JPH0624384B2 - Polling transmission method - Google Patents

Description

The present invention relates to a polling transmission system, and more particularly to a slave station in which a state change occurs in a system in which a master station and a plurality of slave stations are connected by a multi-drop line. The present invention relates to a polling transmission method suitable for collecting state change data from.

[Conventional technology]

Conventionally, in a distribution system, etc., a system in which a master station and multiple slave stations are connected by a multi-drop line, data is exchanged between the master station and slave stations, and the status of each slave station is monitored by the master station. Has been adopted. In this type of remote monitoring system, a polling transmission system is used in which data is transmitted and received between a master station and each slave station via a data transmission line by a polling signal and a response signal. When a status change occurs in any of the slave stations, the status change data is transmitted via the status change notification signal line provided in the data transmission line, as described in JP-A-63-187800. The method is adopted.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technique, the point of shortening the collection time of the state change data and the line length between the master station and the slave station are not taken into consideration. When transmitting state change data from the station to the master station, the open state of the state change notification signal line must be detected, and the state change data can be transmitted only after this detection. Not enough to save time. In addition, when the data transmission line is configured by the tree-like multi-drop method, even if the open state of the status change notification signal line is detected, if the distance between the slave stations is long, the line loss is restricted. ,
It may be difficult to detect the open state of the line.

An object of the present invention is to provide a polling transmission method capable of transmitting state change data to a master station regardless of the open state of a line when a state change occurs in a slave station.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides, as a first method, a master station and a plurality of slave stations are connected via a pair of data transmission lines and at the same time via an auxiliary line, and the master station and the slave stations are connected. Data is transmitted and received to and from the station via polling signals and response signals via each data transmission line, and when a state change occurs in any of the slave stations, a state change signal including information specific to the slave station from the slave station. Is transmitted to the auxiliary line for a certain period of time, the polling signal transmission is temporarily stopped when the master station receives the status change signal, and when the master station identifies the slave station in which the status change has occurred from the status change signal, the slave station When a status change slave station polling signal including information specifying a station is transmitted to one of the data transmission lines and the slave station having the status change receives the status change slave station polling signal, the status change data from the slave station is received. To the auxiliary line Is obtained by employing a polling transmission method resumes transfer of data by a polling signal and the response signal after receiving the state change data.

As a second method, the master station and a plurality of slave stations are connected via a pair of data transmission lines and also via an auxiliary line, and the master station and the slave stations are connected via each data transmission line. Data is transmitted and received by a polling signal and a response signal, and when a status change occurs in any of the slave stations, the slave station transmits a status change signal containing information specific to the slave station to the auxiliary line for a certain period of time, and the master station When the status change signal is received, transmission of the polling signal is temporarily stopped, and when the master station cannot identify the slave station with the status change from the status change signal, the master station sequentially sends status change polling signals to all slave stations. And the status change station search signal are transmitted through one of the data transmission lines, and when the slave station with the state change identifies the called station from the state change station search signal, the status change data is transmitted to the auxiliary line. , For all slave stations In which the transmission of status change polling signal and a state change station search signal is employed to resume polling transmission system exchanges data by a polling signal and the response signal after completion.

As a third method, a plurality of slave stations are divided into a plurality of groups, the slave stations of each group and the master station are connected via a pair of data transmission lines, and also connected via an auxiliary line, so that Data is transmitted / received to / from a slave station via each data transmission line by a polling signal and a response signal, and when a status change occurs in a slave station of any group, information specific to the group is transmitted from the slave station. When the master station transmits the status change signal including the status change signal to the auxiliary line for a certain period of time, suspends the polling signal transmission when the master station receives the status change signal, and the master station identifies the group in which the status change has occurred from the status change signal. In addition, a status change slave station polling signal including information specifying the group is transmitted to one of the data transmission lines, and when the status change slave station receives the status change slave station polling signal, the status change slave station status is received from the slave station. Change Polling transmission in which the master station receives the status change data and the status change slave station polling signal is transmitted to all the slave stations in the group after the master station receives the status change data The method is adopted.

As a fourth method, a master station and a plurality of slave stations are connected via a pair of data transmission lines, and a polling signal and a response signal are transmitted via each data transmission line between the master station and the slave stations. Data is exchanged, and when a status change occurs in any of the slave stations, a status change signal whose carrier frequency is different from the response signal is transmitted from the slave station instead of the response signal, and the master station receives the status change signal. Sometimes the polling signal transmission is temporarily stopped, and the master station transmits the status change polling signal and the status change station search signal in order to all the slave stations. State change data is transmitted when a call is received from the local station, and after the transmission of the state change polling signal and the state change station search signal to all slave stations is completed, data exchange with the polling signal and the response signal is restarted. To do It is obtained by adopting the method.

As a fifth method, a plurality of slave stations are divided into a plurality of groups, the slave stations of each group and the master station are connected via a pair of data transmission lines, and each data is transmitted between the master station and each slave station. Data is transmitted and received by a polling signal and a response signal via a transmission line, and when a state change occurs in a slave station of any group, the carrier frequency differs from the response signal from the slave station and information unique to the group is transmitted. When the master station receives the status change signal, the polling signal transmission is temporarily stopped when the master station receives the status change signal, and the master station identifies the group in which the status change has occurred from the status change signal. A status change slave station polling signal including information identifying the group, and when the slave station with the status change receives the status change slave station polling signal, the status change data is transmitted from the slave station, Station Change data in which the transmission state changes slave station polling signal is employed to resume polling transmission system exchanges data by a polling signal and the response signal after the end for all slave stations in the group received the.

As a sixth method, a master station and a plurality of slave stations are connected via a pair of data transmission lines, and a polling signal and a response signal are transmitted between the master station and each slave station via each data transmission line. Data is transmitted and received, and when a status change occurs in any of the slave stations, the carrier frequency is different from the response signal from the slave station, and a status change signal containing information specific to the slave station is transmitted instead of the response signal and transmitted. When the master station receives the status change signal, the polling signal transmission is temporarily stopped, and when the master station identifies the slave station whose status has changed from the status change signal, the status change slave station including information for specifying the slave station. When a slave station transmitting a polling signal and having a status change receives a status change slave station polling signal, it transmits status change data from the slave station, and after the master station receives the status change data, Data by response signal Polling transmission system resumes the transfer is obtained by the adoption.

As a seventh method, a master station and a plurality of slave stations are connected via a pair of data transmission lines, and a polling signal and a response signal are transmitted between the master station and each slave station via each data transmission line. Data is transmitted and received, and when a status change occurs in any of the slave stations, the carrier frequency is different from the response signal from the slave station, and a status change signal containing information specific to the slave station is transmitted instead of the response signal and transmitted. When the master station receives the status change signal, it temporarily stops the transmission of the polling signal, and when the master station cannot identify the slave station whose status has changed from the status change signal, the master station sequentially polls all slave stations for status change. Signal and status change station search signal are transmitted, status change data is transmitted when the slave station in which the status change occurs identifies the called station from the status change station search signal, and status change polling is performed for all slave stations. Signal and state change station In which the transmission of over switch signal is employed to resume polling transmission system exchanges data by a polling signal and the response signal after completion.

[Action]

In a system in which a master station and a slave station are connected via a pair of data transmission lines and an auxiliary line, when any one of the slave stations changes in state, a status change signal containing information specific to the slave station from the slave station. To the auxiliary line for a certain period of time, and when the master station identifies a slave station that has changed state, it transmits a signal to the slave station to transmit state change data, while the slave station that has changed state When it is not possible to identify each of the slave stations, the request was sent to all slave stations to transmit the status change data from the slave stations that had a status change. It becomes possible to transmit the state change signal to the master station. Further, in this system, when the slave stations are divided into a plurality of groups, when a status change occurs in any of the slave stations, a status change signal including group-specific information is transmitted from the slave station to the auxiliary line for a certain period of time. , The master station outputs the signal requesting the transmission of the status change data of the group in which the status change occurs, so the status change signal is output from the slave station in which the status change occurs regardless of the open status of the auxiliary line. You can
Since the master station may request the specific group to transmit the state change data, the state change data can be collected in a shorter time.

In a system in which a master station and a plurality of slave stations are connected via a pair of data transmission lines, when a status change occurs in one of the slave stations, the carrier frequency is different from the response signal from the slave station. The change signal is transmitted instead of the response signal, and the master station outputs a signal to all slave stations in order to request transmission of the state change data, so data is transmitted from the slave station to the master station. Even if a state change signal is transmitted regardless of the open state of the data transmission line, it is possible to identify the slave station in which the state change has occurred, and the state change data can be sent from the slave station in which the state change has occurred for a short time. Can be collected at. Also, in a system in which the slave stations are divided into multiple groups, and the slave stations of each group and the master station are connected via a pair of data transmission lines, the response signal from the slave station in which the status change occurs is the carrier. Since the state change signal with different frequency and containing group-specific information is transmitted instead of the response signal, and the master station outputs a signal requesting transmission of state change data to a specific group, It becomes possible to output a state change signal from the slave station to which the state change has occurred to the master station regardless of the open state of the transmission line, and to collect state change data in a short time. Furthermore, when a status change occurs in any of the slave stations, if the carrier frequency is different from the response signal from the slave station and a status change signal containing information specific to the slave station is transmitted instead of the response signal, the master station changes the status. When the generated slave station can be identified, the status change data can be collected only by outputting a signal requesting the slave station having the status change to return the status change data. On the other hand, when the master station cannot identify the slave station in which the status change has occurred, if the master station outputs a signal requesting transmission of status change data to all slave stations in sequence,
It becomes possible to reliably collect the state change data.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a master station and slave stations 2-1 ... 2-n are connected in a tree form via a downlink data transmission line 100 and an uplink data transmission line 102, and an auxiliary line 104.
Are connected in a tree shape via. Data transmission line 1
A polling signal is transmitted to 00, and the data transmission line 1
A response signal is transmitted to 02 and a state change signal is transmitted to the auxiliary line 104.

The master station 1 controls a polling process, a response signal process, a state change signal reception process, and a mode change process after the state change signal is received. The demodulation unit 5 demodulates the response signal from the demodulator 102 and the demodulation unit 15 demodulates the state change signal from the auxiliary line 104.

The slave stations 2-1 ... 20-n are configured of the same one, and the slave station 2-1 will be described as a representative. Child station 2-1
The demodulator 5-1 for demodulating the polling signal from the line 100, the response signal to the polling signal, the state change signal when the state change occurs, the modulator 4-1 for modulating the state change data, and the line 102 in the normal state are selected. Then, the line selection unit 7 that selects the auxiliary line 104 when the state change occurs-
1. Performs a called process for identifying the called station by a polling signal and a state change station search signal, a transmission process for transmitting a response signal to the called station and state change data, and a state change detection process for detecting a state change occurrence. It is composed of a logic unit 3-1. The line selection unit 7-1 is the logical unit 3
The auxiliary line 104 is selected by the state change detection signal 6-1 output from -1.

An example of a case where a single slave station changes its state while collecting data by the polling transmission method between the master station 1 and the slave stations in the above configuration will be described with reference to FIG.

First, the polling signal is sequentially transmitted to the slave stations 2-1 ... 2-n according to a sequence preset in the logic unit 3. When the polling signals are sequentially transmitted, the demodulation units 5-1 ... 5-n of the slave station group demodulate the polling signals, and the logic units 3-1 ... 3-n demodulate the slave station number in the polling signal and the own station. Is compared with the slave station number of No. 1, and only the slave stations whose contents match each other detect the called and the response signal is modulated by the modulators 4-1 ... 4
-N, the line selectors 7-1 ... 7-n, and the line 102 are transmitted to the master station 1. The master station 1 sequentially receives the response signals from the slave stations 2-1 ... 2-n via the demodulation unit 5, and transmits the polling signal again to the next slave station.

In such a situation, if a state change occurs in the slave station 2-n while data is being exchanged between the master station 1 and the slave station 2-2, the slave station 2-n will be the master station. Station 1 to slave station 2-
After the transmission of the polling signal for 2 is completed, the slave station 2
A state change signal is sent from -n to the auxiliary line 104. For this state change signal, a signal composed of a state change frame including a child station address as information unique to the child station is used, and this state change signal is output to the auxiliary line 104 for a certain period of time. When the state change signal is demodulated by the demodulation unit 15 of the master station 1, the slave unit address in the state change signal is extracted by the logic unit 3. When the status change slave station 2-n is identified from this address collation, the master station 1 suspends the transmission of the polling signal, and transmits the status change slave station polling signal to the slave station 2-n.
It is sent out via the data transmission line 100.

When the slave station 2-n demodulates the status-changed slave station polling signal from the master station 1 and the logic unit 3-n detects the called station, the status change data is transmitted from the modulator 4-n to the auxiliary line 104.
Transmit to. After this, the line selection unit 7-n selects the line 102 and returns to the original state. And the master station 1 and the slave station 2-
When the state change data from n is received, the state change data collection mode is ended and the transmission of the polling signal to the next slave station 2-3 is restarted.

As described above, in the present embodiment, when the state change occurs in the slave station, the state change signal including the information specific to the slave station is transmitted to the auxiliary line 104 for a certain period of time. Even if the state change signal is transmitted without detection, the master station can identify the slave station in which the state change has occurred from the state change signal. Then, by transmitting a signal requesting the return of the state change data to the slave station in which the state change has occurred, it becomes possible to collect the state change data in a short time.

Next, an operation example when a plurality of slave stations simultaneously change states will be described with reference to FIG.

When data is being exchanged between the master station 1 and the slave station 2-3, if status changes occur at the slave station numbers 1 and n at the same time, the slave station from which the status change has occurred becomes the slave station. A state change signal including an address is output to the auxiliary line 104 for a certain period of time. In this case, since the state change signal overlaps and is demodulated by the demodulator 15, it becomes impossible to extract the slave station address from the state change signal. Therefore, by detecting the carrier of the state change signal, the master station 1 suspends the transmission of the polling signal, assuming that the state change has occurred in any of the slave stations, and sequentially transmits the state change polling signal to all slave stations. The state change station search signal is transmitted via the modulator 4 and the line 100. As the state change search signal, for example, a mark (1-Δ) and a space (1+)
A signal obtained by repeating () is used.

In response to the status change polling signal, each slave station adjusts the change point counting status from the mark of the status change station search signal to the space, counts the change points of the status change station search signal, and this count value is the own station number. When it matches with, the status change data is sent out because the call reception of the local station is detected. For example, when the change station of the state change station search signal has the first change point and the child station of the child station number 1 detects the called of the own station, the child station of the child station number 1 sends the state change data through the line 104. Further, when the slave station with the slave station number n detects the called of the local station at the nth change point of the status change station search signal, the slave station with the slave station number n sends the status change data through the auxiliary line 104. At this time,
The master station 1 detects the carrier including the status change data from the slave station number 1 and holds the status change station search signal in the mark state. After the collection of the state change data from the slave station number 1 is completed, the mark hold state of the state change station search signal is released, and the transmission of the state change station search signal by repeating the mark and space is restarted. Further, when the master station 1 receives the status change data from the slave station number n as in the case of the slave station number 1, the mark status of the status change station search signal is held and the mark hold status is released after data collection. Then, the collection of the state change data ends.
After that, the master station 1 restarts the transmission of the polling signal to the next slave station 2-4.

As described above, in the present embodiment, even when a plurality of slave stations simultaneously change their states, a state change signal including information specific to the slave station is transmitted from each slave station to the auxiliary line 104 for a certain period of time. Even if the state change signal is always output regardless of the open state of the auxiliary line 104, it is possible to identify that the state change has occurred in the master station. And in this case, since the slave station in which the state change has occurred cannot be specified,
Since all slave stations request to transmit the state change data from the state change slave stations, the state change data can be reliably collected.

Next, an example in which the slave stations 2-1 ... 2-n are divided into a plurality of groups and a state change occurs in any of the slave stations will be described with reference to FIG.

When a state change occurs in the slave station 2-n while data is being exchanged between the master station 1 and the slave station 2-2, the slave station 2-n polls the slave station 2-2. When the signal transmission is completed, a state change signal including group-specific information is sent to the tn auxiliary line 104 for a certain period of time. When the master station 1 demodulates the status change signal and detects the occurrence of the status change, the transmission of the polling signal is temporarily stopped, the reception time verification in the status change signal is performed, and the slave station group in which the status change occurs is identified. To do. Then, the master station 1 adds a mark (1-Δ
), A state change station search signal composed of pace (1 + Δ) is transmitted via the line 100. At this time, slave station 2-
A slave station belonging to the same group as n counts the falling change points from the mark to the space in the status change station search signal sent after the polling signal, and when the count value matches the called station, the status is changed. The changed slave station 2-n transmits the state change data to the master station 1 via the modulator 4-n and the auxiliary line 104.

At this time, when the master station 1 receives the status change data, it holds the status change station search signal in the mark state and sequentially receives the status change data. When the end of reception of the state change data is detected, the hold of the mark state of the state change station search signal is released, and the state change station search signal continues to be sent to other slave stations in the group where the state change has occurred. Do it. Then, when the transmission of the state change station search signal to all the slave stations of the group in which the state change has occurred is completed, and when the collection of the state change data is also completed, the transmission of the polling signal to the slave station 2-3 is restarted.

As described above, in the present embodiment, the state change signal including the glue-specific information is output to the auxiliary line 104 for a certain period of time when the state change occurs in the slave station, so that it does not depend on the open state of the auxiliary line 104. It becomes possible to output the state change signal, and the master station only identifies the group in which the state change has occurred, and if the signal requesting the return of the state change data is output to the identified group, the state change signal can be output. The state change data can be collected from the slave station in which the state change occurs, and the state change data can be collected in a shorter time.

Next, an example in which the present invention is applied to a system in which the master station 1 and the slave station group are connected by a pair of data transmission lines will be described from FIG.

In the case of the system shown in FIG. 5, the master station 1 is provided with a state change signal detection section 8 for detecting a state change from the output signal of the demodulation section 5 instead of the demodulation section 15, and the slave station 2 −
1 ... 2-n are provided with state change signal modulators 10-1 ... 10-n for transmitting a state change signal 1-.DELTA. Having a carrier frequency different from that of the response signals. +-. Switching unit 12-1 ... 1 that selects one of modulation units 4-1 ... 4-n and state change signal modulation units 10-1 ... 10-n and outputs it to data transmission line 102 instead of -n.
2-n is provided and the other structure is the same as that of the above-described embodiment, and therefore, the same components are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, when a state change occurs in the slave station 2-n while data is being exchanged between the master station 1 and the slave station group, the slave station 2-n switches to a response signal. Then, a state change signal having a carrier frequency different from that of the response signal is transmitted to the master station 1 side via the line 102. At this time, the master station 1 has a slave station 2
-N and a response signal from another slave station are input, but the state change signal has a different carrier frequency from the response signal, so the state change signal detection unit 8 of the master station 1 detects the state change signal. . When the slave station status change signal 9 from the status change signal detector 8 is generated, the master station 1 suspends the normal polling signal transmission, sets the mode to the status change data collection mode, and targets all slave stations. A change polling signal and a state change station search signal consisting of repetitions of marks and spaces are sent to the line 100 via the modulator 4. At this time, on the side of the slave stations 2-1 ... 2-n, transmission of the state change signal is stopped under the condition of the state change polling signal and the state change of the own station, and the change of the state change station search signal from mark to space. Point counting is performed, and when the change point count value of the slave station 2-n in which the state change occurs coincides with the number n of the own station, the call reception of the own station is detected and the state change data is sent to the line
2 to the master station 1.

The master station 1 demodulates the status change data from the slave station 2-n, and when the theoretical section 3 detects the existence of the status change data, holds the status change station search signal in the mark state and waits for the reception of the status change signal. . When the end of reception of the state change data from the slave station 2-n is detected, the mark hold state of the state change station search signal is released, and the state change station search signal is repeatedly sent to other slave stations. When the transmission of the state change station search signal is completed and the collection of the state change data is completed, the state change data mode is switched to the normal polling mode, and the polling signal is transmitted to the slave station whose transmission of the polling signal is interrupted. Resume sending.

As described above, in this embodiment, even when the master station and the slave station group are connected by a pair of data transmission lines, when the slave station has a status change, a response signal when the status signal changes and a carrier frequency different carrier frequency Is transmitted to the master station 1 side, it becomes possible to successively output the state change signal from the slave station in which the state change has occurred, without detecting the open state of the data transmission line. Furthermore, in this case, since the master station requests all slave stations to send back the status change data in order, it is possible to reliably collect the status change data from the slave station where the status change has occurred. Becomes

Next, an embodiment in which the state change signal is composed of a tone signal will be described with reference to FIGS. In this case, as shown in FIG. 7, the master station 1 has a state change signal for receiving the state change signal composed of the hybrid transformer 13 for branching the response signal and the state change signal and the tone signal. The receiver 14 is provided, and the slave station 2-1 ...
2-n are provided with state change signal transmitting sections 18-1 ... 18-n for modulating and transmitting tone signals (tn) instead of the state change signal modulating sections 10-1 ... 10-n, The slave stations 2-1 ... 2-n are divided into a plurality of groups.

In the system shown in FIG. 7, when a state change occurs in the slave station 2-n while data is being exchanged between the master station 1 and the slave station group, as shown in FIG. By the operation of the switching unit 12-n, the state change signal transmission unit 18-n sends a state change signal to the line 102. This state change signal is composed of tone signals assigned to each slave station group, and this signal is sent to the master station 1 via the line 102. Then, this signal is branched to the state change signal receiving unit 14 side by the hybrid transformer 13,
It is sent to the logic unit 3 via the state change signal receiving unit 14. When the logic unit 3 identifies the slave station group having the status change from the output signal of the status change signal receiving unit 14, the normal polling signal transmission is interrupted and the slave station group having the status change is targeted. The state change polling signal and the state change station search signal are transmitted. At this time, the slave station belonging to the same group as the slave station 2-n sequentially counts the change points of the status change station search signal in response to the status change polling signal, and when this count value matches the own station number, The slave station 2-n that has changed its state sends the state change data. When this state change data is sent to the line 100, this data is branched to the demodulation unit 5 by the hybrid transformer 13 and input to the logic unit 3. At this time, the logic unit 3 holds the mark state of the state change station search signal by inputting the state change data, and waits for the reception of the state change data. When the reception of the state change data is detected, the mark hold state of the state change station search signal is released, and the state change station search signal is repeatedly sent to other slave stations. When the transmission of the state change station search signal to the remaining slave stations is completed and the collection of the state change data is completed, the normal polling mode is entered.

In the present embodiment, when the slave station is divided into a plurality of groups, a carrier signal whose carrier frequency is different from the response signal in which the status change occurs and a status change signal including group-specific information is transmitted instead of the response signal. Therefore, the state change signal can always be transmitted regardless of the open state of the data transmission line. Further, in this case, since the master station requests the specific group to send back the state change data, it becomes possible to collect the state change data in a short time.

Next, a system in which a signal whose carrier frequency is different from that of the response signal and whose frequency is divided is used as the state change signal will be described with reference to FIGS. 9 to 11.

In this embodiment, the master station 1 has a state change signal receiving unit 1
4, a state change signal demodulation section 20 for demodulating the state change signal 2 ± Δ is provided, and the slave station 2-1 ...
19-n for demodulating and transmitting the state change signal (2 ± Δ) instead of the state change signal transmitters 18-1 ... 18-n. It is provided.

In the system shown in FIG. 9, when a state change occurs in a single slave station, for example, as shown in FIG.
When the state change occurs at -2, the state change signal modulator 19-n sends a state change signal to the line 102 by the operation of the switching unit 12-n. This state change signal is a signal whose carrier frequency is different from that of the response signal and is frequency-divided.
A signal forming a state change frame including a slave station address is used. When the state change signal is sent, the switching unit 1
2-n returns to the original state. When the state change signal is sent to the master station 1, this signal is branched to the state change signal demodulation unit 20 side by the hybrid transformer 13, demodulated by the demodulation unit 20 and then input to the logic unit 3. Logic part 3
When the input of the state change signal is detected by, the normal sending of the polling signal is interrupted, and the slave station in which the state change has occurred is identified by the state change signal. Then, when the child station whose state has changed is identified as the child station 2-n by this identification, the state change child station polling signal is transmitted from the parent station 1 to the child station 2-n. Then, when the slave station 2-n receives this signal and detects the called station, the state change data is transmitted from the slave station 2-n via the modulator 4-n and the switch 12-n to the line 102.
Sent to. This data is hybrid transformer 13
The signal is branched to the demodulation unit 5 via, and after being demodulated, is input to the logic unit 3. The logic unit 3 receives the state change data as a response signal to the state change polling signal, and resumes the normal polling signal transmission.

As described above, in this embodiment, since the carrier frequency is different from the response signal from the slave station in which the state change occurs, the state change signal containing information specific to the slave station is transmitted instead of the response signal. Even if the state change signal is transmitted regardless of the open state of the data transmission line, the master station can identify the slave station in which the state change has occurred. Further, since the master station requests the slave station in which the status has changed to return the status change data, it is possible to reliably collect the status change data.

Next, in the system shown in FIG. 9, when data is exchanged between the master station 1 and the slave station group, if a plurality of slave stations simultaneously change states, for example, the slave station number When 1 and n state changes occur at the same time, state change signals are simultaneously sent to the line 102 from each slave station. In this case, since the master station 1 receives a plurality of state change signals, it is not possible to identify the slave station in which the state change has occurred. However, in order to detect the occurrence of the state change from the carrier frequency, the time shown in FIG. Similarly, the state change polling signal and the state change station search signal are sequentially transmitted to all slave stations. Then, in response to the status change polling signal at each slave station, the change point of the status change station search signal is measured, and when the measured value matches the number of the own station, the called station of the own station is detected and the status change occurs. If the state change data is sequentially transmitted from the slave stations, that is, the slave station numbers 1 and n, the master station 1 can surely receive the state change data from each slave station as in the case of FIG. It will be possible. After the collection of these data is completed, the normal polling signal transmission is restarted.

As described above, in the present embodiment, when the status changes occur simultaneously in a plurality of slave stations, the master station requests all slave stations to send back the status change data. Even if there is a change, the state change data can be reliably collected from each slave station.

〔The invention's effect〕

As described above, according to the present invention, in a system in which a master station and a slave station group are connected via a pair of data transmission lines and auxiliary lines, information specific to the slave station from the slave station in which the state change occurs or Since the status signal including the information unique to the group is transmitted to the auxiliary line for a certain period of time, the state change signal can be transmitted to the master station regardless of the open state of the auxiliary line. When the master station can identify the slave station in which the status change has occurred, it requests the slave station to return the status change data, and when the master station cannot identify the slave station, the status change data is sent to all slave stations. Since the return is requested, the state change data can be reliably collected from the slave station in which the state change has occurred, and the state change data can be collected in a short time. Furthermore, if the slave stations are divided into a plurality of groups, the state change data can be collected in a shorter time.

In a system in which a master station and a slave station group are connected only by a pair of data transmission lines, a status change signal whose carrier frequency is different from the response signal from the slave station in which the status change occurs is transmitted to the master station side. Therefore, the state change signal can be transmitted regardless of the open state of the data transmission line. When the master station can identify the slave station in which the status change has occurred from the status change signal, only the slave station is requested to return the status change data, and the master station side identifies the slave station in which the status change has occurred. When it is not possible, all the slave stations are requested to return the state change data in order, so that the state change data can be reliably collected from the slave stations in which the state change has occurred.
Therefore, it is possible to collect the state change data in a short time. Furthermore, if you divide the slave station group into multiple groups,
It becomes possible to collect the state change data in a shorter time.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation when a state change occurs in a single slave station in the system shown in FIG. 1, and FIG. FIG. 4 is a diagram for explaining the action when a state change occurs in a plurality of slave stations in the system shown in FIG. 1, and FIG. 4 shows a case where the slave stations are divided into a plurality of groups in the system shown in FIG. FIG. 5 is a diagram for explaining the action, FIG. 5 is a configuration diagram showing a second embodiment of the present invention, FIG. 6 is a diagram for explaining the action of the system shown in FIG. 5, and FIG. FIG. 8 is a configuration diagram showing a third embodiment, FIG. 8 is a diagram for explaining the operation of the system shown in FIG. 7, FIG. 9 is a configuration diagram showing a fourth embodiment of the present invention, and FIG. FIG. 1 is a diagram for explaining the operation when a state change occurs in a single slave station in the system shown in FIG.
FIG. 1 is a diagram for explaining the operation when a state change occurs in a plurality of slave stations in the system shown in FIG. 1 ... Master station, 2-1 ... 2-n ... Slave station, 3,3-1 ... 3-n ... Logic section, 4,4-1 ... 4-n ... Modulation section, 5,5- 1 ... 5-n ... Demodulation section, 7-1 ... 7-n ... Line selection section, 8 ... State change signal detection section, 10-1 ... 10-n ... State change signal modulation section, 12-1 ... 12-n ... switching section, 13 ... hybrid transformer, 14 ... state change signal receiving section, 15 ... demodulation section, 19-1 ... 19-n ... state change signal modulation section, 20 ... state change Signal demodulation unit, 100, 102 ... Data transmission line, 104 ... Auxiliary line.

Front page continuation (72) Inventor Katsuyoshi Nakayama 52-1 Omika-cho, Hitachi-shi, Ibaraki Inside the Omika factory, Hitachi, Ltd. (72) Takashi Uchida 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Omika Plant (72) Inventor Kunio Miyata 52-1 Omikacho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Omika Plant (56) References JP-A-63-187800 (JP, A) JP 63-109694 (JP, A) JP 55-132158 (JP, A) JP 55-102954 (JP, A)

Claims (7)

[Claims] 1. A master station and a plurality of slave stations are connected to each other via a pair of data transmission lines and an auxiliary line, and polling is performed between the master station and the slave stations via each data transmission line. Data is transmitted and received by a signal and a response signal, and when a state change occurs in any of the child stations, a state change signal containing information specific to the child station is transmitted from the child station to the auxiliary line for a certain period of time,
When the master station receives the status change signal, the transmission of the polling signal is temporarily stopped, and when the master station identifies the slave station in which the status change has occurred from the status change signal, the status change including information for specifying the slave station. The slave station polling signal is transmitted to one of the data transmission circuits, and when the slave station having the status change receives the status change slave station polling signal, the slave station transmits the status change data to the auxiliary line and the master station A polling transmission method in which the exchange of data by a polling signal and a response signal is resumed after receiving state change data. 2. A master station and a plurality of slave stations are connected via a pair of data transmission lines and also via an auxiliary line, and polling is performed between the master station and the slave stations via each data transmission line. Data is transmitted and received by a signal and a response signal, and when a state change occurs in any of the child stations, a state change signal containing information specific to the child station is transmitted from the child station to the auxiliary line for a certain period of time,
When the master station receives the status change signal, it temporarily stops the transmission of the polling signal, and when the master station cannot identify the slave station whose status has changed from the status change signal, the master station sequentially sets the status to all slave stations. The change polling signal and the status change station search signal are transmitted through one of the data transmission lines, and when the slave station that has changed the status identifies the called station from the status change station search signal, the status change data is an auxiliary line. A polling transmission method in which the transmission and reception of data by the polling signal and the response signal is restarted after the transmission of the status change polling signal and the status change station search signal to all slave stations is completed. 3. A plurality of slave stations are divided into a plurality of groups, and the slave stations of each group and the master station are connected via a pair of data transmission lines and also connected via an auxiliary line, and the master station and each slave station are connected. Data is transmitted and received to and from the station via polling signals and response signals via each data transmission line, and when the status change occurs in the slave station of any group, the slave station includes information specific to the group. When the status change signal is transmitted to the auxiliary line for a certain period of time, the master station temporarily stops transmitting the polling signal when the status change signal is received, and the master station identifies the group in which the status change has occurred from the status change signal. , A status change slave station polling signal including information specifying the group is transmitted to one of the data transmission lines, and when the slave station with the status change receives the status change slave station polling signal, the status change from the slave station Data Transmitted to the auxiliary line, resumes polling transmission method to exchange data by the response signal polling signal after transmission of the end of state change slave station polling signal to all slave stations in the group master station receives the state change data. 4. A master station and a plurality of slave stations are provided as a pair of data transmission circuits.
Each data transmission between the master station and each slave station by connecting via the line
Data by polling signal and response signal via the line
When a status change occurs at any of the slave stations
The carrier frequency is different from the response signal from the slave station.
The change signal is transmitted instead of the response signal, and the master station
Transmission of polling signal is temporarily stopped when a signal is received.
Then, the master station sequentially polls all slave stations for status changes.
Signal and status change station search signal is transmitted to cause status change
The slave station detected the called station from the status change station search signal.
Sometimes the status change data is transmitted and the status change is sent to all slave stations.
Transmission of the active polling signal and status change station search signal
And then send and receive data by polling signal and response signal
Transmission method to restart. 5. A plurality of slave stations are divided into a plurality of groups, the slave stations of each group and the master station are connected via a pair of data transmission lines, and each data transmission is performed between the master station and each slave station. Data is transmitted / received by a polling signal and a response signal via a line, and when a state change occurs in a slave station of any group, the carrier frequency is different from that of the response signal from the slave station and includes group-specific information. When the master station receives the status change signal and transmits the status change signal instead of the response signal, it temporarily stops the transmission of the polling signal, and when the master station identifies the group in which the status change has occurred from the status change signal. A status change slave station polling signal including information for identifying the group is transmitted, and when the slave station having the status change receives the status change slave station polling signal, the status change data is transmitted from the slave station to the master station. Changes state Resumes polling transmission system exchanges data by a polling signal and the response signal after the transmission of the status change slave station polling signal has been completed for all slave stations in the group received the over data. 6. A base station and a plurality of slave stations are connected via a pair of data transmission lines, and data by a polling signal and a response signal is transmitted between the master station and each slave station via each data transmission line. When a status change occurs in any of the slave stations, the carrier frequency is different from the response signal from the slave station and a status change signal containing information specific to the slave station is transmitted instead of the response signal, and the master station transmits the status change signal. When a status change signal is received, the transmission of the polling signal is temporarily stopped, and when the master station identifies the slave station in which the status change has occurred from the status change signal, the status change slave station polling including information for specifying the slave station When a slave station transmitting a signal and having a status change receives a status change station polling signal, it transmits status change data from the slave station, and after the master station receives the status change data, a polling signal and a response signal Data exchange by Resume polling transmission system. 7. A base station and a plurality of slave stations are connected via a pair of data transmission lines, and data by a polling signal and a response signal is transmitted between the master station and each slave station via each data transmission line. When a status change occurs in any of the slave stations, the carrier frequency is different from the response signal from the slave station and a status change signal containing information specific to the slave station is transmitted instead of the response signal, and the master station transmits the status change signal. When the status change signal is received, transmission of the polling signal is temporarily stopped, and when the master station cannot identify the slave station with the status change from the status change signal, the master station sequentially sends status change polling signals to all slave stations. And the status change station search signal, the status change data is transmitted when the slave station that has changed the status identifies the called station from the status change station search signal, and the status change polling signal is sent to all slave stations. And status change station search Resumes polling transmission system exchanges data by a polling signal and the response signal after the transmission of the No. has been completed.