JP2662320B2 - Transmission data synchronization method for disaster prevention monitoring system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission data synchronization system for eliminating a data transmission error between a receiver and a terminal device in a disaster prevention monitoring system.

[0002]

2. Description of the Related Art Conventionally, in a disaster prevention monitoring system such as a fire monitoring system, a transmission line is drawn from a receiver installed in a central monitoring room or the like to each monitoring area, and a fire detector is connected to these transmission lines. By connecting terminal devices such as gas sensors and repeaters, and adopting a so-called polling method, the receiver calls these terminal devices in order and receives response data from each terminal device, thereby The monitoring area is centrally monitored.

That is, an example of data transmission in the conventional polling method will be described with reference to FIGS.
A unique address is set in advance for each terminal device, and FIG.
As shown in FIG. 6A, when call data P (i), P (i + 1), P (i + 2)... Are transmitted from the receiver to the terminal device at a predetermined period, FIG. As shown, the terminal device designated by each call data sets response data I indicating the status of the monitored area.
(i), I (i + 1), I (i + 2)..., and the receiver receives these response data. Then, the receiver analyzes these response data to determine whether an abnormality has occurred in the monitored area.

[0004] As shown in FIG. 7, the call data transmitted from the receiver in each cycle includes start bits S1 and S1.
2, a command field, an address field, and a checksum field separated by S3 and stop bits E1, E2, E3. The command field is composed of 1 byte for instructing the terminal device to return response data. In the command data and address field, address data for specifying a terminal device is set, and in the checksum field, checksum data for detecting a transmission error is set.

Further, the data structure of each field is as follows:
As shown in FIG. 8, a start bit having a logical value “L” indicated by a reference symbol S, a parity bit for detecting 1-byte field data and transmission errors indicated by reference characters b0 to b7, and a logical value “H” indicated by a reference character E The bit b0 is the least significant bit and the bit b7 is the most significant bit. When the signal is transmitted from the receiver to the terminal equipment, the data is transmitted in time series from the start bit in synchronization with a predetermined transfer rate. Is done.

The terminal device detects start and stop bits indicating the start and end of each field, thereby synchronizing with the receiver, and the terminal device designated by each field data receives the response data. Return to the machine side. As another conventional example, as shown in FIG. 9, a synchronization code consisting of predetermined bit data may be added before a command field in order to clarify the delimitation of each call data and reduce transmission errors. Was. By performing such a transmission method, it is possible to reduce the problem of synchronization being lost due to the influence of noise or the like in the transmission path, and to improve reliability, as compared with synchronization based on only the start bit and the stop bit. Can be done.

[0007]

However, in such a conventional transmission system, that is, the transmission system described with reference to FIGS. 7 and 8, a synchronization code of a predetermined bit is added before the command field. If noise occurs on the transmission line connected from the receiver to the terminal device, the terminal device determines that the noise is a start bit or stop bit, and the sampling position of each field data in the call data is shifted. There is a problem that a terminal device different from the one designated by the device responds, or the receiver and the terminal device lose synchronization and malfunction.

[0008] In the transmission method shown in FIG. 9, the command
A sync code of a predetermined bit is added before the field.
As a result, the amount of data to be transmitted is increased, so that transmission efficiency is reduced, and it is difficult to realize high-speed polling processing. The present invention has been made in view of such a problem, and aims to eliminate the influence of noise generated during transmission and realize high-speed polling processing while synchronizing between a receiver and a terminal device. It is an object of the present invention to provide a transmission data synchronization method for a disaster prevention monitoring system that can perform the operation.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a plurality of terminal devices are connected to a first transmission line and a second transmission line drawn from a receiver. Sends the call data in a voltage via the first transmission line, and the terminal device designated by the call data
In the transmission data synchronization method of the disaster prevention monitoring system that returns response data by current through the transmission path of the terminal, each terminal device transfers response data during the response period when specified by the call data, and specifies the response data by the call data. If not, reception of data from the first transmission line is prohibited during the response period.

[0010]

According to such a transmission data synchronization method of the disaster prevention monitoring system, the terminal device specified by the call data sent from the receiver returns the response data, and the response until the next call data is sent is returned. During the period, the remaining unspecified terminal devices stop receiving data from the receiver, so during the response period in which the receiver does not transmit the call data, each terminal device may be affected by noise and the like. And malfunction due to noise or the like can be prevented.

[0011] Further, this data reception is only stopped during the response period, and synchronization is not performed by special synchronization data, so that data transmission is not delayed and high-speed polling processing is realized. can do.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. First, a system configuration of the disaster prevention monitoring system in this embodiment will be described with reference to FIG. In FIG. 1, a receiver 1 installed in a central monitoring room or the like and a plurality of terminal devices Q1 to Qn installed in a monitoring area are connected via transmission lines L1 and L2. When the calling data is sent out by voltage through the terminal, the terminal device corresponding to the calling data returns response data by current through the transmission line L2, that is, a so-called polling system.

The receiver 1 includes a central control unit 2 having a built-in microprocessor for forming call data and analyzing response data, a display unit 3 for displaying monitoring status and the like, and a serial data transmitting circuit for transmitting call data serially. 4. A serial data receiving circuit 5 for receiving response data from the terminal device. That is, the central control unit 2 supplies call data in a predetermined format to the serial data transmission circuit 4 at a predetermined cycle, and the serial data transmission circuit 4 converts the call data into time-series data and sends it to the transmission line L1.

Here, the format of each cycle of the call data is, as shown in FIGS. 7 and 8, 1-byte command data, 1-byte address data, 1-byte checksum data, and Each data field is composed of a parity bit for detecting a transmission error, and a start bit and a stop bit for delimiting. For example, when requesting each terminal device to return response data related to disaster prevention monitoring, the command data becomes monitoring command data composed of a predetermined binary code, and the address data changes in each cycle and is unique to each terminal device. The checksum data is a sum (modulo 256) of the command data and the address data. or,
The call data is generated at predetermined intervals by the central control unit 2, converted into time-series data by the serial data transmission circuit 4, and transmitted to the transmission line L1. Therefore, as shown in FIG. 2, the receiver 1 changes the calling data P to a predetermined period τ
1, .tau.2, .tau.3,... While transmitting to the terminal devices Q1 to Qn while changing the designated address.

In this embodiment, as shown by the call data P in FIG. 2, a special synchronization code is transmitted from the first terminal device Q1 in the period τ0 before the polling process is started, and all the terminal devices Q1 are transmitted. Each time the polling process for .about.Qn is completed and the polling process is started again from the first terminal device Q1, the transfer is always performed with this special synchronization code at the head. This special synchronization command is for checking whether or not the terminal device used in the disaster prevention monitoring system is a genuine device.When the genuine terminal device receives this special synchronization command, it is provided at one end of the terminal device. The illuminated indicator lights up to indicate that the device is genuine.

On the other hand, as a representative of the terminal device Q1, each terminal device includes a serial data receiving circuit 6 for receiving the call data transferred from the transmission line L1, and a transmission slave control unit 7 incorporating a microprocessor. A sensor unit 8 for sensing a fire or a gas, a serial data transmitting circuit 9 for returning response data as current serial data, and a signal transmitted from the receiver 1 via the transmission line L1. A stop bit detection circuit 10 for synchronizing incoming call data is provided.

That is, upon receiving the time-series call data, the serial data receiving circuit 6 detects only the data portion superimposed on the power supply for the terminal device and supplies it to the transmission slave unit control unit 7. When the transmission slave control unit 7 determines that the self is specified by the call data, the terminal status data detected by the sensor unit 8 and the checksum data obtained by adding the terminal status data and the self address data are calculated. Is supplied to the serial data transmission circuit 9. Then, the serial data transmission circuit 9 sends the response data as time-series current data to the transmission line L2, and transmits it to the serial data reception circuit 5 of the receiver 1.

Further, when the stop bit detection circuit 10 detects a stop bit added after the checksum data in the call data shown in FIG. 7, the stop bit detection circuit 10 interrupts the transmission slave unit control unit 7. Synchronizes at the time of detection of the stop bit. Note that, in response to this interrupt, the transmission cordless handset control unit 7 performs a process unique to the present invention so as not to be affected by noise described later.

The other terminal devices Q2 to Qn have the same configuration, each sensor unit has a sensing function unique to each terminal device, and the terminal device specified by the call data responds and returns response data. I do. Therefore, the terminal device specified by the address data in the call data P shown in FIG. 2 returns the response data when confirming its own address. For example, if the first terminal device Q1 is specified by the call data in the period τ1, the terminal device Q1 is transmitted between the time points t2 and t3 before the next call data is transferred.
1 returns the response data I1. When the second terminal device Q2 is designated by the call data in the period τ2, the terminal device Q2 similarly returns the response data I2 between the time points t4 and t5. Similarly, only the designated terminal device returns the response data for the other terminal devices.

During a period in which each terminal device returns response data via the transmission line L2 (hereinafter referred to as a response period), one transmission line L1 is held at the "H" level, and the next transmission line L1 is held at the "H" level. "L" at the first start bit of the call data
Level. Then, the terminal device changes the timing from “H” to “L” level at times t1, t3, t5, t7,.
.. Are detected to determine the start of the call data.

Further, the function of the stop bit detection circuit 10 will be described in detail with reference to FIG. FIG. 3 shows the checksum data in the call data for a certain ith terminal device Qi, the command data in the call data for the next (i + 1) th terminal device Qi + 1, and the ith terminal. The timing when the device Qi returns the response data Ii to the receiver 1 is shown.

In this figure, the ith terminal equipment Qi
Only the terminal device returns the response data during the response period, but if the remaining terminal devices determine that they are not specified, the terminal device detects the stop bit added next to the checksum data and transmits the response data at the same time . The control unit 7 is interrupted. And transmission of these unspecified terminal devices
The slave controller 7 controls the transmission line L1 for a time equal to the response time.
And stops receiving data from the transmission line L2. The setting of the reception suspension period Td corresponding to the response time is realized by starting a time setting program ( program timer), which is made into firmware in advance in the transmission slave unit control unit 7, from the point of interruption.

As described above, when the reception stop period Td for forcibly stopping the reception of data from the receiver 1 is provided, the transmission path L1 is transmitted while the terminal device specified by the call data returns the response data. Even if noise is superimposed on the terminal device, the terminal device is not affected at all, and no malfunction or the like occurs. Next, the operation of this embodiment will be described with reference to the flowcharts shown in FIGS. FIG. 4 shows the operation of the receiver, and FIG. 5 shows the operation of the terminal device.

First, when the power of the receiver 1 is turned on, in step 100, a predetermined initialization process for starting the polling process is performed. Next, in step 110, the central control unit 2 of the receiver 1 sets an address of a terminal device to be specified first in an address counter (not shown). Next, in step 120, before polling the first terminal device, data of a special synchronization command including a predetermined data code is transmitted.

Next, in step 130, after stopping transmission for a time Td equal to the response period,
At 0, the calling data including the first address data set in the address counter is transmitted to the terminal device via the transmission line L1. In response to the transmission of the call data, each terminal device performs the processing shown in FIG. First, step 20
At 0, if it is confirmed that the data is special synchronous data,
In step 210, a process for detecting the first start bit added to the head of the command data in the call data is performed. That is, in step 210,
The start bit is detected by repeating the strobe processing at high speed for the data transferred via the transmission line L1.

When the start bit is detected, step 2
The processing shifts to 20, where the command data and the checksum data are analyzed, and it is further determined whether or not the address data specifies a self-address. Then, only the terminal device specified by the call data performs the process of step 230, so that the response data including the terminal status data detected by the sensor unit 8 indicating the status of the monitored area and the address data indicating the own address is transmitted to the transmission line. It is returned to the receiver 1 via L2.
On the other hand, the remaining unspecified terminal devices are
The process shifts to 40, and during this response period, reception from the transmission line L1 is stopped for a time Td.

Returning to FIG. 4 again, the receiver 1 performs step 1
At step 50, the response data is received and the terminal status data is analyzed.
To be displayed. The processing period of step 150 corresponds to a response period. Next, in step 170, it is determined whether or not the address data AD set in the address counter has exceeded the value of the final address ADR of the terminal device installed in the disaster prevention monitoring system, and the address has not yet reached the final address. If not, after adding 1 to the data of the address counter in step 180, the processing from step 140 is performed again, and the same processing is repeated to sequentially perform the polling processing up to the terminal device of the final address.

When the polling process for the terminal device at the final address is completed, the process from step 110 is started again, and the polling process is repeated in order from the first terminal device. Thus, according to this embodiment,
During the period in which the terminal device responding to the call data from the receiver is returning the response data, the remaining terminal devices prohibit the reception of data from the transmission line L1 by themselves. It is not affected by noise or the like generated on the road. Then, the end point of the prohibition period is synchronized with the start point at which the receiver transmits the next call data, so that the next call data can be received. Therefore, since there is no data received from the transmission line L1 during the response period, the unnecessary reception operation is forcibly stopped during this period so that the reception operation is not affected by noise or the like. Generation can be prevented beforehand.

[0029]

As described above, according to the present invention, the terminal device specified by the call data transmitted from the receiver returns the response data, and during the response period until the next call data is transmitted. Made the remaining terminal devices that were not specified stop receiving data from the receiver,
During this response period in which the receiver does not transmit the call data, each terminal device is not affected by noise or the like, and malfunction due to noise or the like can be prevented.

Further, the data reception is only stopped during the response period, and synchronization is not performed by special synchronization data, so that data transmission is not delayed and high-speed polling processing is realized. can do.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram illustrating a configuration of a disaster prevention monitoring system according to an embodiment.

FIG. 2 is an explanatory diagram illustrating a timing of a polling process according to an embodiment;

FIG. 3 is an explanatory diagram showing timing of response data in call data.

FIG. 4 is a flowchart for explaining a polling processing operation of the receiver.

FIG. 5 is a flowchart for explaining a response operation of the terminal device.

FIG. 6 is an explanatory diagram showing the timing of a conventional polling process.

FIG. 7 is an explanatory diagram showing a configuration of conventional call data.

FIG. 8 is an explanatory diagram showing the structure of conventional call data in more detail.

FIG. 9 is an explanatory diagram showing another configuration of conventional call data.

[Explanation of symbols]

 1; Receiver 2: Central control unit 3: Display unit 4: Serial data transmission circuit 5; Serial data reception circuit 6; Serial data reception circuit 7; Transmission unit control unit 8; Sensor unit 9; Serial data transmission circuit 10; Stop bit detection circuit Q1 to Qn; terminal equipment L1, L2; transmission line Td; reception stop period

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H04Q 9/00 321 H04L 11/00 321

Claims (1)

(57) [Claims] 1. A plurality of terminal devices are connected to a first transmission path and a second transmission path drawn from a receiver, and the first transmission path is connected to the first transmission path from the receiver.
The transmission data synchronization of the disaster prevention monitoring system in which the call data is sent out at a voltage via the transmission path of the above, and the terminal equipment specified by the call data returns the response data at the current through the second transmission path during the response period. In the system, each of the terminal devices transfers response data during the response period when specified by call data, and transmits data from the first transmission line during the response period when not specified by call data. A transmission data synchronization method for disaster prevention monitoring systems, characterized in that reception is prohibited.