JP3352871B2 - Programmable controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
Function chart (Sequential Fanction Char)
The present invention relates to a programmable controller that executes a program instruction according to SFC (hereinafter, abbreviated as SFC), and more particularly to a programmable controller that reduces input / output processing time.

[0002]

2. Description of the Related Art Programmable controllers (hereinafter referred to as PCs)
(Abbreviated as "abbreviated as"), which executes the control program stored in the program memory at high speed (cyclic scan method) to perform input / output processing of many digital and analog signals with various control targets. so,
Public systems such as steel and paper mills, water and sewage,
Or, it is generally used for program control of industrial systems such as an assembly line in the automobile industry.

In a large-scale industrial system, a plurality of PCs are used, and data may be exchanged with each other. In the cyclic scan method, batch input / output processing is performed to update all input / output data each time the control program is scanned once.

As a control program, a ladder diagram-type program instruction is generally used, but recently, an SFC-type program instruction has been used in a mixed manner. FIG. 6 shows an example of a control program using SFC program instructions, which is a control method suitable for step-increment type program control in which the control state sequentially transitions to step numbers n-1, n, n + 1. When the active step (control state) is the step number n, a signal for turning on the external output Y52 is output when the condition R26 by the internal output is turned on. When the condition X60 by the external input is turned on, the control state transits from the step number n to the step number n + 1, and the active step changes. Conventionally, batch input / output processing has been performed even when the above-described SFC program instruction is used.

[0005]

However, in the above-described conventional PC, all input / output data is updated each time the control program is scanned once, and is not necessary in the control state at the time of each scan execution. Since the update is performed including the input / output data, there is a problem that when a large amount of input / output data is handled, the time required for updating the data increases, the scan cycle of the control program increases, and the real-time controllability decreases.

The present invention has been made in view of the above problems, and has as its object to extract input / output points required for controlling each control state of a control program by an SFC, and to extract the extracted input / output points. The object of the present invention is to provide a programmable controller in which data is updated and the input / output processing time is reduced.

[0007]

According to the present invention, a programmable controller scans and executes a control program based on a sequential function chart stored in a program memory. An update target map memory for storing a condition update map for extracting position information of an input / output register to be updated based on the current active step of the current active step. Update the output data. (Claim 1) Further, a condition update map is created by extracting position information of an input / output register to be updated based on the current active step of the sequential function chart each time the control program is scanned, and creating the condition update map. Means for updating the contents of the update target map memory based on the created condition update map. (Claim 2) Further, each time the control program based on the sequential function chart is scanned and executed, the condition update map creating means recognizes the current active step and the input / output instructions of the steps before and after the active step and updates the input and output instructions. A condition update map is created by extracting the position information of the output register. (Claim 3) Further, the condition update map creating means extracts position information of an input / output register to be updated during execution of the control program. (Claim 4) Further, the condition update map creating means extracts the position information of the input / output register to be updated after the scan of the control program is completed. (Claim 5) The control program includes a ladder diagram and a sequential function chart program, and the update target map memory extracts the position information of the input / output register of the control program based on the ladder diagram. And a condition update map memory for storing the condition update map. (Claim 6) Further, there is provided an unconditional update map creating means for extracting the position information of the input / output register of the control program by a ladder diagram to create an unconditional update map. Store it in the update map memory. (Claim 7) Further, the unconditional update map creating means searches the control program for a control program based on a ladder diagram, extracts position information of a register of an input / output instruction based on the ladder diagram, and creates an unconditional update map. I do.
(Claim 8) Further, the unconditional update map creating means creates the unconditional update map before starting scan execution of the control program. (Claim 9)

[0008]

FIG. 1 shows an embodiment of a hardware configuration of a PC according to the present invention, wherein 1 is a PC, 2 is a CPU for controlling the whole PC, and 3 is an operation program. A system memory, 4 is a program memory for storing a control program, 5 is a programmer interface for exchanging information with the programming device 12, and 6 is an input / output register assigned to an input / output signal and data during a calculation. A memory for storing data for determining an input / output register to be updated each time the control program is scanned; and 8, an input / output bus interface. Connected by 10
Is an input / output device (I / I) that exchanges information with external devices.
O) and 11 are transmission devices for performing data transmission with an external device, and these are connected to the input / output bus interface 8 via the I / O bus 13. A programming device 12 loads a control program and monitors the execution state of the program control.

FIG. 2 shows an embodiment of the map memory 7 to be updated. The map memory 7 includes an unconditional update map memory 7a and a condition update map memory 7b. The position (address) information of the input / output register to be updated each time the scan is executed is stored, and the position (address) of the input / output register to be updated in accordance with the position of the active step at that time each time the scan is executed is stored in the condition update map memory 7b. Information is stored, and bit positions (addresses) are assigned to the positions (addresses) of the respective input / output registers.

When the PC is started in the above configuration, C
The PU 2 performs the processing shown in FIG. 3 based on the operation program stored in the system memory 3. First, an unconditional update map creation process 21 is executed, and a search for a control program stored in the program memory 4 is performed. The control program is composed of a ladder diagram and an SFC, and an identification label for discriminating the program system is provided at the head of each ladder diagram and the SFC. The unconditional update map is obtained by retrieving an input / output instruction (input / output register) used for a program part in the ladder diagram and setting 1 to a bit of the unconditional update map memory 7a corresponding to the input / output register. create. Next, initial setting 22 of the condition update map is executed, and 1 is set to all bits of the condition update map memory 7b. Thereafter, the program control activation process 23 is performed, and the scan execution of the normal program control is started.

When the scan execution of the program control is started, first, a batch input / output processing 24 is executed. In the case of the present invention, the batch input / output processing is performed by the unconditional update map memory 7a.
And the input / output register corresponding to the bit position where the bit data of the condition update map memory 7b is set to 1 is to be updated.
Since 1 is set to all bits of b, all input / output data is updated. Next, scan execution processing 25 under normal program control is performed. In the case of the present embodiment, when the execution of one scan is completed, the active step (control state) of the control program by the SFC is determined, so that a process 26 for holding the number of the active step is performed. After that, a condition update map update process 27 is executed,
The program portion corresponding to each of the current active step, the previous step, the subsequent step, and the transition leading to the current active step is set as a search range, and an input / output register existing in any of them is searched. The bit position of the condition update map memory 7b is set to 1 and the others are cleared to 0. Thereafter, the process returns to the batch input / output processing 24, and the scan execution of the program control is repeated. Therefore, in the second and subsequent batch input / output processing 24, the input / output data is updated based on the bit position set in the unconditional update map memory 7a and the condition update map memory 7b updated in the previous scan.

In the SFC operating specification, only the currently active step and the transitions connected under that step are relevant to the current control operation. Also, paying attention to the time when the step transition occurs,
Steps before and after the currently active step also need to be considered as related to the control operation at that time. According to the present embodiment, input / output signals irrelevant to the control operation at that time can be excluded from data update processing, the number of processing points can be reduced, the processing time of batch input / output can be reduced, and scanning can be performed. Time can be reduced.

FIG. 4 shows the details of the unconditional update map creation processing 21. First, in step 21a, a search is started from the beginning of the control program stored in the program memory 4, and in step 21b, whether or not the SFC program is It is determined whether or not. Step 2 if it is an SFC program
Returning to 1a, the next search is performed, and if it is a program other than SFC, it is determined in step 21c whether or not it is an input / output instruction. If it is an input / output instruction, an input / output register used as an operand of the input / output instruction is extracted in step 21d, and 1 is set to a bit position of the unconditional update map memory 7a corresponding to the input / output register. If the program part contains a subroutine,
The input / output registers are similarly extracted from the subroutine, and 1 is set to the corresponding bit position of the unconditional update map memory 7a. FIG. 2 shows an example in which input / output registers at addresses 0 and 1 are marked as unconditional update targets. If it is not an input / output instruction, step 21d is skipped. Step 21e determines whether or not the control program is END.
The same processing is repeated until it returns to END.

FIG. 5 shows the details of the condition update map creation processing 27. First, all bits of the condition update map memory 7b are reset to 0 in step 27a. Next, the instruction word in the program portion corresponding to the active step held in step 27b is examined, the input / output register used as the operand is extracted, and the bit of the condition update map memory 7b corresponding to the input / output register is extracted. Set 1 to the position. When a subroutine is included in the program portion, the input / output registers are similarly extracted from the subroutine, and 1 is set to the bit position of the corresponding condition update map memory 7b. Further, for the steps before and after the active step and the transition connected under the active step, the input / output registers are similarly extracted,
"1" is set to the bit position of the corresponding condition update map memory 7b. For example, when the active step is a step number n as shown in FIG.
1. The external output bit operands Y50, Y52, and Y55 of the current active step n and the succeeding step n + 1, and the external input bit operands X60 and X68 of the transition connected to the current active step n are determined to be updated. External input bit operands X39 and X77
Are determined not to be updated. Since R25 and R26 are internal bit operands, they are not subject to this determination.

The condition update map memory 7b of FIG. 2 stores extracted external output bit operands Y50, Y52, Y5.
5 is a bit operand belonging to address 5 of the output register, and external input bit operands X60 and X68 are bit operands belonging to address 6 of the input register. Therefore, the input / output registers at addresses 5 and 6 are updated, and all the input / output bit operands belonging to them are updated. Thereafter, in step 27d, it is determined whether or not there are any other active steps. The same processing is performed for all the active steps, and the process ends.

In this embodiment, the case in which the selection update map is updated at the end of the execution of each scan has been described. However, the update can be performed during the execution of the scan. Also, S
The input / output registers to be updated corresponding to each step of the FC may be stored in advance as a map before executing the scan, and the input / output registers to be updated may be determined based on the map and the active steps. . In this case, the information of the input / output register to be updated extracted from the control program by another device is received,
It is also possible to store it in the update map memory.

[0017]

According to the programmable controller of the present invention, when executing a sequential, function, or chart control program, only input / output signals related to the control operation at that time are subjected to the batch input / output processing, The number of update data can be reduced, the batch input / output processing time can be reduced, the scan time can be reduced, and real-time controllability can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of hardware of a programmable controller according to the present invention.

FIG. 2 is a detailed configuration diagram of an update target map memory;

FIG. 3 is a flowchart showing processing contents of an operation program.

FIG. 4 is a flowchart showing processing contents of an unconditional update map;

FIG. 5 is a flowchart showing processing contents of a condition update map.

FIG. 6 shows an example of a control program using SFC program instructions.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Programmable controller 2 ... CPU 3 ... System memory 4 ... Program memory 5 ... Programmer interface 6 ... Data memory 7 ... Update target map memory 7a ... Unconditional update map memory 7b ... Condition update map memory 8 ... I / O bus interface 9 ... CPU bus 10 ... I / O device 11 ... Transmission device 12 ... Programming device 13 ... I / O bus 21 ... Unconditional update map creation process 22 ... Initial setting of condition update map 23 ... Program control activation process 24 ... Batch input / output Processing 25: Program-controlled scan execution processing 26: Active step retention 27: Condition update map update processing

Claims (9)

(57) [Claims] 1. A programmable controller that scans and executes a control program based on a sequential function chart stored in a program memory should be updated based on the current active step of the sequential function chart every time the control program is scanned. An update target map memory for storing a condition update map for extracting position information of the input / output register is provided, and the input / output data is updated based on the information of the update target map memory every time a scan is performed. Programmable controller. 2. The programmable controller according to claim 1, wherein each time the control program is scanned, position information of an input / output register to be updated is extracted based on a current active step of a sequential function chart, and the condition update is performed. A programmable controller comprising a condition update map creating means for creating a map, and updating the contents of the update target map memory based on the created condition update map. 3. The programmable controller according to claim 2, wherein the condition update map creating means scans and executes a control program based on a sequential function chart to input and output a current active step and steps before and after the current active step. A programmable controller, which recognizes an instruction, extracts position information of an input / output register to be updated, and creates a condition update map. 4. The programmable controller according to claim 2, wherein said condition update map creating means extracts position information of an input / output register to be updated during execution of the control program. 5. The programmable controller according to claim 2, wherein said condition update map creating means extracts position information of an input / output register to be updated after scanning of the control program is completed. 6. The programmable controller according to claim 1, wherein the control program includes a ladder diagram and a sequential function chart program in a mixed manner, and the update target map memory stores the control program based on the ladder diagram. A programmable controller comprising: an unconditional update map memory for storing an unconditional update map for extracting position information of an output register; and a condition update map memory for storing the condition update map. 7. The programmable controller according to claim 6, further comprising an unconditional update map creating means for extracting position information of an input / output register of a control program by a ladder diagram to create an unconditional update map. A programmable controller storing an unconditional update map in the unconditional update map memory. 8. The programmable controller according to claim 7, wherein the unconditional update map creating means searches the control program for a control program based on a ladder diagram, and extracts position information of a register of an input / output instruction based on the ladder diagram. And generating an unconditionally updated map. 9. The programmable controller according to claim 7, wherein said unconditional update map creating means creates said unconditional update map before starting scan execution of said control program. .