JPH04150341A - Data link acquisition system - Google Patents

Abstract

PURPOSE:To realize data transfer among plural equipments through one line inexpensively and easily by devising the system such that an equipment desiring transmission reception receives a reply signal from an opposite equipment to acquire a token in a data link line and makes data transmission and reception. CONSTITUTION:An equipment 11 sends an acquisition statement of a call number and a data link line 3 to other equipments 12, 13 to monitor the reply. The other equipments 12 and 13 receive a signal and sends a reply signal when the number of the signal is coincident with a set number. Simultaneously, a timer 32 in the equipment 12 is started to monitor a restriction time in the line 3. The equipment 11 sending a call number is a master equipment of a data link line to control the entire master link line. The equipment 12 sending a reply signal is a slave equipment to make data transmission reception with the equipment 11. The equipment 13 not being the master and the slave is a monitor equipment and cannot access the data link line till the data link line is released.

Description

[Detailed Description of the Invention] [Summary] An object of the present invention is to provide a data link acquisition method with high transfer efficiency for transferring data between transmission devices in a data transmission system. (1) In a data transmission system in which data is sent and received between any two of n devices connected to each other by a data link line, the device that wishes to send and receive data among the n devices A first control unit is provided in the n devices to send a signal declaring the use of the data link line and an identification signal specifying the other device to devices other than the own device connected to the link line, A device that desires to send and receive data acquires a data link line after receiving a response signal from the other device;
(2) While a device that wishes to send and receive data has acquired a data link line, a device that has not acquired a data link line measures the time since the data link line was acquired, and A second control unit that releases restrictions on the use of the data link line when the time limit is exceeded is provided in n devices.

[Industrial application field]

The present invention relates to an improvement in a data link acquisition method for transferring data between transmission devices (hereinafter referred to as devices) in a data transmission system.

In recent years, as devices have become more efficient, it has become necessary to exchange data between devices, and as a means of achieving this, it is necessary to efficiently utilize data links.

Therefore, there is a need for a data link acquisition method with high transfer efficiency.

[Conventional technology]

FIG. 4 is a block diagram showing the configuration of a conventional system.

As shown in FIG. 4(a), when a plurality of devices 1-1 to 1-4 transmit and receive data through one data link line 3, each device 1-1 to 1-4 sends and receives data to the arbitration device 2. A control signal is sent out via the data link control line 4. Mediation device 2
According to the control signals from each of the devices 1-1 to 1-4, acquisition and release of the data link line 3 is arbitrated to prevent data from a plurality of devices from colliding within the data link line 3.

In addition, in the case of a point-to-point system (point-to-point system) as shown in FIG.
A function was provided to transfer data between -1, 5 and 2 by data through, and data was sent and received between a plurality of devices.

[Problem to be solved by the invention]

However, in the above method, when transmitting and receiving data between multiple devices using a single data link line, an arbitration device and a data link control line are required, which causes problems in terms of cost and efficient use of the line. was there.

Furthermore, when a data through function is provided, data must be terminated once and then transferred to another data link line, which increases the processing load. Further, there is a problem in that each device is always in an operating state, resulting in lower transfer efficiency.

Therefore, an object of the present invention is to provide a delink acquisition method with high transfer efficiency.

(Means for Solving the Problems) The above problems are solved by the configuration of the apparatus shown in FIG.

That is, in FIG. 1, (]) Which of the n devices 110-1 to 110-n connected to each other by the data link line 300 is
In a data transmission system in which data is sent and received between two devices, 210 is provided in the n devices 110-1 to 110-n, and 210 is used to send and receive data among the n devices 110-1 to 110-n. For devices other than the own device that are connected to the data link line 300, the device desiring the
This is the first control unit that sends a signal declaring the use of 00 and an identification signal specifying the partner device.

The configuration is such that a device desiring to send and receive data acquires the data link line 300 after receiving a response signal from the partner device.

(2) In a state where the device desiring to send and receive data has acquired the data link line 300, the data link line 3
The device that has not acquired 00 is the data link line 300.
n devices 110-1 to 11 control a second control unit 220 that measures the time from the time when the data link line 300 is acquired and releases restrictions on the use of the data link line 300 when the specified time is exceeded.
0-n.

[For production]

In FIG. 1, (1) n devices 110-1 to 110
-n, for example, device 110-1 desires to send and receive data. Then, the first control unit 2 of the device 110-1
10 to all devices other than the own device connected to the data link line 300.
A signal declaring the use of 0 is sent together with a calling number for identifying the partner device.

Then, the device 110-1 that desires to send and receive data receives a response signal from the other device and connects the data link line 30-1 to the device 110-1.
0, and sends and receives data to and from the other party's device.

(2) A device that wishes to send and receive the data, for example 110
-n has acquired the data link line 300,
Device 110- which has not acquired data link line 300
2 to 110-n measure the time from the time when the data link line 300 is acquired by the second control unit 220, and release the restrictions on the use of the data link line 300 when the specified time is exceeded. Then, the data link line 300 is enabled to be used by any of the devices 110-1 to 110-n connected to the data link line 300.

As a result, by using only the data link line and without having a data through function, it is possible to inexpensively and easily realize data transfer between a plurality of devices using a single data link line.

〔Example〕

FIG. 2 is a block diagram showing the configuration of a system according to an embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

The same reference numerals indicate the same objects throughout the figures.

In FIG. 2, among the devices 11 to 13 connected to - data link lines 3, for example, device 11 is connected to device 1.
Assume that you are trying to transfer data to 2.

Then device 11 will be connected to all other devices (in this case 12.1
For 3), a call number to call the data transfer partner (in this case, the number preset in the device 12)
and sends out a signal indicating the declaration of acquisition of the data link line 3. This is done using software in the CPU 21 provided in the device 11. At the same time, a timer 31 provided in device II is activated and set to a constant value, and the presence or absence of a response from devices 12 and 13 within a certain period of time is monitored. The value set in each timer 31 shall be a value sufficient until a response is returned. (Step 1 in FIG. 3 (hereinafter referred to as S1)
(Same for Step 2 and subsequent steps). ) All other devices (10-2.1O-3 in this case) must receive a signal indicating the calling number and the declaration of acquisition of the data link line (see 313.322 in Figure 3), which is preset in their own device. When the numbers match (see 314 and S23 in the figure), a response signal is sent to the device 111 that sent the calling number as soon as data transfer preparations are completed. In this case, if the calling number in the device 12 matches the number preset for the device itself, the device 12 sends a response signal to the device engineer 1 using software in the CPU 22. At the same time, the timer 32 provided within the own device 12 is activated to monitor the constraint time within the data link line 3 (see SI5 in FIG. 3). In addition, even in the device I3 where the calling number and the number preset for the device do not match, the timer 33 provided in the device engineer 3 is activated to monitor the locking time in the data link line 3 (
(See 324 in Figure 3).

The device 11 that sent the calling number becomes the master device of the data link line when it receives response No. 15, and controls the entire master link line (see 32 in Figure 3).
. The device 12 that sent the response signal becomes a slave device that exchanges data with the master device 11. The device 13, which is neither a master device nor a slave device, becomes a monitor device and cannot access the data link line until the data link line is released.

Incidentally, if the aforementioned signals indicating the declaration of acquisition of the data link line 3 are outputted by the device 11 and the device 13 at the same time, for example, a collision occurs within the data link line 3. For this reason, in the device 11, no response signal is returned even when the time set in advance by the timer 31 described above has elapsed, so that the timer 31 exceeds the threshold value.

Therefore, the device 11 and the device 13 send a signal indicating the declaration of acquisition of the data link line 3 to the other device again, but at this time, weighting is done for each device in advance to avoid re-collision when sending the signal indicating the acquisition declaration. Try to prevent it.

For example, if the timer 31 of the device 11 is set to a count of 100, and the timer 33 of the device 13 is set to a count of 1 to 150, the device 11 can resend the signal faster than the device 13, so the device 11 A response signal from device 12 can be received.

Next, when the device 11 (master device) acquires the data link line 3 as described above, it cancels the setting of the threshold value for monitoring the presence or absence of a response to the timer 31, and instead receives the data. Activation is performed to set the permissible transfer time and monitor the timeout (see 84 in FIG. 3). Then, data transfer to the device 12 is started (see 35 in the figure). Meanwhile, the device 12 (slave device) also starts transferring data to the device 11 (see 316 in the figure).

When the device 11 receives a termination command (command) after exchanging data with the device 12, it transmits a signal indicating abandonment declaration of the data link line 3 to the other device I2.13.
and completes the data transmission/reception (S6.3 in the same figure).
10. (See S12). On the other hand, when the device 12 (slave device) and the device 13 (monitor device) receive a signal indicating the abandonment declaration of the data link line 3, they release the dependent relationship within the data link line 3 and terminate the process (see Fig. 3). No. 3
18, S20, S21 and 326.328.329).

Further, when the device 11 (master device) has not received the above-mentioned end command, it is determined whether the timer 31 has exceeded a preset time. When the timer 31 has timed out, it sends a signal indicating the abandonment declaration of the data link line 3 to the other devices 12 and 13, as in the case of the end command described above, and ends the data transmission and reception (as shown in the figure). (See S7.5IO1S12).

Next, when the timer 31 of the device 11 has not timed out, the CPU 21 uses software to determine whether there is still data to be transferred.

When there is no data to be transferred, a signal indicating abandonment of the data link line 3 is sent to the other devices 12 and 13, as in the case of the above-mentioned termination command or when the timer 31 has timed out, and the data (See S8.5IO1S12 in the figure).

Furthermore, when the device 11 determines that there is still data to be transferred, it sends a signal indicating a declaration of continued acquisition of the data link line 3 to the other devices 12 and 13 (see 39 in the same figure).
. On the other hand, in the devices 12 and 13, for example, the CPUs 22 and 23 each use software to determine whether or not a signal indicating a declaration of continued acquisition of the data link line 3 has been received (see 317 and S25 in the figure). Equipment 12.1
3, the timers 32 and 33 are cleared to return to the initial state, and the timers 32 and 33 are activated again in the same manner as described above to monitor the constraint time within the data link line 3.

(See 317' and S25' in FIG. 3). Then, as described above, it is determined whether a signal indicating the abandonment declaration of the data link line 3 has been received (318, S26 in the same figure).
reference).

When the device 12 (slave device) and the device 13 (monitor device) have not received a signal indicating the abandonment declaration of the data link line 3, it is determined whether the timers 32 and 33 have reached a preset time. do. timer 3
2 and timer 33 reach the preset time,
The dependency in the data link line 3 is released, the constraint is discarded, and the process ends (S19, S20, 321 and 327 in FIG. 3).
328, S29). Furthermore, when the timers 32 and 33 have not reached the preset time, the device 12 determines that there is still data to be transferred and continues to transfer the data (see 316 in the same figure). On the other hand, the device 13 determines that the data link line 3 is still being used, and determines whether it has received a signal indicating the declaration of continued acquisition of the data link line 3 (325 in the same figure). reference).

On the other hand, the device 11 (master device) sends a signal indicating the declaration of continued acquisition of the data link line 3 to the other devices 12.
．． 13, the timer 31 is cleared to return to the initial state and set to a constant time. Then, data transmission and reception with the device 12 (slave device) continues.

Note that when a failure occurs in the device 11 (master device) for some reason and the device 11 enters an abnormal state, a failure detection circuit (not shown) in the device 11 detects this and declares abandonment of the data link line 3. 12.1.
3 and ends (35', S10, S in Figure 3)
12). The device 12.13 receives the signal indicating the abandonment declaration of the data link line 3, releases the dependency within the data link line 3, and ends the process (318, S20 in the same figure).
(See S21 and 326, S28, and S29).

In this way, data link lines were acquired and arbitrated.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to inexpensively and easily transfer data between multiple devices using a single data link line without having a data through function by using only a data link line. It can be realized.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a block diagram showing the system configuration of an embodiment of the present invention, Fig. 3 is a flowchart for explaining the operation of the embodiment, and Fig. 4 is a diagram of the conventional example. FIG. 1 is a block diagram showing the configuration of the system. In the figure, 210 indicates a first control section, and 220 indicates a second control section. 1-1 (I setting) 1-2 (Device) (F)) Aro-tsuk diagram showing the structure of the system of Part 1

Claims (2)

[Claims] (1) In a data transmission system in which data is sent and received between any two of n devices (110-1 to 110-n) connected to each other by a data link line (300), Among the n devices (110-1 to 110-n), the device that wishes to send and receive data is connected to the data link line (300).
a first control unit (210) that sends a signal declaring the use of the data link line (300) and an identification signal specifying the other device to a device other than the own device connected to the device;
) is provided in the n devices (110-1 to 110-n),
A data link acquisition method characterized in that a device desiring to send and receive data acquires the data link line (300) after receiving a response signal from the partner device. (2) When a device that wishes to send and receive data has acquired the data link line (300), a device that has not acquired the data link line (300) The time from the time of acquisition is measured, and when the specified time is exceeded, the data link line (300)
a second control unit (220) that releases restrictions on the use of the
2. The data link acquisition method according to claim 1, wherein: is provided in the n devices (110-1 to 110-n).