JP3358759B2 - Data trace method for programmable controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data trace method for a programmable controller using a processor having a debug interrupt function.

[0002]

2. Description of the Related Art Conventionally, a timing chart of a data trace method of a programmable controller is shown in FIG. As shown in the drawing, a program (hereinafter, a user program unless otherwise specified) is repeatedly executed by the operating system at regular time intervals TS. Access to variables used in the program is executed a plurality of times from the start to the end of the program, for example, at timings indicated by P1 to P4. The data trace process reads the value of the variable specified by the user and records it in the trace buffer.
The history of the recorded variable values is displayed on a monitor device or the like. Here, the timing at which the variable values are read and recorded in the trace buffer, that is, the timing of the data tracing process, is fixed by the operating system, and is generally processed after the end of the program when executing the system program 2 in FIG.

[0003]

When a user of a programmable controller performs debugging or maintenance work on a program, the value of a variable used in the program may not take an expected value. In this case, it is effective to check the address of the program accessing the variable (that is, the program number and the program step number) and the value of the variable at the time of access in order to know which part of the program has the cause. It is. However,
In the prior art, the execution of the data trace processing is fixed at a specific timing. Therefore, when a program accesses a variable more than once from a data trace processing at a certain time to the next data trace processing, the variable during that time is used. There was a problem that it was not possible to grasp the change of. The present invention has been made in order to solve such a problem. Each time a program accesses a variable, the address of the program that executed the program and the value of the variable at that time are automatically recorded. It is an object of the present invention to provide a data tracing method for a programmable controller capable of performing the above.

[0004] In order to solve this problem, the present invention comprises a processor having a debug interrupt function, a memory for storing user programs, variables, and trace data, and a monitor device for displaying the contents of the memory. Specified by the user for tracing in the data trace method of a programmable controller that executes
The address of the variables in the debug registers of the processor
Set and store the user program number, the user program step number, and the value of the variable in the trace buffer each time a debug interrupt occurs upon access to the address, read the contents of the trace buffer, and display the contents on the monitor device. Is what you do.

[0005]

By using such means, the user of the programmable controller can grasp the address of the program executing the variable and the value of the variable at that time every time the variable is accessed by the program.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. A programmable controller 10 includes a processor 11 and a memory 13, and is connected to a monitor device 20. The monitor device 20 is used for setting and displaying data of the programmable controller 10. The processor 11 is connected to the memory 13. The processor 11 has a debug interrupt function like 80486 manufactured by Intel Corporation, for example, and incorporates a debug register 12. If an arbitrary address of data is set in the debug register 12, a debug interrupt can be generated immediately after the address is accessed. The memory 13 has a program 14 and a variable 15
And the trace buffer 16 are stored. Next, the operation of the present invention will be described with reference to FIGS. FIG. 2 is an example of a display screen of the monitor device 20. PN1 to PN4 are program numbers, PS1 to PS4 are step numbers, D1 to
D4 is the value of the variable. In the figure, there are four trace data with one variable name AAAA (indicated by trace numbers 1-4)
An example is shown. The user of the programmable controller sets a variable name while viewing the screen of the monitor device 20. The set variables are converted into absolute addresses recognizable by the processor 11 by the operating system, and then set in the debug register 12.
FIG. 3 is a timing chart showing the operation of the present invention. The program is repeatedly executed by the operating system at regular time intervals TS. During execution of the program, the debug register 12
When the address set to is accessed, the processor 1
1 generates a debug interrupt. The operating system reads the program number (PN1 to PN4) and the program step number (PS1 to PS4) of the program currently being executed and the values (D1 to D4) of the accessed variables in the debug interrupt handler, and reads the trace buffer 16 To be stored. The monitor device 20 reads the data of the trace buffer 16 from the memory 13 and displays the data on the screen of the monitor device.

[0007]

As described above, according to the present invention, each time a variable is accessed by a program, the address of the program executing the variable and the value of the variable at that time can be ascertained. The execution status of a program can be easily monitored during debugging or the like.

[Brief description of the drawings]

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

FIG. 2 is an example of a display screen of a monitor device.

FIG. 3 is a timing chart showing the operation of the present invention.

FIG. 4 is a timing chart showing the operation of the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Programmable controller 20 Monitoring device 11 Processor 12 Debug register 13 Memory 14 Program 15 Variable 16 Trace buffer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05B 19/04-19/05 G06F 11/28

Claims (1)

(57) [Claims] 1. A data tracing method for a programmable controller, comprising: a processor having a debug interrupt function; a memory for storing user programs, variables, and trace data; and a monitor device for displaying the contents of the memory; User traces
Set the address of the specified variable in the debug register of the processor, and store the user program number, user program step number and the value of the variable in the trace buffer each time a debug interrupt occurs when accessing the address. And reading the contents of the trace buffer and displaying the contents on the monitor device.