JPH1028119A - Processing system for time setting among a plurality of equipments - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly set the time for terminal equipment by permitting a master device to calculate transmission path delay through the use of informa tion returned from the terminal equipment being a time setting object and executing re-transmission to the terminal equipment by means of time informa tion obtained by correcting it. SOLUTION: In the time setting processing of the master device, a present time is transmitted and the time for time setting information to reach the designated terminal equipment is adopted as (the set time-a return reception time)/2. When the time for time setting information to reach the designated terminal is shorter than one second, self time correction is not executed. At the time it is longer than one second, a value obtained by adding a difference value to the self time in time information to be transmitted it re-transmitted. Thus, the delay of a transmission path is calculated in realtime at the time of distributing time information, the time where it is added is set and the time of the terminal equipment is correctly set. The summing-up of transmission path delay is executed between the equipments connected by the plural transmission paths and the time is corrected by this so as to be set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network operation system having a function of setting or reading control information for a plurality of terminal devices connected by a transmission line.
In particular, the present invention relates to a time setting processing method for setting time between a plurality of devices.

[0002]

2. Description of the Related Art Conventionally, in a system composed of a plurality of terminal devices, one of them is defined as a master of time information, and in a system in which this master device distributes time information to other terminal devices, the master device described above is used. The device manages the configuration information of the other terminal devices, and sequentially transmits the time of the internal clock as information to each terminal device in accordance with the information. The terminal device that has received the time information sets this time as the internal clock.

[0003]

In the prior art described above, when time information is set for a plurality of terminal devices,
The transmission line delay between the master device and each terminal device is not considered at all, and the time set in the terminal device is delayed by the transmission line delay time from the time of the master device. In addition, since the transmission line delay time is different in a plurality of transmission lines, the time set between the devices is not constant.

According to the present invention, when time information is set for a plurality of terminal devices connected by a plurality of transmission lines, the time information is corrected in consideration of the delay of each transmission line, and the time information between the plurality of devices is corrected. The purpose is to minimize the time error.

[0005]

According to the present invention, a master device manages configuration information of another terminal device, and sequentially transmits the time of an internal clock to each terminal device as information in accordance with the management information. The terminal device that has received this sets the time in the internal clock and sends the information back to the master device as it is, and the master device calculates the transmission path delay using the information returned from the terminal device whose time is to be set. A time setting processing method between a plurality of devices, characterized in that retransmission is performed to the terminal device with the corrected time information.

Further, according to the present invention, the master device sets the value obtained by dividing the difference between the time of the information returned from the terminal device whose time is to be set and the time at which the time information was received into two, as the set time. When the value is larger than the minimum unit, a time setting processing method between a plurality of apparatuses is obtained, in which time information to be transmitted is retransmitted by adding the difference value to its own time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A time setting processing method according to the present invention will be described below.

When the time is set from the master device to each terminal device, the transfer is made one-to-one. Therefore, the terminal device that relays the time information only transfers this information and does not perform its own time correction (first processing). The terminal device whose time has been corrected sends the information back to the device serving as the master (second process). The master device is a minimum unit of the set time (1 second), which is a value obtained by dividing the difference between the time of the information returned from the terminal device of the time setting target (the time when the information is transmitted) and the time when the information is received by two. If it is larger, the time information to be transmitted is retransmitted by adding the above difference value to its own time (third process). Then, the third process is performed on all the devices.

Next, the above processing will be described in detail with reference to FIG. FIG. 1A is a diagram showing a method of setting the time for a terminal device connected by one transmission line, and FIG. 1B is a diagram showing a terminal connected by a plurality of transmission lines. FIG. 3 is a diagram illustrating a method of setting a time on an apparatus. In the time setting process in the master device, the current time is transmitted (first process), the time at which the time setting information reaches the designated terminal device is set to (set time−return transmission / reception time) / 2, and the designated terminal device If the time when the time setting information arrives is shorter than 1 second, the processing of the next device (the above-described first processing) is performed. Is added as the setting information. Thereafter, the processing excluding the first processing is repeated.

As described above, when the time information is distributed, the delay of the transmission path is calculated in real time, and the time obtained by adding the delay is set, so that the time of the terminal device can be set accurately.

[0011] Further, transmission delays between devices connected by a plurality of transmission lines can be summed up and set at a time corrected.

Further, even when the delay time fluctuates due to the load on the transmission line, the time of the terminal device can be accurately set by determining the delay time of the transmission line and resetting it if the delay time is equal to or more than a certain value.

[0013]

According to the present invention, the time setting for a plurality of terminal devices connected by a plurality of transmission lines can be performed.
The influence of the transmission path delay time is minimized, and the difference in the internal time of each terminal device can be suppressed within plus one second with respect to the master device.

[Brief description of the drawings]

FIG. 1A is a diagram showing a method of setting a time for a terminal device connected by one transmission line,
(B) is a diagram showing a method of setting time for terminal devices connected by a plurality of transmission paths.

Claims (2)

[Claims] The master device manages the configuration information of another terminal device, and sequentially transmits the time of an internal clock to each terminal device as information in accordance with the configuration information. While setting the internal clock, the information is sent back to the master device as it is, and the master device calculates the transmission line delay using the information returned from the terminal device whose time is to be set, and corrects the terminal delay with the corrected time information. A time setting processing method between a plurality of devices, wherein retransmission is performed to the device. 2. The master device according to claim 1, wherein a value obtained by dividing a difference between the time of the information returned from the terminal device whose time is to be set and the time at which the time information is received by two is larger than the minimum unit of the set time. The time setting processing method according to claim 1, wherein the time information to be transmitted is retransmitted by adding the difference value to its own time.