JPH08122467A - Time transmission equipment - Google Patents

Abstract

PURPOSE: To eliminate asynchronism between devices and to facilitate application to a control device by providing a serial transmission part which transfers data on time to a subordinate device after a main device generates a synchronous signal. CONSTITUTION: In a main device 5, time is obtained by making a clock 2 operate constantly. When a power source 1 is made, data on the time thereof are transferred serially to a serial reception part 6 after a synchronous signal generated by a timing generating circuit 4 is transmitted from a serial transmission part 3. As for timing, the timing of msec or μsec for synchronization as a control device is necessary, not that for indication in seconds such as clock indication. In serial transmission of 1MBPS, for instance, asynchronism can be reduced to several microseconds or below. In a subordinate device 7, the synchronous signal and the time data received by the serial reception part 6 are synchronized by a synchronizing circuit 8 and the time is obtained by a time preparing part 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time transmission device which has only one time among a plurality of devices and obtains the time by transmitting to another device at a constant interval during power-on.

[0002]

2. Description of the Related Art In the first prior art, a power source is backed up for each device and a clock is provided to obtain the time.
That is, FIG. 2 is a view showing an example of the conventional art.
0, 12, 14 are backup power supplies, 11, 13, 15
Is a clock, and 16, 17 and 18 are devices. Each device 16,
Backup power supplies 10, 12 and 17,
There are clocks 11, 13 and 15 backed up in 14, and the time can be obtained for each device.
In addition, as a second conventional technique, as disclosed in Japanese Examined Patent Publication No. 1-48719, there is a technique in which the time is transmitted in a bit-serial manner at regular time intervals, and each terminal clock is driven by a terminal device receiving the time.

[0003]

However, in the first prior art, in a system having a plurality of devices, each device has a clock, so that the number of circuits is increased and there is a time difference between the devices. There was a drawback that became inconsistent. Also,
In the second conventional technique, the time and control data are sent from the master clock to the slave clock at every certain time, and the data of the slave clock is attached to the next slave clock in sequence, and the processing circuit is complicated and It is difficult to set the timing of synchronization, and there is a drawback that it is difficult to apply it to a device such as a control device of a servo motor that requires quick response. Therefore, an object of the present invention is to provide a time transmission device that eliminates synchronization deviation between devices and facilitates application to a control device.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a time transmission apparatus including a main unit that constantly operates a timepiece and a slave unit that receives time from the main unit by serial transmission. In the above, the main device is provided with a serial transmission unit for transferring time data to the slave device after generating a synchronization signal.

[0005]

By the above means, since only the main unit has the clock, backup and maintenance are easy. Also, the timing of synchronization between the devices can be accurately set, and there will be no time difference between the devices.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 is a backup power supply, 2 is a clock, 3 is a serial transmission unit, 4 is a timing generation circuit,
Reference numeral 5 is a main device, 6 is a serial reception unit, 7 is a slave device, 8 is a synchronization circuit, and 9 is a time generation unit. The operation of the time transmission device configured as described above will be described. In the main device 5, the clock 2 is constantly operated to obtain the time. When the power is turned on, the time data is serially transferred to the serial reception unit 6 after transmitting the synchronization signal generated by the timing generation circuit 4 from the serial transmission unit.
The timing is not for displaying in units of seconds like clock display, but m for synchronizing as a control device.
Timing of sec and μsec is required. For example, in 1 MBPS serial transmission, the synchronization deviation can be suppressed within a few μsec. The slave device 7 synchronizes the synchronization signal received by the serial receiver 6 with the time data by the synchronization circuit 8
The time generation unit 9 obtains the time. That is, the timer is reset when the synchronization signal is received, and the time is reproduced by the subsequent time data. After that, the time can be reproduced only by the synchronization signal. In particular,
Time = basic time + timer time is taken, the basic time is updated at a certain synchronization interval, and the timer is cleared at that time. The time data is obtained only once after the power is turned on, and the time is always obtained in the slave device. In this way, the master device and the slave device can obtain the same time. In addition, the device of the present embodiment is 3
However, the same can be done with two or more, and the time is transmitted from the main device 5 at a certain time, and the master and slave devices each have a transmission / reception circuit, and only when there is a request from the slave device to the master device. It can also be transmitted only.

[0007]

As described above, according to the present invention, it is possible to provide a highly accurate time transmission device which eliminates the synchronization deviation and can be applied to the control device, and the time of a phenomenon or the like which may occur when an abnormality occurs. When looking at, since it is standardized among the devices, it is easy to track.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a specific embodiment of the present invention.

FIG. 2 is a configuration diagram of a specific example of a conventional example.

[Explanation of symbols]

 1, 10, 12, 14 Backup power supply 2, 11, 13, 15 Clock 3 Serial transmission unit 4 Timing generation circuit 5 Main device 6 Serial reception unit 7 Slave device 8 Synchronization circuit 9 Time generation unit 16, 17, 18 Device

Claims (1)

[Claims] 1. A time transmission device comprising: a main device that constantly operates a clock; and a slave device that receives time from the main device by serial transmission. After the main device generates a synchronization signal, A time transmission device comprising a serial transmission unit for transferring time data to a slave device.