JPH0326580B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is designed to receive signals transmitted from a central control device (center device) at a distance, and output them to an output target such as a large display device. The present invention relates to a transmission control method in a system consisting of a terminal that outputs to a device and inputs an operation signal and transmits it to the center device. It is desirable that this type of system not only be able to configure the system at a low cost, but also that the display content as output data from the terminal can be updated more quickly, and that the operation content of the operation switch input to the terminal can be transmitted to the center device more quickly. .

[Conventional technology]

There are various transmission control methods in this type of system for centrally monitoring and controlling terminals located far from a center device, and it is difficult to generalize about conventional methods. However, from the perspective of standardization, the transmission method itself is: (1) serial transmission as a hardware standard;
RS232C method, parallel transmission GP-iB method,
There are current loop methods for serial transmission, etc. (2) In addition, there are various transmission procedures such as synchronous methods and asynchronous methods as software standards.

[Problem to be solved by the invention]

However, since the above-mentioned method must have high reliability for various general-purpose applications, the reality is that it is handled by increasing redundancy in principle. For this reason, there is a problem in that the manufacturing cost of the system inevitably increases in terms of both hardware and software.

The transmission method of the present invention has been devised as a method suitable for a dedicated system, regardless of these standard methods.

This invention meets the following requirements: (1) It is possible to transmit signals from a center device to a large number of distant display devices and other output target devices via a terminal using simple equipment.

(2) Ability to quickly respond to input signals from a remote terminal such as an operating switch.

(3) The system configuration is simple, inexpensive, and highly reliable.

(4) To reduce the burden on the functions of the center device as much as possible.

The purpose is to provide a transmission control method that can satisfy the following requirements.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a center device 1 and a plurality of terminal devices 300 to 30 respectively connected to the center device via lines.
As a communication cycle with n, the center device specifies a terminal device and sends out an output command 311 to control the output target device connected to the specified designated terminal device.
1, T2, and a reception cycle T3 in which the center device specifies a terminal device and sends input data 341 from an input device connected to the specified terminal device from the specified terminal device to the center device, If the center device determines that there is no need to send input data from the terminal device, it executes a transmission cycle, and if the center device determines that it is necessary to send input data from the terminal device, it executes a reception cycle. In such a transmission control system, signals 200, 201, 20 are sent by the center device to specify a terminal device in a communication cycle.
2, a priority communication request signal 321 that requests the center device to send the input data for each address of the specific terminal device in response to a change in the input data to the specific terminal device to be prioritized; and the specific terminal device. Or a terminal device other than a specific terminal device, in response to a change in input data to a designated terminal device that is a terminal device designated by the center device during its transmission cycle or reception cycle. A self-terminal communication request signal 322 in which the designated terminal device itself requests data transmission; and a corresponding input to the center device in response to a change in input data to other terminal devices other than the designated terminal device and the designated terminal device. A common communication request signal 323 that requests data transmission from the other terminal device regardless of the address of the other terminal device.
and, when a priority communication request signal is detected, the center device executes the reception cycle in a predetermined order with the specific terminal device that sent the priority communication request signal, and then receives the common communication request signal. When detected, other terminal devices are sequentially investigated in a predetermined order following the reception cycle of the specific terminal device that sent the priority communication request signal and the designated terminal device that sent the self-terminal communication request signal. After finding another terminal device that sent the common communication request signal and executing a reception cycle with this terminal device, if the own terminal communication request signal is detected, the designated terminal that sent this own terminal communication request signal If the device is a specific terminal device, it is assigned an address higher in rank than the specific terminal device and sends out its own terminal communication request signal in the order following the reception cycle with the specific terminal device that sent the priority communication request signal. If the designated terminal device is a terminal device other than the specific terminal device, the designated terminal device that sent the own terminal communication request signal and the reception cycle in the order following the reception cycle with the specific terminal device that sent the priority communication request signal. After executing , the program returns to the next communication cycle (receive cycle or transmit cycle).

[Effect]

If the above technical means causes a change in the input data to the terminal device and it becomes necessary to send the latest input data to the center device, if this terminal device is a specific terminal device that should be prioritized. is a priority communication request signal 321 for each address assigned to a specific terminal device, and if the terminal device is a specific terminal device or a terminal device other than the specific terminal device, and the terminal device is a specific terminal device or a terminal device other than the specific terminal device, and it is sent from the center device in the communication cycle (transmission cycle or reception cycle). If the terminal device is the designated terminal device, or if the terminal device currently executing the reception cycle has input data that cannot be sent in the reception cycle, the own terminal communication request signal 322 is sent to the terminal device. is a terminal device other than the specific terminal device and the designated terminal device, the common communication request signal 323
are sent to the center device from the terminal device whose input data has changed, and the center device that receives these communication request signals performs the communication according to the priority order assigned in advance to the terminal device that sent these communication request signals. In addition, a large number of terminal devices are assigned to a small number of communication request bits by skipping terminal devices that have not sent a communication request signal and sequentially specifying terminal devices that have sent a communication request signal and performing a reception cycle. Changes in input data on the terminal device side are made to follow the priority of that terminal device, and changes in input data from terminal devices with lower priority can also be sent to the center device as quickly as possible. , the responsiveness and transmission efficiency of the transmission system as a whole can be improved.

〔Example〕

The present invention will be explained below based on FIGS. 1 to 5.
The same reference numerals in the figures indicate the same or relative parts.

FIG. 1 shows a configuration diagram of a terminal that performs such control. FIG. 2 shows a timing chart for communicating with a center device using this terminal. Figure 3 shows the communication format between the terminal and the center equipment, Figure A shows the transmission format from the center equipment to the terminal, and Figure B
Figure C shows the data format of the output data sent from the center device to the terminal, and Figure D shows the data format of the read result of the input signal at the terminal sent to the center device. Each is shown below. Further, FIG. 4 shows the configuration of the system of the present invention, and FIG. 5 shows the configuration of the RAM in the center device.

In Fig. 4, 1 sends display data output to a display device outside the terminal (referred to as external) to the terminal, receives and stores input data input to the key matrix of the terminal, and performs necessary processing. This is a center device that has a function of transmitting the data as the display data. Reference numeral 2 denotes a signal transmission path connecting the center device 1 and a plurality of terminals, and here it is composed of two wires. 30 (300 to 30n) are terminals in this system, the configuration of which is shown in FIG. That is, each terminal 30 has a one-chip microcomputer (hereinafter referred to as microcomputer) 32 as a central control device.
In addition to the communication circuit 31 for communicating with the center device 1 via the two-wire transmission path 2, an external display device 3
Display output unit 33 for displaying 64 points on 7 (this output unit 33 is a static output (latch output)
It is possible to switch between output and dynamic output. An example of the most suitable use of this output section 33 is for display. ), a text output signal 36 for static output such as display of 8-point test signals, and a key matrix 35 for reading ON/OFF operation inputs from 64 external key contacts 38.
A test switch section 39 includes a test loss switch for testing the operation of the microcomputer 32 in the own terminal and an address switch for setting the address of the own terminal, and a test switch section 39 that decodes the address signal output from the microcomputer 32 into the own terminal. It has a display output section 33, a decoder 34 for supplying data to a key matrix 35, and the like. The test output section 36 displays status information based on the test switch and the address of the own terminal set by the address switch for confirmation.

Here, the configuration of the terminal 30 shown in FIG. 1 shows one example, and various methods can be used for output such as external display and input methods for external key contacts. Either method allows output from the microcomputer 32 to the outside, and the external signal can be output from the microcomputer 32 to the outside.
It would be good if it could be read into.

Also, in Figure 1, there are 64 points of display output and 64 points of key contact input, but this means that there can be a considerable amount of output signals and input signals, so it is especially limited to 64 points. It's not a translation. The number of these input/output points can be determined depending on the application.
Furthermore, although the display output is shown in Figure 1,
Depending on the purpose, the display output section 33 may also be used for other purposes besides display.
It can be used for applications such as driving a relay to sound a buzzer or drive a motor.

Each of these terminals 30 (300 to 30n in FIG. 4) outputs data to various external loads such as a display based on the data transmitted from the center device 1. At the same time, the contact input signal connected to the terminal is read, and when a change occurs in the contact input signal, the contact input status is transmitted to the center device 1.

A timing diagram of such communication between the center device 1 and the terminal 3 is shown in FIG. In the figure, 200, 201, 202 are 20-bit terminal address designation data sent from the center device 1 to the terminal 30, and 210, 211 are the terminals designated by the terminal address designation data 200, 201 and others. 8-bit terminal response data returned from the terminal 30 to the center device 1, 220,2
Reference numeral 21 indicates 73-bit display output data transmitted from the center device 1 to each designated terminal 30 as data for display, and 232 indicates a terminal whose contact input signal has changed as described later. Based on the terminal response data 211 including the communication request signal, the terminal input data is transmitted from the terminal 30 specified by the center device 1 by the terminal address designation data 202 to the center device 1, and the key input to the terminal 30 is This is 80 bit data including read data. However, in the terminal input data 232,
The terminal response data 2 includes a communication request signal from a terminal other than the terminal whose contact input signal has changed.
It also includes partial data (terminal response data section 341) that has the same purpose and configuration as No. 10 and 211, which will be described later.

Here, each terminal address specification data 200, 20
T1, T2, T3 determined by the beginning of 1,202
The period of
When T1, T2, and T3 are distinguished from each other, in each of these communication cycles, the center device 1 sends or receives data to or from the terminal specified by the terminal address designation data 200, 201, and 202 (i.e., the display output Data 220, 221 or terminal input data 232) are distinguished, and the former is called a transmission cycle, and the latter is called a reception cycle.

Further, FIG. 3A is a format showing the 20-bit configuration of the terminal address designation data 200, 201, 202, etc. in FIG. 2, and 310 is a start bit,
311 is an address, 312 is a command, 313,
Reference numeral 314 indicates an inverted address and an inverted command obtained by inverting the numerical values of the address 311 and command 312 (this is one of the methods for improving the reliability of addressing, which is called so-called inverted double transmission).

Figure 3B is the terminal response data 210, 21 in Figure 2.
The format shows the 8-bit configuration of 1,...
This configuration is shown in Figure 2, terminal input data 232,...80
It has exactly the same structure as the start bit 340 and terminal response data section 341 in the format of FIG. 3D showing the bit structure, and has the same purpose. Here, 321 is a priority communication request bit, 3
22 is an own terminal communication request bit, 323 is a common communication request bit, and 324 is a terminal transmission data abort signal. The reason why the terminal response data section 341 is included in the terminal input data 232, . . . is that regardless of the transmission cycle or reception cycle, if there is a change in signal input (change in key contact input) to any terminal, This is to enable the terminal to request the center device 1 to transmit key reading data as quickly as possible. If the center device 1 receives requests for this communication from multiple terminals, it will enter a reception cycle by specifying the terminals according to their priorities as described later, but in general, within the same priority, the terminals are ordered in the order of their addresses. We often communicate.

Figure 3C is Figure 2 display output data 220, 22
The format shows the 73-bit configuration of 1,...
330 is star bit, 331 is display data, 3
32,333 is parity.

The first 8 bits of the 80 bits of the terminal input data in FIG. 3D have been described above, but the remaining part 342 is key read data, and 343 and 344 are parti. The signal from the center device 1 is read simultaneously by a plurality of terminals 300 to 30n, but since an address is assigned to each terminal,
Terminal address designation data 200 in FIG.
Using the addresses 201 and 202 (A311 in Figure 3), the center device 1 specifies the address of the terminal to communicate with, and also sends the command (A31 in Figure 3).
2) specifies the type of data to be subsequently communicated. This 20-bit terminal address designation data is processed by the center device 1 in the data format shown in FIG.
1 and command 312, those addresses 311,
Inverted data 313 and 31 of each command 312
4 and is transmitted to all terminals 3003 to 30n. Only the terminal 30 that matches the data of this address 311 receives the display output data 220 or 221 shown in FIG. 2, and similarly, only the terminal 30 transmits the terminal input data 232 to the center device 1. The data format of this display output data 220 or 221 has the format shown in FIG. 3C, and the H start bits 330 and 6
In addition to the 4-bit display data, 8-bit parity signals (parity 332, parity 333) are provided. The data of parity 332 and 333 is created as horizontal and vertical parity in units of 4 bits, and this creation method has already been specified in Japanese Patent Application Laid-Open No. 59-62238 "Error Check Method in Multiplex Transmission System" by the present applicant. are doing.
If the start bit 330 is confirmed and the display data 331 and its parities 332 and 333 are matched, then this received data is correct, and the external display device (first The output can be displayed in Figure 37).

Returning to FIG. 2 again, the center device 1 sends terminal address setting data 200 to call one terminal 30, obtains terminal response data 210 (described later) from that terminal and other terminals 30, and calls those terminals 3.
When it is determined that 0 is not waiting for new data (key read data) to be transmitted to the center device 1, the display output data 220 is then sent to the relevant terminal 30, and communication cycle T1 (transmission cycle) with that terminal is performed. After that, the center device 1 specifies the next terminal 30 in a predetermined order using the terminal address designation data 201, obtains the terminal response data 211 in the same manner as above, and
Display output data 221 is sent and communication cycle T2
(transmission cycle) ends. Here, if it is found from the terminal response data 211 that there is new key reading data in the terminal in question or other terminals 30, the center device 1 uses the terminal address designation data 211.
2 specifies the terminal 30 having new key read data as will be described later, receives the terminal input data 232 from this terminal 30, and ends the communication cycle T3 (reception cycle). The format of the terminal input data 232 at this time is shown in FIG. 3D as described above, and in FIG. Parities 343 and 344 are added to the data 342, and the data is sent back from the terminal to the center device 1 in accordance with the synchronization pulse sent from the center device 1. If it is determined from the terminal response data section 341 in the terminal input data 232 that there remains a terminal that has new key read data and requests transmission, the center device 1 Either specify it directly as in cycle T3, or after searching for it through scan communication (described later), communicate with the terminal that requested transmission in a receive cycle similar to the receive cycle T3, and in this way, new key read data can be obtained. When communication with all the terminals having T is completed, a terminal 30 in a predetermined order following the terminal address designation data 201 is designated again, and the transmission cycle T
Execute the transmission cycle in the same way as in 2, and send the corresponding terminal 3.
0 to display output data, and in this way perform a reception cycle with the next terminal in sequence.

That is, basically, the center device 1 sequentially designates the terminals 300 to 30n one by one in a predetermined order using the terminal address designation data 200, 201, . . . and provides display output data 220, 221, . Once the communication is complete, the transmission cycle continues again. If, in the middle of this transmission cycle, the terminal response data 211,... or the terminal input data 232 (the terminal response data section 341),
When it is determined that there is a terminal that has new key read data and is requesting communication, data input (receiving cycle) from all of the terminals is performed like an interrupt process, and then the basic Return to the previous transmission cycle and continue this.

Next, this communication method will be explained in detail.

In the general method, after sending output data such as display, the contact input signal of the relevant terminal is sucked up to the center device each time, and this is repeated to all terminals, so that the signal input status of the terminal is transmitted to the center device. knows a lot. However, since signal input at a terminal is not performed very frequently, such as when it is done manually, the center device is normally notified of the signal input status of each terminal every time it communicates with that terminal. There's no need. The disadvantage of adopting a method in which the center device receives signal input from the terminal in question for each communication is that it communicates with the same frequency with both terminals whose signal input changes little and with terminals whose signal input changes rapidly. There is a risk of failing to capture changes in terminals with rapid input changes.
To prevent this without changing the communication method, it is necessary to increase the communication speed, which increases the cost of system equipment.

Another method for improving the above-mentioned problem is a method in which the center device takes in the signal input from each terminal in advance and then notifies the center device only of changes in the signal input.

The method of the present invention is a new method for solving the above-mentioned problems, as described above.
32..., the center device 1 receives signal input only from the terminal 30 that needs to receive the signal input, and the terminal response data 21
This is illustrated by the format of 0.0,211 in FIG. 3B and the format of terminal input data 232 in FIG. 3D. The second to fifth bits (priority communication request bit 321) following each start bit 320, 340 in FIGS. This is a control signal bit assigned to each of the three terminals (also called priority terminals), and the center device 1 outputs "Low" with this bit.
A clock pulse of a signal (hereinafter referred to as L) is generated. In this control signal bit (priority communication request bit 321), only the priority terminal is assigned to the corresponding terminal in the priority communication request bit 321 in order to notify the center device 1 when there is a change in the key signal input of the terminal. It is possible to send an H signal back to the received bit.

Here, four terminals considered to be used frequently are specially selected from the viewpoint of effective use of signal bits, and are assigned to the second to fifth priority communication request bits 321 as the priority terminals. Note that the number of priority terminals does not need to be a specific number of four.

Here, the method by which the terminal returns the H signal is a two-wire transmission method using Japanese Patent Application Laid-Open No. 56-34256 "Data Transmission Method" by the present applicant, and it is easy to notify.

When an H signal is returned to the priority communication request bit 321, the center device 1 immediately returns the terminal (any one of addresses 0 to 3) that returned the H signal after completing the communication cycle with the terminal currently communicating. At this time, if the H signal is returned from multiple terminals, the terminal usually sends addresses 0, 1, 2, 3, etc.
The terminals that returned the H signal are sequentially designated in priority order of 0, 1, . . . , and a signal input is taken from the designated terminal to complete the reception cycle, and then the normal transmission cycle is resumed.

Next, the 6th bit in the figure is the self-terminal communication request bit 322, which indicates that the terminal specified by the terminal address designation data 200, 201, 202 in Fig. If the specified data 200, 201, 2
This bit 322 is returned as an H signal in the terminal response data 210, 211 or terminal input data 232 following 02.

In this way, the terminal response data (210, 2
11), if this bit 322 is returned as an H signal, if the priority communication request bit 3
21 is H, the reception cycle with the priority terminal corresponding to that bit 321 is given priority, and then the reception cycle with the terminal whose own terminal communication request bit 322 is H is performed. be exposed.

Next, the seventh bit in FIGS. 3B and 3D is a common communication request bit 323, which is returned as bit H when any terminal other than the priority terminal and the designated terminal has a new signal input.
In this case, after executing the reception cycle for the priority terminal and the designated terminal (however, if there is no corresponding terminal, the reception cycle is omitted), the new Other terminals having signal inputs are scan-investigated by the center device 1 using the scan communication method described in Japanese Unexamined Patent Application Publication No. 58-130691 "Distant Monitoring Control System" by the present applicant. A communication (referred to as a communication requesting terminal confirmation communication) is provided during the communication cycle), and after the reception cycle with the other investigated terminal is completed, the basic transmission cycle returns.

Furthermore, the terminal transmission data abort signal 324 of the 8th bit in FIGS. If not, this bit is returned as H. Therefore, even if a terminal that has undergone a receive cycle is addressed again, if there is no change in the signal input to this terminal, this bit remains high and there is no need to perform another receive cycle after that receive cycle. It shows that there is no

Note that this terminal transmission data abort signal 324 can also be used for the scan communication by the center device 1.

Furthermore, in FIG. 3D, all the input conditions of the 64 key contacts are sent back to the center device, but as already mentioned, only the changes may be sent. The terminal notifies the center device of a change in key input for each key operation, and the center device can know the key operation of the terminal by comparing it with previous notification results.

Next, the functions of the center device 1 will be explained as follows. Figure 5 shows the inside of the center device 1.
A configuration diagram of RAM is shown. 12 is output RAM,
For example, if the output data such as the display of the terminal 30 is 64 bits, it has as many bits as the number of connected terminals, with 64 bits as one unit. Here, the number of terminals is assumed to be 16, so 16 units are built in, and the transmission cycle is sequentially repeated for all 16 terminals to output them cyclically.

On the other hand, 13 is a key input RAM for setting key input signals for 30 terminals, each of which is arranged in address order. This part of RAM13 is terminal 30
The state of the key contact signal is transmitted to the center device 1 and set by the process described above. Therefore, by determining changes in data in the RAM 13 within the center device 1, the center device 1 can know the progress of key contact operations on the terminal 30 or simply the comparison with previous data.
A center device 1 and a terminal 30 having such functions
By using , it is possible to easily process the data in the RAM inside the center device 1 and then output it to the terminal 30 at a distant point.
The output target device of this terminal 30 can be a display device 37 (FIG. 1) having a display panel, and more sophisticated control is also possible by using a buzzer, relay output, etc. in a part of the display device 37 (FIG. 1). In addition, it is possible to efficiently transmit and notify the state of the signal input through the terminal-side contact (which may be a semiconductor switch) to the center device, and when the center device 1 detects this remote switch operation. , the center device 1 executes the operation assigned to that switch, and the processing result is used as the output for the data to be displayed.
Since the data is input to the RAM 12 (FIG. 5), by receiving the data in the RAM 12 on the terminal side, the operation result can be known, for example, in the form of a centralized display control panel.

〔Effect of the invention〕

In this invention, dozens of signals are constantly sent cyclically from the center device to the terminal as display output, and the terminal receives these signals and reads the operation signal input from the outside and changes this input signal. If so, it has the function of notifying the center device of the occurrence of the above signal input change and notifying the center device of the signal input status (key read data) upon receiving a designation from the center device. It has a function to output the display data received from the external device. Furthermore, all communications between the center and terminals have multiple communication request notification bits, among which a priority communication request bit is assigned to a specific address and a common communication request bit is assigned to terminals at other addresses. Has bits.

By configuring as described above, the following effects can be obtained in the present invention.

(1) Dozens of output points and dozens of input points can be configured in one unit (terminal), and can be configured at low cost.

(2) A communication request bit is included in every communication cycle with the terminal, allowing changes in input signals on the terminal side to be efficiently and quickly transmitted to the center device.

(3) This communication request bit can be specially assigned to a specific terminal whose signal changes frequently.
Using these bits, signals can be transmitted efficiently.

(4) In addition, in a small-scale system with a small number of terminals, communication request bits can be assigned to all terminals, and in a large-scale system with many terminals, a large number of communication request bits can be assigned to a small number of communication request bits. By assigning terminals, the system can be configured flexibly.

This invention does not specify the object in particular,
Transmit and display data, output to a distant place,
It can be used for various purposes such as collecting data from a distance.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the configuration of a terminal according to the present invention, FIG. 2 is a diagram showing the timing of communication between the terminal and the center device, and FIG. 3 is a diagram showing the timing of communication between the terminal and the center device. FIG. 4 is a diagram showing the configuration of a system to which the present invention is applied, and FIG. 5 is a diagram showing the configuration of the RAM in the center device according to the present invention. Code explanation, 1... Center device, 2... Transmission line,
30,300-30n...terminal, 37...display device, 38...key contact, 200,201,202
...Terminal address specification data, 210, 211...
...Terminal response data, 341...Terminal response data section, 220, 221...Display output data, 232
...Terminal input data, 331 ...Display data, 3
42...Key read data, 321...Priority communication request bit, 322...Self terminal communication request bit, 3
23...Common communication request bit.

Claims (1)

[Scope of Claims] 1. As a communication cycle between a center device and a plurality of terminal devices each connected to the center device via a line, the center device specifies the terminal device and the designated designation is performed. a transmission cycle in which an output command is sent to control an output target device connected to a terminal device; and a transmission cycle in which the center device specifies the terminal device and sends input data from an input device connected to the specified terminal device. a reception cycle for transmitting input data from the designated terminal device to the center device; and when the center device determines that there is no need to transmit input data from the terminal device, execute the transmission cycle; In the transmission control method, the center device executes the reception cycle when it determines that it is necessary to send input data, the signal sent by the center device to designate the terminal device in the communication cycle. Next, a priority communication request signal that requests the center device to send the input data for each address of the specific terminal device in response to the occurrence of a change in the input data to the specific terminal device to be prioritized; a self-terminal communication request signal in which the designated terminal device itself requests the center device to send the input data in response to a change in the input data from the device to the specified terminal device; and the specific terminal device. and, in response to the occurrence of a change in the input data to other terminal devices other than the designated terminal device, transmit the input data to the center device from the other terminal device regardless of the address of the other terminal device. a common communication request signal to request, and when the center device detects the priority communication request signal, the center device executes the reception cycle in a predetermined order with the specific terminal device that sent the priority communication request signal. After that, when the common communication request signal is detected, the other terminals are sent in the order following the reception cycles of the specific terminal device that sent the priority communication request signal and the designated terminal device that sent the self-terminal communication request signal. sequentially investigates the terminal devices in a predetermined order to find other terminal devices that have sent the common communication request signal;
After executing the reception cycle with this terminal device, when the own terminal communication request signal is detected,
If the designated terminal device that sent this self-terminal communication request signal is the specific terminal device, an address with a higher rank than that of the specific terminal device is assigned, and the specified terminal device that sent the priority communication request signal is In the order following the reception cycle, if the designated terminal device that sent out the own terminal communication request signal is a terminal device other than the specific terminal device, in the reception cycle with the specific terminal device that sent out the priority communication request signal. A transmission control system characterized in that, after executing the receiving cycle with the designated terminal device that sent the terminal communication request signal in the next order, the process returns to the communication cycle in the next order.