JPH07117844B2 - Search method for relay coil in ladder diagram display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for displaying a sequence program of a programmable controller in a ladder diagram format and searching for a relay coil corresponding to a predetermined relay contact by the display.

(Prior Art) When machining is performed by a numerically controlled (hereinafter referred to as NC) machine tool, a machine element of the NC machine tool is controlled by a command from an NC device. Many relay circuits have been conventionally used for this control. However, as the controlled object becomes complicated, a programmable controller in which a relay circuit is replaced with a sequence program has come to be used from the viewpoint of cost and reliability. This sequence program is displayed on the display device in a ladder diagram format that includes a combination of relay contacts and relay coils, so when you search for a predetermined relay contact and follow the operating conditions of the corresponding relay coil to search for a fault, It is valid. However, when the size of the sequence program becomes large, the entire ladder diagram cannot be displayed on the display device at one time, so it is necessary to display it in a divided manner, and depending on the sequence program, there may be several tens of screens. In such a case, when trying to search for a trouble, switching of screens becomes complicated and there is a problem that it takes too much time.

Therefore, a series of screen numbers is added to each screen where the relay contact is displayed and each screen where the relay coil is displayed, and the relay coil corresponding to the relay contact is displayed near the displayed relay contact. There has been proposed a method for displaying a screen number and conducting a search (Japanese Patent Application No. 58-88700-Japanese Patent Application Laid-Open No. 59-214908).

FIG. 5 is a diagram showing an example of a screen on which the above-mentioned relay contact is displayed, and FIG. 6 is a diagram showing an example of a screen on which a relay coil corresponding to the relay contact I6 in FIG. 5 is displayed. Is. The screen numbers "AAAA" and "BBBB" are added to each screen, and the screen number "BBBB" is displayed near the relay contact I6. The operator has the number “A
After searching for the relay contact I6 on the "AAA" screen, if you want to check the operating condition of the relay coil corresponding to the relay contact I6, enter the screen number "BBBB" to display the relay coil corresponding to the relay contact I6. The displayed screen can be easily displayed.

(Problems to be Solved by the Invention) In the search method described above, when the number of relay contacts increases, the display space of the screen number displayed in the vicinity of the relay contacts decreases or disappears. It was easy to take. In addition, when the ladder diagram is complicated, it may be necessary to return from the screen displaying the relay coil to the screen displaying the relay contacts.At this time, the operator remembers the screen number where the relay contacts are displayed. There was a drawback in that you had to confirm it.

The present invention has been made under the circumstances as described above, and an object of the present invention is to provide a ladder diagram display in which a screen displaying a ladder diagram can be easily switched to quickly search for a failure. It is to provide a search method for a relay coil.

(Means for Solving the Problem) According to the present invention, a sequence program is displayed in a ladder diagram format including a combination of a relay contact and a relay coil, and a failure search is performed by following an operating condition of the relay coil corresponding to the relay contact. The present invention relates to a method, and when the cursor directs a predetermined relay contact to input a search command, the display range of the ladder diagram currently displayed and the cursor position are stored, and the command is performed. The sequence program including the relay coil corresponding to the relay contact is read, the ladder diagram currently displayed is switched to the ladder diagram of the read sequence program and displayed, and the ladder diagram of the read sequence program is displayed. When a return command is input after the display,
This can be achieved by switching and displaying the read ladder diagram of the sequence program to the stored ladder diagram showing the display range and the cursor position.

(Operation) In the method of searching the relay coil in the ladder diagram display of the present invention, the ladder diagram in which the relay contact is displayed is stored when the relay coil is searched. Therefore, the stored data should be read. Can easily redisplay the ladder diagram.

(Embodiment) FIG. 1 is a block diagram showing an example of a programmable controller that realizes a method for searching a relay coil in a ladder diagram display according to the present invention. A predetermined relay is performed by a cursor movement command CM from a cursor movement command unit 8. The cursor position is controlled to indicate the contact point, and the relay coil search command CLS from the search / return display area switching command unit 9
Alternatively, it has a relay contact instruction cursor control unit 6 for saving or rereading the cursor position PC currently displayed in the ladder display area / cursor position storage unit 7 by a relay contact return command CTS. Further, the sequence program that determines the ladder display range APR1 of the sequence program PR1 from the sequence program storage unit 1 and includes the relay coil corresponding to the relay contact RC pointed by the cursor from the relay contact instruction cursor control unit 6 PR2 is read from the sequence program storage unit 1, the ladder display range APR2 of the read sequence program PR2 is determined, and the current relay coil search command CLS or relay contact return command CTS from the search / return display area switching command unit 9 Displayed sequence program PR1, PR
The ladder display area determination unit 5 saves or reads back the two ladder display ranges APR1 and APR2 in the ladder display area / cursor position storage unit 7. Then, the sequence programs PR1 and PR2 from the sequence program storage unit 1 are loaded into the ladder display range APR1 and APR from the ladder diagram display area determination unit 5.
The ladder diagram display conversion unit 2 for converting into the ladder diagram display data DT according to 2, and the ladder diagram display data DT from this ladder diagram display conversion unit 2 and the ladder diagram according to the cursor position command SPC from the relay contact instruction cursor control unit 6 The ladder diagram display control unit 3 displays the cursor on the ladder diagram display unit 4.

In such a configuration, an example of the operation will be described with reference to the flowchart of FIG. 2, and it is confirmed whether or not to search the relay coil (step S1). For example, the ladder diagram shown in FIG. 3 is currently displayed on the ladder diagram display unit 4, and relay contacts are used to check the operating conditions of the relay coil M2.
When searching for a relay coil corresponding to I6, the operator presses the function key F2 to send a relay coil search command from the search / return display area switching command section 9.
CLS is output, and the ladder display area determination unit 5 and the relay contact instruction cursor control unit 6 store the ladder display area and cursor position (hatched area in the figure) of the sequence program PR1 currently displayed in the ladder display area and cursor position storage. It is evacuated to the section 7 (step S2). Then, in the ladder display area determination unit 5, the relay contact instruction cursor control unit 6
The relay coil corresponding to the relay contact I6 pointed to by the cursor from is determined (step S3), and the sequence program PR2 including the specified relay coil is searched and read in the sequence program storage unit 1 (step S3).
4) Determine the ladder display range APR2 of the sequence program PR2. The ladder diagram display conversion unit 2 converts the sequence program PR2 from the sequence program storage unit 1 into ladder diagram display data DT according to the ladder display range APR2 from the ladder display area determination unit 5, and the ladder diagram display control unit 3
Then, the ladder diagram display data DT from the ladder diagram display conversion unit 2
And according to the cursor position command SPC from the relay contact instruction cursor control unit 6, the ladder diagram as shown in FIG. 4 is displayed on the ladder diagram display unit 4, and the cursor is placed on the first relay contact displayed on the ladder diagram. Display them together (step S5).

Then, when returning to the ladder diagram in which the relay contact I6 is displayed (step S6), the operator presses the function key F3 to output the relay return command CTS from the search / return display area switching command unit 9, and the ladder The display area determination unit 5 and the relay contact instruction cursor control unit 6 read back the ladder display range and cursor position of the sequence program PR1 saved earlier (step S7), and the ladder diagram of the currently displayed sequence program PR2. Further, the ladder diagram of the sequence program PR1 in which the cursor is read back and the cursor are switched and displayed (step S8).

When examining another relay contact, the cursor is controlled to move to that relay contact, and the same operation is performed (steps S9 and S10).

After finishing each of the above operations, it is confirmed whether or not the search for the relay coil by the ladder diagram display is completed (step S11),
When the search for the relay coil by the ladder diagram display is not completed, the process returns to step S1 and the above-mentioned operation is repeated,
When the search for the relay coil by the ladder diagram display is completed, all the operations are completed.

(Effects of the Invention) As described above, according to the method of searching for a relay coil in the ladder diagram display of the present invention, the burden on the operator is reduced, so that accurate fault search can be performed quickly and the number of steps can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a programmable controller that realizes a method of searching a relay coil in a ladder diagram display of the present invention, FIG. 2 is a flowchart explaining an example of its operation, and FIGS. FIG. 5 is a diagram showing an example of a ladder diagram used in the method of the invention, and FIGS. 5 and 6 are diagrams showing examples of ladder diagrams used in the conventional method. 1 ... Sequence program storage unit, 2 ... Ladder diagram display conversion unit, 3 ... Ladder diagram display control unit, 4 ... Ladder diagram display unit, 5 ... Ladder display area determination unit, 6 ... Relay contact instruction cursor Control unit, 7 ... Ladder display area / cursor position storage unit, 8 ... Cursor movement command unit, 9 ...
Search / return display area switching command section.

Claims (1)

[Claims] 1. A sequence program is displayed in a ladder diagram format including a combination of a relay contact and a relay coil, and when a fault search is performed by following an operating condition of the relay coil corresponding to the relay contact, a predetermined relay contact is selected with a cursor. When a search command is input by instructing, the display range of the ladder diagram currently displayed and the cursor position are stored, and the sequence program including the relay coil corresponding to the instructed relay contact is read out to display the current display. The ladder diagram being read is switched to the ladder diagram of the read sequence program and displayed, and when a return command is input during the display after switching, the ladder diagram of the read sequence program is displayed in the stored display range and The special feature is that the ladder diagram showing the cursor position is switched and displayed. Search method of the relay coil in the ladder diagram display to.