JPH01112404A - Programmable controller - Google Patents

Abstract

PURPOSE:To monitor the change of input output information and internal memory information without fail by outputting a condition changing signal when the internal memory information is monitored and one of them is changed. CONSTITUTION:A comparing device 8 transfers the information from external equipment, the information outputted to the external equipment and the internal memory information of an internal memory RAM 5 for operation to a RAM 7. The device 8, next, compares the previous data of the RAM 7 and the present data of RAMs 4 and 5 and a comparing result is transferred to a RAM 9. Further, the device 8 detects whether or not the comparing result of the RAM 9 is wholly coincident, and when a different point is detected, the signal of the change point presence is sent to a CPU 1. An action is repeated until the command of monitoring continuation is not executed. On the other hand, the CPU 1 sends a condition change signal through a communication control equipment 6 to a peripheral equipment and the change point is monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a programmable controller, and in particular to shortening the readout time when monitoring internal information with a peripheral device.

[Conventional technology]

Figure 3 shows a conventional programmable controller (PC
This is a block diagram showing the configuration of a central processing unit (hereinafter referred to as CPU) (1), a ROM for program execution (2), a program storage RAM (3), and an input/output information storage RAM (4). , internal memory RAM for calculation
(5) and a communication control device (6) are connected. Here, the input/output information storage RAM (4) stores input information taken in from external devices such as switches and sensors, and output information outputted to external devices such as lamps, solenoids, and valves. The memory RAM (5) stores internal memory information used as a work area for internal calculations.

As shown in FIG. 4, the PC (10) configured in this manner is connected to a peripheral device (2o) by a communication cable (3o), so that various information can be exchanged with each other.

By the way, in the system shown in Fig. 4, P C(
10) When monitoring changes in the main unit's crowd angle information or internal memory information, the peripheral device (2o)
), the information in the input/output information storage RAM (4) and the internal calculation memory RAM (5) is read out, and then monitor data is displayed based on this information. In this case, the peripheral device (2o) reads information → monitor display -
The information on the PC (10) was constantly monitored while repeating the operation of reading information → displaying on the monitor.

[Problem that the invention seeks to solve]

As described above, in the method in which the peripheral device (20) constantly monitors the PC (10) while alternately reading out information and displaying information on the monitor, as the amount of information to be monitored by the peripheral device (2o) increases, The time required from the current information reading to the next information elicitation also becomes longer. For this reason, there is a problem in that it becomes impossible to monitor changes in input/output information or internal memory information that change in a time shorter than the time interval of information reading.

This invention was made to solve the above-mentioned problems, and it provides a PC that can reliably monitor changes in input/output information and internal memory information even when the amount of information to be monitored on peripheral devices increases. The purpose is to obtain.

[Means for solving problems]

The PC according to the present invention monitors input/output information for external equipment and internal memory information used as a work area for internal calculations, and outputs a state change signal when at least one of these pieces of information changes. It is equipped with change monitoring means.

[Effect]

In this invention, only when the information change monitoring means outputs a state change signal, the peripheral device only needs to read the information at the point of change, so even if the amount of information to be monitored increases, the input/output information Changes in internal memory can be reliably monitored.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and the same elements as in FIG. 3 are given the same reference numerals and their explanations will be omitted. Other than these (7) are input/output information storage RAM (4) and internal memory for calculation RA
Information storage RAM 1 that stores the previous contents of M (5)
(8) is a comparison device that compares the contents stored in this information storage RAM (7) with the current contents of the input/output information storage RAM (4) and the internal memory for calculation RAM (5); (9) is the comparison result storage RA that stores this comparison result.
It is M. In this case, the newly added elements (7) and (8
), (9) and cpU(1) correspond to the information change monitoring means of the present invention.

The operation of the present embodiment configured as described above is measured by a comparison device (
8) will be explained below according to the flowchart of FIG. 2 showing the specific processing procedure.

First, in step (101), the comparison device (8) reads the input information taken in from the external device stored in the input/output information storage RAM (4), the output information to be output to the external device, and the internal memory RAM for calculation. The internal memory information in (5) is transferred to the information storage RAM (7), and step (102)
Check whether execution of the transfer program has been completed. If the transfer is not completed, the operation is repeated until it is completed.

Next, the comparison device (8) compares the previous data in the information storage RAM (7) with the current data in the input/output information storage RAM (4) and the internal memory for calculation RAM (5), Comparison results are stored in RAM (9)
Transfer to.

Next, in step (104), the comparator (8) detects whether all the comparison results in the comparison result storage RAM (9) match, and if they all match, these Repeat the comparison operation. On the other hand, if a different point is detected in step (104), c
A signal indicating a change point is sent to p U (1).

Then, in step (tOa), it is checked whether a command to continue monitoring has been issued or not, and the above-described operation is repeated until this command is no longer issued.

On the other hand, c p U (1), which has received the signal indicating that there is a change point, sends the peripheral device (20) (fourth
(Figure) sends a state change signal. The peripheral device (20) that receives this state change signal can monitor the change point by reading the comparison result.

In this way, the peripheral device (20) only needs to wait for a status change signal from the PC (10), and there is no need to read a large amount of information, which takes time as in the conventional monitor method, and the process can be completed in a short time. It is possible to reliably monitor changing input/output information and changes in internal memory.

【Effect of the invention〕

As is clear from the above explanation, according to this invention,
Since the PC itself is equipped with an information change monitoring means, the peripheral device only needs to read the information at the change point when the information change monitoring means outputs a status change signal. This has the effect that changes in input/output information and internal memory information can be reliably monitored even when the amount increases.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a flow chart for explaining the operation of the same embodiment, FIG. 3 is a block diagram showing the configuration of a conventional programmable controller, and FIG. 4 is a connection diagram of this programmable controller with peripheral devices. (1): Central processing unit, (4) Two person output information storage RAM, (5): Internal memory RAM for calculation. (6): Communication control device, (7): Information storage RAM. (8): Comparison device, (9); Comparison result storage RAM. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Monitors changes in input information taken in from external equipment, output information outputted to external equipment, and internal memory information used as a work area for internal calculations, and outputs a status change signal when at least one of the above information changes. A programmable controller characterized by being equipped with information change monitoring means.