JPH11143506A - Control system device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system device which prevents communication load in a field bus from being increased even though there is screen display by a device for operation supervision. SOLUTION: In this control system device provided with an operator station 26 having a screen for displaying the operation state of a field equipment 12 such as an operation terminal and a detection terminal and with a control unit 24 connected to the field equipment through a field bus 10 and also connected to the operation station through an upper bus 30, a variable table 242 which reads the variable of the equipment 12 in a fixed cycle and a set value table 244 which reads the set value of the device 12 in a non-fixed cycle, to access the tables 242 and 244 by the operation station 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system device for a process industry such as a steel industry or a petrochemical industry, and more particularly to a set value in a device for performing an information interface between a field bus and a distributed control device (DCS). Regarding the improvement of the reading function of.

[0002]

2. Description of the Related Art In the field of process automation, a digital bidirectional communication path between an intelligent field device called a field bus and a control system device, which replaces the conventional 4-20 mA transmission system, is used in the field of process control and factory control. Is being developed as a future standard. In the field bus, a plurality of variables can be simultaneously read from a field device by a high-speed digital transmission technology, and it has become possible to monitor an operation state of a functional block of the field device.

FIG. 3 is a block diagram showing the configuration of a conventional distributed control system. The field bus 10 includes a field device 12 having functional blocks such as an analog input block AI and an analog output block AO, a personal computer PC,
And a gateway 14 is connected. The gateway 14 connects the field bus 10 and the middle-level bus 20 and has an interface function for converting a communication protocol. The control unit 24 reads data such as the process input value PV and writes data such as the set value SP to the field device 12 via the intermediate bus 20. The upper bus 30 is connected to the control unit 24.
And a communication protocol suitable for transmitting information required for safe operation of the plant with high reliability and high speed.

FIG. 4 is an explanatory diagram showing a state in which an operator station accesses a field device. The data handled by the functional blocks of the field device 12 include input / output data between functional blocks, such as the process input value PV and the output command value OUT, and internal parameters of the functional blocks. The internal parameters include a variable (dynamic) that is internally updated according to the operation of the function block, and a set value (static) that is defined by a user and that does not fluctuate on a daily basis, such as scale information and limit values. Operator station 2
6 has a screen for displaying an instrument, a variable representing an operation mode such as automatic or manual or a process input value PV is constantly updated as an instantaneous value, and set values such as an upper limit and a lower limit in operation are displayed on the screen. Reading is executed only when.

In the field bus 10, a group of variables that "change each time" and a group of "variable values that are read once unless changed" are usually considered unnecessary in order to reduce the reading load when displaying a screen. The settings are divided into two groups. In the screen display program of the operator station 26, the variables are read at regular intervals or at high frequency, while the set values are read from the actual functional block in the field device at the time of updating the screen such as opening a window or turning a page. ing. The set value can be updated every time as well as the variable, but it is not practical because the communication load on the field bus 10 increases and the variable update cycle is delayed by reading the set value.

[0006]

However, in the field bus, since the writing operation for the internal parameters of the function block is not limited to one device, it is possible to change the set value in addition to a certain operation monitoring device. Has become. Therefore, for example, a portable setting change device (handy terminal) that is temporarily connected to a field bus and adjusts the device writes internal parameters that are read only when the screen of the operation monitoring device is updated. Even
There is a problem that the changed setting value cannot be displayed at the operator station in the control room. The present invention has solved such a problem, and a first object is to provide a control system device capable of preventing an increase in a communication load on a field bus even when a screen is displayed by an operation monitoring device. It is a second object of the present invention to provide a control system device capable of immediately displaying a changed set value even if the set value is changed from a device other than the operation monitoring device.

[0007]

In order to achieve the first object, the control system apparatus of the present invention has (1) a screen for displaying an operation state of a field device 12 such as an operation end and a detection end. In a control system device having an operator station 26 and a control unit 24 connected to the field device via the field bus 10 and connected to the operator station via a higher-level bus 30, The control unit is provided with a variable table 242 for reading device variables at regular intervals and a set value table 244 for reading set values of the field devices at irregular intervals, and the operator station accesses the variable table and the set value table. It is characterized by doing.

According to the present invention, in the communication between the field device and the control unit, the variables in the variable table are read at a constant period. Is reduced compared to Since the communication between the operator station and the control unit is performed by a high-order bus capable of high-speed communication, the communication is performed smoothly.

In order to achieve the second object, the control system apparatus according to the present invention comprises: (2) an operator station 26 having a screen for displaying the operating state of the field device 12 such as an operation end and a detection end; In a control system device having a control unit 24 connected to a field device via a field bus 10 and connected to the operator station via a higher-level bus 30, a variable of the field device is set to a fixed period. The control unit is provided with a variable table 242 to be read at a time and a setting value table 244 to read the setting value of the field device at an irregular period. The setting value of the field device is changed by the setting change device 16 connected to the field bus. The means 122 for identifying that the setting has been changed and the setting change identifying means Another was the time that the control unit is characterized by updating the contents of the setting value table reads the set value of the field device.

According to the present invention, when the setting change identifying means identifies that the setting value of the field device has been changed by the setting changing device connected to the field bus, the control unit causes the control unit of the field device to change. Since the set value is read and the contents of the set value table are updated, the change of the set value is immediately reflected on the screen displaying the operation state of the field device of the operator station.

(3) The control unit has a lower bus interface unit 246 for converting between a communication protocol on the field bus and a communication protocol on the upper bus. Communication is performed at a fixed interval, and the set values in the set value table are set to be communicated when the start of screen display of the operator station or when the setting change identification means identifies a change. The conversion between the communication protocol and the communication protocol in the upper bus is performed exclusively, and the efficiency of the protocol conversion is increased.

(4) The timing at which the lower bus interface unit communicates with the set values in the set value table is as follows.
When the configuration is such that the communication with the fixed-cycle communication for the variables in the latest variable table is performed at the same time, the communication between the variables and the set values is performed at the same time, so that the communication efficiency of the field bus is increased.

(5) The setting change identification means is written for the purpose of retaining a history when the setting value of the field device is changed by a setting changing device other than the operator station having the authority to change the setting value of the setting value table. It can be automated by using the message sent by the device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration block diagram showing one embodiment of the present invention. In FIG. 1, components having the same functions as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted. Here, the field device 12 includes a setting change identification unit 122 that identifies that the setting value of the field device 12 has been changed by the setting changing device 16 connected to the field bus 10. The setting change device 16 is, for example, the above-described handy terminal.

The control unit 24 controls the field device 12
A variable table 242 for reading the variable of the field device 12 at a fixed period, a setting value table 244 for reading the set value of the field device 12 at a non-fixed period, and conversion between the communication protocol on the field bus 10 and the communication protocol on the upper bus 30 are performed. It has a lower bus interface unit 246. The lower bus interface unit 246 has, for example, a function of converting the gateway 14 and the middle bus 20 in FIG. 3 and a communication protocol between the buses.

The operation of the apparatus having the above-mentioned configuration will be described below. FIG. 2 is an explanatory diagram of a data flow in the device of FIG. The lower bus interface unit 246 includes a buffer circuit Buf that stores variables in a field bus format.
f1 and a buffer circuit Bu for storing variables in DCS format
ff2, a buffer circuit Buff3 for storing set values in a fieldbus format, and a buffer circuit Buff4 for storing set values in a DCS format. Variable table 2
42 and the set value table 244 are stored in a face plate block which is a type of functional block of the control unit 24. The number of screens of the operator station 26 may be one or plural.

Next, the operation at the time of reading variables will be described. First, as a steady process, the lower bus interface unit 246 reads out variables among the internal parameters of the field device 12 in synchronization with the operation cycle of the functional block, and stores the variables in the buffer circuit Buff1. Next,
The lower bus interface unit 246 is the field device 1
The data in the fieldbus format read in step 2 is converted into the DCS format and stored in the buffer circuit Buff2 on the transmission side. Subsequently, the DCS format data of the buffer circuit Buff2 is transmitted to the control unit 24 by a fixed-cycle communication function provided in the DCS, and stored as a process input value of a variable table 242, which is a type of functional block. Then, the operator station 26 takes in the process input value of the variable table 242 and displays it on the screen so that the operator can confirm it.

At this time, as for the set value, the value initially read from the field device 12 is the set value table 244.
Therefore, the read communication on the field bus 10 at the fixed period as described above is not executed. Then, along with the transmission of the variable table 242, the data of the set value table 244 is transmitted in accordance with the screen display.

Next, the operation when the set value is changed by the setting changing device 16 will be described. First, the setting value of the field device 12 is changed by the setting changing device 16 connected to the field bus 10. Then,
The setting change identification unit 122 of the field device 12 sends a message called an update event to the field bus 10 together with the rewritten function block and rewrite time.

Then, upon receiving the update event, the lower bus interface unit 246 reads out the set value again to the field device 12 having the rewritten functional block and stores it in the buffer circuit Buff3. Then, the lower bus interface unit 2
Reference numeral 46 converts the setting value in the fieldbus format read by the field device 12 into the DCS format and stores it in the buffer circuit Buff4 on the transmission side. Subsequently, the buffer circuit Buff is operated by the fixed-cycle communication function provided in the DCS.
4 is transmitted to the control unit 24,
It is stored as a set value of a set value table 244 which is a kind of functional block. Then, in (10), the setting value table 2
The operator station 26 captures the set value of 44 and reflects the change of the set value on the screen display.

In the above embodiment, the case where the variable table 242 and the set value table 244 are provided as function blocks of the control unit 24 has been described. However, the present invention is not limited to this, and the operator station 2
Any device may be used as long as it reads and stores the variables and set values of the internal parameters of the field device 12 connected to the field bus 10 in a fixed period or an irregular period in the device connected to the upper bus 30 and the device 6.

[0022]

As described above, according to the control system of the present invention, (1) the variable table 242 for reading the variable of the field device at a fixed period, and the setting for reading the set value of the field device at the non-fixed period. A value table 244 is provided in the control unit, and the operator station accesses the variable table and the set value table. Here, since the communication between the field device and the control unit reads the variables in the variable table at regular intervals, the communication load on the field bus is reduced as compared with the case where the access is performed sequentially according to the read command from the operator station. You. Since the communication between the operator station and the control unit is performed by a high-order bus capable of high-speed communication, the communication is performed smoothly.

Further, according to the control system of the present invention, (2) the variable table 242 for reading the variable of the field device at a fixed period and the setting value table 244 for reading the set value of the field device at an irregular period are controlled. A unit 122 for identifying that the setting value of the field device has been changed by the setting change device 16 connected to the field bus, and when the setting change identification unit has identified the change, the control unit A configuration in which the setting value of the device is read and the content of the setting value table is updated, and when the setting change identification means identifies that the setting value of the field device has been changed by the setting change device connected to the field bus, Since the control unit reads the set value of the field device and updates the contents of the set value table, Change the settings on the screen to view the field operating conditions of the equipment of the operator station is immediately reflected.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a data flow in the device of FIG. 1;

FIG. 3 is a configuration block diagram of a conventional distributed control system.

FIG. 4 is an explanatory diagram of a state where an operator station accesses a field device.

[Explanation of symbols]

 10 Field Bus 12 Field Device 24 Control Unit (FCU) 242 Variable Table 244 Setting Value Table 246 Lower Bus Interface 26 Operator Station (OPS) 30 Upper Bus

Claims (5)

[Claims] A field device (1) such as an operation end or a detection end.
An operator station (26) having a screen for displaying the operation status of 2) is connected to this field device via a field bus (10), and to this operator station via an upper bus (30). A control system device having a control unit (24) connected to the control unit (24), a variable table (242) for reading the variable of the field device at a fixed period, and a set value table (242) for reading the set value of the field device at a non-fixed period. 244) is provided in the control unit, and the operator station accesses the variable table and the set value table. 2. Field devices (1) such as an operation end and a detection end.
An operator station (26) having a screen for displaying the operation status of 2) is connected to this field device via a field bus (10), and to this operator station via an upper bus (30). A control system device having a control unit (24) connected to the control unit (24), a variable table (242) for reading the variable of the field device at a fixed period, and a set value table (242) for reading the set value of the field device at a non-fixed period. 244) provided in the control unit, and a setting change device (16) connected to the field bus.
Means (122) for identifying that the set value of the field device has been changed, and when the setting change identifying means has identified the change, the control unit reads the set value of the field device and reads the set value. A control system device for updating the contents of a table. 3. The control unit has a lower bus interface section (246) for converting between a communication protocol on the field bus and a communication protocol on the upper bus. 3. The control system according to claim 2, wherein communication is performed at a fixed period for the setting value table, and communication is performed for the set values in the set value table when the screen display of the operator station is started or when the setting change identifying means identifies the change. apparatus. 4. The control according to claim 3, wherein the timing at which the lower bus interface unit communicates with the set value in the set value table is the same as the fixed-cycle communication with respect to the latest variable table variable. System device. 5. The apparatus according to claim 1, wherein said setting change identifying means keeps a history when a setting value of said field device is changed by a setting changing device other than an operator station having a right to change the setting value of the setting value table. The control system apparatus according to claim 2, wherein