JPWO2020065863A1 - Programmable logic controllers, methods, and programs - Google Patents

Abstract

In the CPU unit (100) of the programmable logic controller, the execution unit (103) executes a program at a set cycle. The device data storage unit (101) stores device values including input values and output values of the program. The history data storage unit (102) stores the update history of the device value. The loop monitor unit (105) determines whether or not there is loop processing in the program, and when there is loop processing in the program, the execution unit (103) updates by executing the instruction in the loop processing. The update history of the device value is stored in the history data storage unit (102).

Description

The present invention relates to programmable logic controllers, methods, and programs.

In order to control the device to be controlled, the programmable logic controller executes each instruction of the program at each scan time, which is a set cycle, and performs an operation using the value indicated by the input signal supplied from the detector. , The output signal based on the value indicating the calculation result is supplied to the device to be controlled. In the programmable logic controller, the value indicating the input signal supplied from the detector and the value indicating the output signal supplied to the controlled device are stored in an area on the memory called a device memory.

For example, the user monitors the data in the device memory via an external device such as a program development tool or a programmable display in order to confirm whether or not the operation of the program of the programmable logic controller is normal. Patent Document 1 describes that a programmable display reads a device value from a device memory at each scan time and displays the read device value on a display.

Japanese Unexamined Patent Publication No. 2003-88411

As described in Patent Document 1, when a conventional programmable logic controller receives a monitor request instructing to read a device memory from an external device such as a development tool or a programmable display, I / O (Input /) Output: Input / output) At the refresh timing, the device memory value specified in the monitor request is sent to the external device. I / O refresh refers to batch exchange of device memory data between a programmable logic controller, a detector, and a device to be controlled. The I / O refresh is executed at the end of the scan time, that is, after all the instructions of the program have been executed.

Here, the data stored in the device memory may be rewritten during the execution of the program. For example, the same device memory value may be sequentially updated in a loop process, which is a process in which a specific process is repeated under a specific condition.

When debugging a program, it may be necessary to check the value of device memory that is updated during loop processing. Since the conventional programmable logic controller returns a response to the monitor request at the end of the scan time, the user cannot confirm the value of the device memory that is sequentially updated in the loop processing. Therefore, in order to check the device memory value that is sequentially updated in the loop processing, the user adds debug code to the program to output the device memory value to the debug log file at any time. I was checking the contents of the log file for debugging after executing. In the past, users had to do this to debug their programs. As a result, the man-hours for debugging the program tended to increase.

The present invention has been made in view of the above circumstances, and enables the user to acquire the update history of device values that are sequentially rewritten in the loop processing without performing complicated work, and the man-hours related to program debugging. The purpose is to reduce.

In order to achieve the above object, in the programmable logic controller of the present invention, the execution means executes a program at a set cycle. The device storage means stores device values including input values and output values of the program. The history storage means stores the update history of the device value. The history management means determines whether or not there is a loop process in the program, and if there is a loop process in the program, the update history of the device value updated by the execution means executing the instruction in the loop process. Is stored in the history storage means.

The history management means of the programmable logic controller of the present invention determines whether or not the program has loop processing, and if there is loop processing in the program, the executing means updates by executing the instruction in the loop processing. The update history of the device value is stored in the history storage means. By providing such a configuration, the user can acquire the update history of the device value that is sequentially rewritten in the loop processing without performing complicated work, and the man-hours related to program debugging can be reduced.

A block diagram showing a hardware configuration of a programmable logic controller and an engineering tool according to an embodiment. Functional block diagram of CPU unit and engineering tool according to the embodiment The figure which shows an example of the user program which concerns on embodiment The figure which shows an example of the input screen of the device monitor of the engineering tool which concerns on embodiment. The figure which shows an example of the execution result screen of the device monitor of the engineering tool which concerns on embodiment. The figure which shows the other example of the input screen of the device monitor of the engineering tool which concerns on embodiment. The figure which shows the other example of the execution result screen of the device monitor of the engineering tool which concerns on embodiment. Flowchart of monitor response processing according to the embodiment Flowchart of monitor response processing according to the embodiment The figure which shows an example of the notification screen of the number of data related to the modification

Hereinafter, the programmable logic controller 1 according to the embodiment of the present invention will be described in detail with reference to the drawings.

(Embodiment)
The programmable logic controller 1 shown in FIG. 1 controls a detector 901 including sensors, switches and the like operating in a production system, a control system and the like, and a controlled device 902 including an actuator, a solenoid valve, an indicator light and the like. The programmable logic controller 1 is supplied from a CPU (Central Processing Unit) unit 100 that controls the entire programmable logic controller 1, an input unit 200 that inputs an input signal supplied from the detector 901 to the CPU unit 100, and a CPU unit 100. It includes an output unit 300 that outputs the output signal to the controlled device 902, and a base unit 400 for mounting each unit.

The CPU unit 100 executes an instruction of the user program 111 described later according to the input signal supplied from the input unit 200, and supplies the output signal to the output unit 300. For example, when the input signal indicating that the sensor of the detector 901 is turned on is input, the CPU unit 100 executes the instruction of the user program 111 and outputs indicating that the actuator of the controlled device 902 is turned on. Output a signal. The CPU unit 100 sequentially starts the instructions of the user program 111 at a set cycle, executes the END instruction which is the last instruction, and then ends the execution of the user program 111. The CPU unit 100 starts executing the user program 111 again in the next cycle. In one cycle, the execution of the user program 111 from the first instruction to the last instruction may be scanned. This set cycle is called the scan time.

Further, when the CPU unit 100 receives a monitor request for a device value from the engineering tool 500 described later, the CPU unit 100 transmits the device value specified in the monitor request to the engineering tool 500.

The device value is a value stored in an area reserved in the memory 110 of the CPU unit 100 called the device memory 113. The device value is a value indicating an input signal supplied from the input unit 200, and is a value indicating an input value of an operation of the user program 111 and an output signal supplied to the output unit 300, and is a value indicating the output signal of the user program 111. Includes the output value of the operation.

The monitor request is a command transmitted by the engineering tool 500 to the CPU unit 100 in order to request reading of the device value of the device memory 113. Further, the response that the CPU unit 100 sends to the engineering tool 500 in response to the monitor request is called a monitor response. The CPU unit 100 sets the specified device value in the monitor response and transmits it to the engineering tool 500.

The CPU unit 100 has a function of transmitting a device value at the time when one scan is completed to the engineering tool 500 as a monitor response. It should be noted that this function is a function conventionally provided in the CPU unit 100.

Further, the CPU unit 100 has a function of transmitting an update history of device values sequentially updated by loop processing to the engineering tool 500 as a monitor response. This function is a characteristic function in the CPU unit 100 according to the embodiment. The loop process is a process of repeating a specific process under specific conditions. Note that the loop processing may be simply referred to as a loop. The details of the monitor request will be described later.

A detector 901 is connected to the input unit 200. The input unit 200 converts the on / off input signal supplied from the detector 901 into a predetermined signal level, and inputs the converted input signal to the CPU unit 100. A controlled device 902 is connected to the output unit 300. The output unit 300 converts the on / off output signal supplied from the CPU unit 100 into a predetermined signal level, and outputs the converted output signal to the controlled device 902.

The CPU unit 100, the input unit 200, and the output unit 300 are mounted on the base unit 400. The CPU unit 100, the input unit 200, and the output unit 300 are connected to a power supply unit (not shown) via the base unit 400, and operate by the electric power supplied from the power supply unit. Further, the CPU unit 100, the input unit 200, and the output unit 300 are connected to each other via the shared bus 410, and communicate with each other via the shared bus 410.

Further, the engineering tool 500, which is a development tool, can be connected to the CPU unit 100 of the programmable logic controller 1. The configuration of the engineering tool 500 will be described later.

The CPU unit 100 shown in FIG. 1 has a hardware configuration of a memory 110 for storing various programs and data, an input / output interface 120 for communicating with the input unit 200 and the output unit 300, and a tool for communicating with the engineering tool 500. The interface 130 and the arithmetic unit 140 that controls the entire CPU unit 100 are provided. The memory 110, the input / output interface 120, and the tool interface 130 are connected to the arithmetic unit 140 via the bus 190, and communicate with the arithmetic unit 140.

The memory 110 includes a volatile memory and a non-volatile memory, and stores various programs and data used when the programs are executed. The memory 110 stores a user program 111 executed for each scan time and a monitor response program 112 for responding to a monitor request received from the engineering tool 500. The user program 111 is an example of the program of the present invention.

The memory 110 further includes a device memory 113. The device memory 113 is an area on the memory for storing the input value and the output value of the user program 111. The input value of the user program 111 is a value indicating an input signal supplied from the detector 901 to the CPU unit 100, and the output value of the user program 111 is a value indicating an output signal supplied to the controlled device 902. The input value and the output value stored in the device memory 113 may be referred to as a device value. Device memory is sometimes referred to simply as a device.

The device value is stored in the area according to the type of data. For example, the area where the value of the input signal is stored is defined as "X", the area where the value of the output signal is stored is defined as "Y", and the area where other values are stored is defined as "D". A plurality of device values are stored in each of the areas of "X", "Y", and "D", and each device value is assigned a number indicating the number of data in the area. There is. For example, when the first number of the "X" area is "1", the data stored in the "X100" is the 100th data in the "X" area.

The user program 111 is a program created by the user in order to cause the programmable logic controller 1 to control the controlled device 902. The user program 111 is executed by the arithmetic unit 140. For example, the arithmetic unit 140 executes the user program 111, performs an calculation using the value indicated by the input signal supplied from the detector 901, and supplies an output signal based on the value indicating the arithmetic result to the controlled device 902. To do.

The monitor response program 112 is a program for transmitting a monitor response including a device value specified by the engineering tool 500 to the engineering tool 500 when the CPU unit 100 receives a monitor request from the engineering tool 500.

Specifically, the monitor response program 112 transmits the specified device value to the engineering tool 500 when the CPU unit 100 requests the device value at the time when one scan is completed from the engineering tool 500. It is a program to do. Further, the monitor response program 112 extracts the loop processing included in the user program 111 when the CPU unit 100 requests the update history of the device value updated by the loop processing from the engineering tool 500. This is a program for transmitting the update history of the device value updated in the loop process to the engineering tool 500. The monitor response program 112 is executed by the arithmetic unit 140.

The input / output interface 120 is a communication interface for the CPU unit 100 to communicate with the input unit 200 and the output unit 300. The input / output interface 120 converts the data supplied from the arithmetic unit 140 into an electric signal, and transmits the converted signal to the output unit 300 via the shared bus 410. Further, the input / output interface 120 restores the electric signal received from the input unit 200 into data and outputs it to the arithmetic unit 140.

The tool interface 130 is a communication interface for the CPU unit 100 to communicate with the engineering tool 500 described later. The tool interface 130 converts the data supplied from the arithmetic unit 140 into an electric signal, and transmits the converted signal to the engineering tool 500 via the communication cable 905. Further, the tool interface 130 restores the electric signal received from the engineering tool 500 into data and outputs it to the arithmetic unit 140.

The arithmetic unit 140 has an MPU (Micro Processing Unit) and executes various programs stored in the memory 110 to realize various functions of the CPU unit 100. For example, the arithmetic unit 140 executes the user program 111 every scan time. Further, the arithmetic unit 140 executes the monitor response program 112 and transmits the monitor response to the engineering tool 500.

The engineering tool 500 is a development tool in which a dedicated application is installed on a personal computer. The engineering tool 500 has a function of monitoring the device value of the CPU unit 100. Therefore, the user can monitor the device memory 113 of the CPU unit 100 by using the engineering tool 500. The engineering tool 500 may further have a program creation function. The engineering tool 500 is an example of the external device of the present invention.

As a hardware configuration, the engineering tool 500 includes a memory 510 for storing programs and data, an input device 520 for detecting a user's input operation, an output device 530 for outputting an image, and a communication interface 540 for communicating with the CPU unit 100. And a computing device 550 that controls the entire engineering tool 500. Each part of the engineering tool 500 is connected by a bus 590.

The memory 510 includes a volatile memory and a non-volatile memory, and stores various programs and data used when the programs are executed. In the embodiment, the memory 510 stores a monitor program 511 for monitoring the device value of the CPU unit 100.

Further, the memory 510 stores device definition information 512 in which the data length for each type of device is defined. The device definition information 512 is information in which the type of device and the data length of one data are defined for each area of the device memory. For example, for the devices of "X" and "Y", the device type is defined as "bit device" and the data length of the device value is defined as 1 bit. For the device of "D", the device type is defined as "word device" and the data length of the device value is defined as 2 bytes (16 bits).

The input device 520 includes an input device such as a keyboard and a mouse, detects a user's input operation, and supplies a signal indicating the detected user's input operation to the arithmetic device 550. The output device 530 includes a display and displays an image based on the signal supplied from the arithmetic unit 550 on the display. The communication interface 540 communicates with the tool interface 130 of the CPU unit 100 via the communication cable 905. The communication interface 540 converts the data supplied from the arithmetic unit 550 into an electric signal, and transmits the converted signal to the CPU unit 100 via the communication cable 905. Further, the communication interface 540 restores the electric signal received from the CPU unit 100 into data and outputs it to the arithmetic unit 550.

The arithmetic unit 550 has a CPU and executes various programs stored in the memory 110 to realize various functions of the engineering tool 500. In the embodiment, the arithmetic unit 550 executes the monitor program 511, transmits the monitor request of the device memory 113 to the CPU unit 100, and displays the contents of the monitor response received from the CPU unit 100 on the display of the output device 530. Display on.

Subsequently, the functional configuration of the CPU unit 100 will be described with reference to FIG. Functionally, the CPU unit 100 includes a device data storage unit 101 that stores device values, a history data storage unit 102 that stores device values that are updated in loop processing, and an execution unit 103 that executes a user program 111. , A command processing unit 104 that performs processing related to device value monitoring, a loop monitoring unit 105 that sequentially acquires the specified device value value in loop processing, and a command transmission / reception unit 106 that transmits / receives commands to / from the engineering tool 500. To be equipped.

The device data storage unit 101 shown in FIG. 2 stores the input value and the output value of the user program 111 at the current scan time, that is, the device value. By the I / O refresh, the input value of the user program 111 supplied from the input unit 200 is written in the device data storage unit 101. Further, by executing the user program 111, the output value output by executing the user program 111 is written in the device data storage unit 101. The function of the device data storage unit 101 is realized by the device memory 113 of the memory 110 shown in FIG. The device data storage unit 101 shown in FIG. 2 is an example of the device storage means of the present invention.

The history data storage unit 102 stores the history of device values updated in the loop process. A device value is written in the history data storage unit 102 by the loop monitor unit 105, which will be described later. The function of the history data storage unit 102 is realized by the memory 110 shown in FIG. The history data storage unit 102 shown in FIG. 2 is an example of the history storage means of the present invention.

The execution unit 103 executes the user program 111 every scan time. Specifically, the execution unit 103 executes each instruction of the user program 111 according to the value indicating the input signal stored in the device data storage unit 101, and stores the calculation result in the device data storage unit 101. After executing the END instruction which is the last instruction of the user program 111, the execution unit 103 notifies the command processing unit 104 that the END instruction has been executed. The function of the execution unit 103 is realized by the arithmetic unit 140 of FIG. The execution unit 103 shown in FIG. 2 is an example of the execution means of the present invention.

When the command processing unit 104 receives a notification from the execution unit 103 that the END instruction, which is the last instruction of the user program 111, has been executed, the command processing unit 104 engineers the monitor response when receiving the monitor request from the engineering tool 500. Process for returning to the tool 500. The function of the command processing unit 104 is realized by the arithmetic unit 140 of FIG. The command processing unit 104 shown in FIG. 2 is an example of the request processing means of the present invention.

In the embodiment, the monitor request received by the CPU unit 100 from the engineering tool 500 includes (1) a monitor request requesting a device value after scanning, and (2) an update history of the device value updated in the loop processing. Includes monitor requests and requests.

(1) Monitor Request for Requesting Device Value after Scanning A monitor request for requesting a device value after scanning is stored in the device data storage unit 101 when the execution unit 103 executes the END instruction of the user program 111. It requests the device value that is present. Hereinafter, a monitor request that requests the device value after scanning is referred to as a normal monitor request. The normal monitor request includes a value that specifies an area of the device, and a start number and an end number that indicate a range to be read in the area.

When the command processing unit 104 has received the normal monitor request from the engineering tool 500 at the time when the execution of one scan of the user program 111 is completed, the command processing unit 104 has the order specified in the normal monitor request as the monitor response to the normal monitor request. Reads the device value from the device data storage unit 101, and outputs the read device value to the command transmission / reception unit 106.

For example, in a normal monitor request, a device value from the start number "100" to the end number "150" of the device "X" and a device value from the start number "50" to the end number "100" of the device "D". Is requested. In this case, the command processing unit 104 outputs data in a state in which the device values of "X100" to "X150" and the device values of "D50" to "D100" are arranged in this order to the command transmission / reception unit 106.

(2) Monitor request for requesting update history of device values updated in loop processing A monitor request for requesting update history of device values updated in loop processing is repeated by the execution unit 103 in the loop processing of the user program 111. It requests the update history of the device value of the updated device data storage unit 101. Hereinafter, a monitor request that requests the update history of the device value updated in the loop processing is referred to as a loop monitor request. The loop monitor request includes a value for specifying an area of the device, a start number and an end number indicating a range to be read in the area, and a value indicating the data length of the device value.

First, an example of updating the device value by loop processing is shown with reference to an example of the user program of FIG. In the loop process, the specified process is repeated a specified number of times. In the example shown in FIG. 3, "FOR 60 ... NEXT" indicates that the instruction repeats the loop 60 times. "MOV X101 D1" in the loop of "FOR 60 ... NEXT" indicates that it is an instruction to store the value of "X101" in "D1". By these instructions, the execution unit 103 repeats the process of storing the value of X101 in D1 60 times.

For example, suppose that a loop monitor request requests that the history of the device value of D1 be read. In this case, the loop monitor unit 105, which will be described later, stores the history of the values stored in D1 in the history data storage unit 102 in the loop repeated 60 times. In order to return the data stored in the history data storage unit 102 to the engineering tool 500, the command processing unit 104 outputs the data to the command transmission / reception unit 106.

“FOR 40 ... NEXT” shown in FIG. 3 indicates that the loop is repeated 40 times. "MOV X102 D2" in the loop of "FOR 40 ... NEXT" indicates that it is an instruction to store the value of "X102" in "D2". By these instructions, the execution unit 103 repeats the process of storing the value of X102 in D2 40 times.

For example, suppose that a monitor request requests that the history of the device value of D2 be read. In this case, the loop monitor unit 105 stores the history of the values stored in D2 in the history data storage unit 102 in the loop repeated 40 times. In order to return the data stored in the history data storage unit 102 to the engineering tool 500, the command processing unit 104 outputs the data to the command transmission / reception unit 106.

Further, "BREAK" in the loop of "FOR 40 ... NEXT" indicates that the instruction is to interrupt the loop. Here, the execution unit 103 executes "BREAK" when the contact is turned on by the input value "X150". By executing "BREAK", the loop of "FOR 40 ... NEXT" is interrupted. As a result, the execution unit 103 exits the loop of "FOR 40 ... NEXT" and executes the next instruction of the loop. When the loop is interrupted, the loop monitor unit 105 stores the history of the device value of D2 until the loop is interrupted in the history data storage unit 102. The command processing unit 104 returns the data stored in the history data storage unit 102 to the engineering tool 500. If the contact is not turned on by the input value "X150", "BREAK" is not executed.

Specifically, when the command processing unit 104 shown in FIG. 2 receives the loop monitor request from the engineering tool 500, the update history of the device value is recorded before the execution of the user program 111 at the next scan time is started. The request, the value specifying the device area, the start number and end number indicating the range to be read in the area, and the value indicating the data length of the device value are output to the loop monitor unit 105. Therefore, at the next scan time, the loop monitor unit 105, which will be described later, stores the update history of the designated device value in the history data storage unit 102. For example, when the specified device value is updated in the loop repeated five times, the loop monitor unit 105 stores the updated five values in the history data storage unit 102.

When the scan is completed, the command processing unit 104 sends the number of data items for each read device stored in the history data storage unit 102 and the update history data of the device value read from the history data storage unit 102 to the command transmission / reception unit. It is transmitted to the engineering tool 500 via 106. After that, the command processing unit 104 deletes the history of device values stored in the history data storage unit 102.

When the command processing unit 104 supplies the fact that the update history of the device value is requested and the information for specifying the device value specified in the loop monitor request, the loop monitor unit 105 first receives the user program 111. The history data storage unit 102 secures an area necessary for storing the device value before the execution in the cycle of is started. Specifically, the loop monitor unit 105 analyzes the syntax of the user program 111, extracts a loop in which the specified device value is updated, and executes the loop once from the specified device value and data length. Calculates the memory storage capacity required to store the specified device value.

For example, suppose that a loop monitor request requests a history of device values of "D1", "D2", and "D3" in the device memory. It is assumed that the data length of these device values is 2 bytes. If the values of the devices "D1" and "D2" are updated once in a loop in the user program 111, the memory storage capacity required to execute the loop once is 4 bytes. is there. Further, it is assumed that the values of the devices "D2" and "D3" are updated once in each of the other loops in the user program 111. In this case, the storage capacity of the memory required to store the device value when this loop is executed once is 4 bytes. In this case, the loop monitor unit 105 needs to store in the memory 110 the information for identifying the loop in which the specified device is updated and the calculated storage capacity of the memory for each loop. The information that identifies the loop is, for example, a step number indicating the execution order of each instruction in the user program 111.

Further, the loop monitor unit 105 is in the process of executing each instruction of the user program 111, and the loop monitor unit 105 is specified to repeat the loop in the user program 111 at the timing when the loop processing is started. The number of times the loop is repeated is determined. The timing at which the loop processing is started is, for example, the timing at which the execution unit 103 executes the FOR instruction indicating the loop processing for the first time. The loop monitor unit 105 stores the history of device values when the loop is executed, based on the number of times the determined loop is repeated and the memory storage capacity required when the loop is executed once, which is calculated in advance. Calculate the storage capacity of the memory required for. After that, the loop monitor unit 105 secures a necessary area in the history data storage unit 102 from the calculated storage capacity of the memory.

In this way, the number of repetitions is determined at the timing of starting the loop because the actual number of repetitions cannot be determined until the timing of starting the loop. This is due to the following reasons. This is because the loop of the user program 111 may not be executed depending on the input value. The user program 111 realizes a circuit of a relay sequence, and each instruction is executed when a contact is turned on according to an input value. On the other hand, the instruction is not executed when the contact is turned off according to the input value. Therefore, the loop processing itself may not be executed, or a specific instruction in the loop processing may not be executed. Further, the number of repetitions is not a fixed value, but may be a number dynamically determined by the execution of the instruction of the user program 111.

The loop monitor unit 105 stores the updated value of the device value specified in the loop monitor request in the history data storage unit 102 each time the loop is repeated. Specifically, each time the execution unit 103 executes the NEXT instruction shown in FIG. 3, the loop monitor unit 105 stores the device value specified in the loop monitor request in the history data storage unit 102. Further, the loop monitor unit 105 counts the number of times the loop is repeated.

Further, in the loop in which the execution unit 103 updates the specified device value, the loop break instruction may be executed according to the input value to exit the loop. Once the loop break instruction is executed, the specified device value will not be updated repeatedly. For example, in the example shown in FIG. 3, "BREAK" is executed when the input value "X150" is turned on in the loop of "FOR 40 ... NEXT". In this case, the execution unit 103 exits the loop of "FOR 40 ... NEXT" and executes the next processing of the loop.

When the execution unit 103 executes the loop interruption instruction, the loop monitor unit 105 shown in FIG. 2 corrects the number of repetitions determined before the start of the loop, and uses the corrected number of repetitions as the number of data in the history data storage unit 102. Store. For example, suppose that when the loop monitor unit 105 determines that the number of repetitions is 30 before the start of the loop, the execution unit 103 executes the loop interruption instruction after repeating the loop 15 times. In this case, the loop monitor unit 105 corrects the number of repetitions from 30 to 15. The loop monitor unit 105 corrects the number of repetitions for the following reasons. As described above, since the command processing unit 104 transmits the number of data items to the engineering tool 500 together with the device value stored in the history data storage unit 102, the accurate number of data items is stored in the history data storage unit 102. There is a need. When the loop is not interrupted, the loop monitor unit 105 stores the number of repetitions determined before the start of the loop as the number of data in the history data storage unit 102 for each designated device. The function of the loop monitor unit 105 is realized by the arithmetic unit 140 shown in FIG. The loop monitor unit 105 is an example of the history management means of the present invention.

Further, despite the fact that the command processing unit 104 has requested the update history of the device value and the information for specifying the device value specified in the loop monitor request has been supplied to the loop monitor unit 105, the user program There may be no loop processing in 111. In this case, since the loop is not repeated, the loop monitor unit 105 stores 0 data items in the history data storage unit 102. Alternatively, even if the loop processing exists in the user program 111, the execution unit 103 may not execute the loop processing because the contact is not turned on depending on the input value. In this case as well, the loop monitor unit 105 stores 0 data items in the history data storage unit 102.

The command transmission / reception unit 106 shown in FIG. 2 receives a normal monitor request or a loop monitor request from the engineering tool 500, and outputs the received normal monitor request or loop monitor request to the command processing unit 104. Further, the command transmission / reception unit 106 transmits a monitor response in which a header is added to the data including the device value supplied from the command processing unit 104 to the engineering tool 500. The function of the command transmission / reception unit 106 is realized by the tool interface 130 and the arithmetic unit 140 of FIG.

Subsequently, the functional configuration of the engineering tool 500 will be described with reference to FIG. Functionally, the engineering tool 500 displays a command transmission / reception unit 501 that sends / receives commands to / from the CPU unit 100, a monitor request unit 502 that generates a monitor request for a device value specified by the user, and the contents of the monitor response. It is provided with a display unit 503.

The command transmission / reception unit 501 transmits to the CPU unit 100 a monitor request in which a header is added to data indicating the contents of the monitor request supplied from the monitor request unit 502.

Further, the command transmission / reception unit 501 receives the monitor response from the CPU unit 100 and outputs the received monitor response to the monitor request unit 502. The function of the command transmission / reception unit 501 is realized by the communication interface 540 and the arithmetic unit 550 of FIG.

The monitor request unit 502 receives the user's input operation, generates data indicating the content of the monitor request of the device value indicated by the user's input operation, and outputs the data indicating the content of the generated monitor request to the command transmission / reception unit 501. .. The data indicating the content of the loop monitor request generated by the monitor request unit 502 includes data for specifying the device area specified by the user, a start number and an end number, and device value data defined in the device definition information 512. A value indicating the length is included.

Further, when the monitor request unit 502 receives the monitor response from the CPU unit 100 via the command transmission / reception unit 501, the monitor request unit 502 performs the following processing. The monitor request unit 502 calculates the storage capacity of the memory required to store the monitor response data from the number of data items included in the monitor response and the data length of the device value defined in the device definition information 512. .. The monitor request unit 502 secures in the memory 510 an area required for storing monitor response data from the calculated storage capacity of the memory. After that, the monitor request unit 502 stores the monitor response data in the reserved memory 510 area, and notifies the display unit 503 that the monitor response data is stored in the memory 510.

The display unit 503 displays the monitor response data stored in the memory 510 on the display of the output device 530. The function of the display unit 503 is realized by the output device 530 and the arithmetic unit 550 of FIG.

Subsequently, a method for the user to monitor the device value of the CPU unit 100 by using the engineering tool 500 will be described. As shown in FIG. 1, the user operates the input device 520 such as a keyboard and a mouse in a state where the engineering tool 500 and the CPU unit 100 are connected to each other via the communication cable 905 to execute the monitor program 511. to start. The arithmetic unit 550 executes the monitor program 511 in response to the user's operation, and realizes the following functions.

The arithmetic unit 550 displays the input screen of the device monitor as shown in FIG. 4A on the output device 530. On the input screen, the user can select an area of the device to be monitored and enter a start number and an end number indicating the range in the selected area. Furthermore, the user requests the device value after scanning depending on whether or not the check box of "Output the history of the device value in the loop processing" is checked, or the update history of the device value updated in the loop processing is displayed. You can specify whether to request it. On the screen shown in FIG. 4A, the user operates an input device 520 such as a keyboard and a mouse to select a device to be monitored, inputs a start number and an end number indicating a range in the area, and clicks a "send" button. Suppose you press.

In response to the user's operation, the arithmetic unit 550 transmits to the CPU unit 100 a monitor request including a value specifying an area of the selected device and a start number and an end number indicating a range to be read in the area. In the illustrated example, since the check box is unchecked, the arithmetic unit 550 makes a normal monitor request to request the device values of "X100" to "X150" and the device values of "D50" to "D100" to the CPU. Send to unit 100. In response to this, the CPU unit 100 reads the device value specified in the normal monitor request, and sends a monitor response including the read device value to the engineering tool 500. Here, the CPU unit 100 reads and reads the device values of "X100" to "X150" and the device values of "D50" to "D100" from the device data storage unit 101 shown in FIG. 2 in a designated order. The device value is sent to the engineering tool 500.

When the arithmetic unit 550 receives the monitor response from the CPU unit 100, the arithmetic unit 550 displays the result screen of the device monitor as shown in FIG. 4B on the output device 530. In the illustrated example, the arithmetic unit 550 is the number data in the area where each device value is "X" based on the device value received from the CPU unit 100 and the start number and end number input by the user. The device number indicating is also displayed. Further, when the user presses the "save" button, the arithmetic unit 550 saves the device value included in the monitor response received from the CPU unit 100 in the memory 510.

Further, as shown in FIG. 5A, the user selects the area of the device to be monitored on the input screen, inputs the start number and the end number indicating the range in the selected area, and "device value in the loop processing". It is assumed that the check box of "Output the history of" is selected and the "Send" button is pressed. In this case, the arithmetic unit 550 transmits a loop monitor request to request the device values of "Y100" and "Y201" to the CPU unit 100. In response to this, the CPU unit 100 stores the history of the device value specified in the loop monitor request in the history data storage unit 102. The CPU unit 100 transmits a monitor response including a device value read from the history data storage unit 102 to the engineering tool 500. Here, the CPU unit 100 reads the update history data of "Y100" and "Y201" from the history data storage unit 102 shown in FIG. 2 in the updated order, and sets the read device value as an engineering tool. Send to 500.

When the arithmetic unit 550 receives the monitor response from the CPU unit 100, the arithmetic unit 550 displays the result screen of the device monitor as shown in FIG. 5B on the output device 530. In the illustrated example, the arithmetic unit 550 also displays a number indicating the number of times the device value is updated in the loop. Further, when the user presses the "save" button, the arithmetic unit 550 saves the device value included in the monitor response received from the CPU unit 100 in the memory 510.

Next, when the CPU unit 100 receives the monitor request from the engineering tool 500, the monitor response process for returning the monitor response to the engineering tool 500 will be described. The following processing is realized by the arithmetic unit 140 shown in FIG. 1 executing the monitor response program 112.

The arithmetic unit 140 executes the user program 111 every scan time, and determines whether or not a monitor request has been received after executing the END instruction of the user program 111. When the arithmetic unit 140 determines that the monitor request has been received from the engineering tool 500, the arithmetic unit 140 starts the following monitor response processing. The arithmetic unit 140 shall perform monitor response processing in parallel with the execution of the user program 111.

As shown in FIG. 6A, the arithmetic unit 140 determines whether or not a loop monitor request has been received from the engineering tool 500 (step S11). When the arithmetic unit 140 determines that the loop monitor request has been received (step S11; Yes), the arithmetic unit 140 calculates the storage capacity of the memory when the loop is executed once (step S12). Specifically, the arithmetic unit 140 performs parsing of the user program 111, extracts a loop in which the device value specified in the monitor request is updated, and loops from the data length of the device value specified in the monitor request. Determine the storage capacity of the memory required to store the update history data of the device value when it is executed once. The arithmetic unit 140 stores in the memory 110 the information for identifying the extracted loop and the storage capacity of the memory required when the loop is executed.

The arithmetic unit 140 starts the execution of the user program 111 at the timing set as the next cycle. When the arithmetic unit 140 sequentially executes each instruction of the user program 111 and determines that the loop in which the device value specified in the loop monitor request is updated is started (step S13; Yes), the arithmetic unit 140 executes the process of step S14. In step S14, the arithmetic unit 140 determines the number of times the specified loop is repeated, and executes all the loops from the number of times the loop is repeated and the memory storage capacity required for each loop calculated in step S12. In order to calculate the storage capacity of the memory required in this case and store the update history data, an area of the calculated storage capacity is secured in the memory 110 (step S14). Further, the arithmetic unit 140 stores in the memory 110 information for identifying the loop in which the device is updated and the number of times the loop is repeated.

The arithmetic unit 140 executes the instruction in the loop (step S15). The arithmetic unit 140 determines whether or not the interruption instruction has been executed in step S15 (step S16). When the arithmetic unit 140 determines that the interruption instruction has not been executed (step S16; No), the arithmetic unit 140 stores the device value specified in the loop monitor request in the memory 110 (step S17). For example, the arithmetic unit 140 stores the designated device value in the area reserved for storing the update history data of the memory 110 when the loop is executed once. Further, the arithmetic unit 140 counts the number of times the loop is executed, and stores the counted value in the memory 110. When the arithmetic unit 140 determines that the loop has not been repeated the number of repetitions determined in step S14 (step S18; No), the arithmetic unit 140 executes the process of step S15 again.

When the arithmetic unit 140 determines in step S16 that the interruption instruction has been executed (step S16; Yes), the arithmetic unit 140 corrects the number of times the loop is repeated (step S19). For example, if the arithmetic unit 140 executes the interrupt instruction before updating the specified device value in the current loop, the arithmetic unit 140 calculates in step S14 and calculates the number of times the loop is repeated for each device stored in the memory 110. , Correct by counting the number of times the loop is actually repeated. When the arithmetic unit 140 executes the suspend instruction after updating the specified device value in this loop, the number of loop repetitions for each device calculated in step S14 is calculated as the number of times the loop is actually repeated. Correct by adding 1 to the counted value.

Further, after executing step S17, the arithmetic unit 140 determines that the instruction has been executed a specified number of times (step S18; Yes), and when the END instruction is executed (step S20; Yes), it is stored in the memory 110. The data of the update history of the existing device value and the number of data items are transmitted to the engineering tool 500 (step S21). After that, the arithmetic unit 140 deletes the data of the update history of the device value stored in the memory 110, releases the reserved area, and ends the monitor response process.

On the other hand, in step S11, when the arithmetic unit 140 determines that the loop monitor request has not been received from the engineering tool 500 (step S11; No), that is, when the normal monitor request is received, as shown in FIG. 6B, The instructions of the user program 111 are sequentially executed (step S22), the END instruction is executed (step S23; Yes), and then the scanned device value stored in the memory 110 is transmitted to the engineering tool 500 (step S24). ).

As described above, in the programmable logic controller 1 according to the embodiment, it is possible to monitor the device value that is rewritten in the iterative processing of the program. Therefore, when debugging a program, the user does not need to add debugging code to the program or interrupt the execution of the program at any time as in the conventional case. This makes it possible to reduce the man-hours for developing the program.

(Modification example)
In the embodiment, the CPU unit 100 transmits the number of data items and the data to the engineering tool 500 as a monitor response, but the present invention is not limited to this. For example, the CPU unit 100 may notify the engineering tool 500 of the number of data items before transmitting the monitor response. In this case, the arithmetic unit 550 of the engineering tool 500 calculates the memory capacity required for storing the update history data by the loop processing from the notified number of data, and stores the update history data in the memory 510. Can be determined whether or not is possible. Alternatively, the CPU unit 100 may notify the engineering tool 500 of the memory capacity required for storing the update history data calculated from the number of data items before transmitting the monitor response.

When the arithmetic unit 550 determines that the update history data can be stored in the memory 510, the arithmetic unit 550 may send a notification to the CPU unit 100 that the monitor response can be received. On the other hand, when the arithmetic unit 550 determines that the update history data cannot be stored in the memory 510, the arithmetic unit 550 may send a notification to the CPU unit 100 to cancel the reception of the monitor response. In such a configuration, it is possible to prevent the CPU unit 100 from transmitting a large amount of data that cannot be stored in the memory 510 of the engineering tool 500 to the engineering tool 500.

Alternatively, the arithmetic unit 550 of the engineering tool 500 sets information indicating whether or not prior notification is required regarding the number of monitor response data when transmitting the monitor request, and sends the monitor request to the CPU unit 100. It may be sent to. In this case, the CPU unit 100 may notify the engineering tool 500 of the number of data items before transmitting the monitor response only when it is necessary to notify the number of data items in advance.

Alternatively, if the arithmetic unit 550 determines that all the update history data cannot be received from the number of data items or the memory capacity notified from the CPU unit 100, the CPU unit can receive a part of the data. You may notify 100. For example, the arithmetic unit 550 may receive only the first half of the update history data, or may receive only the second half of the update history data. In this case, the arithmetic unit 550 may receive data in a range specified by the user.

For example, when the arithmetic unit 550 determines that it is impossible to secure the calculated storage capacity of the memory, it is impossible to acquire all the history of the specified device values as shown in FIG. A message indicating the presence is displayed on the display of the output device 530. In the illustrated example, the arithmetic unit 550 displays the number of cases notified from the CPU unit 100 of 5,000 and the options of the receiving method. Here, the options are to receive only the first half of the data, to receive only the second half of the data, and to cancel the loop monitor request. Here, it is assumed that the user operates the input device 520 to select one of the options and presses "send".

The arithmetic unit 550 transmits an instruction indicating the option selected by the user to the CPU unit 100. When the user selects "receive 2500 cases in the first half", the arithmetic unit 550 sends a notification to the CPU unit 100 that the 2500 cases in the first half are received. Further, the arithmetic unit 550 calculates the storage capacity of the memory required for receiving 2500 data, and secures the area of the calculated storage capacity of the memory in the memory 510. In this case, the CPU unit 100 transmits the data corresponding to the notification from the engineering tool 500 to the engineering tool 500. Alternatively, when the user selects "receive 2500 cases in the latter half", the arithmetic unit 550 sends a notification to the CPU unit 100 that the 2500 cases in the latter half are received. Further, the arithmetic unit 550 calculates the storage capacity of the memory required for receiving 2500 data, and secures the area of the calculated storage capacity of the memory in the memory 510. In this case, the CPU unit 100 transmits the data corresponding to the notification from the engineering tool 500 to the engineering tool 500. Alternatively, when the user selects "Cancel the monitor request", the arithmetic unit 550 sends a notification to the CPU unit 100 to cancel the monitor request. In this case, the CPU unit 100 does not send data to the engineering tool.

In the embodiment, the engineering tool 500 has been described as an example as an external device for monitoring the device value, but the external device may be a programmable display or can communicate with the CPU unit 100. It may be another information processing device.

In the embodiment, as shown in FIG. 3, an example of "FOR ... NEXT" has been described as an instruction indicating the iterative processing, but the instruction for the iterative processing is not limited to this. As another instruction of the iterative process, for example, there is "DO ... WHILE". In this case, the loop monitor unit 105 determines that the loop processing has started when the execution unit 103 executes the DO instruction for the first time. The loop monitor unit 105 determines the number of times the loop is repeated at the timing when the execution unit 103 executes the WHILE instruction for the first time, calculates the required memory storage capacity, and determines the area required for storing the device value. It is secured in the history data storage unit 102. Further, the loop monitor unit 105 may store the device value in the history data storage unit 102.

In the embodiment, the user uses the engineering tool 500 to specify the device value and issues an update history monitor request to the CPU unit 100, but the present invention is not limited to this. The user may issue a monitor request to the CPU unit 100 by designating a loop and a device value. In this case, even if the same device value is updated in a plurality of loops, only the update history in the specified loop can be monitored.

As the recording medium for recording the above program, a computer-readable recording medium including a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, a semiconductor memory, and a magnetic tape can be used.

The present invention allows for various embodiments and modifications without departing from the broad spirit and scope. Moreover, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiment but by the claims. Then, various modifications made within the scope of the claims and the equivalent meaning of the invention are considered to be within the scope of the present invention.

1 Programmable logic controller, 100 CPU unit, 101 device data storage unit, 102 history data storage unit, 103 execution unit, 104 command processing unit, 105 loop monitor unit, 106,501 command transmission / reception unit, 110,510 memory, 111 user program , 112 monitor response program, 113 device memory, 120 input / output interface, 130 tool interface, 140,550 arithmetic unit, 190,590 bus, 200 input unit, 300 output unit, 400 base unit, 410 shared bus, 500 engineering tool , 502 monitor request unit, 503 display unit, 511 monitor program, 512 device definition information, 520 input device, 530 output device, 540 communication interface, 901 detector, 902 controlled device, 905 communication cable.

In order to achieve the above object, in the programmable logic controller of the present invention, the execution means executes a program at a set cycle. The device storage means stores device values including input values and output values of the program. The history storage means stores the update history of the device value. History management means determines whether or not there is a loop in a program, if there is a loop in the program, the update history of the updated device value by executing means executes an instruction in the loop As a result, the updated device values corresponding to the number of times the loop processing is repeated are stored in the history storage means.

The history management means of the programmable logic controller of the present invention determines whether or not the program has loop processing, and if there is loop processing in the program, the executing means updates by executing the instruction in the loop processing. As the update history of the device value, the updated device value corresponding to the number of times the loop processing is repeated is stored in the history storage means. By providing such a configuration, the user can acquire the update history of the device value that is sequentially rewritten in the loop processing without performing complicated work, and the man-hours related to program debugging can be reduced.

In order to achieve the above object, in the programmable logic controller of the present invention, the execution means executes a program at a set cycle. The device storage means stores device values including input values and output values of the program. The history storage means stores the update history of the device value. When the update history of the device value updated in the loop processing of the program is requested , the history management means determines whether or not there is loop processing in the program, and executes it when there is loop processing in the program. As the update history of the device value updated by the means executing the instruction in the loop processing, the updated device value corresponding to the number of times the loop processing is repeated is stored in the history storage means.

The history management means of the programmable logic controller of the present invention determines whether or not there is loop processing in the program when the update history of the device value updated in the loop processing of the program is requested , and loops in the program. When there is a process, the updated device value corresponding to the number of times the loop process is repeated is stored in the history storage means as the update history of the device value updated by the executing means executing the instruction in the loop process. By providing such a configuration, the user can acquire the update history of the device value that is sequentially rewritten in the loop processing without performing complicated work, and the man-hours related to program debugging can be reduced.

Claims (9)

Execution means to execute the program at each set cycle,
A device storage means for storing device values including input values and output values of the program, and
A history storage means for storing the update history of the device value and
It is determined whether or not there is a loop process in the program, and when the loop process is in the program, the update of the device value updated by the executing means executing an instruction in the loop process. A history management means for storing the history in the history storage means and
Programmable logic controller with. The history management means stores, as the update history of the device value, the updated device value corresponding to the number of times the loop process is repeated in the history storage means.
The programmable logic controller according to claim 1. The history management means calculates a storage capacity required to store the update history of the device value according to the number of repetitions of the loop process, and secures the calculated storage capacity in the history storage means. ,
The programmable logic controller according to claim 2. The history management means stores the update history of the device value designated by the external device in the history storage means.
The programmable logic controller according to any one of claims 1 to 3. When the external device requests the update history of the device value, the history management means repeatedly executes an instruction in the loop process of the program in the cycle to be started next. The updated history of the device value is stored in the history storage means as the update history of the device value.
The programmable logic controller according to claim 4. A request processing means for transmitting the update history of the device value stored in the history storage means to the external device is further provided.
The programmable logic controller according to claim 4 or 5. The request processing means calculates a storage capacity required to store the update history of the device value according to the number of times the loop processing is repeated, and transmits the calculated storage capacity to the external device.
The programmable logic controller according to claim 6. A programmable logic controller that executes a program at set intervals
A step of determining whether or not there is a loop process in the program, and
When there is the loop process in the program, a step of storing the update history of the device value which is the input value and the output value of the program and is updated by the execution of the instruction in the loop process in the storage means.
How to do. To the programmable logic controller that executes the program at the set cycle
Determine if there is loop processing in the program
When the loop processing is performed in the program, the storage means stores the update history of the input value and the output value of the program and the device values updated by the execution of the instruction in the loop processing.
program.

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