JPS6332636A - Starting system for fixed cycle interruption program - Google Patents

Abstract

PURPOSE:To execute the programs having the same interruption level and the same cycle in a fixed cycle by setting a start delay time to each fixed cycle interruption program and eliminating the cycle variance caused by the difference of the program processing times. CONSTITUTION:When two programs A and B having the same interruption level and to be executed in the same cycle T are available, the start delay times of both programs are set at T10 and T20 respectively. Then a fixed cycle table is produced after retrieval of programs and those start delay time are set to this table. When the times T10 and T20 are counted down by 1 to zero, the corresponding program is executed and at the same time the cycle T is set to the fixed cycle table. Thus both programs A and B are executed in the cycle T and therefore the cycle variance due to the difference of processing times between both programs. Then it is possible to execute plural programs having the same interruption level and the same cycle in a fixed cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for starting a periodic interrupt program, such as an application program of a programmable controller, which is executed by interrupt processing at regular intervals.

[Conventional technology]

When starting a fixed cycle program, a fixed cycle table is used in which the cycle T of each program is set.

FIG. 3 shows an example of a periodic table. As shown in the figure, this fixed period table stores the fixed period interrupt program number (interruption) and the period T ('r+, T2 . . . ).

Figure 4 shows the hands and tops for creating a periodic table. In other words, each program is searched at the time of initialization (■
), then create a fixed cycle table (see ■), set the cycle of each program in this table, and complete (see ■).

Based on the fixed-period table thus created, each program is executed according to the procedure shown in FIG.

First, it is determined whether the number of registered programs is zero (
■Reference). Normally, it is not zero, so by interrupt processing by the timer, the cycles (counts corresponding to cycles) of all registered periodic programs are sequentially counted down one by one (see ■).

Next, set all startup flags for programs whose cycles have become zero (see ■), and from then on, processing is performed according to these flags and the priority (interrupt) level of the program (■, ■
reference). In other words, among programs whose period is zero,
Preset all cycles of the program with the highest interrupt level (see ■), perform program startup processing (see ■), and execute the program (see ■). When this process is completed, it is checked again whether or not there are activation flags that have been set. If so, the process is performed starting from the one with the highest interrupt level. This procedure is repeated until there are no activation flags that are set. At this time, if there are a plurality of programs with the same interrupt level and the same cycle, they will be started at the same time and executed in the order of priority registered in the program.

[Problem that the invention seeks to solve]

However, with this method, there is a problem in that if there is variation in the processing time of the first program to be executed at the same interrupt level, there will be a shift in the cycle of the second and subsequent programs.

FIG. 6 specifically shows this point. This means that programs with the same interrupt level and the same period are A in this case.
, B, and program A has a higher registration priority than program B, and program A has a fixed cycle (T) Ej! from the start time t8 of the interrupt processing program shown in FIG.
Later time t. The processing time when executed at tl is time t. An example is shown in which t2 is the processing time after a certain period (T) has elapsed from As a result, a fixed cycle cannot be guaranteed.

Therefore, the present invention eliminates the deviation in the period T due to the difference in program processing time in programs having the same interrupt level and the same cycle as described above, and allows programs having the same interrupt level and the same cycle to be processed at a constant cycle. The purpose is to make it viable bait.

[Means for solving problems]

A startup delay time from a reference time is set for each of the fixed-cycle interrupt programs that have the same interrupt level and are executed in the same synchronization, and each program is started at a fixed cycle after this startup delay time has elapsed. .

[Effect]

By setting a startup delay time for each fixed-cycle interrupt program, programs with the same interrupt level and the same cycle can be prevented from being affected by the execution time of other programs with the same level, and can always be executed at a constant cycle. It should be implemented to improve safety and reliability.

〔Example〕

FIG. 1 is a flow chart for explaining the invention in detail, and FIG. 2 is a time chart for explaining the operation of the invention.

First, in addition to assigning each program number, the operating cycle T and startup delay time Ti from the start of the program are defined in advance by a special instruction (for example, a Prog instruction), and the 1st
Using the hand and neck as shown in the figure, the activation delay time 'ri is set in a fixed periodic table similar to that shown in FIG. After that, as in the conventional case, Ti is counted down by 1, and when it reaches zero, the corresponding program is executed, and at the same time, the period T
By setting the period T in the fixed period table, the corresponding program is executed at the period T. Note that the above program number is given to each program in consideration of the interrupt level, priority order, etc.

FIG. 2 shows the above situation. Here, the programs that have the same interrupt level and are executed at the same period T are A,
An example where there are two programs A and B, and the startup delay time of programs A and B are each set to TlG + T'2o.
It is shown.

In this way, by making it possible to set the startup delay time for the fixed-cycle interrupt program of the programmable controller, programs with the same interrupt level and the same period T can be executed regardless of variations in the execution time of other programs at the same level. , will always be executed exactly with period T.

〔Effect of the invention〕

According to this invention, since it is possible to set the startup delay time for programs with the same interrupt level and the same cycle,
This provides the advantage that programs having the same interrupt level and having the same cycle can be executed at a constant cycle by eliminating cycle shifts due to processing time. This results in the advantage of providing a programmable controller with high stability and reliability.

[Brief explanation of drawings]

Fig. 1 is a flowchart for explaining the invention in detail, Fig. 2 is a time chart for explaining the operation of the invention, Fig. 3 is a schematic diagram showing a fixed periodic table, and Fig. 4 is a fixed periodic table. FIG. 5 is a flowchart for explaining the interrupt processing procedure, and FIG. 6 is a time chart showing an example of operation according to the conventional fixed-period program starting method. Symbol explanation T + T1 + T2 “”” period, T i * T
'to # T20 """Startup delay time, tl, t2
······processing time. W+Figure 2 Figure 2 0 Wahum + 1 Note No. 11! 1 Fill 4 Figure 5

Claims (1)

[Scope of Claims] In a plurality of fixed period interrupt programs having the same interrupt level and executed in the same cycle, a startup delay time from a reference time is set for each of the fixed period interrupt programs, and A fixed-cycle interrupt program startup method characterized by starting each program at regular intervals after a startup delay time has elapsed.