JPH0123801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact logic circuit reader that tracks addresses as they move, and a programmable logic controller equipped with the same.

As with all products, a drawback with conventional low-cost programmable logic controller processors is that low cost is not compatible with ease of programming or maintenance.

If we wanted to keep the price low, it would be difficult to use because it would require programming or status display for each contact.On the other hand, if we wanted to display a logic diagram of multiple contacts on a CRT (cathode ray tube) screen to make it easier to program, We had to devise a processor to decipher this.

Here, an object of the present invention is to provide means for filling the gap between the two.

FIG. 1 is a block diagram of one embodiment of the present invention.

CRT is a CRT display device for displaying the contact logic diagram stored in the contact logic storage device M1;
KB is a keyboard for inputting information regarding each component of the contact logic diagram into the contact logic storage device M1, and M2 stores a program for the CPU (central processing unit) to decode the contents of the contact logic storage device M1. The contact logic decoding program storage device S5 is a storage device for storing the result of converting the contact logic circuit into a logical formula [Last in first out Last
-In-First-Out (hereinafter referred to as LIFO) register...
The stored results require less memory than storing them in an (i, j) matrix...], S3
is a LIFO register (last-in, first-out storage device for storing AND results) that is used to temporarily store the logical product in the process of deciphering the contact logic, and S2 is used to temporarily store the logical sum in the process of deciphering the contact logic. The LIFO register (last-in first-out storage device for storing OR results) S1 temporarily stores the address of the contact logic storage device M1 that was interrupted during the process of decoding the contact logic.
LIFO register (last-in first-out storage device for sequential storage), FLG is a logical sum end storage device that indicates the end of the logical sum operation, MC is a contact logic memory M1
A matrix address count storage device that specifies the execution address within the matrix address counter, MC' is a temporary storage register used as an auxiliary for the matrix address counter (...this is not necessarily required, calculations are made from the matrix address counter storage device MC). ), CT is a logical result storage device in which intermediate results of logical operations are stored, CT′ is a logical result auxiliary storage device used as an auxiliary for the logical result storage device CT, and INPUT is an external An interface for obtaining more contact information, OUTPUT is an interface for giving coil information to the outside,
BS1 is a start button switch that gives the timing to start execution, and BS2 is a stop button switch that gives the timing to stop execution.

The logical result storage device CT is necessary to store the result of the previous logical operation and use it for the current logical operation, and the logical result auxiliary storage device CT' stores information from the last-in first-out storage device S3 for storing the logical product result. When extracted, this is memorized and the logical result storage CT
The temporary storage register MC' is necessary to perform logic with the information of This is used to calculate the execution coordinates, and is not necessarily necessary, but is provided to make the execution state easier to understand.

Therefore, when there is no temporary storage register MC′, the matrix address count storage device MC
There is a signal flow (indicated by dotted lines) from to the sequential storage last-in-first-out storage S1.

FIG. 2 is a contact logic diagram for this embodiment.

This shows an example of a contact logic diagram displayed on a CRT display.

The screen is divided into a two-dimensional matrix of (i, j)=(3,8), and each element of the matrix can display at most one component of the contact logic diagram.

The components of the contact logic diagram consist of the following 12 types.

The contact point is... -‖- (normally off logic element), ―‖／― (normalion logic element), The output coil is... -○ (coil logic element) The connection is... − (horizontal extension logical element), | (vertical extension logical element), 〓(downward branch logic element), 〓 (upward branch logic element), 〓 (right branch logical element), 〓 (left branch logical element), 〓 (crossover logic element), 〓(rightward bending logic element), 〓(Left bending logic element) Each is shown with .

FIG. 3 shows the contact logic storage device M1 of this embodiment.
FIG.

At each address, an instruction code and operand (only the input number of the contact and the output number of the output coil) corresponding to the component of the contact logic diagram are stored.

However, only horizontal extension logic elements or downward branch logic elements are allowed for (i, j)=(1, 1).

FIG. 4 is a flowchart of the logic decoding program stored in the logic decoding program storage device M2.

In this flowchart, the symbol ( ) means data stored in the device listed in ( ), the symbol → means storing data, and the symbol -----→ POP means data stored in the LIFO register. The symbol ――――――→ PUSH means to store data as the newest data in the LIFO register, and the symbol ∩ means logical product. (and), and the symbol ∪ means logical sum (or).

By the way, this flowchart shows the temporary storage register.
This is the case when MC' is present, but if this temporary storage register MC' is not present, the calculations in each step are read as follows.

(MC)+1→MC′ is (MC)+1→MC, MC′ ―――――→ PUSH S1 is MC ――――――→ PUSH S1
Then, (MC) + j → MC becomes (MC) −1 + j → MC.

FIG. 5 shows the transition of data held in each device when the example shown in FIG. 2 is executed.

That is, in each column of MC, MC', CT, and CT', the upper left column represents the state before execution, and the lower right column represents the state after execution.

Here, the operation of the present invention will be explained.

The contact logic to be executed is input from the keyboard KB and stored in the contact logic memory M1.

The contents of contact memory M1 are converted into a two-dimensional matrix and displayed on a CRT display.

After confirming that there are no mistakes in the contact logic,
When the start button BS1 is pressed, the central processing unit CPU executes the logic decoding program stored in the contact logic decoding program storage device M2 according to the flow shown in FIG.

While the logic decoding program is running, the central processing unit
The CPU reads instruction codes and operands from the contact logic memory M1, and updates the contents of the logic result storage device CT one after another.

After the last OUTPUT instruction (-○) is executed, the central processing unit CPU presses the stop button BS.
If 2 is not pressed, the command in the contact logic memory M1 is decoded and executed again.

If the stop button BS2 is pressed, the central processing unit CPU stops decoding.

The execution order of the components of the contact logic diagram in Figure 2, which are arranged in a matrix, starts from the upper left ((1, 1) in the matrix), moves downward depending on the type of connection element, and then reaches the lower limit. Go right at a dead end, and move upwards at a right-hand dead end (sometimes moving left).

Execution is terminated by executing the last OUTPUT instruction.

In the above embodiment, only one screen of the contact logic diagram (Figure 2) was explained, but by storing multiple screens of contact logic diagrams in the contact logic memory, it is also possible to decode and execute them continuously. It is.

In this embodiment, the contact logic arranged and stored in a matrix is used as is to perform decoding, but the matrix-like memory arrangement has poor memory utilization.

When storing a large number of screens, it is a good idea to first convert the program into memory-efficient instructions (compile), store the converted program for the large number of screens in other memory, and then run it. Sometimes.

In this case, this can be achieved by converting only the portion related to execution in the flow of FIG. 2 into a compilation routine.

Examples thereof are shown in FIGS. 6 and 7.

Comparing Figures 4 and 6, it can be seen that the logic for tracking is the same, and the only difference is whether the logic is solved or the logic is arranged.

Combining the instruction codes MC, MC', and S1 in FIG. 5 with FIG. 7 will show the transition of the processing results in FIG. 6.

The results are stored in S5, which is a LIFO register, but it does not necessarily have to be a LIFO register, and any storage device that has a function of arranging them in order can be used.

When the contents of the LIFO register S5 are written horizontally, it can be seen that the contact logic circuit diagram is expressed as a logical formula.

(IN2 + IN1) (IN4 + IN3・IN5) (=OUT1) In other words, the logical sum of IN2 and IN1...(a) The logical sum of IN4 and the logical product of IN3 and IN5...(b) The logic of (a) and (b) This means that the product is OUT1.

However, I would like to make an additional comment regarding the step in the routine for moving in the column direction in Figure 6, which says END mark -------→ PUSH S1.

That is, although the LIFO register S1 normally stores a numerical value for storing the order, it is necessary to store this fact only when the trace instruction code downward branch logic element appears. Only when a downward branch logic element appears, a code that can be identified by the central processing unit CPU other than a numerical value, such as a code corresponding to E in alphabet, is pushed into the LIFO register S1 as an END mark.

Alternatively, a value that never appears in the matrix of the contact logic storage device M1, for example 99, may be used as an END mark and pushed into the LIFO register S1.

The present invention can be summarized as follows.

Contact logic elements arranged in a matrix of dimensions (Imax, Jmax) in the storage device, namely normally-off logic elements, normally-on logic elements, coil logic elements, horizontal extension logic elements, vertical extension logic elements, downward branch logic elements, Starting from the starting point of a contact logic circuit consisting of all or part of an upward branch logic element, a right branch logic element, a left branch logic element, a crossover logic element, a right twist logic element, and a left twist logic element. When moving an address, if the contact logical element of the current address (i, j) is a vertical extension logical element or a left branch logical element while moving in the row direction, a crossover logical element is added to (i+1, j). , if it is a right-turning logic element, store the address (i, j+1) in the LIFO register, then (i+1, j) is an upward branch logic element, and if it is a right-turning logic element, then (i, j+1).
If it is a left bending logic element, it moves to the address read from the LIFO register, and while moving in the column direction, the contact logic element at the current address (i, j) is a normally on logic element or a horizontal extension logic element. If so, it will be at (i, j+1), if it is a crossover logic element, left branch logic element, upward branch logic element, or left bend logic element, it will be at the address read from the LIFO register, and if it is a downward branch logic element, it will be at the address read from the LIFO register. j+1) address
After storing in the LIFO register (i+1,j),
Unless it is a coil logic element and the logic circuit is the end
This is a contact logic circuit reader that tracks contact logic circuits by moving the address to the address read from the LIFO register. In other words, the specific invention of the present invention is the block surrounded by the one-dot chain line in FIG.

Furthermore, using this contact logic reading device, if the contact logic element at the current address (i, j) during row direction movement is a crossover logic element or a left branch logic element, the coil information is read from the AND result storage LIFO register S3. The logical sum of the current coil information and the current coil information is used as the new current coil information, and if it is an upward branch logic element or a left bend logic element, new current coil information is obtained in the same manner as above, and then the new current coil information is obtained using the above method. When moving in the column direction, this is stored in the LIFO register S2 for storing the OR result, and if it is a normally-off logic element when moving in the column direction, or a normally-on logic element, the specified signal is kept as it is, or it is inverted and ANDed with the current coil information. and use this as new current coil information,
If it is a crossover logic element, left branch logic element, upward branch logic element, or left bend logic element, store the current coil information in the LIFO register S2 for OR result storage,
The coil information read from the OR result storage LIFO register S2 is used as the new current coil information.
Furthermore, if there is no END mark, the coil information is stored in the OR result storage LIFO register S2 again, and if it is a coil logic element, the current coil information is output to the specified signal, and if the contact logic circuit is not at the end, the OR This is a programmable controller in which the coil information read from the result storage LIFO register S2 is used as new coil information.

Thus, while the conventional method for deciphering multi-contact logic diagrams displayed on a CRT (cathode ray tube) requires dedicated hardware, the present invention provides a means for deciphering them using a particularly inexpensive microcomputer. I believe there are many benefits to this industry.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure is a contact logic diagram of this embodiment, FIG. 3 is a storage state diagram of the contact logic storage device M1 of this embodiment, and FIG. 4 is a flowchart of the logic decoding program stored in the logic decoding program storage device M2. , Figure 5 is a diagram of the transition of data held in each device when the example problem in Figure 2 is executed, and Figures 6 and 7 are diagrams for
It is a flowchart data transition diagram when only the portion related to execution in the flow shown in the figure is changed to a compile routine. CRT...CRT (cathode ray tube) display device, KB...
Keyboard, M1...Contact logical storage device, M2...
...Contact logic decoding program storage device, S5...Storage device for storing the result of converting the contact logic circuit into a logical formula [Last-In-First-Out]
Out (LIFO) register], S3...Used for temporary storage of AND in the process of deciphering contact logic
LIFO register (for AND result storage), S2... LIFO register (for OR result storage) used for temporary storage of OR in the process of deciphering contact logic, S1...
...LIFO register (for sequential storage) in which the address of the contact logic storage device M1 that was interrupted in the process of decoding the contact logic is temporarily stored, MC...Matrix address counter that specifies the execution address in the contact logic storage device M1 Storage device, MC'...Matrix address counter storage device Temporary storage register used as an auxiliary to MC, CT...Logic result storage device in which intermediate results of logical operations are stored, CT'...Logic result storage device CT A logical result auxiliary storage device used as an auxiliary device, INPUT... An interface for obtaining contact information from the outside, OUTPUT...
Interface for giving coil information to the outside, BS1... Start button switch that gives the timing to start execution, BS2... Stop button switch that gives the timing to stop execution, FLG...
...A disjunction end storage device that indicates the end of the disjunction operation.

Claims (1)

[Claims] 1. A central processing unit that controls and manages storage means and input/output means and executes necessary calculations and transfer processing, and normally off, on, coil, horizontal, vertical extension, downward, upward, rightward, left branch, crossover, right,
A contact logic deciphering program storage device that stores a program for deciphering a contact logic consisting of some or all of the logical elements of a left bend, and a storage device for storing a contact logic deciphering program that is provided with information regarding each component of the contact logic diagram to be executed. A contact logic storage device, a first last-in first-out storage device that sequentially stores the results of converting the contact logic circuit into a logical formula, and a matrix address count that specifies an execution address in the contact logic storage device. A contact logic storage device, each comprising: a matrix address count storage device; and a second last-in, first-out storage device for temporarily storing in order the addresses of the contact logic storage device that are interrupted in the process of decoding the contact logic. 1. A contact logic circuit reading device, characterized in that a contact logic circuit made up of contact logic elements arranged within the contact logic circuit is tracked while moving addresses according to the functions of the contact logic elements. 2. A central processing unit that performs the necessary calculations and transfer processing to control and manage storage means and input/output means, and normally off, on, coil, horizontal, vertical extension, downward, upward, rightward, leftward branching, crossover Right side,
A contact logic deciphering program storage device that stores a program for deciphering a contact logic consisting of some or all of the logical elements of a left bend, and a program storage device that stores information regarding each component of the contact logic diagram to be executed. a first last-in, first-out memory for sequentially storing the results of converting the contact logic circuit into a logical formula; and a matrix address count for specifying an execution address in the contact logic memory. a second last-in, first-out memory device that temporarily stores the addresses of the contact logic storage device that are interrupted in the process of deciphering the contact logic; and a second last-in, first-out storage device that stores the results of intermediate logic operations. a third last-in-first-out storage device used for temporary storage of the logical sum and a fourth last-in first-out storage device used for temporary storage of the logical product in the process of decoding the contact logic; and a logical result auxiliary storage device for storing the information extracted from the fourth last-in first-out storage device and performing logic with the information in the logical result storage device, each of which is provided in the contact logic storage device. A contact logic circuit reader is provided, which sequentially decodes the logic according to the functions of the arranged contact logic elements, provides the logic result to a logic result storage device, and converts the contact logic circuit into a logic formula. programmable controller.