JPH10104373A - Time adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reversal of generating order of event by calculating the shift in an internal clock in a device out of a standard at correcting time and adding the shift time to the generated event within the shift time or using the generation time as it is when there is no generation of event. SOLUTION: A master 1 and slaves 21 and 2n are connected with busses or by way of communication lines and the master 1 and slaves 21 and 2n are constituted with a control part, a clock part, a memory part, a transmission part and an event detection part. In the case an event is transmitted or received among a plurality of devices by adding the generation time, the control part takes in the time of the clock part when the event detection part detects the event, stores in combination with the event in the memory part and transmits with the transmission part to other station. First at the moment of time correction, the shift from the self clock is obtained. In the case an event generates within the shift time, the shift time is added to determine the event generation time. In the case no event generates in the shift time, the event generation time is used as it is. By this, reversal of event generation order can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system in which a plurality of devices such as a supervisory control system are connected, in which time information is attached between devices and event data is transmitted and received. Time adjustment method.

[0002]

2. Description of the Related Art In a monitoring control system, there are a master for collecting monitoring data and a slave for providing monitoring data. When a time at which an event occurs is added to monitoring data of the slave, a clock function is provided to the slave. It is necessary to have.

A slave reads the time when an event occurs from its own clock function, stores the time in a memory or the like in combination with the event, and transmits data stored in the memory by polling or the like from the master, or Notify the master voluntarily.

At this time, when a plurality of slaves are installed, it is necessary to provide a clock function for each slave, and each slave sets the time indicated by the clock function provided by its own station together with an event to the master. Send or notify.

[0005]

When a plurality of slaves exist in the monitoring and control system, the time is referred to by the clock function of each slave. These clocks always have an error, and a time error occurs between slaves. For this reason, it is necessary to adjust the time of each slave at an appropriate cycle.

[0006] In this time adjustment, the master clock (reference clock) is performed by the master or any of the slaves.

However, when the time setting is notified from a certain station, the clock of the own station is advanced, and an event occurs at that time, if the corrected time is combined with the event, the event that occurred immediately before May be reversed, and the order of event occurrence may be reversed.

For example, FIG. 7 shows an internal clock and an event occurrence situation in the slave n.
Event A occurs at the time of “2” and the time “00: 0”
After assembling “2”, the time of the internal clock is set to “00:00” by a time correction notification from another station at time “00:04”.
Event B occurs immediately after this, and the time "0"
In the case of “0:01”, the order in which events actually occurred is event A → event B, whereas the order in which events occurred due to time correction is recorded as event B → event A. Become.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a time adjustment method which eliminates the phenomenon of reversing the order of occurrence of events due to time adjustment.

[0010]

SUMMARY OF THE INVENTION According to the present invention, event data is transmitted and received between a plurality of devices by attaching time information, and other devices are internally notified by a time notification from a reference device among the devices. In the time adjusting method for adjusting the time of the clock, the other device obtains a difference from the clock in the own station when the time is corrected, and when an event occurs within the shifted time, the other device determines the difference. It is characterized in that the time of event occurrence is added by the time, and the time of event occurrence is used as it is when no event occurs within the shifted time.

Further, according to the present invention, event data is transmitted and received between a plurality of devices by attaching time information, and another device sets the time of its internal clock by a time notification from a reference device among the devices. In the time adjustment method, the other device obtains a time difference from the clock in the own station when the time is adjusted, and sets the time to the occurrence of an event during the time until the time difference has elapsed. Is reserved, and after the lapse of the shifted time, the correction time is set as the occurrence time in the order of the reserved events.

Further, according to the present invention, event data is transmitted and received between a plurality of devices by attaching time information, and another device sets the time of its internal clock by a time notification from a reference device among the devices. In the time adjustment method, the other device records the event that occurred as a set of the time and a series of serial numbers, and records and shifts the set of the time and the serial number as a notification of the time correction as an event occurrence. It is characterized in that time is recorded, the serial number is set as the order of occurrence of the event, and the interval of occurrence of the event is obtained based on the difference time.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 illustrates an example of a configuration of a monitoring control system, the master 1 and n of slaves 2 ₁ to 2 _n are coupled through bus connection, or communication lines.

FIG. 2 shows a master 1 and slaves 2 ₁ to 2 _n.
The control unit 3, the clock unit 4, the storage unit 5, the transmission unit 6, and the event detection unit 7 are connected by a bus.

As described above, when a plurality of devices transmit and receive an event by adding the time of occurrence to the event, the control unit 3 fetches the time of the clock unit 4 when the event detection unit 7 detects the event, and determines the event. The information is stored in the storage unit 5 as a set, and this information is transmitted to another station by the transmission unit 6.

Here, the time adjustment processing by the control unit 3 is performed by the following method.

(1) When the time is corrected, a deviation from the clock of the own station is obtained.

(2) When an event occurs within a time lag, the time of the event occurrence is added by the time lag.

(3) If an event does not occur within the offset time, the offset is not added and the time of occurrence of the event is used as it is.

FIG. 3 shows an example of time correction according to this embodiment. Event A occurs at time “00:02” in the internal clock of slave n, and time “00:00” at time “00:04”.
, A time lag “00:04” during this time is calculated.

Then, when the event B occurs at the corrected time "00:01", since the event occurs within the delay time, the occurrence time of the event B is shifted to "00:01" by "0".
0:04 ”is recorded as time“ 00:05 ”.

When the time reaches the corrected time "00:05", the addition of the shift time is canceled. For example, if event C occurs thereafter, the corrected time "00: 0" is set.
"6" is recorded as the time of occurrence of event C.

As a result, the occurrence time of event A is “00: 0”
2, the occurrence time of event B is "00:05", the occurrence time of event C is "00:06", and the occurrence time interval of each event deviates from the actual time, but between events A, B, and C In the order of occurrence times in the above can be eliminated.

(Second Embodiment) In the present embodiment, the time adjustment processing by the control unit is performed by the following method.

(4) When the time is corrected, a deviation from the clock of the own station is obtained.

(5) Until the time lag has elapsed, a set of times is reserved for the occurrence of an event during that time.

(6) After the lapse of the shifted time, the clock is corrected, and the time is sequentially combined with the reserved events.

FIG. 4 shows an example of time correction according to this embodiment. Event A occurs at time “00:02” in the internal clock of slave n, and time “00:00” at time “00:04”.
When the correction is notified to the internal clock, "00: 0"
4 ”is calculated in advance.

The time is not corrected until the calculated time "00:04" has elapsed, and the time of the internal clock is corrected to "00:04" at time "00:08". If event B occurs during this time, the time record for this event B is kept.

Then, the time "00:08" is changed to the time "0".
When the time is corrected to “0:04”, the occurrence time of the reserved event B is recorded as the corrected time “00:04”. Thereafter, when event C occurs, the corrected time “00: 0”
6 "is recorded as a set.

As a result, the occurrence time of event A is “00: 0”
2 ", the occurrence time of event B is" 00:04 ", and the occurrence time of event C is" 00:06 ", so that the inversion of the order of occurrence times among events A, B, and C can be eliminated.

(Third Embodiment) In the present embodiment, in the time adjustment processing by the control unit, a series of serial numbers are recorded in combination with the occurred event and time, and the event occurrence order is specified in the order of the serial number. The inversion of the event occurrence time order is eliminated by correcting the times in order.

FIG. 5 shows an example of time correction according to this embodiment. Event A occurs at time “00:02” in the internal clock of slave n, and time “00:00” at time “00:04”.
Immediately upon receiving a correction notification to
0:00 ”. At this time, the time correction is set as an event B, and the shift "00:04" from the internal clock is calculated and recorded together with the serial number.

After the time is corrected, the event C occurs at the time "00:01", the time "00:01" is recorded, and the event D occurs at the time "00:06".
0:06 "is recorded. In these records, a series of serial numbers is assigned to events.

As a result, the records of the event and the time are as shown in the following table.
However, since the shift time “00:04” is recorded and the event occurrence order is recorded by the serial number, the reverse phenomenon can be eliminated by the shift time “00:04”. Further, since the shift time is recorded, the occurrence interval of each event can be obtained by calculation.

[0036]

[Table 1]

In this embodiment, the recording time of the event B when the time is corrected is changed to the corrected time “00:
00 may be recorded. An example of the time correction in this case is shown in FIG. 6, and the recording result is shown in the following table.

[0038]

[Table 2]

[0039]

As described above, according to the present invention, when the time is corrected, a difference from the clock in the own station is obtained, and when an event occurs within the shifted time, the shifted time is calculated. Is added to make the time of event occurrence, so that the order of event occurrence does not reverse when the time is adjusted.

Further, when the time is corrected, a deviation from the clock in the own station is obtained, and until the time when the deviation elapses, a set of times is reserved for the occurrence of an event during that time. After the elapsed time, the correction time is set to the occurrence time in the order of the reserved events, so that the occurrence order of the events does not reverse due to the time adjustment.

Further, since the event and the time are recorded together with a series of serial numbers, it is possible to prevent the event occurrence order from being reversed from the serial numbers even when correcting the time. Further, the occurrence interval of the event can be obtained from the shift time.

[Brief description of the drawings]

FIG. 1 is a configuration example of a monitoring control system.

FIG. 2 is a configuration example of a master or a slave in FIG.

FIG. 3 is an example of time correction in the embodiment.

FIG. 4 is a time correction example according to another embodiment.

FIG. 5 is a time correction example according to another embodiment.

FIG. 6 is a time correction example according to another embodiment.

FIG. 7 shows an internal clock and an event occurrence state in the conventional time adjustment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 master 2 ₁ , 2 _n slave 3 control unit 4 clock unit 5 storage unit 6 transmission unit 7 event detection unit

Claims (3)

[Claims] 1. A time adjustment method for exchanging event data by attaching time information between a plurality of devices, and adjusting the time of an internal clock of another device based on a time notification from a reference device among the devices. In the above, the other device obtains a difference from the clock in the own station when the time is corrected, and when an event occurs within the shifted time, adds by the shifted time to generate the event. A time adjustment method characterized by using a time, and when an event does not occur within a time lag, an event occurrence time is used as it is. 2. A time adjusting method for exchanging event data by attaching time information between a plurality of devices, and adjusting the time of an internal clock of another device based on a time notification from a reference device among the devices. In the other device, when the time is corrected, the difference from the clock in the own station is determined, and until the time when the difference elapses, a set of times is reserved for the occurrence of an event during the time. A time adjustment method in which, after a lapse of a shifted time, a correction time is set as an occurrence time in the order of the reserved events. 3. A time adjustment method for exchanging event data by attaching time information between a plurality of devices, and adjusting the time of an internal clock of another device based on a time notification from a reference device among the devices. In the other device, the generated event is recorded as a set of the time and a series of serial numbers, and the time and the serial number are set as the occurrence of the notification of the time correction, and the recording and the deviation time are recorded. In addition, the serial number is set to the order of occurrence of the event, and the interval of occurrence of the event is obtained based on a shift time.