JPS63257353A - Transmission start control method for local network - Google Patents

Abstract

PURPOSE:To improve the leading performance of transmission start by sending an initial start signal to a master station till a polling from a master station is received in parallel with the application of the polling of the master station after a prescribed time elapses at power restoration in a slave station so as to eliminate collision and retardation at power restoration. CONSTITUTION:In case of recovering power to the master station and the slave stations 3a, 3b,... simultaneously, the slave stations 3a, 3b,... receive pollings Pa, Pb,... within a succeeding prescribed time after the release of power supply reset and do not send any initial start signal B during this time and in the succeeding time. When the master station 1 restores its power with a delay from the slave stations 3a, 3b,... and receives no polling within a succeeding prescribed time after the release of power supply reset of the slave stations 3a, 3b,..., the initial start signal B is sent repetitively after a prescribed time elapses, and in case of receiving the signal by the master station 1, the transmission is stopped. Thus, no collision exists and the prescribed time is set to a comparatively short time including the polling time to all slave stations, then the time required to start the transmission is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control method for avoiding collisions in a local network when starting transmission when power is restored due to a power outage or the like.

(Prior art) C5MA is one of the local network access methods that connects a large number of devices via a bus and exchanges information between them.
/CD method, and how to avoid collisions when this method is used in a housing complex management system is disclosed in Japanese Patent Laid-Open No. 61-26.
It is disclosed by Japanese Patent No. 5937.

In the above-mentioned apartment complex management system, the m devices that make up the system, such as the housing information panel, common entrance panel, and central monitoring panel, are often wired through the same power system, and the operating status of these system components is centrally monitored. When power is restored after a power outage, devices other than the central monitoring panel transmit an initial start signal to the central monitoring panel to report the status at the time of power restoration. In order to understand the operating status of the system component devices at the time, it is necessary to poll all connected devices in order to collect the reported status.

(Problem to be solved by the invention) However, in the above method, when the power is restored, all the system component devices start transmitting at the same time, and a process is followed in which the normal state is restored while avoiding collisions. Become.

During this time, depending on the number of system components, the bus may be in a jam for several minutes to several tens of minutes, and for example, it may not be possible to call up the housing information board from the common entrance panel and make a call, or to unlock the electric lock at the common entrance from the housing information board. There was a problem.

An object of the present invention is to eliminate the above-mentioned problems of collisions and traffic jams during power restoration and to provide a system with excellent startup performance at the start of transmission.

(Means for Solving the Problems) In order to solve the above-mentioned conventional problems, the present invention provides a system in which one master station and a plurality of slave stations connected to a transmission line via a bus mutually transmit and receive data. In a transmission start control method for starting data transmission when the power is restored to the local network, the master station continuously polls all slave stations sequentially after the power reset of the master station is canceled, and each slave station polls the relevant slave stations. If polling for the slave station is not received within a predetermined time period including the time required for polling all the slave stations after the power reset of the slave station is canceled, the master station receives an initial start signal after the predetermined time elapses. It will be sent repeatedly until it is sent.

(Operation) When power is restored to the master station and slave stations at the same time, each slave station receives polling within a predetermined period of time following the cancellation of the power reset of each slave station, and during this time and thereafter, the initial start signal is not sent. Not done.

If the master station recovers power later than the slave station and does not receive polling within the predetermined time period following the cancellation of the power reset of the slave station, the initial start signal is repeatedly sent after the predetermined time elapses. , when the master station receives this, transmission is stopped.

(Embodiment) FIG. 1 is a diagram of an apartment complex management system showing an embodiment of the present invention.

In the figure, 1 is a central monitoring panel, 2 is a common entrance panel, and 38 to 3f are housing information panels, each connected to the control bus 4. The centralized monitoring panel 1 serves as a master station for each of these devices, and the common entrance panel 2
, the housing information boards 3a to 3f are used as slave stations to check the operation of each of these devices and collect information.

Next, the operation of the system shown in FIG. 1 will be explained.

Figure 2 is a timing chart when power is restored for the system in Figure 1, including the central monitoring panel 1, the common entrance panel 2, and the housing information panel 3a.
3f shows the timing of polling and its response when power reset is canceled all at once by power restoration S.

The centralized monitoring panel l will be disconnected from each device 2 and 3 by canceling the power reset.
Polling is performed sequentially for a to 3f to obtain the device status.

First, polling P2 is performed on the common entrance panel 2, and a polling response A2 is received. Next, polling Pa is performed on the housing information panel 3a, and a polling response Aa is received. Thereafter, polling is similarly performed for each of the housing information panels 3b to 3f, and responses are received.

Although not shown, the polling response data is responded to by the status information of the alarm input signal of the common entrance panel 2 and the housing information panels 3a to 3f, and the central monitoring panel 1 checks changes in the alarm status based on the polling response information. be able to. Although not shown, if a polling response cannot be received in response to polling, the polling is retransmitted up to three times. If a polling response cannot be received for all three pollings, it is assumed that the device is not normal (hereinafter referred to as device abnormality) and the polling of the next device is started.

FIG. 3 is a timing chart of initial start signal transmission when the power is restored to the common entrance panel 2 and the housing information panels 3a to 3f.

When the power reset of the common entrance panel 2, housing information panels 3a to 3f, etc. is canceled due to power restoration S, a built-in timer (not shown) is activated, and an initial start signal B is sent to the central monitoring panel 1 after a predetermined 3 minutes. to be transmitted.

Each polling P2. for all the devices 2.3a in FIG. 2 described above. Pa... and each response A2. The time required for Aa... is set to about 2 minutes, and each device 2.3a...
If the power restoration S of ~3f is at the same time as the centralized monitoring board 1 or slightly later than the centralized monitoring board 1, the polling will be received within the 3 minutes mentioned above.

If there is a response to this polling, or if there is a reception response (not shown) from the centralized monitoring board 1 to the initial start signal B, no subsequent initial start signal will be transmitted. If there is no response, the initial start signal B is transmitted up to three times, and thereafter the initial start signal B is transmitted three times every minute until there is a response.

In this way, for example, if power is restored to the entire system at the same time, the polling shown in FIG. 2 is performed from the centralized monitoring panel 1 within 3 minutes after the power restoration shown in
Initial start signals from 3a to 3f are picked up without collision.

The system power supply is divided into multiple systems,
If the power is restored separately, for example, if the power is restored to the housing information panels 2a to 2f before the central monitoring panel 1, then the housing information panels 2a to 2f
2f transmits the initial start signal B according to the time chart shown in FIG. 3, and when the power is restored to the central monitoring board 1, the initial start signal is picked up by each polling Pa-Pf.

Also, when the power is restored to the housing information panels 2a to 2f after the centralized monitoring panel 1, the housing information panels 2a to 2f respond to P a - P f at the time of polling from the centralized monitoring panel 1 before the power is restored. However, three minutes after power is restored to the housing information panels 2a to 2f, the initial start signal B is transmitted and the centralized monitoring panel 1 receives the same signal, causing the device to malfunction. Recover.

In addition, if the owner of the housing unit changes or the owner is absent for a long period of time, the housing information board 2a-2
If the power of f is turned on from "off" alone, the central monitoring board 1 will treat the housing information board as a device error while the power of housing information panels 2a to 2f is "off". Then, when the power is turned on due to moving in or returning home, the central monitoring panel 1 automatically recovers from the equipment abnormality of the housing information panel and can start services for that housing unit.

(Effects of the Invention) As explained above, according to the present invention, when the power is restored, the slave station continues to poll the master station until it receives polling from the master station in parallel with polling from the master station after a predetermined time has elapsed. Since the initial start signal is sent to the station,
Since the rising time of the start of transmission with the slave station is allocated by polling of the master station, collisions are eliminated. Since the predetermined time can be set to a relatively short time that includes polling time for all slave stations, the time required to start transmission is also shortened.

[Brief explanation of the drawing]

Fig. 1 is a diagram of an apartment management system showing an embodiment of the present invention, Fig. 2 is a timing chart of polling and response when power is restored in the system shown in Fig. 1, and Fig. 3 is an initial diagram of the system shown in Fig. 1. 5 is a timing chart of start signal transmission. 1... Central monitoring board (master station) 2... Common entrance board

Claims (1)

[Claims] In a transmission start control method for starting data transmission when power is restored to a local network, in which one master station and a plurality of slave stations connected to a transmission line by a bus exchange data with each other. , The master station continues to poll all the slave stations sequentially after the power reset of the master station is canceled, and each slave station polls all the slave stations in turn after the power reset of the slave station is canceled. A transmission start control method for a local network, characterized in that when a polling signal for the slave station is not received within a predetermined time period including a predetermined time period, an initial start signal is repeatedly sent after the predetermined time period has elapsed until the master station receives the initial start signal.