JPS6143725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sequence control device using a computer.

In sequence control, it may not be possible to know whether the sequence determined at the design stage is optimal until the plant is actually operated. In that case, it is necessary to modify the sequence during a trial run and determine the optimal sequence. Therefore, it is desirable that the sequence control device be designed such that correction and maintenance of the sequence can be easily performed.

There are various types of sequence control devices, such as relay logic type, pinboard type, and computer type.Among them, computer type sequence control devices are far superior to other types of devices in terms of their ability, so they are gradually gaining popularity. It is becoming widely used. An example of such a sequence control device is one that can be handled in the same way as a relay logic type. In this device, the programmer's console contains logic such as AND circuits and OR circuits.
Keys corresponding to the elements are provided, and by operating these keys in the same way that a programmer would assemble a relay logic circuit, a corresponding sequence control program can be created. This program can be displayed as a relay logic circuit on a CRT display device, and when modifying a sequence, the operator operates keys while looking at the display to rearrange the relay logic circuit, that is, modify the sequence program. .

However, in a relay logic circuit, the correspondence between sequence transition conditions and operation output cannot be known until the relay logic circuit is operated, so how the overall sequence changes by rearranging the relay logic circuit. Kaha,
You can't understand unless you give transition conditions one by one and follow the operation of the relay logic circuit. Therefore, displays that utilize a relay logic circuit type display are inconvenient to maintain and difficult to handle unless one is familiar with relay logic.

An object of the present invention is to provide a sequence control device that uses a computer and is easy to maintain.

The device of the present invention uses a sequence table in which pairs of transition conditions and operation outputs are registered for each step as a program storage method for the sequence control program.During maintenance, this is displayed on a display device and key operations are performed. This is done in such a way that it can be rewritten.

The present invention will be explained below with reference to the drawings. FIG. 1 is a conceptual configuration diagram of a process control device to which the present invention is applied. In FIG. 1, 1 is a computer control device, 2 is an operator operating device, and 3 is a process to be controlled. A computer control device 1 consists of a computer and various interfaces, and controls a process 3 to be controlled.
and sends and receives signals through the marking wiring 4. The operator operating device 2 is connected to the computer by a data transmission line wired under the floor, and communication between the operator and the computer can be performed through a color CRT 21 and keyboards 22 and 23.

FIG. 2 conceptually shows this process control device focusing on the sequence control function. In FIG. 2, 100 is a sequence control device. This sequence control device 100 actually consists of a computer and its peripheral devices, but here it is expressed functionally. In the sequence control device 100, 111 is a sequence table provided in the main memory, in which various information regarding sequence control is written, and the computer uses the information in this table to perform sequence control. do. The sequence table 111 stores a sequence control program, and its detailed configuration will be described later, but briefly,
The sequence table 111 is divided into four parts, vertically, horizontally, and horizontally, with an operation start signal written in the upper left column and an operation signal written in the lower left column. The operation start signal is an input signal that becomes a sequence transition condition, and the operation signal is an output signal given to a controlled object. The sequence operation start condition is written in the upper right column, and the operation command is written in the lower right column. The operation start condition and the operation command are paired with those belonging to the same column, and when the input signal given from the controlled object matches the operation start condition, the operation signal specified by the paired operation command is It is designed to be output to the controlled object. Such operations are performed by a computer program. The next transition destination in the sequence is step counter 112
It is now possible to specify by The step counter 112 is the sequence table 11
1 based on the operation start conditions and the information read out at any time. However, this step counter 112 is conceptual and is actually realized by a computer program. 113,11
3' is an internal switch, and 114 is an internal preset.
A counter, 115 is an internal timer, and 116 is a clock pulse generator. These generate input signals that are checked against the operation start conditions of the sequence table 111, and are provided as many as necessary.
An identification number is attached.

2 is an operator's console, 4 is a message printing device, 34 is a contact input device, 35 is a pulse input device, 36 is a contact output device, 37 is an analog input device, 38 is an analog output device, and 190 is a feedback control device. In the feedback control device 190, 191 is a control unit;
192 is a switch unit, 193, 193'
is a manually operated unit. Operator's console 2 operates internal switch 113, internal preset counter 114 and internal timer 115.
Setting values can be manipulated. Message printing device 4
is operated by the output signal of the sequence table 111 to print a predetermined message. The contact input device 34 inputs a contact signal according to the state of the controlled object into the sequence table 111. The pulse input device 35 inputs a pulse signal corresponding to the state of the controlled object to the internal preset counter 113. Contact output device 36 is sequence table 1
A contact signal corresponding to the operation signal given from 11 is output to the controlled object. The analog input device 37 inputs an analog signal corresponding to the state of the process to the feedback control device 190, and the analog output device 38 operates the process in response to the analog output signal given from the feedback control device 190. A control unit 191 of the feedback controller 190 provides an alarm signal or the like to the sequence table 111 as an input signal. sequence·
An operation signal is given to the switch unit 192 from the table 111, and the manual operation devices 193, 19
Switch 3'. Feedback control device 190
is controlled by a sequence control device and performs batch control, etc. Contact input device 34, pulse input device 3
5, contact output device 36, analog input device 37,
A necessary number of analog output devices 38 and feedback control devices 190 are provided, and each is given an identification number.

The column structure of the sequence entry form for creating the sequence table 111 is shown in FIG. The column structure of this sequence entry form is the same as the structure of the sequence table 111. In Figure 3,
A is the table number entry field, B is the title entry field,
C and M are columns for entering the number of the following table, D is a step number entry column, E and F are operation start signal columns, G is an operation start condition column, H and I are operation signal columns, J is an operation command column, K , L are step number designation fields. In operation start signal columns E and F, the tag numbers or combinations of tag numbers and additional conditions for all operation start signals in one sequence control are entered in column E, and the combinations of tag numbers and additional conditions are entered in column F. An explanatory text is entered. In the operation start condition column G, operation start conditions based on a combination of operation start signals are entered. In the operation signal columns H and I, H
In the column, tag numbers or combinations of tag numbers and additional conditions are entered for all operation signals in one sequence control, and the I
Explanations of those signals are entered in the columns. In the operation command column J, a combination of operation signals to be output when the operation start condition is satisfied is entered. Both the operation start condition and the operation command are arranged in one vertical column, each forming one condition and command, and those in the same column form a pair. Then, when an input signal matching the operation start condition is received, an operation output based on this pair of operation commands is output. For example, enter "1" in the G column and J column as "Y" for the binary signal.
(Yes), write “0” as “X” (No), and write “Don't Care” in a blank space or with a Z mark. Such entries can be easily made by a person who is familiar with relay logic type sequence controllers, pinboard type sequence controllers, or computers, or even by a person who is not familiar with any of them. Up to 32 operation start signals and operation signals can be entered on one entry form. If there are more signals, each can be recorded on a separate sheet. If you write the operation start signal on a separate sheet, write the table number of that sheet in column C; if you write only the operation signal or both the operation start signal and the operation signal on separate sheets,
Write the table number of the paper in column M. These considerations are made so that separate sequence tables can be integrated and used in a computer. Also, when there are 32 or more pairs of operation start conditions and operation commands, a separate sheet is used and the table number is written in column C. The identification number of the sequence step is entered in the step number field D, and the identification number for designating the next sequence step is entered in the step designation fields K and L. By using these, it is possible to define a plurality of pairs of operation start conditions and operation commands in the same step, and to branch the next step in a plurality of ways depending on the input signal. Of the step designation columns K and L, K indicates the transition destination when the input signal matches the operation start condition (THEN), and L indicates the transition destination when the input signal does not match (ELSE). If the sequence is simple, these fields may not necessarily be used.

The sequence entry form filled out in this way is compiled and given to the computer, and as a result, a sequence table 111 as shown in FIG. 2, which is the same as the contents of the sequence entry form, is stored in the main memory as data. - Formed as a base. Using this sequence table 111, the computer compares the input signal with the operation start condition, and performs sequence control while generating the output specified by the operation command according to the result. Sequence tables have a structure very similar to decision tables often used in the field of computer software, so they can be handled with relatively simple programs.

Such a sequence control device has the following characteristics.

(1) Since the description of the sequence control contents is in a table format, it is easy to understand and describe for experts and non-experts of any type of sequence control device. Additionally, the sequence table can be used as is as a specification for sequence control. Therefore, in other words, once the sequence control specifications are written, the design of the sequence control device is virtually completed.

(2) Sequence control contents may be described in the order of thought.

(3) It is easy to expand the scale of sequence control;
It is highly flexible as it is easy to add, delete, and change processes.

Now, maintenance of such a sequence control device will be explained as follows. During maintenance, the operator operates the keyboard 23 of the operator operating device 2 to call up a desired sequence table in the computer control device 1 and display it on the CRT 21. An example of the screen displayed on the CRT 21 is shown in FIG. The operator rewrites a desired part of such a screen by operating the keyboard 23. An example of the keyboard 23 is shown in FIG. Among the various keys in FIG. 5, only those related to the following explanation are pointed out: 231 and 232 are selection keys, 233 is a display key, and 234 is an entry key.
The key 235 is a tag number key.

Rewriting is performed as follows. Operation explanatory diagrams are shown in FIGS. 6 to 9. When you press the selection key 231 or 232, an arrow will appear on the screen (6th
figure). This arrow can be moved upward or downward by pressing the selection key 231 or 232, respectively, so press either one to move the arrow to the item you want to rewrite. If we were to rewrite the operation start signal number 14, we would align the arrow with it.

Next, when the display key 233 is pressed, the tag number and rule for the operation start signal No. 14 are displayed in the area at the bottom of the screen (Fig. 7).

Next, operate the tag number key 235 to specify a new tag number and a new rule for the operation start signal No. 14 (FIG. 8). New tag numbers and rules are written under the original tag numbers and rules as keys are operated. This makes the contrast between old and new clear. The instructions for the rules are the same as the instructions for filling in the sequence table shown in Figure 3. Press keys X and ``0'', ``1'', and ``ignore'' respectively.
Instruct with Y and Z.

When all instructions regarding the operation start signal No. 14 are completed, the entry key 234 is pressed after confirming the contents. As a result, number 14 in the operation start signal field changes to the new tag number and rule (Figure 9).

If other items need to be rewritten, the same procedure is used to rewrite them. When all desired items have been rewritten, key W among tag number keys 235 is pressed. As a result, the contents of the new sequence table that have been rewritten are transferred to the computer control device 1. Thereafter, the computer control device 1 performs sequence control according to the new sequence table. After the transfer of the sequence table is completed, the same table is displayed on the CRT 21 again, and the operator reconfirms it.

When the sequence table is displayed on the CRT 21, a strip-shaped display section B appears at the border between the operation start condition field and the operation command field at the center of the screen. In the display section B, each band partially changes color, and the current status of the sequence step is indicated by the color.
If the next step is not specified in the THEN or ELSE columns, red color represents the step where the operation start condition is met, and green color represents the step where the operation start condition is not satisfied. When the next step is specified in the THEN or ELSE column, the step that is being executed when the operation start condition is met is shown in red, the step that is being executed when the operation start condition is not met is shown in green, and the step that is not being executed is shown in red. Represented in yellow.

Therefore, based on this display, the operator can diagnose the control situation based on the new rewritten sequence table. If a defect is found as a result of the diagnosis, the sequence table is corrected again using the same procedure as described above.

As described above, in the present invention, the sequence table that stores the sequence control program is
Since maintenance is performed by copying the contents onto a CRT and rewriting the contents using key operations, the correspondence between transition conditions and operation outputs is obvious at a glance, and maintenance work can be carried out by specialists or non-specialists in any type of sequence control device. It is extremely easy to perform even for experts.

Additionally, since the current status of the sequence is displayed on the CRT, it is easy to conduct trial or actual operation of the plant and maintain the sequence online while observing the process.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a process control device to which the present invention is applied, Fig. 2 is a conceptual diagram of the device in Fig. 1 rewritten with a focus on sequence control functions, and Fig. 3 is a configuration diagram of a sequence table. , FIG. 4 is an example of a CRT screen, FIG. 5 is an example of a keyboard, and FIGS. 6 to 9 are illustrations of operations.

Claims (1)

[Scope of Claims] 1. For each step of the sequence, an operation start condition consisting of a sequence step number of that step, a combination of a binary signal and an ignore signal that are transition conditions from that step to the next step; An operation command consisting of a combination of a binary signal and an ignore signal that determines the output signal that pairs with this operation start condition, and the next sequence step number that pairs with this operation command are recorded on the sequence recording medium. A computer that stores information as a sequence table, which is connected to this computer via a data transmission line and displays the contents of the sequence table, and also converts the contents of this sequence table into a binary signal and an ignored signal according to the operator's instructions. an operator operating device having a color CRT and a keyboard configured to be able to be rewritten by a combination of the following: when the sequence table is projected onto the color CRT, the operator operating device performs operations at the center of the color CRT screen; A sequence control device characterized in that a strip-shaped display section is displayed at the boundary between a start condition column and an operation command column, and the strip-shaped display section partially changes color to display the current status of the sequence step by the color. .