JPH0324840A - Inactivity monitor and control device - Google Patents

Abstract

PURPOSE:To prevent the load from being applied to a central processing unit in the idle state by not interrupting the central processing unit but transmitting a control code to the central processing unit at the time of the absence of transmission data. CONSTITUTION:At the time of the absence of transmission data, an EOT transmitting means 31 does not interrupt a central processing unit 40 but transmits the control code to the unit 40 based on information of an EOT transmission indication flag 33 and gives the indication, which sets transmission information to the transmission indication flag 33, to a transmission report flag setting means 36. This means 36 sets transmission information to an EOT transmission report flag 35 based on this set information. A flag access means 42 of the unit 40 manages the transmission indication flag 33 and confirms information of the transmission report flag 35 based on the control signal outputted from a time counting means 41 at intervals of a prescribed time and initializes this flag thereafter. Thus, the load is not applied to the unit 40 and a control station 10 detects that a device is inactive when the device is in the idle state not to have transmission data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applied to an inactivity monitoring and control device for dependent stations of a polling control system in a communication network system.

In particular, it relates to inactivity monitoring control of a dependent station to reduce the load on the central processing unit in the so-called idle state when the dependent station has no data to transmit, and to allow the central processing unit to monitor the inactivity of the control station. .

〔overview〕

The present invention provides a transmission instruction flag and a control code having information on whether or not to transmit a control code notifying that there is no transmission data for polling reception in a communication control means in an inactivity monitoring and control device for a dependent station. A transmission notification flag is provided with information on which data has been transmitted, and when polling is received, the transmission instruction flag is referred to, and if there is no transmission data, a control code is sent to the control station without interrupting the central processing unit. At the same time, by setting the transmission information in the transmission notification flag and checking the information in the transmission notification flag at predetermined intervals in the central processing unit, it is possible to avoid placing a load on the central processing unit when it is in an idle state with no transmission data. , and it is possible to detect when the control station becomes inactive.

[Conventional technology]

Conventionally, an inactivity monitoring control device for a dependent station generates an interrupt from the communication control means to the central processing unit when it receives polling from the control station, and the central processing unit stops and starts the timer, and the timer until the interrupt occurs. I was watching. Alternatively, if there is no transmission data in response to polling, the communication control means returns a control code (hereinafter referred to as EOT) indicating that there is no transmission data without interrupting the polling.

[Problem that the invention seeks to solve]

However, in such conventional dependent station inactivity monitoring control devices, when polling is received, the communication control means generates an interrupt to the central processing unit, and each time an interrupt occurs, the central processing unit analyzes the interrupt. After recognizing that it is a polling interrupt, the timer is stopped and started, and an EOT transmission instruction is given to the communication control means, which has the drawback of increasing the load on the central processing unit. Alternatively, if the communication control means returns an EOT to the control station in response to polling, the central processing unit determines whether or not it has received the polling from the control station in order to prevent the communication control means from generating an interrupt to the central processing unit. This had the disadvantage that it was not possible to monitor the control station for inactivity.

The present invention solves the above-mentioned drawbacks, and provides an inactivity monitoring and control device that can detect when a control station becomes inactive without placing a load on the central processing unit when it is in an idle state with no transmitted data. The purpose is to provide.

[Means for solving problems]

The present invention is provided in a slave station of a polling control system connected to a control station via a communication network, and includes a central processing unit and a transmitting means for receiving polling and transmitting a control code to the control station when there is no data to be transmitted. In the inactivity monitoring control device, the communication control means includes a first storage means including a transmission instruction flag having instruction information for transmitting the control code in response to polling;
a second storage means including a transmission notification flag having information indicating that the control code has been transmitted, and the transmission means transmits the control code based on the information of the transmission instruction flag when polling is received. and includes means for instructing the transmission notification flag to be set, the communication control means includes transmission notification flag setting means for setting transmission information in the transmission instruction flag based on the setting instruction, and the central processing unit The present invention is characterized by comprising: a timer for outputting a control signal every time; and a flag access means for managing the transmission instruction flag, checking information on the transmission notification flag based on the control signal, and initializing the flag. do.

[Effect]

A first storage means for storing a transmission instruction flag having instruction information for transmitting a control code in response to polling and a second storage means for storing a transmission notification flag having information for transmitting the control code are provided. When the transmitting means receives the polling, if there is no data to be transmitted based on the information in the transmission instruction flag, the transmitting means transmits a control code without interrupting the central processing unit, and instructs the transmission instruction flag to set transmission information. It is given to the transmission notification flag setting means. The transmission notification flag setting means sets transmission information to the transmission notification flag based on this setting information. The flag access means of the central processing unit manages the transmission instruction flag, checks the information of the transmission notification flag based on the control signal output from the timer at predetermined time intervals, and then initializes this flag. With the above-described operation, it is possible to detect that the control station has become inactive without placing a load on the central processing unit during an idle state in which there is no data to be transmitted.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram of an inactivity monitoring and control device according to an embodiment of the present invention. In FIG. 1, the inactivity monitoring control device is connected to a control station 10 via a communication network, is provided in a dependent station 20 using a polling control system, and is connected to a central processing unit 40.
and a communication control means 30 including an EOT transmission means 31 as a transmission means for transmitting EOT as a control code to the control station 10 when polling is received and there is no transmission data.

Here, the feature of the present invention is that the communication control means 30
has an EOT transmission instruction flag storage means 32 as a first storage means, which includes an EOT transmission instruction flag 33 as a transmission instruction flag having instruction information for transmitting an EOT in response to polling, and information indicating that the EOT has been transmitted. It includes an EOT transmission notification flag storage means 34 as a second storage means that includes an EOT transmission notification flag 35 as a transmission notification flag, and the EOT transmission means 31 stores the EOT transmission instruction flag 33 when polling is received. The communication control platform 30 includes a means for transmitting the EOT based on the information and instructing the setting of the EOT transmission notification flag 35, and the communication control platform 30 serves as a transmission notification flag setting means for setting transmission information in the EOT transmission notification flag 35 based on the setting instruction. The central processing unit 40 includes a timer control means 41 as a clock means for outputting a control signal at predetermined intervals.
and a flag access means 42 which manages the EOT transmission instruction flag 33, checks the information of the EOT transmission notification flag 35 based on the control signal, and initializes this flag.

The operation of the inactivity monitoring and control device having such a structure will be explained. Figure 2 shows the EOT of the inactivity monitoring and control device of the present invention.
FIG. 3 is a diagram showing the contents of a transmission instruction flag.

FIG. 3 is a diagram showing the contents of the EOT transmission notification flag of the inactivity monitoring and control device of the present invention. FIG. 4 is a diagram showing transition states of the EOT transmission instruction flag and the EOT transmission notification flag of the inactivity monitoring and control device of the present invention. FIG. 5 is a diagram showing inactivity detection of the control station of the central processing unit of the inactivity monitoring and control device of the present invention.

In FIG. 1, when the communication control means 30 receives polling from the control station 10, the EOT transmission means 3l sends the EOT
The EOT transmission instruction flag storage means 3 indicates whether or not to transmit T.
It is determined whether or not to transmit the EOT based on the information of the EOT transmission instruction flag 33 that the terminal 2 has. If the EOT is not transmitted, an interrupt is generated in the central processing unit 40,
When transmitting the EOT, before transmitting the EOT, the EOT transmission notification flag setting means 36 is notified that the EOT will be transmitted, and the EOT is transmitted. E. The OT transmission notification flag setting means 36 sets information about the returned EOT in the EOT transmission notification flag 35 of the EOT transmission notification flag storage means 34 according to the instruction from the EOT transmission means 31.

When the central processing unit 40 is notified of timeout at predetermined intervals by the timer control means 41, it uses the flag access means 42 to read out the EOT transmission notification flag 35.
Identify whether OT has been sent.

If EOT has been transmitted, it is assumed that polling has been received, and the flag access means 42 is used to initialize the EOT transmission notification flag 35, and the process waits for the next timeout or generation of transmission data.

If the EOT has not been transmitted, it is assumed that the polling has not been received and the control station is inactive.

Figures 2 and 3 show the EOT transmission instruction flag 33 and the EO
This is an example of the T transmission notification flag 35, in which the state of the EOT transmission instruction flag 33 is set to on (“l”) when generating an interrupt in response to polling from the control station IO, and the state of the EOT transmission instruction flag 33 is set to the on state (“l”) when an EOT is transmitted. ○The state of the T transmission instruction flag is set to the off state (“0”).Similarly, the state of the EOT transmission notification flag 35 when transmitting the EOT is set to the on state (rl
J), and the state of the EOT transmission notification flag 35 when the EOT is not transmitted is set to the off state (rOJ).

An example of transition between the EOT transmission instruction flag 33 and the EOT transmission notification flag 35 at this time will be explained using FIG. 4.

When there is transmission data to the control station 10, the EOT
The transmission instruction flag 33 is turned on (330) and waits for reception of the port IJ. When the transmission process is completed and there is no data to be transmitted next, the EOT transmission instruction flag 33 is turned off (331) and the EOT transmission notification flag 35 is turned off.
Also make it into off-state B340. When a poll is received,
Set the EOT transmission notification flag 35 to ON state 341 and send EO
Transmit T and wait for the next transmission data.

FIG. 5 is an example of detecting inactivity. When monitoring inactivity from time T1, the E○T transmission instruction flag 33 is set to the OFF state 332 at the time T1, and the E○T transmission notification flag 35 is similarly set to the OFF state 342. Control station 10
When the polling 500 is received, the communication control means 30 sets the EOT transmission notification flag 35 to the ON state 343 and transmits the EOT 600.

E○ when polling 510 is received from control station IO
Since the T transmission notification flag 35 is in the ON state 343, the communication control means 30 transmits the E P T 610 without doing anything.

At time T2, when a monitoring time t has elapsed since time T, the central processing unit 40 reads the EOT transmission notification flag 35 and it is in the ON state 343, so that it can know that the control station 10 is not inactive. Further, at time T2, the EOT transmission notification flag 35 is written again to be in the off state 344. If the central processing unit 40 reads the EOT transmission notification flag 35 due to a timeout if it has not received a single polling signal by the time point T3 when the monitoring time t has further elapsed from the time point T2, the central processing unit 40 will remain in the off state 344. 40 can detect that the control station 10 is inactive.

〔Effect of the invention〕

As described above, the present invention has an excellent effect of being able to detect that a control station has become inactive without placing a load on the central processing unit in an idle state where there is no data to be transmitted.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an inactivity monitoring and control device according to an embodiment of the present invention. FIG. 2 is a diagram showing the contents of the EOT transmission instruction flag of the inactivity monitoring and control device of the present invention. FIG. 3 is a diagram showing the contents of the EOT transmission notification flag of the inactivity monitoring # device of the present invention. FIG. 4 is a diagram showing transition states of the EOT transmission instruction flag and the EOT transmission notification flag of the inactivity monitoring control device of the present invention. FIG. 5 is a diagram illustrating inactivity detection of the control station of the central processing unit of the inactivity monitoring and control device of the present invention. lO...Control station, 20...Subordinate station, 30...Communication control means, 3l...EOT transmission means, 32...EO
T transmission instruction flag storage means, 33... EOT transmission instruction flag, 34... E○T transmission notification flag storage means, 3
5... EOT transmission notification flag, 36... EOT transmission notification flag setting means, 40... Central processing unit, 41.
... timer control means, 42 ... flag access means,
330... EOT transmission instruction flag on state, 331
, 332... EOT transmission instruction flag off state, 3
40, 342 lug off state, 341 lug on state, 500 610...EOT, T. , , 344 , 343 , 510 T2 , ...EOT return notification f...EOT return notification f...Polling, 600, T3...Time.

Claims (1)

[Scope of Claims] 1. A slave station connected to a control station via a communication network and using a polling control system, which includes a central processing unit and a control code that transmits a control code to the control station when polling is received and there is no data to be transmitted. and a communication control means including a transmission means for transmitting, wherein the communication control means includes a first storage means containing a transmission instruction flag having instruction information for transmitting the control code in response to polling. and a second storage means including a transmission notification flag having information indicating that the control code has been transmitted, and the transmission means stores the control code based on the information of the transmission instruction flag when polling is received. The communication control means includes means for setting transmission information in the transmission instruction flag based on the setting instruction, and the central processing unit , comprising: a timer for outputting a control signal at predetermined time intervals; and a flag access means for managing the transmission instruction flag, checking information on the transmission notification flag based on the control signal, and initializing the flag. Features an inactivity monitoring control device.