input terminal element 3-.
8, logic element element 3-9, and inter-element path element 3-10
From the state transition logic group 1-8. In addition, the state transition logic diagram synthesis unit 3-7 selects a box or a box according to the current situation 3-11 of the input signal fetched from the input signal holding unit 1-5.
Current status of input terminal 3-12, current status of logic element 3-13 and current status of inter-element path 3-
14 in the state transition logic diagram 1-12. Similarly, the state transition logic diagram synthesizer 3-7 sequentially sets the current status 3-12 of the input terminal, the current status 3-13 of the logic element, and the current status 3-14 of the inter-element path to predetermined positions. Place and create the state transition logic diagram 1-12.

The created output pattern 3-4 (output signal matrix 1-11) and the state transition logic diagram 1-12 are synthesized by the sequence state transition logic diagram synthesis unit 1-9 as described above. , Sequence state transition diagram 1-1
It is set to 0 and displayed on the cathode ray tube display device 1-14.

As described above, according to the embodiment of the present invention, the process currently being executed is identified (color-coded) from the other processes, and the on / off state of the output of the process is identified from the output of the other process. The output signal matrix to be displayed and the input on / off status in the currently executed process and the logic for transitioning to the next state according to the input status are shown by the logic element and the path between the elements, and the progress status in the current step is shown. Since the state transition logic diagram for identifying and displaying the advanced portion of the logic element and the path between the elements is displayed at the same time, accurate information of the current state in sequence control and what condition It is possible to realize a sequence state transition display method and device for displaying on a screen, in real time, accurate information as to whether or not the transition to the next state is established.

Therefore, when the sequence control deviates from the normal operation, it is possible to quickly determine what process, what progress situation, and what input state the normal operation deviates from. The operation controllability and maintainability of the process control system can be improved.

In the above-mentioned example, the state transition logic diagram 1-12 in the present process is configured to be displayed, but the processing unit 1-16 of the process control unit is connected to the console via the communication line 1-28. Based on the status code 1-29 communicated to the processing device 1-1, the candidate of the signal output state to transit to next is determined, and the transition condition of the logical sum element, the logical product element and the negation element A mode in which the combinational logical expression is displayed on the display means 1-14 together with the transition condition logical expression of the signal output state in the current step is also one of the embodiments of the present invention.

[0049]

Since the present invention is constructed as described above, it has the following effects. In sequence control, a method for displaying a sequence state transition, which displays on the screen in real time, accurate information on the current state and accurate information on what condition is next satisfied to transition to the next state, and The device can be realized.

Therefore, when the sequence control is deviated from the regular operation, it is possible to quickly determine what process, what progress situation, and what input state the operation deviates from the regular operation. The operation controllability and maintainability of the process control system can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for implementing a method for displaying a sequence state transition of the present invention.

FIG. 2 is a sequence state transition diagram.

FIG. 3 is a configuration diagram of a sequence state transition combining unit.

FIG. 4 is an overall configuration diagram of a distributed control system.

FIG. 5 is a schematic configuration diagram of the inside of the processing apparatus.

FIG. 6 is a diagram showing a conventional method of displaying a sequence state.

[Explanation of symbols]

1-1 Processing device on console 1-2 Communication data receiving unit 1-3 Communication data analyzing unit 1-4 State code holding unit 1-5 Input signal holding unit 1-6 Output signal matrix and state transition logic diagram extracting unit 1-7 Output Signal Matrix Group 1-8 State Transition Logic Diagram Group 1-9 Sequence State Transition Diagram Synthesis Unit 1-10 Sequence State Transition Diagram 1-11 Output Signal Matrix Holding Unit 1-12 State Transition Logic Diagram 1-13 Image Output unit 1-14 CRT display device 1-15 Keyboard 1-16 Processing device in process control device 1-17 Process input signal input terminal 1-18 Sequence control operation unit 1-19 Output signal matrix group 1-20 Sequence state transition logic Figure group 1-21 Output pattern and status code setting section 1-22 Output pattern 1-23 Process control signal output 1-24 Communication data transmitter 1-25 Status code holder 1-26 Input signal holder 1-27 Process control signal output terminals 1-28, 4-2 Communication line 1-29 Status code 1-30 Input signal 2- 2 CRT screen 2-4 Output terminal arrangement 2-5 Status code arrangement 2-6 Current status row 2-8 Input terminal arrangement 2-9 Input terminal 2-10 Status transition presence / absence reflected terminal arrangement 2-11 To next state Transition presence / absence reflecting terminal 2-12 Inter-element path 2-13 Logic element 3-1 Output pattern synthesizing section 3-2 Output pattern element 3-3 Output terminal element 3-4 Output pattern 3-5 Output terminal Current status 3-6 Output Pattern current status 3-7 State transition logic diagram synthesis section 3-8 Input terminal element 3-9 Logic element element 3-10 Inter-element path element 3-11 Current status of input signal 3-12 Current status of input terminal 3-13 Argument Current status of physical element 3-14 Current status of inter-element path 4-1 Operator table 4-3 Process control device 4-4 Reactor 4-5 Control valve 4-6 Piping 4-7 Flow rate detector 5-6 State transition Figure editor 5-9 Communication text 5-13 Sequence control signal time-sequential output pattern 5-14 State transition condition logic

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akihiro Nakamura 882 Ichige Ichi, Hitachinaka-shi, Ibaraki Hitachi Ltd. Measuring Instruments Division (72) Inventor Shingo Watanabe 832 Nagakubo Horiguchi, Hitachinaka, Ibaraki 2 Hitachi Measurement Engineering Stock Association In-house (56) Reference JP 8-263130 (JP, A) JP 7-104838 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G05B 19 / 00-19/16 G05B 23/00-23/02

Claims (8)

(57) [Claims] 1. An operation console having display means, key input means and operation console processing means, process control means having control processing means for executing sequence control on a process control target, and the operation console and process. In a method of displaying a sequence state transition of a distributed control system including a communication line connecting a control means, in the process control means, from the time of changing the type of output signal output from the process control means to a controlled object to the time of the next change. The state of the output signal of the above is held as a code, and the corresponding state code is communicated to the operator console via the communication line for each sampling cycle of the input signal from the sequence control target, and is stored in the operator console processing means. , The ON / OFF state of all output signals is output in time-series order every time the type of output signal output from the process control means is changed. Holding a helix, depending on the call operation from the key input means, said output signal matrix, the output signal group corresponding to the status code communicated from said process control means,
A method of displaying a sequence state transition, characterized by displaying on the display means a state transition diagram that is displayed on the display means in distinction from other groups and indicates the progress of sequence control executed by the process control means. 2. The sequence state transition display method according to claim 1, wherein the output signal type output from the process control means to the controlled object is changed, and the logic of the signal as a condition for transitioning the signal output state is set forth above. Each time the output signal type is changed, it is held in the console processing means as a logical expression by the combination of the logical sum element, the logical product element and the negation element of the related signals, and according to the calling operation from the key input means. hand,
A sequence characterized by displaying on the display means a logical expression corresponding to a status code communicated from the process control means to the operator console via the communication line at each sampling cycle of the input signal from the sequence control target. How to display state transitions. 3. The sequence state transition display method according to claim 2, wherein the process control means sets an ON / OFF state of an input signal which is a condition for transitioning a signal output state at each sampling cycle of the input signal. , Every time the output signal type is changed, the logic of the signal which is a condition for communicating with the console via the communication line and changing the signal output state in response to a calling operation from the key input means of the console is changed. In the case of displaying on the basis of the ON / OFF state of the input signal communicated from the process control means, the ON / OFF states of the terminals, elements and signal paths in the above logical expression are identified to identify the display means. A method for displaying sequence state transitions, which is characterized in that 4. The method for displaying sequence state transitions according to claim 2, wherein, in response to a calling operation from the key input means, the console is connected from the process control means via the communication line at every sampling cycle of the input signal. Based on the status code communicated to the device, the candidate for the next signal output state to be transitioned is determined, and the transition condition, the logical expression by the combination of the logical sum element, the logical product element and the negation element of the input signal, The method for displaying the sequence state transition, characterized in that the signal is displayed on the display means together with the transition condition logical expression of the signal output state. 5. An operation console having a display means, a key input means and an operation console processing means, a process control means having a control processing means for executing sequence control on a process control target, the operation console and the process. In a display device for sequence state transition of a distributed control system including a communication line connecting control means, the process control means is capable of changing the output signal type output from the process control means to a control target from the next change time. Up to a code holding means for holding the state of the output signal as a code, and a communication means for outputting the corresponding status code to the console via the communication line for each sampling cycle of the input signal from the sequence control target. The above-mentioned console is provided with an output signal for all output signals every time the type of output signal output from the process control means to the controlled object is changed. Matrix holding means for holding the OFF state as an output signal matrix in time series is provided, and the console processing means communicates the output signal matrix from the process control means in response to a calling operation from the key input means. The output signal group corresponding to the generated status code is displayed on the display means separately from other groups, and the state transition diagram showing the progress of the sequence control executed by the process control means is displayed on the display means. A display device for sequence state transitions characterized by the above. 6. The sequence state transition display device according to claim 5, wherein the console processing means changes the output signal type output from the process control means to the controlled object, and changes the signal output state. Each time the output signal type is changed, the logic of the signal is held in the operation console processing means as a logical expression by the combination of the logical sum element, the logical product element and the negative element of the related signals, and the key input is performed. In accordance with a calling operation from the means, the logical expression corresponding to the status code output from the process control means to the console via the communication line at each sampling cycle of the input signal from the sequence control target is displayed on the display means. A display device for sequence state transition, which is characterized in that 7. The sequence state transition display device according to claim 6, wherein the process control means sets an ON / OFF state of an input signal which is a condition for transitioning a signal output state at each sampling cycle of the input signal. , The logic of the signal, which is output to the operator console via the communication line and is a condition for transitioning the signal output state in response to a calling operation from the key input means of the operator console, every time the output signal type is changed. In the case of displaying on the display means, based on the on / off state of the input signal output from the process control means, the on / off states of the terminals, elements and signal paths in the above logical expression are identified by the display means. A display device for sequence state transition, which is characterized in that 8. The sequence state transition display device according to claim 6, wherein the console processing means communicates from the process control means every sampling cycle of the input signal in response to a calling operation from the key input means. Based on the status code output to the console via the line, the candidate for the next signal output status to be transitioned is determined and becomes the transition condition.
A display device for sequence state transition, characterized in that a logical expression obtained by combining a logical sum element, an AND element and a negation element of an input signal is displayed on the display means together with a transition condition logical expression of a current signal output state.