JP4292480B2 - Process system - Google Patents

Description

  The present invention relates to a process control system for process industries such as the steel industry and petrochemical industry, and a process system such as a safety system for ensuring plant safety, and in particular, a process that allows selection of a method for matching the times of controllers. It is about the system.

  Conventionally, in a process system in which a plurality of controllers are connected to a network, it is common practice to match the times of all the controllers in the network. For example, using one controller as a master controller, the master controller informs the time so that the times of all the controllers are matched.

Also, in such a process system, there is a process in which the slave controller notifies the time on behalf of the master controller in order to keep the time of all the controllers consistent even if the master controller goes down (see, for example, Patent Document 1). .)

On the other hand, the distributed control system has an SOE (Sequence of Event) function that collects event data of input / output modules of each controller and arranges them in the order of occurrence time. Such a function requires highly accurate time synchronization. For this reason, there is a configuration in which a controller acquires GPS (Global Positioning System) standard time data and records it in an event data server together with event data (see, for example, Patent Document 2).

JP-A-9-275406 JP 2004-46475 A

FIG. 2 is a configuration diagram showing an example of a conventional process system.
In FIG. 2, a PC (personal computer) 110 has time data generating means 111 together with an operation unit, a display unit, a control program, a database, an event data server function (none of which are shown), and the like. The PC 110 is an operation monitoring station that monitors the operation status of the plant and changes settings.

The time data generation means 111 is a clock function for sending time data (Vnet time) from the PC 110 to the controller, and is constituted by a master clock generator (not shown).
The controller 120 includes at least a CPU module 121 and an input / output module (DI module 123 in FIG. 2). Similarly, the controller 130 includes at least a CPU module 131 and an input / output module (DI module 133 in FIG. 2).
The PC 110 and the controllers 120 and 130 are connected and communicate with each other via a token-passing control bus formed as a bus type called Vnet.

  The CPU modules 121 and 131 in the controllers 120 and 130 detect signals from the field devices via the input / output module based on the control program and database downloaded from the PC 110, and control the opening degree of valves (not shown). Control. The DI modules 123 and 133 are contact input modules, and contact signals from a field device (not shown) are input.

The DI modules 123 and 133 transmit event data information based on the input contact signal to the PC 110 via a general-purpose bus (not shown). In this case, the PC 110 functions as the event data server described above and executes the SOE function.
Other modules for controlling field devices include analog input / output, digital input / output, and DO (contact output) modules.

In addition to the event data, the CPU modules 121 and 131 perform arithmetic processing on the data from the field device on the control program and compare the result with a predetermined reference value to determine the event or alarm. May occur.

The standard time receiver 4 is a means for receiving GPS standard time data, and is connected to the controller 120 via the IRIG-B cable 5. The controller 130 is connected to the standard time receiver 4 via the IRIG-B cable 6 and the controller 120.
Here, IRIG-B is a standard in which a time code indicating a time standard based on GPS or the like is defined, and IRIG-B cables 5 and 6 transmit and receive standard time data in accordance with this standard. This is a dedicated cable.

  In one of the time synchronization methods between the controllers 120 and 130 in such a configuration, the CPU modules 121 and 131 obtain time data (Vnet time) from the time data generation means 111 in the PC 110, and the internal memory There is a synchronization method (hereinafter referred to as a Vnet time synchronization method) performed by storing the data in 122 and 132.

  On the other hand, since the SOE function described above needs to record an accurate time, the DI modules 123 and 133 have high-accuracy standard time data received by the standard time receiver 4. Specifically, the CPU module 121 acquires standard time data (IRIG-B time) via the IRIG-B cable 5 and stores it in the memory 124 in the DI module 123. Similarly, the CPU module 131 acquires standard time data (IRIG-B time) and stores it in the memory 134 in the DI module 133. This constitutes another synchronization method (hereinafter referred to as IRIG-B time synchronization method).

In such a process system, a process control system that performs plant control, or a safety system that constantly monitors the state of the plant and reliably stops the plant when it deviates from a predetermined condition, thereby ensuring the safety of the plant. It is necessary to integrate the SOE from the DI module and the events and alarms generated by the CPU module and use the synchronized time, and it is required to synchronize all the times based on the time of one time master. ing.

In addition, the Vnet time synchronization method has a merit that it is possible to realize sufficient time synchronization as a DCS (distributed control system) with high reliability without preparing special equipment. In order to synchronize the time, the time accuracy is worse than that of the IRIG-B time synchronization method, and between controllers belonging to different domains via the gateway, the time synchronization accuracy between the controllers is considerably worse. There is a limit when accuracy is required.

On the other hand, with the IRIG-B time synchronization method, high-accuracy time synchronization is possible, but for the time synchronization, additional equipment of a standard time receiver (such as a GPS receiver) and the IRIG-B between the standard time receiver and the controller are used. There is a problem that it is inferior to the Vnet time synchronization method in terms of reliability, such as failure of the time receiver and failure of the IRIG-B cable.

  The present invention is intended to solve the problems of such a conventional process system. Since the Vnet time synchronization method and the IRIG-B time synchronization method have their merits and demerits, respectively. It is an object of the present invention to provide a process system that can select time data according to a user's request for each controller from a plurality of time data.

  The present invention is a process system configured as follows.

(1) An operation monitoring station and at least one controller having a calculation control unit and a contact input module are connected via a network, and the controller receives Vnet time data generated from the operation monitoring station and a standard time receiver. In a process system that can acquire standard time data,
The operation monitoring station is
A time synchronization method setting means for setting the selection of the Vnet time data or the standard time data to be used in time synchronization by the arithmetic control unit and the input contact module of the controller and downloading to the controller ;
Both the arithmetic control unit and the contact input module of the controller are time-synchronized with one of the time data based on the downloaded time synchronization method .

(2) The controller adds the Vnet time data or the standard time data set by downloading to both event data generated by the arithmetic control unit and event data generated by the contact input module. The process system according to (1).

(3) The controller includes a determination unit that determines whether the standard time data from the standard time receiver is valid or invalid, and the standard time data is invalid when the standard time data selection is set. Is provided with an automatic switching function that uses the Vnet time data.

The present invention has the following effects.

According to the first aspect of the present invention, it becomes possible to select time data according to a user request for each controller from a plurality of time data for time synchronization.

According to the invention described in claim 2, since the time of the CPU module in the controller and the time of the DI module can also refer to the time of the same time master, the SOE from the DI module and the event alarm generated from the CPU module Even integrated and synchronized time can be used.

According to the third aspect of the invention, the controller can automatically switch between Vnet time synchronization and IRIG-B time synchronization depending on whether the standard time data is valid or invalid.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a process system according to the present invention. In FIG. 1, the same reference numerals are given to the same components as those in the previous drawings. The process system of the present invention includes a process control system that controls the plant, a safety system that constantly monitors the state of the plant, reliably stops the plant when it deviates from a predetermined condition, and ensures the safety of the plant. Is included.

In FIG. 1, a PC 1 is an operation monitoring station having a time synchronization method setting means 11 and a time data generating means 12 together with an operation unit, a display unit, a control program, a database, an event data server function (all not shown), and the like. .

The time synchronization method setting means 11 allows the operator to select either the Vnet time synchronization method or the IRIG-B time synchronization method for each controller from the operation unit such as the keyboard, mouse, or touch panel of the PC 1, and the selected time. Information indicating the synchronization method is stored in the database.
The time data generating means 12 is a clock function for sending time data (Vnet time) from the PC 1 to the controllers 2 and 3, and is constituted by a master clock generator (not shown).

The PC 1, the controllers 2 and 3 are connected to a bus called Vnet (Vnet 8 in FIG. 1), and a network is constructed.
A control program and a database (in which information such as parameters related to the control program are registered) are downloaded to the controllers 2 and 3.

The controller 2 includes at least a CPU module 21 and an input / output module (DI module 23 in FIG. 1). Similarly, the controller 3 includes at least a CPU module 31 and an input / output module (DI module 33 in FIG. 1).
In this embodiment, two controllers are shown, but two or more controllers may be used.

Input / output modules (input / output units) are modules such as DI / DO (contact input / output), analog input / output, and digital input / output. They are field devices such as thermometers and flow meters, and regulators such as valves (sometimes (Not shown) is connected, and the CPU module (arithmetic control unit) performs plant control in accordance with the control program.

In the plant control, the CPU modules 21 and 31 perform arithmetic processing on the data from the field device on the control program, compare the result with a predetermined reference value, and generate an event or an alarm.
An event is also generated from an input / output module by input from a field device. These event data are collected by the event data server function of the PC 1 and displayed and monitored on the display unit.

The standard time receiver 4 is means for receiving, for example, GPS standard time data, and is connected to the controller 2 via an IRIG-B cable 5. The controller 2 and the controller 3 are also connected by an IRIG-B cable 6.

  The standard time is not limited to data from GPS, and may be acquired from other radio waves that are time standards such as standard radio waves. Further, the standard time may be acquired from another facility such as a time server represented by NTP (Network Time Protocol) or SNTP (Simple Network Time Protocol) by a wired line or a wireless line. Furthermore, it is not limited to time data compliant with IRIG-B, but may be transmitted / received by other standards or a general-purpose bus.

  When the PC 1 downloads the database to the controllers 2 and 3, the CPU modules 21 and 31 start up the controllers 2 and 3 on the basis of the information on the time synchronization method on the database, and the Vnet synchronization time method or IRIG-B time synchronization. Operate with either method.

  If the Vnet time synchronization method is selected, the CPU modules 21 and 31 obtain time data (Vnet time) from the time data generating means 12 in the PC 1 and store them in the internal memories 22 and 32 and the DI module 23. , 33 also store the Vnet time. By periodically repeating this operation, the CPU module and the input / output module can be synchronized at the Vnet time, and all the controllers can be synchronized at the Vnet time.

If the IRIG-B time synchronization method is selected, the CPU modules 21 and 31 acquire standard time data (IRIG-B time) from the standard time receiver 4 via the IRIG-B cables 5 and 6, and The standard time data is also stored in the memories 24 and 34 in the DI modules 23 and 33. By periodically repeating this operation, the CPU module and the input / output module can be synchronized with the IRIG-B time, and all the controllers can be synchronized with the IRIG-B time.
The controllers 2 and 3 may be set with different time synchronization methods.

The time data thus synchronized is added to the event data and alarm data as a time stamp when an event or alarm occurs. This control is performed by the CPU module. The CPU module may time stamp events and alarms that occur in the CPU module, and the input / output module may time stamp events that occur in the input / output module.

  As described above, time data according to a user's request can be selected for each controller from a plurality of time data for time synchronization. Specifically, for each controller, either a highly reliable Vnet time synchronization method that does not require special equipment or an IRIG-B time synchronization method that enables highly accurate time synchronization, according to the user's request. So you can make effective use of each advantage.

In addition, since the time of the CPU module in the controller and the time of the DI module can also refer to the time of the same time master, the time stamp of the event or alarm generated in the CPU module and the time stamp of the event generated in the DI module Based on the same time master.
That is, the SOE from the DI module and the event / alarm generated from the CPU module can be integrated to use the synchronized time.

  Further, if the CPU module has a determination function for determining whether the standard time data from IRIG-B is valid or invalid and an automatic switching function based on it, Vnet time synchronization and IRIG- are determined depending on whether the standard time data is valid or invalid. Automatic switching of B time synchronization is possible.

Further, if the installation of IRIG-B is localized only in a controller that requires time accuracy, the cost can be reduced.
For example, when the installation of IRIG-B is localized, the presence / absence of installation of IRIG-B is automatically recognized at startup, and if there is no IRIG-B, the time is the Vnet time, and if there is, the time is the IRIG-B time. Synchronize.

  Furthermore, since the backup of the Vnet time synchronization method can be performed by self-detecting the failure of the standard time receiver depending on whether the standard time data is valid or invalid, it is possible to achieve both reliability and high time accuracy. .

  In addition, since it has a plurality of master times, a time abnormality can be detected by providing the CPU module with a function of comparing and diagnosing the Vnet time and the IRIG-B time.

  The present invention is not limited to the above-described embodiments, and includes many changes and modifications without departing from the essence thereof.

It is a block diagram which shows one Example of the process system which concerns on this invention. It is a block diagram which shows an example of the conventional process system.

Explanation of symbols

1 PC
2, 3 Controller 4 Standard time receiver 5, 6 IRIG-B cable 8 Vnet
11 Time synchronization method setting means 12 Time data generating means 21, 31 CPU module 22, 32 memory 23, 33 DI module 24, 34 memory

Claims (3)

An operation monitoring station and at least one controller having a calculation control unit and a contact input module are connected via a network, and the controller generates Vnet time data generated at the operation monitoring station and standard time data from a standard time receiver. In a process system that can acquire
The operation monitoring station is
A time synchronization method setting means for setting the selection of the Vnet time data or the standard time data to be used in time synchronization by the arithmetic control unit and the input contact module of the controller and downloading to the controller ;
Both the arithmetic control unit and the contact input module of the controller are time-synchronized with one of the time data based on the downloaded time synchronization method . The controller adds the Vnet time data or the standard time data set by downloading to both event data generated by the arithmetic control unit and event data generated by the contact input module. Item 12. The process system according to Item 1. The controller has a determination means for determining whether the standard time data from the standard time receiver is valid or invalid, and when the standard time data is invalid when the standard time data selection is set, The process system according to claim 1, further comprising an automatic switching function that uses Vnet time data.

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