JPS60189037A - Special unit of programmable controller - Google Patents

Abstract

PURPOSE:To cope freely with an abnormal signal by providing a special unit with a power supply detecting circuit and inputting the abnormality signal of a CPU unit to a microprocessor through a data bus. CONSTITUTION:A power supply detecting circuit 4b detects fall of the voltage in a special unit 2 to output the abnormality signal and resets a processor 3b to stop the special function. An abnormality signal 5 from a CPU 1 is inputted to the processor 3b in the special unit 2 through a data bus 6. The processor 3b can discriminate normalcy/abnormality of the CPU unit 1 under the normal function. Thus, the processor 3b discriminates the abnormality signal of the CPU unit 1 inputted through the data bus 6 and the abnormality signal of the special unit 2 inputted from the power supply detecting circuit 4b and executes corresponding abnormality processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to a special unit for a programmable controller.

[Prior art]

Conventionally, there has been a device of this type as shown in FIG.

1 is a central control unit (CPU) that controls the entire programmable controller, and 2 is a special unit that includes a microprocessor 3a. 4a is a power supply detection circuit, and 5 is an abnormality signal output from the CPU unit l.

Next, the operation will be explained. The microprocessor 3a within the CPU unit 1 executes sequence processing in a preprogrammed order. The special unit 2 is for realizing functions that cannot be executed by normal sequence processing, and is equipped with a built-in microprocessor 3b.
to perform special functions. Microprocessor 3al-1 in CPU unit 1: When a drop in the power supply voltage is detected by the power supply detection circuit 4a and when the hardware reset switch is activated, the microprocessor 3a is automatically reset. There is a delay and the execution of sequence processing stops.

Microprocessor 3bu, CPU in special unit 2
An abnormality signal 5 from the unit 1, i.e., a drop in the power supply voltage, activation of the reset switch in the CPU unit 1, an abnormality in sequence processing execution, or other hardware abnormality causes a reset to occur automatically, and a special function is executed. stop.

Conventional special units are configured as described above, so if an error occurs in the CI)U unit, the sequence processing execution of the CPU unit will not only be stopped (,
The drawback is that the functions of all 9 special units under the control of the U unit are also stopped.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by equipping a special unit with a power supply detection circuit and inputting an abnormal signal from the CPU unit to the microprocessor via a data bus, The purpose is to provide a special unit that can freely respond to abnormal signals.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, the same reference numerals as in FIG. 1 indicate the same parts, and 6 is a data bus which inputs an abnormal signal from the CPU cornit 1 and is connected to the microprocessor 3b at one end. 4b is a power supply detection circuit that generates an abnormality signal when detecting an abnormality in the power supply of the special unit 2.

Next, the operation will be explained. '1 (L image detection circuit 4b
When detecting a drop in the power supply voltage within the special unit 2, it outputs an abnormality signal, resets the microprocessor 3b, and stops executing the special function.

However, although the abnormality signal 5 from the CPU unit 1 is input to the microprocessor 3b in the special unit 2 via the data bus 6 of the special unit 2, the microprocessor 3bij: Is the CPU unit 1 normal? Abnormality can be determined based on normal function. in this way,
The microprocessor 3b receives an abnormality signal from the CPU unit 1 that is input via the data bus 6 and the power supply detection circuit 4.
The abnormality signals of the special unit 2 inputted from b are determined respectively, and the optimum abnormality processing corresponding to each is executed.

In addition, for the above embodiment, as shown in FIG.
In addition to putting the abnormality signal 5 of the U unit 1 on the data node (6), an interrupt signal for the microprocessor 3b in the →3 special unit Z may be generated by the interrupt circuit 7 that responds to the abnormality request. .

In this case, microprocessor 3 in special unit 2
bi, j, cpup-knit 1 abnormal signal (C can be quickly responded to.

〔Effect of the invention〕

As described above, according to the present invention, since several units are provided in the power supply detection circuit and the abnormality signal of the KCPU unit is placed on the data bus, it is possible to freely respond to abnormalities in the CPU unit. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional special unit and a CPU unit, FIG. 2 is a block diagram of a special unit and a CPU unit according to an embodiment of the present invention, and FIG. 3 is a block diagram of a special unit and a CPU unit according to another embodiment of the present invention. It is a block diagram of a CPU unit. 1. CPU unit, 2. Special unit), 3a. 3b...Microprocessor +4"+4b...Power supply detection circuit, 6...Data bus, 7...Interrupt circuit. In addition, the same reference numerals in the figures indicate the same or equivalent parts. Person Mitsubishi Electric Corporation Representative Patent Attorney 1) Hiroshi Nsui,' (2 others) Figure 3

Claims (2)

[Claims] (1) In a special unit of the program controller connected to the central processing unit that generates an abnormality signal when an abnormality in the power supply is detected, the central processing unit inputs the abnormality signal via the data bus; A special unit for a programmable controller, comprising: a power supply detection circuit that inputs another abnormality signal to the central processing unit when an abnormality is detected in the power supply unit that supplies the central processing unit. (2) The special unit of the programmable controller according to claim 1, wherein the central processing unit receives an abnormality signal from the central processing unit as an interrupt signal.