JP2590775B2 - Double loop transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-loop transmission system, and more particularly to a double-loop transmission system for transmitting data using a polling response method.

[0002]

2. Description of the Related Art An outline of a conventional double-loop transmission system will be described with reference to FIGS. As shown in FIG. 5, the double-loop transmission system includes two transmission lines 13 through which data is transmitted in the opposite direction, and the parent device 1
One and a plurality of slave devices 12 are connected. Data transmission in this double-loop transmission system is always performed between the master device 11 and one slave device 12,
No data transmission between the slave devices 12 is performed.

[0003] Data transmission from the slave device 12 to the master device 11 is performed when polling of the slave device 12 is transmitted from the master device 11, and the master device 11 transmits both data at a predetermined cycle. It is configured to send polling on the transmission line 13.

For example, when the parent device 11 sends out the polling P ₁ to the subordinate device 12 ₁ , as schematically shown in FIG. 6, the polling P _1A is sent out to the A-system transmission line, and the polling P _1A is sent to the B-system transmission line. Polling P _1B is sent out. Each slave device 12 is configured to send a response R to both transmission lines when the polling P arrives from any of the transmission lines. In this case, the slave device 1 (12 ₁ )
Responds to the polling P _1A input from the A-system transmission line, and the polling response R
_1AA is transmitted, and a polling response _R1AB is transmitted to the B-system transmission line.

At this time, since the polling response R _1AB collides with the polling P _1B coming from the B-system transmission line on the B-system transmission line and is likely to be overwritten, data corruption may occur. the expansion device provided in the system, the data from the transmission path that is different from the person who previously polled P arrives, only the timer value T ₀ set in advance, provided with a mechanism to avoid passing in the previous device Have been.

[0006] In a conventional dual loop transmission system, in order to be able to address all the transmission path arrangement, and set this timer value T ₀ to a large value, accordingly, the parent device sends the polling The period of the operation was also set to a large value.

[0007]

As described above, in the conventional double-loop transmission system, a fixed value is originally used as a timer value to be set according to the arrival time difference of polling. For this reason, the polling cycle of the parent device has become unnecessarily long, and the system cannot exhibit its original function.

An object of the present invention is to provide a double-loop transmission system that can set an optimum polling cycle according to the system configuration.

[0009]

According to the first aspect of the present invention, one parent device and a plurality of subordinate devices are connected to each other by a first transmission line and a second transmission line in which information transmission directions are determined. A double-loop transmission system, which is a system connected in a double loop, is used for (a) delay time measurement using a first transmission line and a second transmission line with respect to a plurality of slave devices constituting the system. A polling is generated based on a delay time measuring signal transmitting means for transmitting a signal and delay time difference information output as a response to the delay time measuring signal transmitted by the plurality of slave devices from the delay time measuring signal transmitting means. A master device having polling period setting means for setting a period; and (b) an arrival time difference measuring device for measuring an arrival time difference between delay time measurement signals respectively input from the first transmission line and the second transmission line. According to the arrival time difference measured by the arrival time difference measuring means, when a polling is received from one transmission path, a timer value is set as a time during which data from the other transmission path is not passed to the preceding device. A slave device is provided in combination with a timer value setting means and a timer value notifying means for notifying the parent device of the timer value set by the timer value setting means.

That is, in the double-loop transmission system according to the first aspect of the present invention, when the slave device receives polling from one of the transmission lines based on the delay time difference measurement signal transmitted from the master device. The master device sets (changes) a timer value that is a time during which data from the other transmission path is not passed to the preceding device, and sets (changes) the polling period based on the timer value notified from the slave device. ).

In order to strictly set the polling period and the timer value, the delay time measuring signal transmitting means in the master device transmits the delay time measuring signal to the plurality of subordinate devices a predetermined number of times. Preferably, the timer value setting means in the slave device sets a timer value based on the maximum value of the predetermined number of arrival time differences measured by the arrival time difference measurement means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

FIG. 1 shows an outline of a double-loop transmission system according to an embodiment of the present invention. FIGS. 2 and 3 respectively show a parent device provided in the double-loop transmission system of the embodiment. 2 shows a schematic configuration of a slave device. As shown in FIG. 1, the double loop transmission system of the embodiment includes an A transmission line 13 _A and a B transmission line 13
Yes constructed by connecting five slave device 12 by _B, as is indicated by arrows, the transmission line 13 _A is a transmission path for transmitting data in a counterclockwise direction, the transmission path 13
_B is a transmission line for transmitting data clockwise.

As shown in FIG. 2, the parent device 11
Receiving circuit 21, receiving system selecting circuit 22, receiving application processing circuit 23, polling cycle setting circuit 24, transmitting data creating circuit 25, delay measuring signal transmitting circuit 26, and transmitting circuit 2.
7 and a polling cycle setting circuit 2
Portions other than 4 and the delay measurement signal transmission circuit 26 have substantially the same configuration as the conventional double loop transmission system.

As shown in FIG. 3, the slave device 12 includes a reception circuit 31, a data selection circuit 32, a delay time difference measurement circuit 33, a reception system selection circuit 34, a reception cutoff timer setting circuit 35, a reception appropriate processing It is composed of a circuit 36, a reception disconnection circuit 37 and a transmission circuit 38.
A data selection circuit 32, a delay time difference measurement circuit 33, and a reception interruption timer setting circuit 35 are added.

The double-loop transmission system of the embodiment includes:
In addition to the normal operation mode, an operation mode named a polling cycle setting mode is provided, and the above-described additional circuit mainly functions in the polling cycle setting mode.

Hereinafter, the operation of the double loop transmission system of the embodiment in the polling cycle setting mode will be described in detail with reference to FIGS.

The polling cycle setting mode is a mode that is executed when the operation of the system is started or when a subordinate device is added to the system. In the double loop transmission system of the embodiment, the parent device is By sending data of a predetermined pattern to the slave devices, each slave device is notified that the polling period setting mode has been entered.

Each of the subordinate devices 12 receiving this notification sends a
Delay time measurement circuit 33 and reception interruption timer setting circuit 35
Is activated, and a signal for delay measurement in the parent device 11 is transmitted.
The output circuit 26 measures the delay measured for each slave device 12.
A fixed signal is created in sequence for a predetermined number of times, and each created delay measurement
The regular signal is transmitted to the A-system transmission line 13._AAnd B transmission line 13 _B
A series of processing of sending the data up is started.

[0020] For example, if the delay measurement signal is to a subordinate device 12 _1, as is shown in FIG. 1, the expansion device number which is installed between the master device 11 and slave devices 12 ₁ A transmission line 13 _A and B transmission line 13
Since different between _B, and the time the parent device 11 is delayed measurement signal sent out to different, and reaches the expansion devices 12 _1. The delay time difference measuring circuit 33 provided in each slave device 11 measures the arrival time difference, and notifies the reception disconnection timer setting circuit 35 of the measurement result. Then, the reception interruption timer setting circuit 35 sets the maximum value of the measurement results to be notified a predetermined number of times to the timer value T _m.
Stored therein as, when receiving the input of the last delay measurement signal, using a reception anniversary processing circuit 36, and notifies the timer value T _m in the parent device 11.

That is, the delay measurement signal transmission circuit 26
When the transmission of a series of delay measurement signals by the
The device 11 has a timer value T for each slave device 12._m1Absent
Then T _m5Has been acquired, and the port in the parent device 11 has been acquired.
The ring cycle setting circuit 24 calculates the timer value T_mMost
Determine the minimum polling cycle interval from the large value and enter that value
Store in the department.

In the normal operation mode, the system functions based on the timer value _Tm and the polling cycle set in this way.

FIG. 4 shows a double-loop transmission system according to the embodiment.
4 shows a time chart during a normal operation in the system. Parent device
Polling P from slave device 1₁Where is sent
In this case, the slave device 1 performs polling P from the A-system transmission line._1ATo
Polling to the A-system transmission line because it will be received first
Response R_1AAAnd sends a polling response R to the B-system transmission line.
_1ABIs sent. Then, the data from the B-system transmission path is
The receiving disconnection circuit 37 is operated so as not to be passed to the device.
The operation time of the reception disconnection circuit 37 is determined by the reception disconnection timer setting time.
By the path 35, in the polling cycle setting mode,
Timer value T stored in reception disconnection timer setting circuit 35_m1
Is controlled in accordance with the time.

Accordingly, in the double-loop transmission system of the embodiment, if the longer of the maximum value of the timer values T _m1 to T _m5 of each slave device or the transmission time of transmission polling, the following is obtained. By the time the poll arrives at the slave device, the reception has been released. For this reason, when the transmission time of the transmission polling is not long, the parent device sets the timer values T _m1 to T _m1 of each subordinate device.
Polling can be transmitted in a short polling cycle of the maximum value of _m5 .

[0025]

As described above, according to the present invention,
Since the length of the reception interruption timer of each slave device can be set to a value suitable for the system configuration, the polling period restricted by the reception interruption timer length can be minimized, and as a result, high-speed data transmission can be performed. A double loop transmission system is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a double-loop transmission system according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a parent device used in the double-loop transmission system of the embodiment.

FIG. 3 is a schematic configuration diagram of a slave device used in the double-loop transmission system of the embodiment.

FIG. 4 is a timing chart of a polling response in the double-loop transmission system of the embodiment.

FIG. 5 is a schematic configuration diagram of a conventional double-loop transmission system. FIG. 2 is a schematic configuration diagram of a slave device used in FIG.

FIG. 6 shows a conventional double-loop transmission system.
It is a timing chart of a polling response.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Parent apparatus 12 Slave apparatus 13 Transmission line 21, 31 Receiving circuit 22, 34 Receiving system selection circuit 23, 36 Receiving response processing circuit 24 Polling cycle setting circuit 25 Transmission data creation circuit 26 Delay measurement signal transmission circuit 27, 38 Transmission circuit 32 Data selection circuit 33 Delay time difference measurement circuit 35 Reception cutoff timer setting circuit 37 Reception cutoff circuit

Claims (2)

(57) [Claims] 1. A system in which one parent device and a plurality of subordinate devices are connected in a double loop by a first transmission line and a second transmission line in which a transmission direction of information is determined. Delay time measurement signal transmitting means for transmitting a delay time measurement signal to the plurality of slave devices constituting the system using the first transmission line and the second transmission line; and the plurality of slave devices. Based on delay time difference information output as a response to the delay time measurement signal sent by the delay time measurement signal sending means, based on a polling cycle setting means for setting a polling generation cycle, the master device, An arrival time difference measuring means for measuring an arrival time difference between the delay time measuring signals input from the first transmission path and the second transmission path, respectively, according to the arrival time difference measured by the arrival time difference measuring means; , When receiving a polling from one transmission path, and the timer value setting means for setting the timer value is a data time that does not pass beyond the device from the other transmission line,
A slave device having timer value notifying means for notifying the parent device of the timer value set by the timer value setting means. 2. The delay time measuring signal sending means in the master device sends a delay time measuring signal to a plurality of slave devices a predetermined number of times, and a timer value setting means in the slave device. 2. The double-loop transmission system according to claim 1, wherein the timer sets a timer value based on a maximum value of a predetermined number of arrival time differences measured by the arrival time difference measuring means.