JPH06339182A - Distributed controller - Google Patents

Abstract

(57) [Summary] [Purpose] When a power failure occurs on the remote input / output device side, specify the method of signal processing after power recovery for each unit of multiple points. A distributed control device comprising a control arithmetic device in charge of control arithmetic and a remote input / output device connected to the control arithmetic device via a remote input / output bus,
The remote input / output device is composed of a plurality of input / output units, and each unit is further configured to handle input / output signals of a plurality of points. Start mode setting means for setting the processing method (start mode) for each unit in the remote input / output device, and the processing after power failure and power recovery based on the start mode set by the start mode setting means It is configured to include a power recovery processing unit that is performed for each time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control device for controlling a process amount such as temperature and pressure, and more specifically, a control arithmetic device responsible for various control arithmetic operations and a control arithmetic operation device separated from each other. -A device that is distributed and consists of multiple remote I / O devices for exchanging signals with sensors and actuators, and ensures the processing after a power failure that occurs on the remote I / O device side In addition, the present invention relates to a distributed control device that can be finely adjusted according to the characteristics of a signal to be handled.

[0002]

2. Description of the Related Art A decentralized control device is configured to input a large number of signals from a process to be controlled and output operation signals to a large number of control ends, and to comprehensively monitor the entire controlled target. A plurality of remote input / output devices are coupled to the control arithmetic unit so that they can be controlled or controlled according to the nature of the work they are responsible for.

Here, a shared memory which can be read / write accessed from both of the control arithmetic unit and the remote input / output unit is provided, and the control arithmetic unit is connected via the remote input / output bus. A cyclic scan transmission is performed for each remote I / O device to maintain (equalize) the contents of the data buffer used by the internal microprocessor and the I / O data on the remote I / O device side. It is being appreciated.

Such cyclic scan transmission is
(A) which input / output point of the input / output device corresponds to which address on the shared memory, (b) which input / output point has what cyclic scan transmission cycle, (c)
The transmission service (reading of input data, exchange of output data and readback data, etc.) for which input / output point is executed is performed according to preset transmission conditions.

In the conventional apparatus of this type, it is assumed that the control arithmetic unit side and the remote input / output unit side are supplied with electric power from the same power supply system to operate, and are supplied to the unit. In the event that the power supply fails and then power is restored, the microprocessor in the control processor is configured to perform the cyclic scan transmission as described above uniformly for each input / output point. .

[0006]

However, when the scale of the process is large, the control arithmetic unit and each remote input / output unit are supplied with electric power from separate power sources. In this case, the control arithmetic unit and the remote input / output unit are powered off and restored at independent timings. Therefore, the operation for each remote I / O device after recovery from power failure is the nature of the I / O signals handled by each remote I / O device (for example, the size of the time constant of the target process or the size of the signal rise time). It is necessary to be able to set in consideration of.

The present invention has been made in view of the above circumstances, and the method of signal processing after power failure recovery (recovery) of the power source in each remote input / output device is detailed depending on the nature of the signal to be handled. An object of the present invention is to provide a distributed control device that can be set to.

[0008]

SUMMARY OF THE INVENTION The present invention which achieves such an object includes a control arithmetic unit in charge of control arithmetic and a remote input / output unit connected to the control arithmetic unit via a remote input / output bus. In the distributed control device, the remote input / output device includes a plurality of input / output units, and each unit is further configured to handle input / output signals at a plurality of points. Is a start mode setting means for setting a processing mode (start mode) after power recovery of the remote input / output device for each unit in the remote input / output device, and a start mode set by the start mode setting means. It is configured to include power recovery processing means for performing processing after power failure power recovery for each unit based on the mode.

[0009]

The remote input / output device and the control arithmetic device are operated by being supplied with electric power from different power sources, and power failure and power recovery independently occur. The start mode after the power is restored on the remote I / O device side is continuous start mode in which the data output immediately before the power failure is re-output, and initialization in which the processing to track a predetermined initial value is performed. Modes are prepared.

Regarding the operation after the power failure and recovery on the remote input / output device side, the control arithmetic unit sets the continuous start mode or the initialization start mode according to the power failure time and the mode set by the start mode setting means. Then, signal processing is started according to the determined mode.

[0011]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a structural conceptual diagram of a distributed control device to which the present invention is applied. In the figure, FC is a control calculation device in charge of control calculation, OP is a monitoring device (operator station) in charge of operation and monitoring of the plant, and these are connected by a communication line VN. PO1, PO2
Are a plurality of remote input / output devices connected to the control arithmetic unit FC via the remote input / output bus BS and the node interfaces NIF1, NIF2.

Each remote input / output device PO1, PO2 ...
Are arranged in a distributed manner with respect to the control calculation device FC, and are configured so that input signals are applied from various sensors installed in the field and operation signals are output to actuators such as valves. Each remote input / output device is composed of a plurality of units U1, U2, U3 ... Which are configured to collectively handle a plurality of remote input / output signals.

Further, each of these units U1, U2 ...
A function to convert the signal from the process into a digital data signal format that can be handled by the control processing unit, or to convert the signal from the control processing unit into a signal format such as an analog signal or contact signal that can be handled by the valve, and a function such as signal isolation. It is composed of a plurality of printed board cards equipped with an electronic circuit that realizes.

Node interfaces IF1, IF2 ...
Is a control arithmetic unit FC via a remote input / output bus BS.
And a function for communicating with each other, so that data can be transmitted between each remote input / output device and the control operation device FC according to a predetermined communication protocol. In this example, both the communication line VN and the remote input / output bus BS have a dual structure, but they may have a single structure.

FIG. 2 shows a monitoring device OP and a control calculation device F.
C is a main functional block diagram in the remote input / output device PI. In the monitoring device OP, reference numeral 10 is a block generally showing the definition means of the remote input / output device, which displays a screen for performing engineering work of the remote input / output device on the display screen, and uses the screen to display a keyboard or the like. By inputting data from, it is possible to define the signal processing operation on the specified remote input / output device side and the signal processing operation after power recovery after each unit. Then, the definition (database) set and constructed by the remote input / output device definition means 10 is downloaded to the control calculation device FC side via the communication line VN. In this example, the remote input / output device defining means 10 is provided in the monitoring device OP,
It may be provided in another workstation connected to the communication line VN, an engineering device, or the like.

In the control arithmetic unit FC, 1 is, for example, P
A control calculation unit (processor) 2 that is in charge of ID control calculation, sequence control calculation, and the like is a power supply circuit in the control calculation device FC, which supplies power to each unit. Reference numeral 3 denotes a non-volatile shared memory, which is read / write accessible from the control operation unit 1 and also has a remote input / output bus B.
A plurality of remote input / output devices PO transmitted via S
Input / output data from 1, PO2 ... Is cyclically written in a cycle of oversampling with respect to the calculation cycle of the control calculation unit (processor) 1.

Reference numeral 4 is a transmission control unit for controlling transmission on the remote input / output bus BS. In this transmission control unit,
Is a start mode setting means for setting the processing method (start mode) after power recovery of each remote input / output device for each unit in the remote input / output device. The start mode setting means 41 is configured by downloading the database constructed by the remote input / output device defining means 10 of the monitoring device OP. Reference numeral 42 is a power recovery time processing means for performing processing after power failure power recovery for each unit based on the start mode set by the start mode setting means 41.

The power failure processing means 42 is an initialization start means 421 for realizing an initialization mode in which a predetermined initial value is tracked when power is restored, and data output immediately before a power failure occurs when power is restored. Continuation start means 422 for realizing a continuation start mode for performing the process of re-outputting
It is configured to include and. Reference numeral 43 denotes a power failure time measuring means, which is configured to measure the power failure time generated therein for each of the remote input / output devices PI1, PI2 .... The power failure time measuring means is realized by a configuration that measures the time during which cyclic scan communication with each remote input / output device is interrupted.

For the remote input / output device which has recovered from the power failure state, the control arithmetic unit FC responds to the power failure time and the start mode set by the start mode setting means 41 of the remote input / output device. It is configured to start signal processing based on the continuous start mode or the initialization start mode. The remote input / output devices PO1, PO2 connected to the remote input / output bus BS via the node interface NIF are composed of a plurality of input / output units U1, U2, ... It is composed of a plurality of printed board cards PC1, PC2 ... Incorporating a signal processing circuit for handling input / output signals and digital input / output signals.

FIG. 3 is a structural conceptual diagram of definition data constructed by the remote input / output device defining means 10 in the monitoring device OP. The definition data defined here is
As shown in (a), it is composed of a node information table for each node (corresponding to the node interface) connected to the remote input / output bus BS. As shown in (b), this node information table is composed of a header and a unit information table for each unit constituting the unit. Then, as shown in (c), this unit information table includes a unit type and a start mode that defines what signal processing is to be performed after recovery from a power failure.

FIG. 4 is a conceptual diagram showing the configuration of the start mode of each unit information table. Here, either the MAN mode (initialization start mode) or the TIM mode (continuous start mode) can be set. Time data is set to specify the TIM mode. This time data is set according to the power failure time within the set time (the time that can be allowed as an instantaneous power failure, for example, 2
Second), it means that the signal processing to output the data output before the power failure again is performed.

The operation of the apparatus thus constructed will be described below. (Operation under normal condition) The control operation device FC and the remote input / output devices PO1, PO2, ... By using this, cyclic scan transmission is performed so that the input / output data handled by the control arithmetic unit FC and the input / output data on the remote input / output unit side are maintained equal. This cyclic scan transmission is cyclically performed in a cycle that becomes oversampling with respect to the control calculation cycle of the control calculation device FC side, and the shared memory 3 has a plurality of remote input / output devices P.
Input / output data from O1, PO2, ... Is written and its contents are updated.

Further, the control arithmetic unit 1 reads out the input / output data written in the shared memory 3 at a control arithmetic period, and executes a predetermined control arithmetic operation using these data,
The calculation result is written in the shared memory 3. Shared memory 3
The output data written by the control calculation unit 1 is sent to the plurality of remote input / output devices PO1, PO2, PO3 ... And reflected on the operation of various actuators connected to the remote input / output devices PO1, PO2.

By such an operation, for example, a control operation is performed in which the degree of opening / closing of the valve (valve) is controlled by following the calculation result of the control calculation unit 1. It should be noted that which of the plurality of remote input / output devices PO1, PO2 ... Corresponds to which address position of the shared memory 3 is set in advance for each Reemoto input / output device at the time of starting the operation of the device. Be present.

(Operation upon occurrence of power failure and after power recovery) The power failure time measuring means 43 monitors the transmission status on the remote input / output bus BS for each unit of each remote input / output device. Now, when a power failure occurs in a remote input / output device, the power failure time measuring means 43 measures the power failure time in the remote input / output device from the transmission interruption time.

When the power is restored from the power failure state, the control arithmetic unit FC controls the start mode setting means 41 to set the start mode information set for each unit of the remote input / output device and the power failure time measuring means 43. The following power failure processing operations are performed for each unit according to the measured power failure time. (A) When the MAN mode is set; the initialization start mode is set, and a predetermined initial value is output (tracking). In this case, the power failure time is not referenced.

(B) When the TIM mode is set; the time data set therein is compared with the power failure time measured by the power failure time measuring means 43, and if power failure time ≧ time data, ( b-1) The operation is similar to that in the initialization start mode, and a predetermined initial value is output.

In case of power failure time <time data, (b-
2) The continuous start mode is entered, and the data output immediately before the power failure is output again. In these power failure processing operations, the initialization start mode is realized by the initialization start means 421, and the continuous start mode is realized.
This is performed by the continuous start means 422.

In this way, the method of signal processing after power recovery depends on the start mode information set in the start mode setting means 41 and the power failure time, such as initialization start and continuous start for each unit. It depends on the nature of the input / output signals handled by the unit. It is assumed that the remote input / output device defining means 10 sets a start mode in advance for each unit of each remote input / output device, but a standard start mode is set in advance for each unit. The remote input / output device defining means 10 may reset the start modes of only the units desired by the user.

[0030]

As described in detail above, the present invention is
When a power failure occurs on the remote I / O device side,
The method of signal processing after power recovery can be designated for each unit of a plurality of points, and the signal processing can be performed more finely according to the nature of the signal to be handled.

[Brief description of drawings]

FIG. 1 is a configuration conceptual diagram of a distributed control device to which the present invention is applied.

FIG. 2 is a main functional block diagram in a monitoring device OP, a control calculation device FC, and a remote input / output device PI.

FIG. 3 is a structural conceptual diagram of definition data constructed by a definition unit 10 of a remote input / output device in the monitoring device OP.

FIG. 4 is a conceptual diagram of a configuration of a start mode of each unit information table.

[Explanation of symbols]

 OP monitoring device FC control calculation device NIF node interface PO1, PO2, ... Remote input / output device U1, U2 ... Unit VN communication line BS remote input / output bus 10 Remote input / output device definition means 1 Control calculation unit (processor) 2 Power supply circuit 3 Shared memory 4 Transmission control unit 41 Mode start setting means 42 Power failure processing means 421 Initialization starting means 422 Continuation starting means 43 Power failure time measuring means

Claims (2)

[Claims] 1. A distributed control device comprising a control calculation device in charge of control calculation and a remote input / output device connected to the control calculation device via a remote input / output bus. The device is composed of a plurality of input / output units, and each unit is further configured to handle input / output signals of a plurality of points. Start mode setting means for setting a method (start mode) for each unit in the remote input / output device, and processing for each unit after power failure recovery based on the start mode set by the start mode setting means A distributed control device comprising a power recovery processing means for performing. 2. A start mode after power recovery of the remote input / output device, a continuous start mode for re-outputting the data output immediately before the power failure, and a process for tracking a predetermined initial value. The remote I / O device has an initialization mode for performing the process from the continuous start mode or the initialization start mode depending on the power failure time after power failure recovery and the mode set by the start mode setting means. The distributed control apparatus according to claim 1, wherein signal processing is started.