JPH01183238A - Network control system - Google Patents

Abstract

PURPOSE:To remove overlap control with respect to a same communication equipment by permitting respective communication equipments to hold state signals showing that respective communication equipments are controlled by either of control stations. CONSTITUTION:A network system consists of the communication equipments CE1-5, the control stations CS6-10 and communication lines 11-20, and respective CEs 1-5 and CSs 6-10 are provided with micro computers muCPs. When CEs 1-5 are controlled by either of CS, the memories of muCPU and the like hold the state signals by the setting of a status flag showing the control. When respective CSs 6-10 control either of CEs on the other hand, the CP of CE checks the state signal of the CE. When the signal is held, control is avoided. Thus, the overlap control with respect to the same communication equipment is prevented end confusion does not occur in a communication state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for a network system including a plurality of communication devices and a control station.

[Conventional technology]

Conventionally, in a network system consisting of multiple communication devices, only a single control station is provided, and each communication device communicates with each other under the control of this control station. In the event of a failure, a problem arises in which the entire system becomes unable to communicate.

As a countermeasure against this problem, a method has been proposed in which a plurality of control stations are provided and each control station performs control alternately or according to conditions.

[Problem to be solved by the invention]

However, when a plurality of control stations are provided, a problem arises in which the communication status becomes confused if multiple control stations perform redundant control over the same communication device.

[Means to solve the problem]

In order to solve the above-mentioned problem, the present invention is constructed by the following means.

That is, in the network system described above, when each communication device holds a status signal indicating that it is under control from one of the control stations, and the control station controls one of the communication devices, Check the status signal of this,
Control is avoided in accordance with the retention of this status signal.

[For production]

Therefore, if a communication device is under control from one of the control stations, the status signal will be held, and other control stations will not perform control depending on the status signal held, so the same Duplicate control over communication devices is eliminated.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to block diagrams showing embodiments.

In the figure, communication devices (hereinafter referred to as Cg) 1 to 5, control stations (hereinafter referred to as CS) 6 to 10, and communication line 11
The network system is configured by ~20,
Each of the CEs 1 to 5 and C86 to 10 is equipped with a microcomputer (hereinafter referred to as μCP), and one of the CSs controls one of the CE1s, and the communication partner and the communication line 11 to
CE1 by specifying what should be used among 20
5 to 5 communicate with each other.

In this case, when cgi~5 is under the control of any C8, a status signal indicating this by setting a status flag etc. is held in the μCP memory, etc., while each C86~10 When controlling any of the CGs, the μCP of the CE checks the status signal of the CE, and if this is held, the control is avoided. is reset and released from holding upon completion of control.

Therefore, for example, C86 is connected to CE5 via CEl.
When controlling the C86, the μcp first checks the CGS status signal, and if it is not held, the CE
Control is performed after setting the status signal to μCP of 5.
Since the status signal is reset in response to the completion of this, even if another C8 tries to control CE5, the control will be avoided according to the status signal set while being controlled by C86, and the "i!L multiple control" Not done.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, each communication device retains a status signal indicating that it is under control from one of the control stations, and the control station When controlling a device, if the status signal of the device is held, the control is avoided). This prevents redundant control of the same communication device, does not cause confusion in the communication state, and prevents multiple devices from controlling each other. A network system having a control station is realized, and remarkable effects can be obtained in a network system that requires high reliability.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of the present invention. 1-5... Communication device, 6-1o... Control station. Patent applicant: NEC Corporation

Claims (1)

[Claims] In a network system comprising a plurality of communication devices and a control station, and in which any one of the control stations controls one of the communication devices, each communication device receives control from one of the control stations. When the control station controls any communication device, the control station checks the status signal of the communication device, and avoids control according to the holding of the status signal. network control method.