JPH0439083B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Field of the Invention The present invention relates to a scanning-type programmable controller represented by a relay ladder diagram, and particularly to one that can easily realize the same functions as a drum-type sequencer. .

(2) Prior art and its problems In general programmable controllers such as conventional relay ladder diagrams, a drum-type sequencer (a cam that operates or does not operate around a rotating drum is provided, and this cam It is designed to operate a micro switch,
In order to realize the same control function (new operation signals can be extracted one after another as the drum advances by a certain rotational angle by the progress signal), shift register commands, stepping switch commands,
Programming can be done using a combination of counter instructions and data comparison instructions.

What is essentially required to realize the control function of a drum-type sequencer is information on the conditions of the stepping signal that controls the rotation of the drum and the position of the cam attached to the periphery of the drum. Nevertheless, when trying to implement the functions of a drum-type sequencer using the above-mentioned instructions with a conventional programmable controller, it is necessary to create a very redundant program, making programming cumbersome and prone to errors. There is a problem. In other words, although the final control function is not very complex, the lack of dedicated instructions necessitates the creation of redundant programs that include complex intermediate logic processes. Also, since it includes such intermediate logical processes,
When revising a program to partially change control contents, the contents of the program are extremely difficult to read and therefore difficult to change, and mistakes are likely to occur.

(3) Purpose of the Invention The purpose of the present invention is to provide a programmable controller in which the functions of a drum-type sequencer can be programmed extremely easily in a form that is directly connected to the essence of its control content, eliminating unnecessary intermediate logic processes. Our goal is to provide the following.

(4) Structure and effect of the invention In order to achieve the above object, the present invention provides S, U/D,
A counter means that can arbitrarily control drum counter commands for CK and R, a state memory that can be read out in bits by the user program, and a numerical range in each area associated with each bit of this state memory. a set value table in which data shown is stored; an input means for writing arbitrary numerical range data into the set value table; and when a drum counter instruction read by the counter means is executed, a comparison means that sequentially compares the counted value with each numerical range data in the set value table and determines whether or not the counted value is within the set numerical range; The present invention is characterized in that a state updating means is provided for determining the logic of each bit of the state memory corresponding to data.

According to this programmable controller,
By setting the control conditions for the counter means (referred to as drum counter) in the user program and writing arbitrary numerical range data in the setting value table, each bit of the state memory can be set in the counting operation of the drum counter. Therefore, it changes to "1" or "0", and each bit can be used arbitrarily in the user program.

In other words, the step condition of the drum of the drum type sequencer corresponds to the step condition of the drum counter mentioned above, and the position of the cam provided around the drum corresponds to the numerical range data mentioned above. Programming can be done using almost the same simple logic, and there is no need to program any complicated intermediate logic processes as in the past.

Furthermore, since the numerical range data stored in the setting value table is separated from the series of steps in the user program, it is possible to accidentally rewrite the above numerical range data when changing a part of the user program, or vice versa. There is no possibility of accidentally destroying the user program, and this also makes programming very easy.

(5) Description of embodiments Figure 1 shows a programmable computer to which this invention is applied.
FIG. 2 is a block diagram showing the overall schematic configuration of the controller. This programmable controller is
A CPU 1 (central processing unit) that is the center of overall control, a system program memory 2 that stores system programs executed by the CPU 1, and a working memory 3 that is used by the CPU 1 as a temporary storage area for various variable data. and,
A user program memory 4 in which a sequence control program arbitrarily set by the user is stored, an input/output device 5 including an input interface to which an external input signal is given and an output interface to send out an external output signal; In addition to the buffer memory area for input/output data corresponding to the device 5, there is also an input/output memory 6 for storing other circuit data called internal relays, auxiliary relays, etc. The program console 7 is provided with a program console 7 on which creation inputs and monitor command inputs are performed, and displays at the time of input, monitor displays, etc. are provided.

Incidentally, in a relatively small-scale programmable controller, the CPU 1, system program memory 2, working memory 3, and input/output memory 6 are constituted by a so-called one-chip microcomputer.

As is well known, the execution operation of a user program in this type of programmable controller involves sequentially reading out user instructions from the user program memory 4, and changing the input/output data stored in the input/output memory 6 according to each user instruction. It performs arithmetic processing and updates specified output data according to the result of the arithmetic processing, and also updates the input data given to the input/output device 5 to a specified location in the input/output memory 6 in synchronization with the execution of this user program. At the same time, an operation is performed in which the output data in a predetermined area of the input/output memory 6 is transferred to the input/output device 5 (output update). Output device 5
This means that the sequence state specified by the user program is created in relation to the external output signal output from the controller.

The subject of calculation processing in this user program is not only the input/output data of the input/output device 5, but also the data stored in the input/output memory 6 or working memory 3, which is called an internal relay or auxiliary relay. As is well known.
It is also well known that the memory 3 or the memory 6 can be used to perform processing that handles numerical data, such as so-called timer instructions and counter instructions. In some cases, it is also possible to process shift register instructions and stepping switch instructions.

Next, the drum counter command, which is the main part of the present invention for realizing the same control function as a drum-type sequencer, will be explained. FIG. 2A shows a symbolic representation of a drum counter command on a relay ladder circuit diagram. Also, FIG. B is a table in which the drum counter commands described above are expressed as mnemonics for each word. The drum counter command of this embodiment requires four types of input signals S, U/D, CK, and R. S is a start signal for operating the drum counter. U/D is a signal specifying whether the drum counter is to be operated up or down. CK is a drum counter step signal.
R is a drum counter reset signal. When setting the drum counter instruction as shown in B,
The above input condition signals S, U/D, CK, and R are set in this order as a load command LD, and then DRUM representing a drum counter command is set.

The programmable controller of this invention is
In order to execute the above drum counter command, a setting table 41 shown in FIG. 3 is allocated in the user program memory 4, and a state memory 61 is allocated in the input/output memory 6. In the drum counter instruction of this example, "1"
It is equipped with 10 points of drum output from "10" to "10", and in the setting table 41, an upper limit value area and a lower limit value area are assigned to correspond to each drum output number and to set arbitrary numerical range data. ing. Arbitrary numerical values can be written in the upper limit area and lower limit area of the setting table 41 by operating the program console 7. The status memory 61 also has a 1-bit data area B1 corresponding to each drum output number.
~B10 is assigned.

Then, when the drum counter command is executed, the following processing is performed. First, the count value of the drum counter is controlled according to the above four types of input signals. Next, a comparison calculation is made to determine whether the counted value is within or outside the numerical range data set corresponding to each drum output number. When the count value of the counter is within the set numerical data range, one bit of the state memory 61 of the corresponding output number is
1". Also, if the count value is outside the set numerical data range, the corresponding status memory 61
Set a certain bit to “0”. This state memory 6
Each of the bits B1 to B10 of 1 can be arbitrarily read out by a user program, and can be used as an output signal as it is, or can be used as a signal to be subjected to some logical operation.

The contents of the above processing are shown in the flowcharts of FIGS. 4 and 5. FIG. 4 is a schematic flowchart of the user program execution routine. First, the program counter PC for addressing the user program memory 4 is cleared, and the instruction in the user program memory 4 indicated by the program counter PC is read (step 100,
101). Next, it is checked whether the read instruction is the END instruction inserted at the end of the user program (step 102), and then it is checked whether the read instruction is a drum counter instruction (step 103), and the drum counter instruction is checked (step 103). If it is a counter instruction, it is executed in step 104, and if it is another instruction, it is executed in step 105. After executing the instruction, the program counter PC is incremented in step 106, and the process returns to step 101 to execute the next instruction. When the last END command of the user program is read out, the process proceeds from step 102 to step 107, where the above-described input/output update operation is performed, and then the process returns to the first step 100.

FIG. 5 is a flowchart showing details of the drum counter command execution routine in step 104. This is executed when the DRUM instruction is read from the user program memory 4.
Signals S, U/D,
The states of CK and R are read into the stack, but
First, in steps 200 to 206, the drum counter is controlled according to these signals S, U/D, CK, and R. That is, if the reset signal R is supplied, the counter is reset. Further, when the start signal S and the clock signal CK are supplied, the counter is incremented or decremented according to the signal state of U/D. Next, 1 is set in register i for designating the drum output number, and the first output number "1" is designated (step 207). Next, the numerical range data corresponding to the designated number of register i is read from the setting table 41, and the data is compared with the data of the counter to determine whether it is within the set range (step 208). If it is within the range, bit Bi of the state memory 61 is set to "1" in step 209, and if it is outside the range, bit Bi of the state memory 61 is set to "0" in step 210. Next, in step 211, it is determined whether register i has reached the last output number "10". If it has not reached "10", the contents of register i are incremented by 1 in step 212, and the process returns to step 208. Return to Repeat the above process up to output number "10". This completes the processing for the drum counter command.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an outline of the hardware configuration of a programmable controller according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a drum counter command, and FIG. 3 is an explanatory diagram of a setting table 41 and a state memory 61. , 4 and 5 are flowcharts showing an outline of the software configuration of the programmable controller. 1... CPU, 2... System program memory, 3... Working memory, 4... User program memory, 5... Input/output device, 6... Input/output memory, 7... Program console, 41...
Setting table, 61...Status memory.

Claims (1)

[Claims] 1 S set in the user program,
A counter means that can be arbitrarily controlled by U/D, CK, and R drum counter commands, a state memory that can be read out in bits by the user program, and an area associated with each bit of this state memory. a set value table in which data indicating each numerical range is stored; input means for writing arbitrary numerical range data into the set value table; and when a drum counter instruction read by the counter means is executed; Comparing means for sequentially comparing the counted value of the counter means with each numerical range data of the set value table and determining whether or not the counted value is within the set numerical range; and state updating means for determining the logic of each bit of the state memory corresponding to each numerical range data.