JP2003333121A - Field equipment communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a field equipment communication device in which operability and a quality of a GUI means are improved by performing communication between the GUI means and a field communication server means as completely asynchronous communication not to be affected by a communication interface of the field communication server means. <P>SOLUTION: In the field equipment communication device which communicates with field equipment from a host device via a controller, the host device is provided with: the GUI means for providing an environment to interface via graphics; a completely asynchronous communication server means for performing complete asynchronous communication with the GUI means; and the field communication server means for performing a semiconductor-synchronous communication with the completely synchronous communication server means and communicating with the field equipment via the controller. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated device management function of field devices in a distributed process control system having a hierarchical structure, and more particularly to improvement of a communication sequence between a host device and field devices.

[0002]

2. Description of the Related Art FIG. 5 is a functional block diagram showing a basic configuration of a distributed process control system having a hierarchical structure.
Reference numeral 1 is a host device that interfaces with a user, and communicates with a controller 3 via a control bus 2. The controller 3 is connected to a plurality of field devices 4 directly or via a field bus, executes control based on a command from the host device 1, and communicates necessary data to the host device 1.

In order to realize an integrated device management function as a subsystem of such a process control system, a GUI means 5 and a field communication server means 6 are provided in the host device 1.
Is provided. Of these, the field communication server means 6 uses a standard function for communicating with the controller 3 in the control system.

The field communication server means 6 has a semi-synchronous communication interface 61 as a standard specification. Therefore, the communication with the GUI means 5 is executed by the semi-synchronous communication 7.

FIG. 6 is a time chart diagram for explaining the communication sequence of the integrated device management function in the case of normal communication, and FIG. 7 is a time chart diagram for explaining the communication sequence of the integrated device management function in the case of communication suspension. Focusing on the field communication server means 6 below, the communication procedure is as follows.

The sequence for normal communication in FIG. 6 is G
"Exclusive lock" in response to the "transmission request" from the UI means 5
Then, the controller 3 sends a “transmission request” to the controller 3, receives a transmission completion notification from the controller 3, and returns to the GUI means 5.

To confirm whether or not the data was actually sent to the field device 4, the "reception request" from the GUI means 5 was received, the "reception request" was sent to the controller 3, and a reply from the controller 3 (WAIT or field (Return data from the device) is received and returned to the GUI means 5, and then "exclusive lock release" is executed.

In the sequence when the communication shown in FIG. 7 is stopped midway, the "transmission request" is received from the GUI means 5, "exclusive lock" is performed, the "transmission request" is sent to the controller, and the transmission from the controller 3 is completed. The notification is received and the process returns to the GUI unit 5.

Reply data from the field device 4 is GU
If the GUI means 5 stops the communication before the I means 5 receives it, the controller 3 is in a state of not accepting the next communication request for about 5 minutes until the reply data is received.

The communication interface 61 of the field communication server means 6 has the following problems. (1) Communication is a semi-synchronous interface, that is, the GUI means 5 is locked until a communication request (transmission request / reception request) arrives at the controller 3 and a reply (transmission completion / WAIT / reception data) is returned from the controller 3. It

In FIG. 6, areas (A1) and (A2)
As described above, the GUI unit 5 deadlocks for several seconds in the time axis periods T1, T2, ... Tn each time communication is performed, which deteriorates the operability for the user. In order to improve the poor operability, the GUI unit 5 intentionally lengthens the period for requesting data. However, by lengthening the communication period, the processing speed decreases and the performance decreases. It was.

(2) Furthermore, in FIG. 6, the field communication server means 6 is exclusively locked at time t1, and at time t.
2, the exclusive lock is released. However, if another transmission request is received during this exclusive lock period (simultaneous access from a plurality of GUI means), as described in the area (B), the exclusive lock is released later. The transmission request issued enters the locked state by the exclusive lock, and the GUI means is in a deadlocked state, which further deteriorates the operability when a plurality of GUI means are used.

(3) In FIG. 7, as shown in the area (C), the GUI means 5 stops the processing in the middle of one sequence of communication (until the transmission request is issued and the reception data can be acquired). When the function is terminated, it takes about 5 minutes until the controller clears the communication status (clears the reply buffer), and communication cannot be performed during that time. Therefore, the GUI unit 5 stops. It is not possible to finish until one sequence of communication is completed after the call is sent, and the termination process becomes complicated.

An object of the present invention is to make the communication between the GUI means and the field communication server means a completely asynchronous type communication independent of the communication interface of the field communication server means, thereby improving the operability and quality of the GUI means. It is to realize an improved field device communication device.

[0014]

In order to achieve such an object, a feature of the invention according to claim 1 of the present invention is that in a field device communication device, a host device communicates with a field device through a controller. The higher-level device includes a GUI unit that provides an environment for interfacing via graphics, a completely asynchronous communication server unit that performs completely asynchronous communication with the GUI unit, and a semi-synchronous type with the completely asynchronous communication server unit. While communicating
Field communication server means for communicating with the field device via the controller.

According to a second aspect of the present invention, the completely asynchronous communication server means performs a completely asynchronous communication interface for communicating with the GUI means in a completely asynchronous manner, and communication for performing a semi-synchronous communication with the field communication server means. The communication processing means having a processing thread and the queuing means having a transmission / reception queue accessed by the completely asynchronous communication interface and the communication processing thread are provided.

A third aspect of the present invention is characterized in that the GUI means performs the completely asynchronous communication from the client PCs of a plurality of users to the completely asynchronous communication server means.

According to a fourth aspect of the present invention, the GUI means performs integrated device management of the field device.

A fifth aspect of the present invention is that the controller is realized by a field control station in a distributed control system.

A sixth aspect of the present invention is that the GUI means is executed as a function of a host device in the distributed control system.

According to a seventh aspect of the present invention, the GUI means is executed by a dedicated field device integrated management device independent of a host device in the distributed process control system.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing an example of a field device communication apparatus to which the present invention is applied. The same elements as those explained in the conventional apparatus of FIG.

A feature of the present invention is the introduction of the completely asynchronous communication server means 8. The completely asynchronous communication server means 8 is inserted between the GUI means 5 and the field communication server means 6, and has a completely asynchronous communication interface 81, a communication processing means 82 having a communication processing thread 821, and transmission / reception. It comprises a queuing means 83 having a work queue 831.

The completely asynchronous communication server means 8 performs the completely asynchronous communication 9 with the GUI means 5 through the completely asynchronous communication interface 81, and at the same time, the communication processing means 8
The same semi-synchronous communication 7 as that of the conventional apparatus is performed with the field communication server means 6 via 2.

FIG. 2 is a time chart diagram for explaining a communication sequence of integrated device management in the case of normal communication of the device of the present invention, and FIG. 3 is a time chart diagram for explaining a communication sequence of integrated device management in the case of communication suspension. is there.
Focusing on the field communication server means 6 below, the communication procedure is as follows.

In the sequence for normal communication shown in FIG. 2, the "transmission request" from the GUI means 5 is received by the completely asynchronous communication interface 81, the transmission request is registered in the queuing means 83, and the GUI means 5 is registered. Return immediately. The lock time of the GUI means 5 in this period T1 is about 10 milliseconds, and the lock time is not felt by the user's operation feeling.

The communication processing means 82 constantly monitors the transmission / reception queue 831. If there is an untransmitted communication request in the transmission / reception queue 831, the communication processing means 82 issues a transmission request to the field communication server means 6 to perform an exclusive lock (time At t1), the lock state is maintained until the processing of the field communication server means is completed (time t2).

The field communication server means 6 sends a "transmission request" to the controller 3, receives a transmission completion notification from the controller 3, returns, and the locked state is released. When the field communication server means returns, the received data is set in the corresponding transmission / reception queue 831, and if there is the next unprocessed transmission request, that processing is executed.

The confirmation as to whether or not the data is actually sent to the field device 4 and the reply data operate as follows.
Upon reception of the "reception request" from the GUI means 5, if there is corresponding reception data in the transmission / reception queue 831, it is acquired and the process immediately returns. WAIT is returned when there is no reception. The GUI unit 5 periodically sends a reception request until the reception data can be acquired. The lock period T2, T3, ... Tn until the response to the reception request is about 10 milliseconds as in T1 as described in the area D, and the lock time is not felt by the user's operation feeling.

In the sequence shown in FIG. 3 when the communication is stopped midway, first, the "transmission request" from the GUI means 5 is sent.
In response, the transmission request is registered in the queuing means 83 and the GUI is displayed.
Immediately return to means 5. When the GUI unit 5 does not perform the reception process, the GUI unit 5 issues a “communication stop notification”.
Will be sent.

When the communication stop notification is received, the queuing means 83
Communication stop is set to, and the reception request process of the GUI unit 5 is stopped. When the reception request for the queue has already been completed (when the reception data is received via the field communication server means 6), the data on the corresponding queue is deleted.

The communication processing means 82 constantly monitors the transmission / reception queue 831. If there is an untransmitted communication request in the transmission / reception queue, the communication processing means 82 issues a transmission request to the field communication server means 6 to perform processing of the field communication server. Will be locked until is completed.

As described above, the field communication server means 6 sends a "transmission request" to the controller 3, receives a transmission completion notice from the controller 3, returns, and the locked state is released. When the communication is stopped, it is judged from the queuing means 83 whether the communication is stopped, the queue data on the corresponding queue is deleted, and then the processing of the next queue data is executed.

According to the configuration of the present invention, the controller 3 from the field device 4 can be used even when the communication suspension is notified.
If there is a reply frame of data to the communication processing means 82
The field communication server means 6 receives the data of the controller 3 in response to the reception request from the controller 3 and returns the data to the communication processing means 82. In addition, the controller 3 does not stagnate.

According to the present invention, by realizing the completely asynchronous communication interface 81, it becomes easy to construct a system having a plurality of GUI means as clients.
An embodiment of a plurality of clients will be described with reference to FIG.

An information bus 10 is connected to the host device 1, and includes an external network such as the Internet. 1
Reference numerals 1 and 12 denote two client PCs connected to this information bus, each having GUI means 51 and 52, and a complete asynchronous communication interface 81 and a complete asynchronous type in the host device 1 via the information bus 10. Communication 91
And 92.

When the device integrated management function is incorporated as a subsystem of the distributed process control system by the field device communication device to which the present invention is applied, as shown in FIG. It is general that the means 5 is executed and the controller 3 is realized by a field control station in a distributed process control system.

The present invention is not limited to such a general configuration, and the GUI means 5 of the device integrated management function can be separated from the host device 1 as an independent device integrated management device as in the embodiment of FIG. The controller 3 may be replaced with a dedicated controller independent of the field control station.

[0038]

As is apparent from the above description,
According to the present invention, the integrated device management function for acquiring, saving, and setting data of field devices in the process control system has the following advantages. (1) The GUI means can issue a communication request to the field device and can receive a reply at an arbitrary timing, so that the configuration of the GUI means is simple and development is easy. (2) Even if the GUI unit is forcibly terminated, communication with the field device can be performed without interruption, and similarly, the configuration of the GUI unit is simple and development is facilitated. (3) The GUI means is not deadlocked for communication, and the performance as a user interface is improved. (4) It is possible to execute a plurality of GUI means as a client, and the performance as a communication server is improved.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration in which the present invention is applied to a distributed process control system having a hierarchical structure.

FIG. 2 is a time chart diagram for explaining a communication sequence of the integrated device management function in the case of normal communication in the device of the present invention.

FIG. 3 is a time chart diagram for explaining the communication sequence of the integrated device management function in the case of communication suspension in the device of the present invention.

FIG. 4 is a functional block diagram showing another embodiment of the present invention.

FIG. 5 is a functional block diagram showing a conventional basic configuration of a distributed process control system having a hierarchical structure.

FIG. 6 is a time chart diagram for explaining a communication sequence of the integrated device management function in the case of normal communication in the conventional apparatus.

FIG. 7 is a time chart diagram illustrating a communication sequence of the integrated device management function in the case of communication suspension in the conventional device.

[Explanation of symbols]

1 Upper device 2 control bus 3 controller 4 field devices 5 GUI means 6 Field communication server means 61 Semi-synchronous communication interface 8 Complete asynchronous communication server means 81 Completely asynchronous communication interface 82 Communication processing means 821 Communication processing thread 83 Queue means 831 Send / Receive queue

Claims (7)

[Claims] 1. A field device communication apparatus in which a host device communicates with a field device via a controller, wherein the host device provides GUI means for providing an environment for interfacing via graphics, and completely asynchronous with the GUI means. A field device including a completely asynchronous communication server unit for performing communication, and a field communication server unit for performing semi-synchronous communication with the completely asynchronous communication server unit and communicating with the field device via the controller. Communication device. 2. The completely asynchronous communication server means has a completely asynchronous communication interface for completely asynchronous communication with the GUI means, and a communication processing thread having a communication processing thread for semi-synchronous communication with the field communication server means. 2. The field device communication device according to claim 1, further comprising: means, and a queuing means having a transmission / reception queue accessed by the completely asynchronous communication interface and the communication processing thread. 3. The field device communication apparatus according to claim 1, wherein the GUI means performs a completely asynchronous communication from client PCs of a plurality of users to the completely asynchronous communication server means. 4. The GUI means performs integrated device management of the field device.
The field device communication device according to any one of 1. 5. The field device communication apparatus according to claim 1, wherein the controller is realized by a field control station in a distributed process control system. 6. The field device communication device according to claim 1, wherein the GUI unit is executed as a function of a higher-level device in the distributed process control system. 7. The GUI unit is executed by a dedicated field device integrated management device independent of a host device in the distributed process control system. Field equipment communication device.