Control monitoring signal transmission system

Abstract

The present invention provides a master station for transmitting and receiving data to and from a control unit, and a plurality of slave stations for transmitting and receiving data to and from the master station via a common transmission line by a transmission synchronization method. Data transmission and reception between the master station and the slave stations are performed by superimposing data on a frame repeatedly transmitted from the master station, a transmission frequency signal employed for synchronization between the master station and the slave stations is configured from a plurality of clock pulses, each clock pulse has a data pulse for data transmission between the master station and the slave stations, the data pulse is distributed to each slave station, and the data pulse is distributed to each slave station. A numerical value, which is an address at which a substation obtains a data pulse allocated to the substation, is set for each substation. The data pulse is divided into a plurality of regions by time, and at least one of the regions is used as a change-possible region for any one of data transmission from the master station and data transmission from the slave station.

Description

Technical Field

[0001] The present invention relates to a control monitoring signal transmission system that saves signal lines between a mother station arranged on the control side and a plurality of substations arranged on the controlled side, connects them with a common transmission line, and transmits data by a transmission synchronization method such as synchronization with a transmission frequency. Background Art

[0002] In a system that centrally controls a large number of devices arranged in a facility, the number of lines is reduced, i.e., so-called line saving. As a general method of this line saving, a method is widely adopted in which a master station and a plurality of slave stations having a parallel signal and a serial signal conversion function are respectively connected to the control unit and the plurality of devices, instead of directly connecting the plurality of devices arranged on the controlled side to the control unit arranged on the control side, and data is transmitted and received by serial signals through a common transmission line between the master station and the plurality of slave stations.

[0003] Furthermore, as a method of transmitting and receiving data through a common transmission line and using a serial signal, a transmission synchronization method such as synchronizing with a transmission frequency is widely adopted. Then, a method of transmitting and receiving data between a master station and multiple slave stations by synchronizing with a serial pulse signal (hereinafter referred to as a "transmission frequency signal") is widely adopted.

[0004] In the method of transmitting and receiving data by synchronizing the transmission frequency signal, the frame repeatedly transmitted from the mother station is divided by time, and a data area with a determined transmission direction (transmission from the mother station to the child station, or transmission from the child station to the mother station) is allocated to each of the multiple child stations, and data is overlapped in the data area. Furthermore, each child station is set with an address representing the numerical value of the timing for obtaining the data area allocated to the self-station, and each of the multiple child stations transmits and receives data with the mother station in the data area allocated to the self-station, thereby preventing the conflict of transmission and reception of multiple child stations.

[0005] As an example of such data transmission and reception, there is a control monitoring signal transmission system proposed in Japanese Patent Application Laid-Open No. 2002-152864.

[0006] [Prior art literature] [Patent Literature] [Patent Document 1] Japanese Patent Application Publication No. 2002-152684 Summary of the invention

[0007] [Problems to be solved by the invention] In the conventional method in which a mother station and a slave station synchronize and send and receive data by transmitting a frequency signal, the frequency of the transmission frequency signal is limited due to the structure of the system. Furthermore, the number of data areas (control data areas) used for data transmission from the mother station to the slave station is the same as the number of data areas (monitoring data areas) used for data transmission from the slave station to the mother station.

[0008] Therefore, when there is a difference between the number of control data areas and the number of monitoring data areas required for data transmission and reception between the mother station and the slave station, the frequency of the transmission frequency signal becomes greater than necessary, so the frame becomes redundant and the response speed is reduced.

[0009] For example, when the number of control data areas or monitoring data areas required for data transmission and reception between the mother station and the slave station exceeds 128, the frequency of the transmission frequency signal has to be 256, and the response speed becomes half of that when using a transmission frequency signal of 128.

[0010] Therefore, the object of the present invention is to provide a control and monitoring signal transmission system that is not limited by the frequency number of the transmission frequency signal for synchronizing the mother station and the slave station, and can correspond to the number of control data areas and the number of monitoring data areas required in the data transmission and reception between the mother station and the slave station without reducing the response speed.

[0011] [Technical means to solve the problem] According to the control monitoring signal transmission system of the present invention, it includes: a mother station for transmitting and receiving data with a control unit and a plurality of substations for transmitting and receiving data with the mother station through a common transmission line and by a transmission synchronization method. The transmission and reception of data between the mother station and the substation is performed by overlapping the data on the signal frame repeatedly transmitted from the mother station. The transmission frequency signal used by the mother station and the substation for synchronization is composed of a plurality of clock pulses, each of which has a data pulse for data transmission between the mother station and the substation, and the data pulse is allocated to each of the substations. For each of the substations, a numerical value of an address is set as the timing for the substation to obtain the data pulse allocated to the substation. The data pulse is divided into a plurality of regions by time, and at least one of the regions is used as a changeable region for either the data transmission from the mother station or the data transmission from the substation.

[0012] A management data area for use by all the substations may also be provided in the signal frame. The mother station uses the management data area to send indication data indicating either a first state in which the changeable area is used for data transmission from the mother station or a second state in which the changeable area is used for data transmission from the substation. The substation receives and sends data corresponding to the indication data.

[0013] A management data area for use by all the substations may also be provided in the signal frame. The mother station uses the management data area and specifies any one of the addresses to send indication data indicating a first state in which the changeable area is used for data transmission from the mother station and a second state in which the changeable area is used for data transmission from the substation. When the specified address is consistent with the address of the substation itself, the substation sends and receives data corresponding to the indication data.

[0014] A management data area for use by all the substations may also be provided in the signal frame. The mother station uses the management data area and specifies any one of the addresses to send indication data indicating a first state in which the changeable area is used for data transmission from the mother station and a second state in which the changeable area is used for data transmission from the substation. When the specified address is consistent with the address of the substation itself, the substation sends and receives data corresponding to the indication data.

[0015] A management data area for use by all the substations may also be provided in the signal frame. The mother station uses the management data area and specifies the address, and collects information on the data received by each substation from the mother station and the data sent to the mother station. Based on the information, for the possible change area of ​​each data pulse, a first state for data transmission from the mother station and a second state for data transmission from the substation are determined. The management data area is used and the address is specified to send indication data representing either the first state or the second state. When the specified address is consistent with the address of the substation itself, the substation receives and sends data corresponding to the indication data.

[0016] [Comparison with the efficacy of existing technologies] According to the present invention, the overlapping data pulses of the data transmitted from the mother station and the data transmitted from the slave station are divided into a plurality of regions by time, and at least one of the regions is used as a changeable region for use in either the data transmission from the mother station or the data transmission from the slave station. Thus, when there is a difference between the number of control data regions and the number of monitoring data regions required for data transmission and reception between the mother station and the slave station, the changeable region can be used as a more necessary region. Therefore, the number of control data regions and the number of monitoring data regions required for data transmission and reception between the mother station and the slave station can be matched without a decrease in response speed, without being limited by the number of frequencies of the transmission frequency signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The diagram shows the transmission sequence of transmission signals of an embodiment of a control monitoring signal transmission system according to the present invention, wherein (a) is a schematic diagram when the entire possible change area is used for data transmission from a substation, (b) is a schematic diagram when the entire possible change area is used for data transmission from a mother station, and (c) is a schematic diagram when a portion of the possible change area is used for data transmission from a mother station and the other portion is used for data transmission from a substation.

[0018] Figure 2 It is a system configuration diagram of the same embodiment.

[0019] Figure 3 This is the functional block diagram of the mother station.

[0020] Figure 4 It is the time series diagram of the transmission signal.

[0021] Figure 5 This is the functional block diagram of the input substation.

[0022] Figure 6 This is the functional block diagram of the output substation.

[0023] Figure 7 FIG. 4 is a time sequence diagram of a transmission signal of another embodiment of the control monitoring signal transmission system according to the present invention. DETAILED DESCRIPTION

[0024] An embodiment of a control monitoring signal transmission system according to the present invention is described.

[0025] This control monitoring signal transmission system is used to centrally control a large number of devices and machines installed in facilities such as factories. Figure 2 As shown, it is composed of a control unit 1 and a master station 2 connected to common data signal lines DP and DN (hereinafter referred to as transmission lines), and a plurality of input substations 4, output substations 5, and input / output substations 6 arranged in the facility as the controlled side and connected to the transmission lines. In addition, the type and number of substations connected to the transmission line can be appropriately determined according to the state of use of the system. Furthermore, Figure 2 For the convenience of illustration, not all substations constituting the system are shown.

[0026] The input unit 7 connected to the input substation 4, the output unit 8 connected to the output substation 5, and the input / output unit 9 connected to the input / output substation 6 are devices arranged in a facility serving as a controlled side.

[0027] As what corresponds to the input unit 7, for example, a reed switch, a micro switch, a push button switch, a photoelectric switch, and other various sensors can be cited, but it is not limited to these.

[0028] Examples of the object corresponding to the output unit 8 include an actuator, a (stepping) motor, a solenoid, an electromagnetic valve, a relay, a transistor, and a light bulb, but the object is not limited to these.

[0029] The input / output unit 9 is a device having the functions of both the input unit 7 and the output unit 8. The device may be a temperature control, timer, counter, or the like, which has both the function of transmitting information to the mother station 2 and the function of performing output operations based on the data transmitted from the mother station 2.

[0030] In addition, the input unit 7 may be an input unit integrated type substation 70 integrated with the input substation 4. Furthermore, the output unit 8 may be an output unit integrated type substation 80 integrated with the output substation 5.

[0031] The control unit 1 includes a management judgment mechanism 11 having a calculation function and an input / output unit 12. The management judgment mechanism 11 receives data from the master station 2 through the input / output unit 12, and performs necessary calculations based on a computer program stored therein.

[0032] <Composition of the mother station> like Figure 3 As shown, the mother station 2 is connected to the transmission line and includes: an output data unit 21, a management data unit 22, a timing generating unit 23, a mother station output unit 24, a mother station input unit 25, and an input data unit 26. Then, the control signal is superimposed on a voltage frequency signal having a predetermined period and duty ratio and sent, and the monitoring data sent from the input substation 4, the output substation 5, and the input / output substation 6 (hereinafter, these are aggregated as "substations 4, 5, 6") are captured and output to the input / output unit 12 of the control unit 1.

[0033] The data output unit 21 delivers the data received from the control unit 1 to the parent station output unit 24 as sequence data.

[0034] The management data unit 22 delivers data necessary for instructing a slave station in a management control data area described later to the master station output unit 24 as sequence data based on the data received from the control unit 1 .

[0035] The timing generating unit 23 is composed of an oscillation circuit (OSC) 31 and a timing generating mechanism 32 . Based on the oscillation circuit (OSC) 31 , the timing generating mechanism 32 generates the timing frequency of the system and delivers it to the mother station output unit 24 and the mother station input unit 25 .

[0036] The mother station output unit 24 is composed of a control data generating mechanism 33 and a line driver 34. The control data generating mechanism 33 transmits a transmission signal having a transmission frequency signal superimposed with control data through the line driver 34 based on the data received from the output data unit 21 and the timing frequency received from the timing generating unit 23.

[0037] In this embodiment, a voltage frequency signal that transmits the timing frequency by using a change in voltage is used as the transmission frequency signal. However, there is no limitation on the method of transmitting the timing frequency, and other methods suitable for the use situation may also be used.

[0038] The voltage frequency signal is composed of multiple clock pulses. Figure 4 In the transmission signal shown, each clock pulse has a period (hereinafter referred to as "high period") during which the voltage potential Ep is higher than the threshold value Est. Furthermore, in this embodiment, the voltage potential Ep is +24V.

[0039] The high period plays the role of the power supply voltage for synchronization frequency and communication, but as long as these are met, the width and voltage level are not limited to this embodiment. It can be appropriately determined according to the use environment and use status. For example, it can also be a negative voltage lower than the ground level for a specified time.

[0040] Each clock pulse further includes a data pulse for data signaling between the master station 2 and the slave stations 4 , 5 , 6 .

[0041] In this embodiment, in each data pulse, the data value is represented by a voltage level. However, the voltage level representing the data value can be appropriately determined according to the use environment and the use state. For example, it can also be a negative voltage lower than the ground potential.

[0042] Each data pulse is divided into four regions in time. In the following description, the four regions of the data pulse are defined as V region, i region, f region and P region in order from the time point closer to the time point when the voltage potential Ep during the high period drops.

[0043] The V area of ​​this embodiment is equivalent to the changeable area of ​​the present invention, and can be used for data transmission from the mother station 2 and data transmission from the slave stations 4, 5, and 6. Furthermore, in this embodiment, the i area and the f area are only used for data transmission from the slave stations 4, 5, and 6, and the P area is only used for data transmission from the mother station 2.

[0044] In addition, each of the V region, i region, f region, and P region can be used separately according to the situation. Specifically, any region of the V region, i region, f region, and P region can be used as a changeable region, or any region can be used for data transmission from a slave station and data transmission from a master station, and multiple changeable regions can be set. However, in this embodiment, considering the function of the synchronization frequency during the high-order period and the power supply voltage for communication, the P region including the rise during the high-order period is preferably used in a state where the high-order period is normal.

[0045] In this embodiment, in any of the V region, the i region, and the f region, the potential VL lower than the threshold value Ect is the voltage level representing the logic data value "1". Furthermore, the potential VM higher than the threshold value Ect is the voltage level representing the logic data value "0". Then, in this embodiment, the threshold value Ect is set between 10V and the ground level (about 6V), but its size is not limited and can be set according to the use status and use environment. In addition, there is no limitation on the correspondence between the voltage level representing the data value and the logic data value, and it can be appropriately determined according to the use environment and use status.

[0046] In the P region of this embodiment, a potential lower than the threshold value Est is a voltage level representing a logic data value "1". Furthermore, a potential higher than the threshold value Est is a voltage level representing a logic data value "0". In addition, as in the V region, i region, and f region, the correspondence between the voltage level representing the data value and the logic data value is not limited and can be appropriately determined according to the use environment and the use status.

[0047] In the voltage frequency signal, a series of high-order periods with a specified number of times appears is regarded as a frame, which is repeatedly sent from the mother station 2. Then, if Figure 1 As shown, a frame includes a management data area and a control and monitoring data area.

[0048] Furthermore, at the beginning of the frame, a start signal ST is sent to maintain the voltage level Ep during the high period longer than the high period, so that each frame is distinguished. In addition, the length of the start signal ST is not limited as long as it can be distinguished from the high period, and can be appropriately determined in consideration of the use conditions.

[0049] In the control monitoring data area, the predetermined areas are allocated to the substations 4, 5, and 6. Then, the control data from the mother station 2 for the output substation 5 and the input / output substation 6 are overlapped in the area allocated to the target substation, or the monitoring data from the input substation 4 and the input / output substation 6 for the mother station 2 are overlapped in the area allocated to the substation that transmits the monitoring data. In this way, the control monitoring data area is used for the transmission and reception of normal data between the mother station 2 and the substations 4, 5, and 6.

[0050] The management data area is used to send and receive non-standard data that cannot be sent and received by the control monitoring data. The instruction data of the present invention is sent using this management data area, and the sending sequence will be described in detail later.

[0051] The mother station input unit 25 is composed of a line receiver 35 and a monitoring data acquisition mechanism 36. The line receiver 35 receives a transmission signal from the transmission line, performs waveform shaping, and delivers the signal to the monitoring data acquisition mechanism 36.

[0052] The monitoring data acquisition mechanism 36 obtains the timing of acquiring the data value by using the timing frequency delivered from the timing generation unit 23, and acquires the data based on the digital value of the voltage level of the voltage frequency signal delivered from the line receiver 35. Then, the normal data DIO overlapped in the control monitoring data area and the management data DEX overlapped in the management data area are delivered to the input data unit 26.

[0053] The input data unit 26 converts the serial input data received from the monitoring data acquisition mechanism 36 into parallel data, and outputs the parallel data to the input / output unit 12 of the control unit 1 as monitoring data and management monitoring data.

[0054] <Input slave station configuration> like Figure 5 As shown, the input substation 4 has a substation input unit 40 that performs main calculation processing, a substation line receiver 48 and a substation line driver 49 arranged between the substation input unit 40 and the transmission line. The substation line receiver 48 receives a voltage frequency signal from the transmission line, and the substation line driver 49 sends monitoring data.

[0055] The substation input unit 40 has a transmission and receiving mechanism 41, a management and control data acquisition mechanism 42, an address acquisition mechanism 43, an address setting mechanism 44, a management and monitoring data transmission mechanism 45, an input mechanism 46, a monitoring data transmission mechanism 47 and a changeable area activation mechanism 61.

[0056] In addition, the input slave station 4 of this embodiment has an MCU as a microcomputer control unit of an internal circuit, and this MCU functions as a slave station input unit 40.

[0057] The substation line receiver 48 receives the transmission signal from the transmission line, performs waveform shaping and delivers it to the transmission receiving mechanism 41 .

[0058] The transmission receiving mechanism 41 determines the threshold values ​​Est and Ect of the voltage level, and delivers the digital value of the voltage level of the transmission signal delivered from the slave station line receiver 48 to the management control data acquisition mechanism 42 , the address acquisition mechanism 43 and the management monitoring data sending mechanism 45 .

[0059] The management control data acquisition mechanism 42 determines the start signal ST based on the digital value of the voltage level of the transmission signal. Then, taking the timing when the start signal ST ends (falling in this embodiment) as the starting point, the management data is acquired based on the digital value of the voltage level of the data IO area in the management data area. Then, it is delivered to the processing mechanism for executing the processing based on the management data. In addition, Figure 6 In the figure, the changeable area enabling means 61 is shown as a processing means when the instruction data is used as management data, but illustrations of other processing means are omitted.

[0060] The address acquisition mechanism 43 determines the start signal ST based on the digital value of the voltage level of the transmission signal, and counts the high period starting from the timing when the start signal ST ends (falling in this embodiment). Then, the timing when this count value matches the self-station address data set by the address setting mechanism 44 is obtained. In addition, this timing is the timing when the area allocated to the self-station (hereinafter referred to as the "self-station area") in the control monitoring data area starts (hereinafter referred to as the "self-station area start timing").

[0061] The address acquisition unit 43 obtains the timing of the V region, the i region, and the f region based on the elapsed time starting from the fall of the high period.

[0062] Then, the address acquisition means 43 which obtains the start timing of the own station area activates the monitoring data signaling means 47 during the period of the i area and f area allocated to the own station and the period of the V area when the signal indicating the activation of the V area is output by the changeable area activation means 61. In addition, when the own station area is composed of a plurality of data pulses, the monitoring data signaling means 47 is activated during the period when the i area and f area allocated to the own station and the activated V area appear until the end of the own station area.

[0063] The management monitoring data signaling unit 45 determines the start signal ST based on the digital value of the voltage level of the transmission signal, and then outputs the monitoring data in the management data area as needed, starting from the timing when the start signal ST ends.

[0064] In addition, the monitoring data transmitted from the management monitoring data transmitting means 45 is transmitted only when the data to be transmitted to the master station 2 is delivered from the processing means for executing processing based on the management data.

[0065] The input mechanism 46 delivers data to the monitoring data transmitting mechanism 47 based on the input from the input unit 7 .

[0066] When the monitoring data signaling mechanism 47 is enabled by the address acquisition mechanism 43 , the data delivered from the input mechanism 46 is transmitted as monitoring data signal through the substation line driver 49 .

[0067] When the changeable area enabling mechanism 61 is delivered indication data from the management control data acquisition mechanism 42, when the indication data represents the second state (the state in which the changeable area is used to send data from the substations 4, 5, and 6), a signal indicating that the V area is enabled is output to the address acquisition mechanism 43.

[0068] <Output substation configuration> like Figure 6 As shown, the output substation 5 has a substation output unit 50 that performs the main operation processing, and a substation line receiver 48 and a substation line driver 49 arranged between the substation output unit 50 and the transmission line. The substation line receiver 48 receives the transmission signal from the transmission line and outputs the information based on the control data to the output unit 8 to activate or stop the output unit 8. Furthermore, when the data in the management data area is sent and received, the monitoring data is sent through the substation line driver 49. In addition, Figure 6 Components that are substantially the same as those of the input substation 4 are given the same reference numerals, and descriptions thereof are simplified or omitted.

[0069] The substation output unit 50 has a transmission and receiving mechanism 41, a management and control data acquisition mechanism 42, an address acquisition mechanism 43, an address setting mechanism 44, a management and monitoring data transmission mechanism 45, a control data acquisition mechanism 51, an output mechanism 52 and a changeable area activation mechanism 61.

[0070] The output slave station 5 of this embodiment also has an MCU as a microcomputer control unit of an internal circuit, similarly to the input slave station 4 , and this MCU functions as a slave station output unit 50 .

[0071] The transmission receiving mechanism 41 of the output substation 5 delivers the digital value of the voltage level of the transmission signal delivered from the substation line receiver 48 to the management control data acquisition mechanism 42, the address acquisition mechanism 43, the management monitoring data sending mechanism 45 and the control data acquisition mechanism 51.

[0072] The address acquisition mechanism 43 of the output substation 5 obtains the start timing of the own station area and the timing of the V area and the P area. Then, the address acquisition mechanism 43 that obtains the start timing of the own station area enables the control data acquisition mechanism 51 during the period of the P area allocated to the own station and the period of the V area when the signal indicating the activation of the V area is output by the changeable area activation mechanism 61. In addition, when the own station area is composed of a plurality of data pulses, the control data acquisition mechanism 51 is enabled every time the P area allocated to the own station and the enabled V area appear until the end of the own station area.

[0073] When enabled by the address capture mechanism 43 , the control data capture mechanism 51 captures control data based on the digital value of the voltage level of the transmission signal delivered from the transmission and reception mechanism 41 , and delivers the control data to the output mechanism 52 .

[0074] The output mechanism 52 outputs information based on the control data delivered from the control data acquisition mechanism 51 to the output unit 8 to activate or stop the output unit 8 .

[0075] When the indication data is delivered to the changeable area enabling mechanism 61 of the output substation 5 from the management control data acquisition mechanism 42, when the indication data is an indication of the first state (the state in which the changeable area is used to send data from the mother station 2), a signal indicating that the V area is enabled is output to the address acquisition mechanism 43.

[0076] <Configuration of input and output substation> The input / output substation 6 has the functions of both the input substation 4 and the output substation 5, and has a substation input / output unit having the structure of both the substation input unit 40 and the substation output unit 50. However, since this structure is substantially the same as the substation input unit 40 and the substation output unit 50, the illustration and description thereof are omitted.

[0077] <Instruction data transmission sequence> Reference Figure 1 , the order of sending the indication data is explained.

[0078] like Figure 1 As shown in (a), when all the changeable areas of the control monitoring data area are used for data transmission from the input substation 4 and the input / output substation 6, the mother station 2 uses the management data area to transmit the indication data indicating the second state to all the substations 4, 5, and 6 in each frame. In the input substation 4 and the input / output substation 6 that receive the indication data, the V area of ​​the changeable area is used for transmission from the own station.

[0079] like Figure 1 As shown in (b), when all the changeable areas of the control monitoring data area are used for data transmission from the mother station 2, the mother station 2 uses the management data area to transmit the indication data indicating the first state to all the substations 4, 5, and 6 in each frame. In the output substation 5 and the input / output substation 6 that receive the indication data, the data in the V area is captured as the control data from the mother station 2.

[0080] like Figure 1As shown in (c), the changeable area of ​​the control monitoring data area can also be used partly for data transmission from the mother station 2, and the other part for data transmission from the input substation 4 and the input / output substation 6. In this case, the changeable area activation mechanism 61 of the substations 4, 5, and 6 has the function of storing instruction data. Then, at a predetermined time such as when the system is started, the mother station 2 uses the management data area to specify the address of each output substation 5 and transmits the instruction data indicating the first state, and specifies the address of each input substation 4 and transmits the instruction data indicating the second state. For the input / output substation 6, either the instruction data indicating the first state or the instruction data indicating the second state is transmitted by specifying the address of the corresponding input / output substation 6 according to the necessary usage method.

[0081] When the designated address matches the address of the own station, the input substation 4, 5, and 6 receive and store the instruction data. The input substation 4 uses the V area for the signal from the own station, and the output substation 5 extracts the data in the V area as the control data from the mother station 2. Furthermore, the input / output substation 6 uses the V area for the signal from the own station and extracts the data in the V area as the control data from the mother station 2 in accordance with the instruction data.

[0082] The state of the changeable area, that is, whether it is the first state or the second state, is determined based on the number of control data areas and the number of monitoring data areas required for data transmission and reception between the master station 2 and the slave stations 4, 5, and 6. Then, although the number of necessary control data areas and the number of monitoring data areas are determined at the time of system design, there are cases where the system configuration is changed in consideration of the device and equipment in use. In such a case, it is preferable to determine the state of the changeable area based on the current system configuration.

[0083] In this embodiment, it is assumed that the mother station 2 specifies the address of each of the slave stations 4, 5, and 6 using the management data area, and collects information about the data received from the mother station 2 and the data sent to the mother station 2 for each of the slave stations 4, 5, and 6. Then, based on the collected information, it is possible to determine whether the first state or the second state is used for the changeable area of ​​each data pulse.

[0084] In this embodiment, the data values ​​of the V region, i region, f region, and P region are captured based on the voltage level detected at a predetermined timing within the region. That is, data is transmitted and received by making the voltage level of the transmission signal correspond to the data value. However, in the P region including the rising of the high period, data can also be transmitted and received by making the rising timing of the high period correspond to the data value.

[0085] Figure 7 The following is a time sequence table of a transmission signal of an embodiment of transmitting and receiving data by making the rising timing of the high period correspond to the data value in the P region. Figure 7 In the description of the embodiment shown, Figures 1 to 6 In the illustrated embodiment, substantially the same parts are assigned the same symbols, and the description thereof is omitted or simplified.

[0086] Figure 7 In the embodiment shown, the rising timing of the high period of the P region corresponds to the data value. In addition, the rising timing of the high period of the P region can be obtained by measuring and calculating the elapsed time from the fall of the high period to the rise.

[0087] Figure 7 In the example, a time TL longer than the specified threshold value indicates a data value "1" corresponding to a small time width, and a time TS shorter than the specified threshold value indicates a data value "0" corresponding to a large time width. There is no restriction on the correspondence between the rising timing of the high-level period and the data value, and it can be appropriately set according to the usage conditions.

[0088]

Explanation of symbols

Claims

1. A control monitoring signal transmission system, comprising: a master station for transmitting and receiving data with a control unit, and a plurality of slave stations for transmitting and receiving data with the master station via a common transmission line in a transmission synchronization manner, The data transmission and reception between the mother station and the slave station is performed by overlapping the data with the frame repeatedly transmitted from the mother station. The transmission frequency signal used by the mother station and the slave station for synchronization is composed of a plurality of clock pulses, each of which has a data pulse for data transmission between the mother station and the slave station. The data pulse is distributed to each substation. For each slave station, a numerical value of an address is set as the timing for the slave station to obtain the data pulse assigned to the slave station. The data pulse is divided into a plurality of regions in time, and at least one of the regions is used as a changeable region for use in either the data signal from the master station or the data signal from the slave station.

2. A control monitoring signal transmission system as described in claim 1, wherein a management data area is provided in the signal frame for use by all the substations, and the mother station uses the management data area to send indication data indicating any one of a first state in which the changeable area is used for data transmission from the mother station and a second state in which the changeable area is used for data transmission from the substation, and the substation sends and receives data corresponding to the indication data.

3. A control monitoring signal transmission system as described in claim 1, wherein a management data area is provided in the signal frame for use by all the substations, the mother station uses the management data area and specifies any one of the addresses to send indication data indicating a first state in which the changeable area is used for data transmission from the mother station and a second state in which the changeable area is used for data transmission from the substation, and the substation sends and receives data corresponding to the indication data when the specified address is consistent with the address of the own station.

4. A control and monitoring signal transmission system as described in claim 1, wherein a management data area for use by all the substations is provided in the signal frame, the mother station uses the management data area and specifies the address, and collects information on the data received by the substation from the mother station and the data sent to the mother station for each substation, and based on the information, for the possible change area of ​​each data pulse, determines a first state for data transmission from the mother station and a second state for data transmission from the substation, uses the management data area and specifies the address to send indication data representing either the first state or the second state, and when the specified address is consistent with the address of the substation, the substation sends and receives data corresponding to the indication data.

Images