JPS63314995A - Time synchronizer in remote supervisory and controlling equipment - Google Patents

Abstract

PURPOSE:To eliminate undefined delay time and to improve the accuracy of time adjustment by making a master station to be ready to receive interruption and temporarily making a circuit to be in a holding state. CONSTITUTION:The master station A fetches an interruption signal sent every fixed cycle T from a master clock 11. Then it has a decision means 13 which decides whether the interruption signal is before the fixed time of time cycle data transmission previously fixed or not, an internal timer 15 which is woken up and outputs an interruption signal (a) after counting priscribed time when the interruption signal is decided to be before the fixed time, a means which interrupts present protocal processing and holds a transmission circuit with a slave station C in a link state when the interruption signal (a) is inputted from the internal timer 15 and a means which immediately moves its operation to the operation of transmission of time adjustment data when the interruption signal (a) is inputted from the master clock 11 when the transmission circuit is in the holding state. The slave station has a means inputs time synchronizing data sent from the master station by interruption. Thus the undefined delay time can be eliminated and the accuracy when time is adjusted in the slave station can be improved.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides monitoring of controlled equipment between a control station (master station) and a controlled station (slave station) using an HDLC transmission method. A time synchronization device that transmits time synchronization data from the master station to the slave stations to synchronize the time to determine the information transmission timing between the master station and the slave stations in a remote monitoring υ1■ device that transmits information necessary for control. Regarding.

(Prior art ~) Conventionally, in a remote monitoring and control device that uses the HDLC transmission method to transmit information between a master station and a slave station, timing is determined for transmitting and receiving information between the master station and slave stations. The time is periodically adjusted for this purpose.

FIG. 6 shows an example of its schematic configuration, and FIG. 7 shows the state of the interrupt signal sent from the master clock. In addition,
FIG. 6 shows a configuration example in which the relationship between the master station and the slave stations is one-to-one. That is, in FIG. 6, the master station A is composed of a main microprocessor 61 and a sub-microprocessor 62 separately provided in the transmission section.
An interrupt signal is input at a fixed period (T) 9, for example, every minute.

On the other hand, slave station C is composed of a main microprocessor 64 and a sub-microprocessor 65 provided in the transmission section.

Now, what about a remote monitoring system with this kind of configuration? n device, the master clock 63 is used to synchronize the time between the master station and slave stations.
The sub microprocessor 62 of the master station A is given a fixed period <T
) 1 For example, when an interrupt signal is sent every minute, the master station A transmits a fixed period To (T<To), which is preset to an internal timer (not shown), for example, every minute. Time synchronization data is transmitted to the slave station C in accordance with an interrupt signal inputted from the master clock 63 every hour.

FIG. 7 shows the state of the signal, in which To sends out time synchronization data at regular intervals to start time adjustment, . . . Tn-1, Tn, Tn+1, . . .・・・・・・
・ is the interrupt input point at which time adjustment should start,...
<In-1), (In), (In+1), --・-=・
is the interrupt input signal from the master clock at the time of interrupt input.

By the way, the master station A interrupts the current transmission protocol processing with the slave station a certain period of time before (to) when the interrupt input signal (In) at the time of starting time adjustment is input, and the interrupt input signal (I
n>Enter samurai state.

In this case, the interrupt signal from the master clock 63 is input to a sub-microprocessor 62 that is separate from the main microprocessor 61 so that processing for the interrupt input signal is exclusively performed. Compared to the case where input processing is performed for the interrupt signal from the station 63, the error factor of the delay time (tl) can be minimized.

When the master station A+ enters the waiting state for an interrupt input signal, the HD
Starts transmission of the flag (8 bits of 01111110) defined in the LC transmission procedure.

Therefore, bit synchronization can be established even when using an asynchronous modem.

Next, the time adjustment start interrupt point (Tn) after the end of flag transmission
When the interrupt signal is input to the sub microprocessor 62, the master station A shifts to time synchronized data transmission processing. When this time synchronization data is transmitted, slave station C performs slave station interrupt processing, and time synchronization is performed for slave station C.

FIG. 8 shows the process from interrupt signal input processing at master station A to interrupt processing at slave station C and the state of transmitted data.
tl is the delay time for the input processing of the master station interrupt signal (the transmission data state is the transmission protocol), tu is the indefinite delay time when the interrupt reception is in the standby state (the transmission state is flag transmission), t
2 is time synchronized data transmission processing time (transmission status is time synchronized data transmission), t3 is transmission path delay time, and t4 is slave station deletion processing delay time.

However, in such a time-synchronized transmission system, as is clear from FIG. 9, the interrupt reception is always in the middle of flag transmission, and it is not possible to proceed to time-synchronized data transmission processing until the flags have been transmitted. This time is a delay time (tLI) that is undefined in the range of 0 to 8 bits. Further, the time synchronization data has a fixed length, and the transmission line delay time including modem communication delay etc. is (t3) in FIG.

On the other hand, in slave station C, the time synchronization data is input as an interrupt, and the slave station υ1 processing delay time until the time adjustment is completed is 8th.
This is (t4) shown in the figure.

Above (tl), (tLJ), (t2), (t3).

The added value of the time delay up to (t4) is the time data correction value (
Δt), and in the conventional slave station, the time was adjusted by adjusting the value of (Δt) to the received time data.

(Problems to be Solved by the Invention) In order to perform time synchronization by transmitting time synchronization data from the master station to the slave station in the conventional remote monitoring control 2'l1VA system, each of the processes described above must be carried out. However, as shown in Figure 9, there are factors that cause a time delay.
The interrupt reception is always in the waiting state until the time data transmission is started after the interrupt is received.
There is a delay time (tu) that is undefined within the bit range (X).

The present invention is based on the indefinite delay time (tu) for O to 8 bits.
It is an object of the present invention to provide a time synchronization device in a remote monitoring and control device, which can improve the accuracy when synchronizing the time at a slave station by eliminating the above.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention performs transmission protocol processing according to the HDLC transmission procedure, and transmits data between a control center (master station) and a controlled station (slave station). ) In a remote monitoring and control device that monitors and controls a controlled device by transmitting the information necessary for monitoring, the master station receives an interrupt signal sent from the master clock at regular intervals, A determining means for determining whether or not the interrupt signal is a predetermined period of time before the time-synchronized data transmission; an internal timer that outputs an interrupt signal, a means for interrupting the current protocol processing and holding the transmission line with the slave station in a linked state when an interrupt signal is input from this internal timer, and a means for holding the transmission line with the slave station. means for immediately transitioning to processing for transmitting time adjustment data when an interrupt signal is input from the master clock when the slave station is in a state where the time synchronization data sent from the master clock is sent to the slave station. It is characterized by having means for inputting and processing data using an interrupt.

(Function) In the present invention having such a configuration, the master station accepts interrupts in the hold state, and once the line is placed in the hold state, time synchronization is performed when an interrupt signal from the master clock is input. It becomes possible to immediately output data to the transmission path, and it is possible to eliminate an indefinite delay time corresponding to Q to 8 pits.

(Example) A practical example of the present invention will be explained below with reference to the drawings.

FIG. 1 shows an example of the configuration of a time synchronization device in a remote monitoring and control device according to the present invention. In Figure 1, 11
is a master clock which generates an interrupt signal at regular intervals (T) in order for the master station A to synchronize the time with the slave station C as shown in FIG.

In addition, the master station A has an input section 12 and a main microprocessor 1.
3, consists of a transmission section '14, a timer 15, and an input section 1
2. Main microprocessor 13 and transmission section 14 are connected via an internal bus.

The input unit 12 takes in time information from the master clock 11 and passes it to the microprocessor 13 via an internal bus. The microprocessor 13 is connected to this human power section 12.
It has a function to recognize an interrupt input signal for time adjustment to the slave station when it receives time information from the slave station, for example, T=1 minute.

When TO=1 hour and the time is adjusted every hour on the hour,
When the microprocessor 13 recognizes one minute before the hour, it notifies the timer 15 of this fact. The timer 15 is recognized by the microprocessor 13 as one minute before the hour, and when a signal to that effect is input, it immediately starts counting, and when a certain period of time before the input of the interrupt signal from the master clock 11, the transmission unit starts counting. 14, which sends an interrupt signal a. The transmission unit 14 performs transmission processing such as a transmission protocol of the HDLC procedure, and is configured to receive an interrupt signal sent from the master clock 11 at regular intervals. When the interrupt signal a is input from the timer 15, the transmission section 14 recognizes that the next interrupt input signal output from the master clock 11 is a signal to start time adjustment, and at the same time, it communicates with the current slave station. It has the function of interrupting transmission protocol processing and placing the line in -H hold state.

On the other hand, since slave station C is the same as that shown in FIG. 6, its explanation will be omitted here.

Next, the operation of the time synchronization device in the remote monitoring and control device configured as described above will be explained with reference to the flowchart shown in FIG.

When the interrupt signal sent from the master clock 11 at regular intervals is input to the main microprocessor 13 via the input section 12, the time information is transferred to the internal timer 15 in step 31.
Determine whether it is the time to start. In this step 31, it is determined that it is the time to start the internal timer 15, and when the start time is recognized, the internal timer 15 starts counting in step 32.

When the interrupt signal a to start time adjustment is input from this internal timer 15 to the transmission section 14, the process proceeds to step 33, at a certain time (to) before the interrupt input point to start time adjustment.
).

If it is determined in step 33 that the predetermined time period (tl+) has passed, an interrupt signal a is sent to the transmission section 14 in step 34. When the interrupt signal a is input to the transmission section 14, the master station A interrupts the current protocol processing with the slave station C and holds the line with the slave station C in a linked state in step 35. As a result, in step 36, the master station A uses the master clock 1.
The interrupt signal (In) from 1 is held. Step 3
When the input of the interrupt signal (In) is recognized in step 6, the transmission section 14 performs a time synchronization data transmission process in step 37.

After such processing, the time synchronization data is sent from the master station Δ to the slave station C via the transmission path. On the other hand, slave station C performs time synchronization data interrupt processing in step 38.

By performing steps 31 to 38 as described above, the final time adjustment can be performed using the correction value Δt'.

Here, in order to compare the time delay factors for each conventional process, the time delay factors for each process of this embodiment and the state of the sent data are shown in FIG.

First, a comparison of time delay factors will be explained. Master station A
As shown in FIG. 7, the current transmission protocol with the slave station C is established a certain period of time before (to) the interrupt input signal (In) at the time (Tn) at which time synchronization from the master clock 11 should start. The process is interrupted and the interrupt input signal <In) wait state is entered.

In this case, the configuration of the master station A is the main microprocessor 1.
3, when the transmission section 14 is equipped with a sub-microprocessor, the input processing delay time (tl) of the interrupt signal from the master station shown in FIG. ) can be minimized.

When master station A enters the waiting state for an interrupt signal (In>), it disconnects the line from -
Set to H hold state. Time adjustment start time including v1 (T
In step n), when the interrupt signal is input, the master station A transmits time synchronized data 1i! Move to 111.

The time synchronized data transmission processing time at that time is (tl). Furthermore, the time synchronization data has a fixed length, and the transmission path delay time (t3) includes modem communication delays and the like. In the slave station C, the time synchronization data is input as an interrupt, and the slave station interrupt processing delay time until the time adjustment is completed is (t4).

The time delay addition Bla (Δ1-) of the above (tl), (tl), (t3), and (t+) becomes the time data correction value, and slave station C adds this (Δtl value to the received time data. to set the time.

In this way, as is clear from the above embodiment, the time data correction value does not include the indefinite delay time (tu),
It is possible to improve the n degree when synchronizing the time at the slave station C.

Next, other embodiments of the present invention will be described.

In the embodiment described above, the time information from the master clock 11 is input to the main microprocessor 13 so that the timer activation start time is recognized, but this may be recognized by the following means. In other words, when a remote monitoring and control device is used in combination with a computer 41 as shown in FIG. In this example, time data is received by issuing a request signal to the computer 41. For example, the master station A sends out a request signal one minute before the hour to receive data from the computer 41. Other internal processing in the master station is completely the same as in the previous embodiment.

This is effective in cases where it is difficult for the main microprocessor 13 to periodically read out the time information of the master clock 11 because the load on the master station A is large.

Next, a case will be described in which the present invention is applied to a time synchronization device in an HDLC remote monitoring and control device using an asynchronous modem. The differences from the previous embodiment are as follows.

When the master station A enters the waiting state for the interrupt signal (In) from the master clock 11, the line is temporarily held in a constant hold state, and then a preamble necessary for bit synchronization pull-in as shown in Fig. 5 is generated. It was designed so that Since the preamble generation time is of a fixed length and no other undefined time delay factors are included, it is possible to improve the accuracy when synchronizing the time at the slave station, as in the embodiment described above.

[Effects of the Invention] As described above, according to the present invention, when transmitting time synchronized data, the time delay factor that becomes unstable is removed, so that the time synchronization with the slave station is improved. A time synchronization device in a remote monitoring and control device that can improve accuracy can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a time synchronization device in a remote monitoring and control device according to the present invention, FIG. 2 is a flowchart for explaining the operation of the embodiment, and FIG. 3 is a diagram showing the embodiment. FIG. 4 is a schematic configuration diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing a transmission diagram showing another practical example of the present invention. A data configuration diagram, FIG. 6 is a configuration diagram showing an example of a time synchronization device in a conventional remote monitoring and control device, and FIG. 7 is a diagram showing an interrupt input signal from a master clock.
FIG. 8 is a diagram showing the time delay factors and the status of transmission data in each conventional process, and FIG. 9 is a diagram showing the status of each reception process in the conventional interrupt process. A... Master station, 11... Master clock, 12.
...Input section, 13...Main microprocessor, 14...Transmission section, C...Slave station. Applicant's agent Patent attorney Takehiko Suzue 1 Usage: ・ 31 Figure 4 QoY Col. 21 people 1.
Bria〉Full iη Tee-5th Death 6 Figure @7 Figure Δt1

Claims (1)

[Claims] In a remote monitoring and control device that performs transmission protocol processing according to HDLC transmission procedures, transmits information necessary for monitoring between a control center (master station) and a controlled station (slave station), and monitors and controls controlled equipment. , a determining means for receiving an interrupt signal sent from the master clock at regular intervals into the master station, and determining whether or not the interrupt signal is received a predetermined period of time before the transmission of time-synchronized data; When this determination means determines that a certain time has elapsed, there is an internal timer that is activated and outputs an interrupt signal after counting for a predetermined time, and when an interrupt signal is input from this internal timer, the current protocol processing is interrupted. Means for holding a transmission line with a slave station in a linked state, and when the transmission line is in a held state by this means and an interrupt signal is input from the master clock, the process immediately shifts to transmitting time adjustment data. A time synchronization device in a remote monitoring and control device, characterized in that the slave station is provided with means for inputting and processing the time synchronization data sent from the master station by interrupt.