JPH03168899A - Monitor and control system and transmitting method - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency and reliability of a monitor and control system by allowing a master station to call a slave station at a transmission speed set up in accordance with the degree of reliability of transmission. CONSTITUTION:At least one slave station, i.e. a terminal equipment 2, is connected to a central monitor and control equipment 1 to be the master station through a common transmission line 3. Each slave station is set up to a transmission speed corresponding to the degree of reliability of transmission with the master station and the master station calls each slave station at the set transmission speed. Consequently, the transmission efficiency can be prevented from being dropped without using an expensive wire material for the transmission line 3 and highly reliable transmission processing can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monitoring control system and a transmission method used in disaster prevention systems, crime prevention systems, etc. [Prior Art] Generally, in a supervisory control system, a plurality of slave stations, or terminal devices, are connected to a central supervisory control device as a master station via transmission lines, and the slave stations are controlled by temperature, smoke, etc. While the detection data signal from the sensor device to be detected is sent back to the master station via the transmission line, the master station sends a command signal to a predetermined slave station via the transmission line, and the slave station that receives the command signal,
Based on this, controlled devices such as smoke prevention equipment and air conditioning equipment are controlled. By the way, conventionally, when transmitting and receiving transmission signals such as borching between a master station and a plurality of slave stations, the master station determines a constant transmission speed for all slave stations, and Transmission was performed at the same transmission speed to all slave stations. [Problem to be solved by the invention] In the past, the transmission speed of transmission signals exchanged between a master station and a slave station was set uniformly, and when there were a large number of slave stations, they spread over a wide range. In such cases, in order to ensure reliable transmission, it was necessary to uniformly set the transmission speed of all slave stations to the one with the worst transmission conditions, that is, the one with the lowest transmission reliability. ．． Accordingly, the transmission speed for all slave stations is set to be low.
The drawback was that efficient transmission could not be performed. One way to prevent such a reduction in transmission speed is to use high-quality, expensive materials for the transmission line, which have minimal waveform distortion even when the transmission signal is transmitted at normal speed under poor transmission conditions. However, when using such expensive materials, there were drawbacks such as the high cost of the entire system. The present invention provides a supervisory control system and a transmission method that can prevent transmission efficiency from decreasing and perform highly reliable transmission processing without using expensive wire materials for transmission lines. The purpose is to. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a system in which each slave station is set to a transmission speed depending on the degree of transmission reliability with the master station, and the master station is Each slave station is called at the specified transmission speed. The transmission speed set for each slave station is maintained in a changeable manner on the master station side, and is set individually for each slave station on the master station side, or is set for at least two children out of each thousand stations. The transmission speed to the station is. If they are the same, the transmission rates for the at least two slave stations are set as a group in the master station measurement. Also, when a slave station receives a call from the master station, it detects the transmission speed, and if the detected transmission rate corresponds to the transmission speed data set for itself, the slave station accepts the call from the master station. It is becoming more crowded. The above-mentioned transmission speed data may be set so that it can be changed by the slave station based on a command from the master station, or it may be set so that it can be changed locally by the slave station. [Operation] Each slave station is individually set to a transmission rate depending on the degree of transmission reliability with the master station on the master station side, or set as a group, and this transmission rate is set, for example. It is held so that it can be changed on the master station side. When a master station calls a certain slave station, it calls the slave station at a transmission rate that is set and maintained in correspondence with this slave station. For example, when a slave station has good transmission conditions, a call is made at a high transmission speed, and when a slave station has poor transmission conditions, a call is made at a slow transmission speed. Furthermore, if the transmission speed data for each slave station is preset by a command from the master station or locally on the slave station side, when the master station calls a particular slave station at a transmission rate suitable for that slave station, The slave station detects the transmission rate of the call from the master station, determines that this corresponds to the transmission rate data preset in the slave station, accepts the call, and performs the prescribed processing. On the other hand, if a master station calls a specific slave station at a transmission rate that is not suitable for that slave station, the slave station determines that the transmission rate of the call does not correspond to the transmission rate data and rejects the call from the master station. It will not be accepted or imported. Therefore, even if there are slave stations with the same address and different transmission speeds on the same transmission path, a particular slave station can be correctly recognized. [Example] Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a schematic block diagram of an embodiment of a supervisory control system according to the present invention. Referring to FIG. 1, the central supervisory control device 1 as a master station has a common transmission line F! At least one slave station, ie, terminal device 2, is connected via @3. FIG. 2 is a diagram showing a configuration example of the master station 1. In this configuration example, the master station 1 includes a central processing unit 11 that performs program control, and a memory that stores processing programs and data for each slave station 2. unit 12, central processing unit 11 and interface 1
The transmission signal R x ,
A transmission circuit 14 that transmits and receives T It is equipped with The storage unit 12 of the master station 1 is provided with a data table 18 for each slave station, and in the example shown in FIG. The transmission speed is set for each slave station 2 accordingly. That is, transmission speeds v1 to Vn are assigned to each slave station #1 to #n, respectively. FIG. 3 is a diagram showing an example of the format of a transmission signal RX sent from the transmission circuit 14 of the master station 1 to each slave station 2, and this transmission signal RX includes a header HD, a transmission type MT, and a transmission type MT. , address ADDR, and data DT. The header HD is provided at the beginning of the transmission signal Rx in order to synchronize with the slave station 2.
The central processing unit 11 of the header HD defines the transmission speed based on the length L of the pulse P of the header HD, and transmits this to the slave station 2 side. Furthermore, the transmission type MT is information for giving various types of instructions to the slave station 2, and the transmission type MT is information for giving various types of instructions to the slave station 2.
can specify a physical address or a logical address. FIG. 4 is a configuration diagram of each slave station 2. Each slave station 2 is provided corresponding to a sensor device 4 that detects temperature, smoke, etc., and controlled devices 5 such as smoke prevention equipment and air conditioning equipment that are controlled by commands from the master station 1. A transmission processing device 6 and a transmission speed detection circuit 7 are provided in the slave station 2. The transmission processing device 6 is, for example, a horizontal structure as shown in FIG.
Memory 21 such as PROM and transmission signal R from master station 1
The reception interface 30 that receives X and the transmission signal RX from the master station 1 store the transmission type MT, address ADDR (physical address or logical address), and data DT that are sent following the header Transmission type register 31. A type identification unit 34 that identifies the transmission type MT stored in the address register 32, data register 33, and transmission type register 31 and performs control according to the transmission type MT, and a physical address unique to the slave station 2 are set. a physical address buffer 35 in which a logical address unique to the slave station 2 is set; and a logical address buffer 36 in which a logical address unique to the slave station 2 is set; an address converter 37 that compares the logical address with the logical address set in the logical address buffer 36 when the logical address is stored in the address register 32; and the data DT stored in the data register 33; is latched and a digital signal D is sent to the sensor device 4 and controlled device 5. a latch circuit 38 for outputting the digital signal D1 from the sensor device 4; a sampling circuit 39 for performing sampling processing on the digital signal D1 from the sensor device 4; and an A/D converter 40 for converting the analog signal A1 from the sensor device 4 into a digital signal. , a return data register 41 in which data F1 from the sampling circuit 39 or the A/D converter 40 or information F2 read from the memory 21 is stored as return data, and the return data stored in the return data register 41 is transmitted. Signal T
a transmission interface 42 that transmits to the master station 1 as x;
It has a transmission speed buffer 46 that stores transmission speed data TV when it is read out as information F2 from the memory 21, and a frequency dividing circuit whose frequency division ratio is determined by the transmission speed data TV of the transmission speed buffer 46. The transmission processing device 6 includes a clock generator 45 that generates a clock signal CLK1 having a frequency corresponding to the clock signal CLK1 to each part of the transmission processing device 6. The transmission speed detection circuit 7 of the slave station 1 has a configuration as shown in FIG. 6, for example, and receives the clock pulse generator 50 that generates the clock signal CLKO and the transmission signal Rx from the master station 1. , a pulse rising detection circuit 51 that detects the rising of the pulse P of the header HD of the transmission signal RX, a pulse falling detection circuit 52 that detects the falling of the pulse P of the header ID, and a pulse rising detection circuit 51. A counter 53 counts the width L of the pulse P by counting the number of clock signals CLKo between the rising edge detection signal A from the pulse edge detection circuit 52 and the falling edge detection signal B from the pulse edge detection circuit 52; Width L of the pulse P
and the transmission speed data 'rv preset in the transmission speed buffer 46, and if they correspond, 7
For example, the comparator 54 outputs an acquisition signal IN for causing the transmission processing device 6 to acquire the transmission signal RX from the master station 1 when they match.

Note that the reception interface 30 of the transmission processing device 6 sends the transmission signal Rx to each register 31, 3 according to the acquisition signal IN.
2.33 is designed to control whether or not to input it. Next, the transmission procedure between master station 1 and slave station 2 in such a configuration will be explained. Normally, the central processing unit 11 of the master station 1 executes a processing program in the storage unit 12, calls each slave station 2 sequentially and cyclically, and
Data such as temperature and smoke concentration detected by the sensor device 4 is collected to monitor fires, gas leaks, etc. Then, if necessary, it can issue a fire alarm or
Control commands are sent to the control equipment 5 to control controlled equipment 5 such as air conditioners and smoke prevention equipment. Before performing such actual transmission control processing, if the transmission processing device 6 of the slave station 2 is configured as shown in FIG. is preset in the physical address buffer 35 by address polling from the master station 1, and the master station 1 specifies the thousand stations 2 having this physical address by polling, and the address is sent from the master station 1 to the logical address buffer 36. A predetermined logical address is set in advance. After the logical address is set in the logical address buffer 36, the master station I can poll and identify the slave station 2 using the logical address, and try to change the logical address set in the logical address buffer 36. Sometimes, the master station 1 sends a new logical address to the slave station 2, and the slave station 2 stores it in a predetermined location in the memory 21 and sends this data back to the master station 1, and the master station 1 sends the new logical address to the slave station 2. After confirming that it is correct, by sending an instruction to that effect to the slave station 2, the slave station 2 can change the logical address held in the memory 21 by setting it in the logical address buffer 36.

In addition, prior to performing the actual transmission control processing as described above, data table 18 in the storage unit 12 of the master station 1 contains data according to the degree of transmission reliability between each slave station 2 and the master station 1. Assume that the transmission speed is set in advance. For example, a high transmission speed v1 is set for a slave station 2 with high transmission reliability, for example #1, and a high transmission speed v1 is set for a slave station 2 with low transmission reliability. For example, for #n, the transmission speed is V, which is slow. Suppose that is set. Also, transmission speed data T corresponding to the transmission speed of each slave station 2 set in the data table 18
V, that is, transmission rate data 1'V when the master station 1 calls the slave station 2, is set in advance in the transmission rate buffer 46 of the transmission processing device 6 of each slave station 2. The setting of the transmission speed data TV to the transmission speed buffer 46 is performed, for example, by the procedure shown in the flowchart of FIG. TV to slave station 2 to which it should be set
A memory write command for writing to a predetermined location in the memory 21 of the transmission processing device 6 is transmitted to the slave station 2 (step Sl). This memory storage command has a format as shown in FIG. 3, in which the address ADDR is the logical address of the specific slave station 2, and the data DT is the transmission speed data TV. When such a memory write command is sent, each slave station 2 first writes the address ADD.
The address converter 37 compares the logical address sent as R with the logical address currently set in the logical address buffer 36. If the results match, it is determined that the slave station 2 has been address polled by the master station 1, and the transmission speed data TV is written to a predetermined location in the memory 21 of this slave station 2 (step 32).

Next, the master station 1 transmits a memory read command to the slave station 2 to confirm whether the transmission speed data DT written in the memory 21 is correct (step S3). At this time, the same logical address specified in step S1 is specified as the address ADI)R. When such a memory read command is transmitted, the same slave station 2 identified in step S2 is identified by the address ADDR, and the transmission speed data TV written in the predetermined location of the memory 21 of this slave station 2 is The data is read out and stored in the return data register 41, and then sent back to the master station 1 via the transmission interface 42 (step S4). The master station 1 confirms whether the returned new transmission speed data is correct (step S5). If this is not correct, it is determined that, for example, the transmission speed data TV was incorrectly specified and transmitted at the time of transmission in step S1, and the process returns to step S1 in order to retransmit the correctly specified transmission speed data TV. return. In this way, in step S5, after confirming that the transmission speed data TV written in the memory 2l is correct, the transmission speed data TV written in the memory 21 is transferred to the transmission speed buffer 46. A memory read command to be transferred to the slave station 2 is sent to the slave station 2 (step S6). At this time, the same logical address specified in steps 31 and 33 is specified as the address ADDR. When such a memory read command is transmitted, the same slave station 2 as that specified in steps S2 and S4 is specified by the address ADDR, and the transmission speed data TV written in the predetermined location of this memory 21 is read out. , are stored in the transmission speed buffer 46. Note that when the transmission processing device 6 has a configuration as shown in FIG.
Without directly transferring and writing V to the transmission rate buffer 46,
Once stored in the memory 21, the master station 1 confirms whether the transmission speed data TV stored in the memory 21 is correct, and then writes it to the transmission speed buffer 46 to set it. The probability that an incorrect transmission rate data TV is set in 46 can be significantly reduced, and the reliability of the transmission rate data TV can be significantly increased. In this way, in accordance with the contents set in the data table 18 of the master station 1, high-speed transmission speed data TV is set for the slave station 2 with high transmission reliability,
A slow transmission rate data TV can be set for the slave station 2 with low transmission reliability. Each slave station 2
After the transmission rate data TV specific to 1 is set in the transmission rate buffer 46, the master station 1 sends the transmission signal Rx in the format shown in FIG. 3 to the slave station 2 in order to perform actual transmission control processing. Send. At this time, the master station 1
The central processing unit 11 reads the transmission speed of each slave station set in the data table 18 of No. 2, and adjusts the width L of the pulse P of the header 1-TD of the transmission signal RX according to the read transmission speed.
and transmits this transmission signal R from the transmission circuit 14 to the two slave stations at the read transmission speed. For example, a width L proportional to the transmission rate set in the data table 18 is given to the pulse P of the header HD, and this is transmitted to the slave station 2 at that transmission rate. The transmission speed detection circuit 7 of each slave station 2 that has received the transmission signal Rx detects the header H based on the transmission signal Rx from the master station 1.
Detect the width L of pulse P of D. That is, Fig. 8 (a
) to (G), when the transmission signal RX is sent out from the master station I (see FIG. 8(b)), the pulse rising edge detection circuit 51 detects the header HD of the transmission signal Rx. The pulse falling detection circuit 52 detects the rising edge of the pulse P and outputs the rising detection signal A (see FIG. 8(C)), and the pulse falling detection circuit 52 detects the falling edge of the pulse P and outputs the falling detection signal B. (See Figure 8(d)). The counter 53 starts counting the clock signal CLKo as shown in FIG. 8(a) from the clock pulse generator 50 in response to the rising edge detection signal A, and stops the counting operation when the falling edge detection signal B is added. do. As a result, the count value CNT of the counter 53 becomes as shown in FIG. be able to.

The comparator 54 of the transmission speed detection circuit 7 compares the counted value CNT of the counter 53 and the transmission speed data TV set in the transmission speed buffer 46, and if they correspond, for example, if they match, is the acquisition signal I
N to the reception interface 30 of the transmission processing device 6;
As a result, the receiving interface 30 determines that the transmission speed instructed by the master station 1 is the one that has been passed to the slave station 2. and receives the transmission signal Rx from the master station 1, and transmits it to the transmission processing device 6.
Make each part perform a specified action. The operations of each part of the transmission processing device 6 at this time are synchronized by a clock signal CLK1 whose frequency is divided based on the transmission speed data TV from the transmission speed buffer 46. On the other hand, when the comparator 54 determines that it is not compatible, the capture signal IN is not output, and the reception interface 30 of the transmission processing device 6 does not capture the transmission signal Rx from the master station 2. In this way, even if the master station 1 attempts to perform address polling by specifying the logical address of a particular slave station 2, the transmission rate of the transmission signal Rx from the master station 1 is set to that slave station 2. If the transmission speed data does not correspond to TV and is incorrect, the slave station 2 will not receive the transmission signal Rx from the master station I, and no processing will be performed based on it, so it will not be reliable. It is possible to perform highly accurate transmission. In other words, even if the same address is set for multiple slave stations, if different transmission speed data are set for each slave station, transmission can be performed normally, and as a result, in effect, You can also increase the address. Further, although the transmission signal Tx sent from the slave station 2 to the master station 1 will not be described in detail here, this transmission signal T is usually
The transmission signal RX is transmitted to the master station I via the return data register 41 and the transmission interface 42 at a speed synchronized with the return timing clock from the master station X2 added to the transmission signal RX. As described above, in this embodiment, the master station 1 calls each slave station 2 at different transmission speeds depending on the degree of transmission reliability. This makes it possible to effectively prevent a decline in the overall transmission speed, or transmission efficiency, and to perform highly reliable transmission without using special wires. In other words, the transmission signal Rx is sent at a high transmission speed to a slave station with high transmission reliability, where the distance between master station 1 and slave station 2 is short, and the distance between master station 1 and slave station 2 is short. The transmission signal R8 is sent at a slow transmission speed only to slave stations with low transmission reliability, such as when the transmission line 3 is significantly long or when the slave station 2 is installed in an environment where it is susceptible to external noise. Therefore, the transmission signal Rx from the master station 1 can be reliably transmitted on the slave station 2 side without greatly affecting the reduction in the overall transmission speed and without significantly increasing the time required for transmitting and receiving the overall signal. You can receive it. In addition, in the above example, the transmission speed of each slave station 2 is the master station 1I.
In Ill, settings are made individually for each slave station as shown in the data table 18 in FIG. In this case, when the optimum transmission speed of each slave station 2 is different from each other, the transmission speeds v1 to Vn set for each slave station 2, that is, #1 to #n in the data table 18 are different from each other. and at least two of each of the slave stations #1 to #n, for example #2. When the transmission speeds V2 and V for #3 are the same (v3=v2), the transmission speeds v and v set for the at least two slave stations #2 and #3 are set to the same value. 23 By the way, at least two of each of the slave stations #1 to #n. For example, transmission speeds v and v for #2 and #3
are the same, instead of the data table 18 shown in FIG. 2, a data table 1 having a configuration in which a plurality of slave stations are grouped as shown in FIG. 9 is used.
9 and multiple slave stations #2.9 for one transmission rate v2 (=v3). You may also assign #3. When using the data table 18, the transmission speed is set individually for each slave station 2, so if the transmission speed of each slave station 2 is changed frequently, the master station 1ff
It becomes easier to manage the data table of 1. On the other hand, when using the data table 19, slave stations with the same transmission speed are grouped and set.
The capacity of the data table 19, ie, the capacity of the storage unit 12, can be reduced. Further, in this embodiment, the transmission speed data TV is stored in the transmission speed buffer 46 on the side of the slave station 2, the transmission speed of the transmission signal Rx from the master station 1 is detected, and the transmission speed data TV is stored in the transmission speed buffer 46 on the slave station 2 side. When slave station 2 is equipped with an inspection management function that compares and checks with speed data TV to determine whether the transmission speed of the transmission signal RX from master station I is correct, it is possible that a different slave station that should not be called may be mistakenly called. It is possible to prevent the situation of being called, and it is possible to further improve reliability. In addition, the slave station 2 of m-kai, which has such an inspection management function,
As mentioned above, reliability can be further improved by using it in combination with the master station 1, which calls each slave station at a transmission speed that corresponds to the degree of transmission reliability. It may also be used in combination with a conventional master station that calls each slave station at the same transmission speed, and in this case as well, it is possible to prevent the master station from calling at the wrong transmission speed and improve reliability. Can be done. In other words, it should be noted that the slave station 2, that is, the terminal device itself having the configuration shown in FIGS. 4 to 6 is new and has unique features and effects that have not been seen before. Furthermore, in this embodiment, the contents of the data buffers 18 and 19 of the storage section 12 of the master station I can be changed by the central processing section 11, so that, for example, what was originally normal transmission speed data can be changed. If transmission errors occur frequently, change the transmission speed data to a slower one, or change the transmission speed data that was initially appropriate but may no longer be appropriate due to changes in the environment, etc. In the event that it disappears,
You can easily change this. Note that when the contents of the data buffers 18 and 19 of the master station 1 are changed, it is also necessary to change the transmission speed data TV set in the transmission speed buffer 46 of the corresponding slave station 2. This change can be done in a similar way to that shown in Figure 7.
This can be easily done at will, that is, by a command from the master station 1. In this way, various transmission speed data can be easily set and changed on the master station 11FI and on the slave station 2 side at any time without the need to change parts.
Even if the system is installed and used in a variety of environments and transmission becomes unavailable, it can be restored immediately, making it possible to extremely reduce the risks associated with transmission. In the above-mentioned embodiment, the master station 1 prepares the transmission speed data TV that is changeably set in the transmission speed buffer 46 of the transmission processing device 6 and sends it from the master station 1. The slave station 2 may be provided with a data setting section such as a digital switch so that the transmission speed data TV can be set locally. In other words, when transmitting the transmission speed data TV from the master station 1, the burden required for setting on the 2 slave stations can be reduced and the master station 1 can manage it all at once, but on the other hand, this To perform the setting work, the master station 1 must send a command, which some operators may find to be a complicated work. In such cases, the slave station
If L is provided with a data setting section such as a digital switch, the transmission speed data TV can be set locally only on the slave station 2 side in accordance with the contents of the data table 18 in the storage section 12 of the master station 1. Can be done. Although the configuration of the data setting section will not be described in detail, it may be configured such that only the transmission speed data TV from the data setting section is locally set in the transmission speed buffer 46, or the transmission speed sent from the master station 1 Transmission speed data T from data TV and data setting section
The configuration may be such that the operator can arbitrarily select either one of V and V to be set in the transmission rate buffer 46. In the above-described embodiment, the header H consisting of a plurality of pulse trains is used to detect the transmission speed of the transmission signal Rx from the master station 1.
Although information regarding the transmission speed is added to D, the transmission signal Rx
is a normal start bit added, and if the next information bit is low level so that the end of the start bit is clear, information about the transmission speed is added to this start bit. It is also possible to detect the transmission speed of the transmission signal RX. Further, in the above embodiment, the clock generator 45 and the clock pulse generator 50 are provided separately, but the clock signal CLK1 from the clock generator 45 is sent to the power counter 53 without providing the clock pulse generator 50 separately. It may also be used as a clock signal.

Furthermore, when building a supervisory control system by connecting at least one slave station 2 to the master station 1, it is not necessary to configure all the slave stations 2 as shown in FIG. 4, and the transmission speed is particularly problematic. Only a specific slave station 2 may have the structure shown in FIG. [Effects of the Invention] As explained above, according to the present invention, the master station calls each slave station at a transmission rate set according to the degree of transmission reliability. It is possible to prevent the transmission efficiency from decreasing and to perform highly reliable transmission without using expensive wire materials for the transmission line. Furthermore, since the set transmission speed is maintained in a changeable manner on the master station side, it can be easily changed to a convenient transmission speed at any time without changing any parts. In addition, when the transmission speed is set individually for each slave station on the master station side, management becomes easier when the transmission speed of each slave station changes frequently. When the transmission speeds for at least two slave stations are the same and these are grouped and set at the parent station, the storage capacity can be reduced. Also, when a master station calls a slave station, if the slave station detects the transmission speed of the call and accepts the call when it corresponds to the transmission speed data set for itself, the master station can The slave station can determine whether the call is correct or not, and prevent incorrect calls from being accepted.
Reliability can be further improved. In addition, the above transmission speed data is locally changeable by a command from the master station or by the data setting section of the slave station, so it is possible to change the transmission speed by changing parts, just like the transmission speed which is held changeably on the master station. The transmission speed data can be easily changed to the appropriate one at any desired time without any problems.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an embodiment of the supervisory control system according to the present invention, FIG. 2 is a diagram showing an example of the configuration of a master station, and FIG. 3 is a transmission signal sent from the master station to the slave stations. FIG. 4 is a diagram showing an example of the format of the slave station, FIG. 5 is a diagram showing an example of the configuration of the transmission processing device of the slave station, and FIG. Figure 7 is a flowchart showing the processing flow when setting and changing transmission speed data in the transmission speed buffer of a slave station based on a command from the master station, and Figures 8 (a) to (e) are diagrams showing an example. FIG. 9 is a time chart for explaining the transmission speed detection operation in the transmission speed detection circuit of the station, and is a diagram showing an example of a song in the data table. 1... Central monitoring and control device (master station), 2... Terminal device (slave station), 3... Transmission line, 4...
Sensor device, 5... Controlled device, 6... Transmission processing device, 7... Transmission speed detection circuit, 18, l. ．． 9...
Data table, 21...Memory, 30...Receiving interface, 45...Clock generator, 46...Transmission speed buffer, 50...Evening lock pulse generator, 51...Pulse rising edge detection circuit , 52...Pulse fall detection circuit, 53...Counter, 54...Converter, Rx, Tx...Transmission signal, HD...Header, IN...Intake signal Fig. 3 4 Figure 7 (Central monitoring and control equipment) (Terminal) Figure 9

Claims (1)

[Claims] 1) In a supervisory control system comprising a master station that performs centralized supervisory control and a plurality of slave stations connected to the master station via transmission lines, each of the slave stations A supervisory control system characterized in that a transmission rate is set according to the degree of reliability of transmission with the station, and the master station calls each slave station at the set transmission rate. 2) The supervisory control system according to claim 1, wherein the transmission rate is changeably maintained on the master station side. 3) The supervisory control system according to claim 1, wherein the transmission rate is individually set for each of the slave stations on the master station side. 4) When the transmission speeds for at least two of the slave stations are the same, the transmission speeds for the at least two slave stations are grouped and set on the master station side. The supervisory control system according to claim 1, wherein: 5) a transmission rate storage means in which the slave station sets and stores transmission rate data corresponding to a transmission rate set for the slave station according to the degree of transmission reliability with the master station;
A transmission speed detection means detects the transmission speed of the call from the master station, and the transmission speed detected by the transmission speed detection means is compared with the transmission speed data set in the transmission speed storage means,
2. The supervisory control system according to claim 1, further comprising comparison/taking means for accepting and taking in calls from the master station when these calls correspond. 6) The transmission speed data is set so as to be changeable in the slave station by a command from the master station, or locally changeable on the slave station side. 5. The terminal device described in 5. 7) In a transmission method in which a master station that performs centralized monitoring and control calls a slave station connected to the master station via a transmission line, the master station calls the slave stations at a transmission speed depending on the degree of transmission reliability. A transmission method characterized by calling a station.