JPH10124118A - Sequencer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sequencer capable of surely and easily compensating the delay of control even in the fluctuation of an input/output responding time. SOLUTION: A remote I/O (input/output device) is provided with a mechanism fold-transmitting input data to a sequencer main body at the time of inputting this data from the sequencer main body, which outputs data for measuring the input/output responding time to the remote I/O after outputting control data, repeatedly measures time until this data is turned back and inputted (S1 to S11), predicts the present state of a device from the changing rate (S13), makes this predicted value the present state of the device (S149, executes arithmetic necessary for controlling the device (S15) and outputs the arithmetic result to the remote I/O device (S16).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote I / O
The present invention relates to a sequencer that controls a device using a (remote input / output device), and more particularly to a delay compensation of input / output processing between a sequencer main body and a remote I / O.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a sequencer of this type. The sequencer body 1 has a man-machine interface 2
The sequence program is loaded by the
The control and monitoring of many control target devices 3 are executed by the CPU _{11 and the} like.

[0003] For this control and monitoring, the sequencer body 1
A remote I / O 4 is provided between the remote I / O 4
O4 is used to input and output control and monitoring (including measurement) data between each device 3 and the sequencer body 1.

Data transfer between the sequencer main unit 1 and the remote I / O 4 is performed in a time-division manner. That is, input and output data are switched at a constant period by the sequencer body 1, I / O scanner 1 _2, distributed by the distributor and collection box 4 ₁ time-division data from the remote I / O4 the I / O scanner 1 ₂ · Each I / O to be collected and become the end of the transmission path
And received between the adapter 4 _2, to exchange control data between the respective devices 3 by the I / O adapter 4 _2.

[0005]

In THE INVENTION Problem to be Solved] Conventional PLC, I / O scanner 1 ₂ due to the delay data scanning, and it is inevitable that input and output delay is caused by the transmission of a remote I / O4. This delay often affects the control accuracy of the device 3.

FIG. 3 shows a sequencer 1 and a remote I / O.
6 shows an input / output processing time chart with O4. Time t
_{In 1} the measurement data of the device 3 is the I / O of the remote I / O 4
Is input to the adapter 4 _2, this data is collected in the distribution and collection boxes 4 ₁ through the transmission path, which is C in I / O scanner 1 ₂ scan timing sequencer body 1
PU1 is incorporated into the _1.

[0007] In CPU 1 _1, performs a calculation using the data collected, the remote I / O control data corresponding to the calculation result in the beginning of the next scan from the I / O scanner 1 ₂
4 is output. Remote I / O data is at time t ₂
4 of the I / O adapter 4 ₂ is output to the device 3.

As described above, the input / output response time from the remote I / O to the output data (time t ₂ ) from the remote I / O to the device 3 with respect to the input data (time t ₁ ) from the remote I / O to the sequencer body 1. The calculation result for the state of the device at time t ₁ is data including a delay until the control at time t ₂ , and when the state of the device changes during that time, it becomes a control delay and becomes highly accurate. No control.

For example, in the case of a system in which each device 3 is an unmanned trolley and the positioning control is performed by acceleration / constant speed / deceleration control of each trolley by the sequencer body 1, when the detected trolley comes to a certain position. When the deceleration control is started and finally stopped at the target position, the deceleration control is delayed due to the delay time from the collection of the position data of the bogie to the output of the deceleration start data. You will not be able to stop.

As a conventional method for compensating for such a delay in the input / output response time, a delay in the input / output response time is assumed, and a fixed expected amount with respect to the control target is added or subtracted in the operation of the CPU ₁₁ . . That is, the moving distance of the bogie due to the delay is estimated, and the vehicle is decelerated XX before the target of the deceleration start,
The cut-and-try method is used to obtain a stop output at the position YY.

However, the delay of the input / output response time fluctuates due to the change in the transmission time due to the increase or decrease in the data transmission load, and the resulting shift in the data fetch timing at the beginning of the scan. Variations in control accuracy cannot be eliminated.

In the conventional delay compensation method, readjustment of the delay compensation time is required in accordance with a change in the specifications of the sequencer such as the scan cycle or a change in the specifications of the control target system.

An object of the present invention is to provide a sequencer capable of reliably and easily compensating for a control delay even when input / output response time varies.

[0014]

According to the present invention, data from a sequencer body reaches a remote I / O,
The input / output turnaround time until the data from the / O reaches the sequencer main unit is measured as the input / output response time. And compensates for the delay of the input / output response time by performing an operation for controlling the device based on the predicted value. The following configuration is based on the state data collected from the device to be controlled. In a sequencer including a sequencer main body for obtaining a control output of the device by calculation and a remote input / output device for inputting / outputting data between the sequencer main body and the device, the remote input / output device transmits data from the sequencer main body. Has a mechanism for transmitting the input data back to the sequencer main body when the control data is output. Output the output response time measurement data to the remote input / output device, measure the time until this data is repeatedly input, and determine the current state of the device from the measurement time and the rate of change of the status data of the device. Predict,
There is provided a means for performing an operation necessary for controlling the device using the predicted value and outputting the result to the remote input / output device.

[0015]

FIG. 1 is a flowchart showing a process for delay compensation according to an embodiment of the present invention. In the figure, S1 to S11 show a processing procedure for measuring the input / output response time of the sequencer, and S12 to S16 show a processing procedure for correcting the operation result of the sequencer according to the measured input / output response time. The sequencer will be described with reference to the configuration shown in FIG.

In this embodiment, the remote I / O 4
Has a mechanism for returning the input data to the sequencer body 1 when data is input from the sequencer body 1. The sequencer body 1 has a mechanism for storing and updating the status data of the device 3 collected from the remote I / O 4 as raw data.

In FIG. 1, the sequencer main body 1 sets the output data for input / output response time measurement to "0" as initialization and transmits the data to the remote I / O 4 at the time of startup (S1) ( S2), and starts counting by setting the input and output response time measurement timer T ₀ simultaneously (S3).

[0018] After this, the sequencer body 1 waits for the output data for input and output response time measurement folded remotely I / O4 complete the scanning by I / O scanner 1 _2.

It is checked whether or not the input data returned by the remote I / O 4 matches the first output setting "0" every scan cycle (S4), and matches the set output (S5).
At this time, the current value Tn of the timer is read (S6), and the counting of the timer is stopped (S7). Processing S2 so far
By S6, the input / output response time in the first scan cycle is obtained as the time Tn.

In the second and subsequent measurements, the output data for input / output response time measurement is incremented (S8). If this data n exceeds the maximum value F (number of scan cycles) assumed for the input / output response time, The output data for measuring the input / output response time is returned to "0" (S10). If the output data is less than the maximum value F, the output data n is incremented. This output data n is output to the remote I / O 4 and the timer count is counted. Resume (S11).

When the timer starts counting, the process returns to step S4 to check the return data from the remote I / O 4 for the output data n. Then, when the input data matching the output data n is folded (S5),
The count value Tn of the timer until the output data n returns is obtained as the input / output response time Tn (S6).

By repeating the above-described processes S4 to S11, the sequencer main unit 1 can store and update the input / output response time Tn for each scan cycle, and perform the processes S12 to S16 by using the measurement results. The control operation with delay compensation is performed to control the device 3.

The sequencer body 1 extracts the previous control state (raw data such as position) L of the device 3 which becomes input data from the remote I / O 4 (S12), and this raw data L and the current raw data L _N The current state of the device 3 (when the control signal is transmitted to the control device) is predicted and calculated using the measured input / output response time Tn (S13). This calculation is performed based on the following equation.

[0024]

Predicted value = d (L−L _N ) / dt × Tn + L _N This means that the amount of change in the control state of the device 3 due to the delay time of the input / output response time Tn is obtained, and this is calculated as the current state L _By adding to _N , the current state after the input / output response time Tn is predicted.

The sequencer body 1 replaces the predicted value with the input raw data _LN (S14), performs a control operation using the predicted value as the current state of the device (S15), and outputs the operation result to the remote I / O4. (S16), remote I / O4
To control the device 3.

Therefore, the sequencer main unit 1 stores the status data of the device 3 from the remote I / O 4 as the previous raw data, and measures the change rate obtained from the raw data and the current raw data, and each scanning cycle. By predicting the current state of the device 3 from the input / output response time Tn to be performed and performing an operation for controlling the device using the predicted value, it is possible to perform control in which a delay due to the input / output response time is compensated. .

The present embodiment can be applied to a case where the sequencer main body and the remote I / O are one-to-one.

[0028]

As described above, according to the present invention, the input / output return time until data from the sequencer body reaches the remote I / O and data from the remote I / O reaches the sequencer body is entered. Measured as output response time,
The present device state is predicted from the measurement time and the rate of change of the state data of the device collected from the remote I / O side, and an operation for controlling the device is performed based on the predicted value. Control with delay compensation due to time can be performed.

Further, since the input / output response time is constantly measured and compensated, control delay can be reliably and easily compensated even in a system in which the input / output response time varies. In addition, as compared with the conventional fixed delay compensation setting, it is possible to cope with a change in system specifications without re-adjustment.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a delay compensation process according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a sequencer.

FIG. 3 is a time chart of sequence control.

[Explanation of symbols]

1. The sequencer body. 1 ₂ … I / O scanner 3… Controlled equipment 4… Remote input / output device 4 ₁ … Distribution / collection box 4 ₂ … I / O adapter

Claims (1)

[Claims] 1. A sequencer body for obtaining a control output of a device to be controlled by an operation based on state data collected from a device to be controlled, and a remote input / output device for inputting and outputting data between the sequencer body and the device. In the sequencer, the remote input / output device has a mechanism for returning the input data to the sequencer main body when data is input from the sequencer main body, and the sequencer main body outputs an input / output response after outputting the control data. It outputs time measurement data to the remote input / output device, measures the time until this data is input back, and predicts the current state of the device from the measurement time and the rate of change of the state data of the device. Means for performing an operation necessary for controlling the device using the predicted value and outputting the result to the remote input / output device. Sequencer that.