JPH0561822B2 - - Google Patents

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.

(Conventional technology) A local network access method that connects a large number of devices via a bus and exchanges information between them.
One example is the CSMA/CD method, and Japanese Patent Laid-Open No. 61-265937 discloses a method for avoiding collisions when this method is used in an apartment complex management system.

In the above-mentioned apartment complex management system, the equipment that makes up the system, such as the housing information panel, common entrance panel, and central monitoring panel, are often wired by the same power supply system, and the operating status of these system components is monitored by the central monitoring board. When the power is restored after a power outage, devices other than the central monitoring board transmit an initial start signal to the central monitoring board 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 sequentially poll all connected devices and collect the reported statuses.

(Problem to be solved by the invention) However, in the above method, when the power is restored, all the system component devices start transmitting data at the same time, and 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 traffic jam for several minutes to several tens of minutes.For example, people may call up the housing information board from the common entrance panel and make a call, or unlock the electric lock at the common entrance from the housing information board. There were problems such as not being able to do so.

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 If polling for the slave station is not received within a predetermined period of time including the time required for polling all of the slave stations after the power reset of the slave station is canceled, the master station transmits an initial start signal after the predetermined time elapses. The message is sent repeatedly until it is received.

(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 performs an initial start during that time and thereafter. No signal is sent.

If the master station returns power later than the slave station and does not receive polling within the predetermined time period following the release 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 diagram, 1 is the central monitoring panel, 2 is the common entrance panel, and 3a
-3f are housing information panels connected to the control bus 4, respectively. The centralized monitoring panel 1 serves as a master station for each of these devices, and uses the common entrance panel 2 and housing information panels 3a to 3f as slave stations to check the operation 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 for the system shown in Figure 1 when the power is restored, and shows the polling and timing chart when the central monitoring panel 1, the common entrance panel 2, and the housing information panels 3a to 3f are all canceled from power reset by the power restoration S. Indicates the timing of that response.

When the power supply is reset, the centralized monitoring panel 1 polls each of the devices 2, 3a to 3f sequentially and begins collecting the status of the devices.

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 board 3a, and a polling response Aa is received. Below, each housing information board 3b-3
Similarly, polling is performed on f, and the response is 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 uses the polling response information to detect changes in the alarm status. You can check. 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.

Figure 3 shows the common entrance panel 2 and housing information panel 3a~
This is a timing chart of initial start signal transmission when power is restored at 3F.

Common entrance panel 2, housing information panels 3a to 3f, etc.
When the power supply reset is canceled by power restoration S, a built-in timer (not shown) is operated, and an initial start signal B is transmitted to the central monitoring board 1 after a predetermined 3 minutes.

Each polling P2, Pa... for all the devices 2, 3a... in FIG. 2 and each response A2, Aa
The time required for . It will receive polling within minutes.

If there is a response to this polling, or if there is a reception response (not shown) from the central monitoring board 1 in response 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 FIG. The initial start signal from 3f is picked up without collision.

If the power supply of the system is divided into multiple systems and the power is restored separately, for example, if power is restored to the housing information panels 2a to 2f before the centralized monitoring panel 1, the housing information panels 2a to 2f will be The initial start signal B is transmitted 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 to Pf.

Also, after the central monitoring board 1, housing information board 2a ~
When power is restored to 2F, housing information boards 2a to 2F
When polling from central monitoring board 1 before power is restored
Since there is no response to Pa to Pf, the equipment becomes abnormal for a while, but 3 minutes after power is restored to the housing information panels 2a to 2f, the initial start signal B is transmitted, and the central monitoring panel 1 receives the same signal. By receiving the information, the equipment abnormality is recovered.

In addition, if the power to the housing information panels 2a to 2f is turned on from "off" alone due to a change in ownership of the housing unit or a long-term absence, please turn off the power to the housing information panels 2a to 2f.
While this is the case, the central monitoring panel 1 will treat the housing information panel as a device error, and when the power is turned on by moving in or returning home, the central monitoring panel 1 will automatically detect a device error in the housing information panel. has been restored and service can begin for that 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, the rising time of the start of transmission with the slave station is allocated by polling of the master station, thereby eliminating collisions. 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. This is a timing chart of the start signal transmission. 1... Central monitoring board (master station), 2... Common entrance board,
3a~3f...Housing information board (child station), P2, Pa~
Pf...Polling, B...Initial start signal.

Claims (1)

[Scope of Claims] 1. Transmission start control 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 via a bus exchange data with each other. In this method, the master station sequentially polls all the slave stations after the power reset of the master station is canceled, and each slave station performs polling of all the slave stations after the power reset of the slave station is canceled. When the polling for the slave station is not received within a predetermined period of time including a corresponding period of time, an initial start signal is repeatedly sent after the elapse of the predetermined period until the master station receives it.Starting transmission of the local network. Control method.