JPH0477144A - Terminal equipment for communication, transmission switching circuit, and communication method - Google Patents

Abstract

PURPOSE:To suppress a line control circuit to the minimum number by providing a gate control register storing gate control signals according to the state of the terminal equipment and switching the connection to other transmission opposite party after receiving the gate control signal. CONSTITUTION:At the time of sucking data to a controller 1 side in a four-wire loop type communication network connecting controller 1 and plural terminal equipment 10 in loop shape, the state of the terminal equipment 10 is stored in a gate control register 12, the line is switched by a switching means 13 to select the controller 1, a line control circuit 11 is connected, the data transmission from the line control circuit 11 to the controller 1 is executed after receiving a polling signal from the controller 1 side, the line switching is performed by the switching means 13 by a state signal changed after the data transmission, the next terminal equipment 10 is selected as the other transmission opposite party to be connected, the next terminal equipment and the line control circuit 11 are connected, and the polling signal is transmitted from the line control circuit 11 to the connected next terminal equipment 10.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figs. 6 and 7) Problems to be solved by the invention Means for solving the problems (Figs. 1 and 3) Figure) Example of operation (Figures 2 to 5) Effects of the invention [Summary] Communication terminal device and switching circuit in a 4-wire loop communication network in which a control device and a plurality of terminal devices are connected in a loop, and Regarding the communication method, the aim is to minimize the number of line control circuits and reduce equipment costs.A 4-wire loop communication network that connects a control device and multiple terminal devices in a loop. In a terminal device that is connected to a terminal device and has a line control circuit that transmits data after inputting a polling signal and outputs a polling signal after transmitting data, a status signal that defines the status of the terminal device is determined, and the transmission destination to be connected is determined by the status signal. , performs line switching to connect either the control device and the next terminal device, connects the control device and the line control circuit, receives a polling signal from the control device side, and then transmits data to the control device. A communication terminal device, a switching circuit, and a communication device configured to execute transmission, and after transmitting the data, perform line switching to connect the next terminal device and the line control circuit, and transmit a polling signal to the next terminal device. This is a method.

[Industrial application field]

The present invention relates to a communication terminal device, a switching circuit, and a communication method in a four-wire loop communication network in which a control device and a plurality of terminal devices are connected in a loop.

(Prior Art) Conventionally, in a four-wire loop communication network in which a control device and a plurality of terminal devices are connected in a loop, as shown in FIG. 2a, 2b or 2c obtains the right to transmit data to the control device 1, transmits the data to the control device 1, and after completing the data transmission to the control device engineer, sends a polling signal to the next stage terminal device 2b or 2C. By transmitting the data, the data is sucked up to the control device l.

Terminal device 2 (2a, 2b) used here.

2c), as shown in FIG.
3 or memory 4, and also sends data to the control device 1 according to instructions from the processing device 3 (for control device)
Data is input from the line control circuit 5 and the next stage terminal device and is passed on to the processing device 3 or memory 4, and data is transmitted to the next stage terminal device according to instructions from the processing device 3 (for terminal device). It has a line control circuit 6.

The data transmission procedure is such that the control device passes the first terminal device 2a that has not issued a data transmission request, passes a polling signal to the second terminal device 2b that has issued a data transmission request, and then sends the data transmission request. The third terminal device 2c that has output is in a state of waiting for a boring signal (Fig. 6 (
a)).

Then, the second terminal device 2b obtains data communication rights,
Data is transmitted to the control device 1 (FIG. 6(b)).

When the second terminal device 2b finishes transmitting data to the control device 1, it transmits a polling signal to the third terminal device 2C (FIG. 6(C)).

Next, the third terminal device 2C obtains data communication rights and transmits data to the control device 1 (FIG. 6(d)).

Then, after completing the data transmission, the third terminal device 2C returns a polling signal to the control device 1 (see FIG. 6(e)).
).

(Problems to be Solved by the Invention) In the conventional four-wire loop communication network described above, the terminal device 2 has two line control circuits 5 and 6 for transmission to the control device 1 and for transmission to the next terminal. In addition, in the case of duplexing, a total of four line control circuits, one for current use and one for backup, are required, resulting in an increase in equipment costs.

The present invention has been made in view of the above-mentioned problems, and the technical problem set for solving the problem is to minimize the number of line control circuits and reduce device costs. An object of the present invention is to provide a communication terminal device, a transmission switching circuit, and a communication method.

(Means for Solving the Problems) As a specific means for solving the above problems, the present invention, as shown in FIG. In a terminal device 10 having a line control circuit 11 that outputs a polling signal after data transmission, a gate control register 12 stores a gate control signal according to the state of the terminal device 10.
and a switching means 13 that receives the gate control signal and switches the connection to the transmission destination, and outputs the data output from the line control circuit 11 to the transmission destination.

The switching means 13 includes a control signal generation section 14 that generates a control signal for line switching from the gate control signal from the gate control register 12, and a control signal generation section 14 that receives the control signal from the control signal generation section 14 and outputs the transmission destination and its destination. It is desirable to have a switching section 15 that selects and outputs data to be output to the transmission destination.

As shown in FIG. 3 or 4, a switching circuit that specifically realizes the switching means 13 generates a control signal for line switching by ANDing a plurality of gate control signals input from the gate control register 34. A control signal generating section 42 or 44 forming a generating gate circuit, and a gate that outputs the AND of the control signal from the control signal generating section and the data to be transmitted as output data to the transmission destination specified by the control signal. A circuit consisting of a switching section 43 or 45 forming a circuit is preferable.

The communication method of this terminal device is that it is connected to a 4-wire loop communication network in which a control device 1 (Fig. 1) and a plurality of terminal devices 10 are connected in a loop, and data is transmitted after inputting a polling signal. In a terminal device having a line control circuit 11 that later outputs a polling signal,
A status signal that defines the status of the terminal device 10 is determined, and based on the status signal, the transmission destination to be connected is switched to either the control device 1 or the next terminal device 10, and if necessary, the current system is switched. and a standby system, connect the control device 1 and the line control circuit 11, receive a polling signal from the control device 1 side, and then execute data transmission to the control device l; In this method, after transmitting the data, line switching is performed to connect the next terminal device 10 and the line control circuit 11, and a polling signal is transmitted to the next terminal device 10.

(Function) With the above-mentioned configuration, the present invention has the following configuration: when data is sucked up to the control device 1 side in a 4-wire loop communication network in which the control device 1 and a plurality of terminal devices 10 are connected in a loop,
A state signal that defines the state of the terminal device 10 is determined and stored in the gate control register 12, and the switching means 13 performs line switching based on the state signal, selects the control device 1 as the transmission partner to be connected, and the control device 1 and line control circuit 11
After receiving a polling signal from the control device 1 side, data transmission from the line control circuit 11 to the control device 1 is executed, and the switching means 13 performs line switching according to the status signal changed after the data transmission. , selects the next terminal device 10 as the transmission destination to be connected, connects the next terminal device 10 and line control circuit 11, and transmits a polling signal from the line control circuit 11 to the connected next terminal device 10.

In this case, if necessary, the gate control register 12
Circuit switching between the active system and the standby system is performed by changing the status signal stored in the system.

In this case, within the switching means 13, the control signal generation section 14 receives the gate control signal from the gate control register 12 and generates a control signal for line switching, and the switching section 14 receives the control signal from the control signal generation section 14. 15 selects a transmission destination and data to be output to the transmission destination based on the control signal, and outputs the selected data to the transmission destination.

In addition, in circuit switching by the active system (standby system) switching circuit, the control signal generation unit 42 (44) generates a control signal for line switching by logical product of a plurality of gate control signals input from the gate control register 34. and switching section 43
(45) outputs the logical product of the control signal from the control signal generator and the data to be transmitted, thereby outputting the data to the transmission destination designated by the control signal.

〔Example 〕

Hereinafter, as an embodiment of the present invention, a case where a switching circuit formed of a gate circuit is provided will be illustrated and explained.

FIG. 2 shows the configuration of the terminal device.

Here, 31 is a terminal device, 32 is a processing device that controls the entire terminal device, and 33 is a memory that stores programs executed by the processing device 32 and data to be processed.

34 is a gate control register, which outputs a status signal (C) (
, *C) f, GA, DR).

Reference numeral 35 denotes a switching circuit, which switches the line depending on whether the destination device for transmission and reception is the control device 1 or another terminal device 31. Also, if two systems, a working system and a backup system, are provided,
Switches between the active system and the backup system.

Reference numeral 36 denotes a reception control circuit, which receives and passes input data from the line switched by the switching circuit 35 and connected to the VC to the processing device 32 or memory 33.

Reference numeral 37 denotes a transmission control circuit, which is switched by the switching circuit 35 in accordance with a command from the processing device 32 and outputs data from the connected line.

A pair of reception control circuit 36 and transmission control circuit 37 forms one line control circuit within terminal control circuit 31.

FIG. 3 shows the configuration of the switching circuit 35a for the active system.

Here, 34 is a gate control register (OCR), which receives a status signal (*CH) depending on the status of the terminal device 31.

GA, DR) are determined and output. Status signal *C
H inverts the signal CH by the NOT gate circuit 34a and outputs it. Reference numeral 42 denotes a control signal generation section, which generates control signals (GAO, DRO, GBO) from the state signal and outputs them. Reference numeral 43 denotes a switching unit that selects data to be output and a partner device based on the control signals (GAO, DRO, GBO) generated by the control signal generator 42, and outputs the data to the partner device.

The control signal generation unit 42 has two status signals *CH and GA.
AND gate circuit 4 which inputs and outputs AND GAO
2a, a not gate circuit 42b that outputs the inverted value *GAO of the value GAO, and two status signals *CH, D.
An AND gate circuit 42c that inputs R and outputs a logical product DRO, a NOT gate circuit 42d that outputs a value tree DRO that is an inversion of the value DRO, and three status signals *C) f
, GA, and DR and outputs a logical product GBO.

The switching unit 43 includes an AND gate circuit 43b that inputs a value obtained by inverting the signal SOI from the control device 1 and the control signal GAO by a not gate circuit 43a and outputs a logical product, and an AND gate circuit 43b that outputs the logical product of the signal SOI from the control device 1 and the control signal GAO. An AND gate circuit 43c inputs GAO and outputs a logical product, and inputs the respective outputs of the AND gate circuit 43b and 43c and a control signal DRO, and outputs a logical sum S00 as transmission data to the next stage. OR gate circuit 43d,
An AND gate circuit 43f inputs the data ROI from the next stage and a value obtained by inverting the control signal GBO by a NOT gate circuit 43e and outputs a logical product, and the transmission data TKO of the own terminal
and the AND gate circuit 43g which inputs the control signal GBO and outputs the AND gate, and inputs the respective outputs of the AND gate circuit 43f and the AND gate circuit 43g and outputs the logical sum ROO as transmission data to the control device 1. An OR gate circuit 43h is provided.

FIG. 4 shows the configuration of the switching circuit 35b for the standby system.

Here, 34 is a gate control register (OCR), which is the same register that outputs status signals (*CH, GA, DR) to the active system. This register 34 outputs the active system signals as well as the standby system status signals (CH, G
A, DR) are output.

44 is a control signal generation unit which generates a control signal (GA
I, DRI, GBI) are generated and output.

A switching unit 45 selects data to be output and a partner device according to the control signals (GAI, DRI, GBI) generated by the control signal generating unit 44, and outputs the data to the partner device.

The control signal generation unit 44 receives two status signals CH.

An AND gate circuit 44a that inputs GA and outputs the logical product GAI, a NOT gate circuit 44b that outputs the inverted value *GA1 of the value GAI, and two state signals CH,
An AND gate circuit 44c that inputs DR and outputs a logical product DRI, a NOT gate circuit 44d that outputs a value *DR1 obtained by inverting the value DRI, and three status signals CH,
It includes an AND circuit 44e that inputs GA and DR and outputs a logical product GBI.

The data switching unit 45 includes an AND gate circuit 45b that inputs the signal SII from the control device 1 and the control signal GAI inverted by a NOT gate circuit 45a and outputs a logical product, and the transmission data TXI of the own terminal and the control signal GAI. An AND gate circuit 45c inputs the signal GAI and outputs the logical product, and inputs the respective outputs of the AND gate circuit 45b and the AND gate circuit 45c and the control signal DRI, and outputs the logical sum SIO as transmission data to the next stage. OR gate circuit 45
d, and an AND gate circuit 45f which inputs data RII from the next stage and a value obtained by inverting the control signal GBI by a not gate circuit 45e and outputs a logical product, and inputs the transmission data TXI and control signal GBI of the own terminal. and an OR gate circuit 45h that inputs the respective outputs of the AND gate circuit 45f and the AND gate circuit 45g and outputs the logical sum RIO as transmission data to the control device 1.

The gate state of this switching circuit 35 is determined as shown in FIG. Here, in FIG. 5(a), there is no polling reception request from the terminal device 31, and the status signals (CH, GA, DR) are
represents the case where all are 0, and the signal from the control device 1 side is passed through to the next stage. In FIG. 5(b), the terminal device 31 is in a polling wait state and the status signals (CH, GA, DR) are
represents a case where (0, 0, 1), a polling signal from the control device 1 side is awaited, transmission to the next stage is not performed, and transmission from the next stage is passed through.

FIG. 5(c) shows a data transmission state in which the terminal device 31 transmits data to the control device 1, and status signals (CH, GA, D
This represents the case where R) is (0, 1, 1), and data transmission to the control device 1 is performed without signal input from the control device 1 side or communication with the next stage.

FIG. 5(d) shows a proxy polling state in which the terminal device 31 transmits a polling signal to the next stage, and the status signals (CH, GA
, DR) are (0, 1, O), there is no signal input from the control device 1 side, a polling signal is transmitted to the next stage, and transmission from the next stage is passed through.

FIG. 5(e) shows a state in which the switching circuit 35 of the terminal device 31 is operating the active system, and the protection system is passed through, and CH among the status signals (CH, GA, DR) is Until it becomes 1 and the system is switched to the standby system, transmissions from the control device 1 side and the next stage side are passed through.

The values of these gate control signals (state signals) are
They are collectively displayed in Figure (f).

In the embodiment configured in this manner, when the terminal device 31 attempts to transmit data to the control device 1, it first changes from a state where there is no polling request to a state where it is waiting for polling by setting DR of the output of the gate control register 34 to 1. Make it.

Since CH is 0, the state signal *CH becomes 1 as its inverted value, so that DRO among the outputs from the control signal generation section 42 becomes 1, and the signal line to the next stage is disconnected.

When a polling signal is received in this state, the state signal G
A and DR each change to 1 and enter the data transmission state,
The switching unit 43 outputs the transmission data TXO of the own terminal as the transmission data ROO to the control device 1, and causes the necessary data to be transmitted to the control device 1.

When the transmission to the control device 1 is completed, the status signal GA becomes 1.
The terminal remains unchanged and DR changes to 0 to enter the proxy polling state, and the switching unit 43 outputs the transmission data TXO of the own terminal as the transmission data S00 to the next stage, and transmits the polling signal to the next stage. Thereafter, the status signal GA changes to O, and the state returns to the through-pass state with no requirements.

Similarly, in the standby system, the processing content is based on status signals CH and GA.
, DR, the control signal generation unit 44 and the switching unit 45
output is controlled and necessary reception and transmission are performed.

The active system and standby system are switched by changing the value of the status signal CHO.

As a result, in the embodiment, the polling method shown in FIGS. 6(a) to 6(e) can be implemented by changing the terminal device 2 to the terminal device 31 having one line control circuit, and by using the switching circuit 35 to can be switched, and transmission to the control device I and transmission to the next terminal can be executed for a partner device that is not temporally simultaneous. Further, in the case of duplex control in which the active/protection system is not accessed simultaneously, the circuit can be switched from the active system to the protection system by the state signal CH output by the gate control register of the switching circuit 35.

Therefore, the number of expensive line control circuits is minimized, the configuration of the terminal device is simplified and the price is reduced, and costs can be reduced.

〔Effect of the invention 〕

As described above, in the present invention, the switching means 13 switches the line of the terminal device 10 connected to the four-wire loop type communication network according to the state signal that defines the state of the terminal device 10, and the control device 1 and the line control Connect circuit 11,
After receiving the polling signal from the control device 1 side, data transmission from the line control circuit 11 to the control device 1 is executed, and after the data transmission, the switching means 1 is activated by the state signal changed.
3 performs line switching, selects the next terminal device 10 as the transmission destination to be connected, connects the next terminal device 10 and the line control circuit 11, and sends a polling signal from the line control circuit 11 to the connected next terminal device 10. By making it possible to transmit data, the terminal device 10 equipped with the minimum number of line control circuits 11 can perform polling communication in a four-wire loop communication network, and the cost of the device can be reduced.

In addition, in this case, if necessary, by changing the status signal stored in the gate control register 12, circuit switching between the active system and the protection system is performed, thereby eliminating the need for the protection system line control circuit 11. It can be done.

Furthermore, in the switching means 13, the control signal generation section 14 receives the gate control signal from the gate control register 12 and generates a control signal for line switching, and the switching section 15 generates the transmission destination and the data to be output to the transmission destination. By making it possible to select and output to the transmission destination based on a control signal, the circuit switching between the control device 1 and the next terminal device 10 or the circuit switching between the active system and the standby system can be easily changed. can be realized.

Furthermore, in the active system (or standby system) switching circuit, the control signal generation section 42 (44) is connected to the gate control register 34.
The switching section 43 (45) constitutes a gate circuit that outputs the logical product of a plurality of gate control signals input from the control signal generating section and the gate circuit that outputs the logical product of the control signal from the control signal generating section and the data to be transmitted. With this configuration, the configuration can be made inexpensive and can be made cheaper than the line control circuit, and the cost of the terminal device can be reduced by reducing the number of line control circuits.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram showing a terminal device of an embodiment, Fig. 3 is a configuration diagram showing a switching circuit (active system) of an embodiment, and Fig. 4 is a block diagram showing a terminal device of an embodiment. , a block diagram showing the switching circuit (standby system) of the embodiment, and FIG. 5 is an explanatory diagram of gate states of the embodiment, where (a) is a no-request state, (b) is a polling wait state, and (C) is a data state. Transmission state; (d) is proxy polling state; (e) is standby system status when using active system; (f) is status table; FIG. 6 is a process explanatory diagram showing the conventional polling method; The figure is a block diagram showing a conventional terminal device. 1...Control device 10...Terminal device 11...-Line control circuit 12.34...Gate control register 13...Switching means 14.42.44...Control signal generation unit 15.43. 4
5...Switching unit 35b Switching circuit of the embodiment (standby system) Figure +a1g! None state + b) Bosong waiting state (cl data sending state fd1 proxy boring state Example gate state explanatory diagram Figure 1990) October 16th

Claims (4)

[Claims] (1) In a terminal device (10) having a line control circuit (11) that transmits data after inputting a polling signal and outputs a polling signal after transmitting the data, the terminal device (10)
a gate control register (12) that stores a gate control signal according to the state of the circuit; and a line control circuit (11) that receives the gate control signal and switches the connection to the transmission destination.
1. A communication terminal device comprising a switching means (13) for outputting data outputted from the terminal to the transmission destination. (2) The switching means (13) includes a control signal generation section (14) that generates a control signal for line switching from a gate control signal from the gate control register (12); 2. The communication terminal device according to claim 1, further comprising a switching unit (15) for receiving a control signal from a transmitting party and selecting and outputting a transmitting party and data to be output to the transmitting party. (3) A control signal generation section (42) that forms a gate circuit that generates a control signal for line switching by the AND of a plurality of gate control signals input from the gate control register (34).
or 44), and a switching unit (43 or 45) forming a gate circuit that outputs the logical product of the control signal from the control signal generation unit and the data to be transmitted as output data to the transmission destination specified by the control signal. A switching circuit characterized by comprising: (4) A line that is connected to a 4-wire loop communication network in which the control device (1) and multiple terminal devices (10) are connected in a loop, and that transmits data after inputting a polling signal and outputs a polling signal after transmitting data. Control circuit (11)
In a terminal device (10) having
Based on the status signal, the transmission destination to be connected is switched to either the control device (1) or the next terminal device (10), and the control device (1) and the line control circuit (11) are connected. After connecting and receiving a polling signal from the control device (1) side, data transmission to the control device (1) is executed, and after the data transmission, line switching is performed to connect the next terminal device (10) and the next terminal device (10). Line control circuit (11
) and transmitting a polling signal to the next terminal device (10).