KR20130137478A - Programmable logic controller and method for examinating programmable logic controller - Google Patents

Abstract

The present invention relates to a programmable logic controller and a method for testing the programmable logic controller capable of measuring the time for performing a PLC command. The present invention is a PLC for testing PLC performance and measuring command execution time that includes a time measurement part measuring a first time before command execution and a second time after the command execution, and a calculation part calculating the command execution time by using the time for performing command execution control information, and a signal block part blocking an external interrupt signal. [Reference numerals] (AA) Start;(BB,DD) No;(CC,EE) Yes;(FF) End;(S401) Is a time measurement command started?;(S403) Input a test object command;(S405) Is a time measurement command finished?;(S407) Measure performing time for an object command and correct the same

Description

PROGRAMMABLE LOGIC CONTROLLER AND METHOD FOR EXAMINATING PROGRAMMABLE LOGIC CONTROLLER}

The present invention relates to a PLC and a PLC inspection method, and more particularly, to a PLC and a PLC inspection method for measuring the time taken to execute a PLC command.

The automation equipment of the industrial site consists of mechanical equipment using relays and so on. It is difficult to change the internal circuit wiring of the equipment in order to change the automatic equipment constituted by the mechanical equipment. In order to overcome such difficulties, PLC (Programmable Logic Controller) is used.

The PLC uses a semiconductor device such as an integrated device, a transistor, etc. to perform a function of a control device such as a relay, a timer, a counter, and the like. In addition to the basic sequence control function, a numerical operation function is added to enable program control. The PLC performs predetermined logic while circulating the beginning and the end of the program stored in the memory inside the PLC in advance, and the PLC can control the automation facility without changing the internal circuit wiring of the facility.

Since the PLC performs various functions, there are various types of inspections to verify the performance of the PLC. If all of the inspections verifying the performance of the PLC are performed, a long inspection time is consumed, which leads to fatigue of the inspector, thereby increasing the probability of error and excessive inspection cost. Therefore, it is necessary to shorten the inspection time.

The present invention provides a PLC and a PLC inspection method that provides reliability for the instruction processing performance inspection of the PLC so that the user can accurately measure the execution time of the PLC instruction.

In addition, the present invention provides a PLC and a PLC inspection method that can easily measure the execution time of a PLC command within a short measurement time.

According to an embodiment of the present invention, a method of checking a PLC performance by measuring an instruction execution time on a PLC may include measuring a first time before executing the instruction, measuring a second time after the execution of the instruction, and Calculating the command execution time using the first time, the second time, and the waiting time for executing the command.

In addition, the PLC for checking the performance of the PLC by measuring the execution time of the command according to an embodiment of the present invention is a time measuring unit for measuring the first time before executing the command, and measuring the second time after the execution of the command, A calculation unit and an external interrupt signal for calculating the instruction execution time by using a first time, the second time, the time spent on the first time measurement and the second time measurement, and the time of processing the instruction execution control information. And a signal blocking unit for blocking.

According to the present invention, since the user can accurately measure the execution time of the PLC instruction, it can provide reliability in the PLC instruction processing performance check.

In addition, according to the present invention, the execution time of the PLC command can be easily measured within a short measurement time.

1 is a block diagram of a PLC according to an embodiment of the present invention.
2 is a block diagram illustrating a time measurement start command according to an embodiment of the present invention.
3 is a block diagram illustrating a time measurement termination command according to an embodiment of the present invention.
4 is a flowchart illustrating a procedure of preparing a LD program according to an embodiment of the present invention.
5 is a flowchart illustrating a method of measuring an instruction execution time according to an exemplary embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a block diagram of a PLC according to an embodiment of the present invention.

Referring to FIG. 1, the PLC 100 according to an embodiment of the present invention includes time measuring units 101, 105, and 107, a signal blocking unit 103, and a calculating unit 109.

The time measuring units 101, 105, and 107 may measure the first time before executing the command and may measure the second time after the execution of the command. In order to measure the time by the time measuring units 101, 105, and 107, the command execution time measurement command may be used according to an exemplary embodiment. That is, the time measuring units 101, 105, and 107 may measure the start time and the end time of command execution by executing the time measurement start command and the time measurement end command including the target command execution control information, which is the target of execution time measurement. The time measuring unit includes a receiving unit 101, a storage unit 105, and an instruction execution unit 107.

The receiver 101 may receive time measurement start command data and time measurement end command data including target command execution control information.

The time measurement start command data received by the receiver 101 may include information necessary to control the execution of the target command. The command execution unit 107 may execute the target command according to the target instruction execution control information received by the receiver 101. The receiver 101 includes a start enable input unit for receiving a time measurement start enable signal, an input / output parameter number input unit for receiving input / output parameter number information of a target command, and an array type parameter input unit for receiving information regarding whether an input / output parameter is an array type The apparatus may include an array size input unit configured to receive array size information of an input / output parameter, a repetition number input unit configured to receive execution count information of a target instruction, and a measurement target input unit.

The storage unit 105 may store the first time according to the execution of the time measurement start command and the second time according to the execution of the time measurement end command. The first time information may be a target command execution start time, and the second time information may be a target command execution end time.

The command execution unit 107 may execute a target command.

The signal blocking unit 103 blocks the external interrupt signal during the execution of the target instruction so that the instruction execution time can be measured more accurately.

The calculation unit 109 calculates the execution time of the target command by using the first time, the second time, and the waiting time for executing the command received from the receiving unit 101, the storage unit 105, and the command execution unit 107. Can be. That is, by calculating the time difference between the first time and the second time, and then excluding the waiting time for executing the command, it is possible to more accurately calculate the time taken to execute the target command. In this case, the waiting time for executing the command may include, for example, a time taken to process the first time measurement step according to the execution of the time measurement start command, a second time measurement step according to the execution of the time measurement end command, and target instruction execution control information. Can be.

2 is a block diagram illustrating a time measurement start command according to an embodiment of the present invention.

Referring to FIG. 2, a function block 200 of a command to start execution time measurement of a target command may include a start enable input unit 201, an input parameter number input unit 203, and an output parameter number input unit. 205, an array type parameter input unit 207, an array size input unit 209, a repeat count input unit 211, a measurement target input unit 213, and a time measurement start output unit 221.

The start time measurement command according to an embodiment of the present invention is a new command for measuring the time taken for the target command to be executed on the PLC. The developer may include the time measurement start command of the present invention in the PLC program, and the user may write a program including the time measurement start command and run it on the PLC. I / O signals and data types of I / O signals required to execute the start time measurement command are as follows. For reference, BOOL (boolean) type data is 1-bit data and has a data range of '0' or '1', and UINT (unsigned integer) type data has 16-bit data and has a data range of '0 to 65535'. The data type is not limited thereto.

The start enable input unit 201 may receive a signal for changing a state so that the time measurement start command is executed or not. When the start enable input unit 201 receives '1' or 'TRUE', the time measurement start command is executed. When the start enable input unit 201 receives '0' or 'FALSE', the time enable start unit is not executed. 201) may receive BOOL type data.

The input parameter number input unit 203 may receive an input parameter number of a target command. The input parameter means, for example, a parameter formed on the left side of the time measurement command function block 200, and the number of input parameters is seven. When the function block of the command to be measured is assumed as described above, the total number of parameters set in the input unit of the target command function block may be input to the input parameter number input unit 203. The input parameter number input unit 203 may receive data of a UINT type, but is not limited thereto.

The output parameter number input unit 205 may receive an output parameter number of a target command. An output parameter is a sum total of the number of parameters set to the output part of a target instruction function block assuming the function block of a target instruction function. The output parameter number input unit 205 may receive UINT type data.

According to one embodiment of the present invention, in order to measure the execution time of the target instruction, a new instruction called a time measurement instruction is executed. Therefore, in order to calculate the execution time of the target instruction, which is an object of the present invention, it is necessary to refer to the time consumed while executing the time measurement instruction other than the target instruction execution time. The number of input and output parameters described above is used as a reference for calculating the time for input data to be transmitted among the time spent for executing the time measurement instruction, not for executing the target instruction.

The array type parameter input unit 207 receives a signal indicating whether the input or output parameter of the target command is an array type. An array type is a variable whose data type is a variable, which means that several constants are input to one variable. The array type parameter input unit 207 may receive BOOL type data, and at this time, 'TRUE' if the input or output parameter of the target command corresponds to the array type, and 'FALSE' if both the input and output data are not array type. Can be input.

The array size input unit 209 receives the size of the data array only when the array type parameter input unit 207 receives 'TRUE' and '0' when the array type parameter input unit 207 receives 'FALSE'. 'Is input.

The repetition number input unit 211 may receive the number of times the target command execution is repeated only when the target command is repeatedly executed two or more times.

The measurement object input unit 213 may receive data regarding an object of execution time measurement. The execution time measurement target may be a general section as well as an instruction. For example, when the measurement target input unit 213 receives BOOL type data, when 'FALSE' is input, the execution time of the target command is measured as described in the embodiment of the present invention, and 'TRUE' is input. In this case, the general duration of the program is measured, not the instruction execution time.

The time measurement start output unit 221 outputs a signal indicating whether the time measurement start command is executed without error. For example, when the time measurement start output unit 221 outputs the BOOL type data, if the time measurement start command function block 200 executes the time measurement start without error, 'TRUE' is output and an error occurs at the time measurement start. If is generated, 'FALSE' is printed.

3 is a block diagram illustrating a time measurement termination command according to an embodiment of the present invention.

Referring to FIG. 3, the function block 300 of the instruction for terminating the execution time measurement of the target instruction includes an end enable input unit 301, a time measurement end output unit 311, a measurement time output unit 313, and a maximum time. An output unit 315 and a minimum time output unit 317 are included.

The time measurement end command according to the embodiment of the present invention is a new command for terminating the time measurement that is required to execute the target command on the PLC. The data types of the input / output signal and the input / output signal required for executing the time measurement end command are as follows, and the input / output signal is not limited to a specific data type. The developer may include the time measurement end command of the present invention in the PLC program, and the user may write a program including the time measurement end command and run it on the PLC.

The end enable input unit 301 may receive a signal for changing a state so that the time measurement end command is executed or not. When the end enable input unit 301 receives '1' or 'TRUE', the time measurement end command is executed. When the end enable input unit 301 receives '0' or 'FALSE', the end enable input unit is not executed. 301 may receive BOOL type data.

The time measurement end output unit 311 outputs a signal indicating whether the time measurement end command is executed without error. For example, when the time-measuring end output unit 311 outputs BOOL type data, if the time-measuring end command function block 300 executes time-measurement termination without error, 'TRUE' is outputted and an error occurs at the time-measuring end. If is generated, 'FALSE' is printed.

The measurement time output unit 313 outputs a target command execution time. In addition, when two or more times are input to the repetition number input unit 211, the measurement time output unit 313 may output a result obtained by dividing the total time for which the target command is executed by the number input to the repetition number input unit 211. have.

The maximum time output unit 315 outputs the longest time taken for the target instruction to be executed once only when the UINT data input to the repetition number input unit 211 is 2 or more.

The minimum time output unit 317 outputs the least time taken to execute the target instruction once only when the UINT data input to the repetition number input unit 211 is 2 or more. By outputting the maximum time and the minimum time, it is possible to detect an error that occurs when the execution of the target instruction is repeated.

The command function block 200 for starting the execution time measurement of the target command and the command function block 300 for ending the time measurement operate in pairs.

4 is a flowchart illustrating a procedure of preparing a LD program according to an embodiment of the present invention.

Referring to FIG. 4, the time measurement start command function block 200 and the time measurement end command function block 300 operate in pairs, and the order thereof is the same as that of the LD program. LD program represents PLC program using graphic symbols used in relay logic diagram.

First, when the time measurement start command is executed (S401), after inserting the target command (S403), when the target command is executed, the time measurement end command is executed (S405). In order to obtain the execution time of the target instruction, by storing the time of two time points when executing the time measurement start command and executing the time measurement end instruction, the time difference between the two time points is subtracted by excluding the time when the process other than the target command execution is executed. , It is possible to more accurately calculate the target instruction execution time (S407). In this case, while one scan time required for program operation is in milliseconds, while the instruction execution time is in microseconds, it is more accurate and easier to measure the instruction execution time using the instruction. The measurement time can be measured and the measurement time can be shortened.

5 is a flowchart illustrating a method of measuring an instruction execution time according to an exemplary embodiment.

Referring to FIG. 5, when an initialization process such as self-diagnosis, data clear, input image region refresh, etc., which are the first stages of the PLC program, is completed, the program operation process start step is completed (S501).

Subsequently, when the start enable input unit 201 receives an input of '1' or 'TRUE', a time measurement start command is executed (S503). As an embodiment of the present invention, when the time measurement start command is executed, the first time measurement is started prior to the execution of the target command. The time measurement start command data includes input data such as the number of input / output parameters, an array type, and an array size of a target command, which is target instruction execution control information.

Subsequently, an external interrupt signal that may occur while the command is being executed is blocked (S505). By blocking the occurrence of an external interrupt signal while measuring the target instruction execution time, the target instruction execution time can be accurately measured.

Subsequently, the start time can be stored in the CPU memory (S507). When the time measurement start instruction is executed, the execution start time of the target instruction which is the first start time is stored in the CPU memory.

Before the target command is executed, the input parameter number input unit 203, the output parameter number input unit 205, the array type parameter input unit 207, and the array size input unit 209 of the time measurement start command function block 200 are received. Input data such as the number of input / output parameters, array type, array size, etc. of the target instruction is transferred to a register that executes the target instruction (S509). Considering the time the input data is delivered, it is possible to calculate the time consumed in addition to the time the target instruction is executed.

If the number of repetitions is not input to the repetition number input unit 211 (S511), the target command is executed once (S515).

On the other hand, if two or more repetitions are input to the repetition number input unit 211 (S511), the target command is repeatedly executed as many times as the input times (S513). As a result of the target command being repeatedly executed, the average value of the target command execution time may be calculated. Since the execution time calculated as the average value is more accurate than the execution time measured once, the object of the present invention can be achieved.

Subsequently, when the target instruction is executed the number of times input to the repetition number input unit 211, the repetition ends (S517).

When the target command is executed, the end enable input unit 301 receives '1' or 'TRUE' to execute the time measurement end command (S519). When the time measurement end instruction is executed (S519), the execution end time of the target instruction which is the second time is stored (S521). The execution end time may be stored in a register that executes a timed instruction. In addition, after reading the start time stored in step S507 from the CPU memory, the time difference between the end time and the start time can be obtained using the first and second time information. When the execution of the target command is repeated, the average of the execution time can be obtained by dividing the execution measurement time obtained from the time difference between the end time and the start time by the number of repetitions.

Subsequently, the external interrupt signal blocked in step S505 is allowed (S523).

Subsequently, in the time correction step S525, a time other than the execution time of the target instruction is excluded from the execution measurement time. The step of obtaining the measurement time such as reading the execution start time from the CPU memory described above with reference to reference numeral S521 and calculating the time difference from the execution end time, and calculating the average value of the execution time is also performed in the time correction step (S525). Can be executed. The time other than the target instruction execution time is, for example, the time spent for processing the time measurement start and end instructions according to the time measurement start and end information before and after the target instruction processing, the time spent for data transfer, the time spent for array processing, and the like. Include. For reference, time such as time spent in data transfer, time spent in array processing, etc., which is time spent controlling execution of a target instruction, may be calculated by referring to input data.

The measurement time output unit 313 may output the execution time of the target command for which the calculation is completed (S527).

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

100: PLC 101: Receiver
103: signal blocking unit 105: storage unit
107: instruction execution unit 109: calculation unit
200: Start time measurement function block
201: start enable input unit 203: input parameter number input unit
205: output parameter number input unit 207: array type parameter input unit
209: array size input unit 211: repeat count input unit
213: measurement target input unit 221: time measurement start output unit
300: Time Measurement End Command Function Block
301: end enable input unit 311: time measurement end output unit
313: measurement time output unit 315: maximum time output unit
317: minimum time output unit

Claims (4)

In the method of checking the PLC performance by measuring the instruction execution time on the PLC,
Measuring a first time prior to executing the command;
Measuring execution of a second time after the execution of the command; And
Calculating the execution time of the command using the first time, the second time, and a waiting time for executing the command.
PLC inspection method. The method according to claim 1,
Blocking the external interrupt signal further;
PLC inspection method. The method according to claim 1,
Calculating the execution time of the command
Calculating a time difference between the first time and the second time; And
Excluding the time spent in the first time measurement step and the second time measurement step, the time for processing command execution control information, which is a waiting time for executing the command, from the calculated time difference.
PLC inspection method. In PLC that checks PLC performance by measuring instruction execution time,
A time measuring unit measuring a first time prior to executing the command and measuring a second time after the execution of the command;
A calculator configured to calculate the command execution time using the first time, the second time, the time spent on the first time measurement and the second time measurement, and the time of processing command execution control information; And
A signal blocking unit for blocking an external interrupt signal
PLC.

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