JPH088573B2 - Data communication method of control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a control system for operating, operating and monitoring various plants using a computer, and particularly to a console side of the control system. The present invention relates to a data communication method for a control system with improved data communication means between a plurality of portable man-machine interfaces at remote locations.

(Prior Art) Generally, in a distributed control system, a plurality of control stations 1 for controlling a plant as shown in FIG.
... and a plurality of operator stations 2, ... functioning as a man-machine interface, and a plurality of these distributed stations 1, ..., 2, ..., a data highway 3 that organically couples each other. There is. In the control system as described above, the operator performs necessary operations while grasping the process state, but the plant state is grasped only from the CRT installed in the operator console room of the operator station 2. Therefore, the operator away from the console room cannot grasp the plant state. Therefore, the operator at the remote place receives the report of the plant state verbally from the operator in front of the operator console through the transceiver.

However, when using the above data communication method,
Not only does it significantly reduce the monitoring ability of the operator in front of the console, but there is also a problem that prompt measures cannot be taken in an emergency.

Therefore, conventionally, in order to solve the above-mentioned problems, a wireless portable man-machine interface (hereinafter referred to as a portable MMI) is adopted as shown in FIG. A system for operating and monitoring while directly accessing the control system has been developed. That is, in this system, a wireless fixed station 4 serving as a master station is provided on the data highway 3 side, while a required number of portable MMIs 5a, 5b, 5c, ... Are arranged outside the console room. The radio master station 4 and each of the portable MMIs 5a, 5b, 5c, ... Have a method of exchanging various data required for process control using a plurality of channel frequencies or modulation frequencies.

(Problems to be solved by the invention) However, as described above, the control system and the portable MMI 5a, 5
The following problems have been pointed out in data communication when wirelessly communicating with b, 5c, ....

a. As the number of portable MMIs 5a, 5b, 5c, ... Increases, the number of channel frequencies or modulation frequencies also increases, which complicates the channel switching means and other configurations, and increases the number of frequency generation sources. It becomes difficult to manage and select free channels.

b. Moreover, if several portable MMIs 5a, 5b, 5c, ... Share one channel frequency, during communication of one MMI, other MMIs cannot communicate and communication status with other stations. Not only is it difficult to find out, but if communication is mistaken, interference will occur, and so-called real-time processing of data will be difficult.

c. Station on Wired Data Highway 3
In general, 1, ..., 2, ... often use the token bus method for data communication, but in such a control system, stations 1, ..., 2, ... Can be attached to and detached from the data highway 3. The number of station departures from the bus system is treated as a station failure. Therefore,
When each station detects a failure, it reorganizes the token ring configuration and performs data communication. During this time, it constantly checks whether the failed station has recovered.
As a result, by having a recovery check routine,
There is a problem that the process data transmission affects the speed at least.

By the way, a control system and multiple portable MMIs 5a, 5b, 5c,
When the token system is adopted between each other, data is exchanged while handing over tokens at predetermined time intervals, so there is no problem in operation if all portable MMIs 5a, 5b, ... are online, Any transportable MMI 5a, 5b, 5c,
If ... repeats offline and online, the offline / online status is frequently monitored, and there is a problem that the data transmission efficiency becomes very poor.

The present invention has been made in view of the above circumstances, and it is possible to reliably manage a plurality of portable MMIs by reducing the channel frequency, and it is possible to guarantee the real-time property and reliability of the data, and it is necessary for an operator outside the console room. Depending on the type
An object of the present invention is to provide a data communication method of a control system capable of exchanging data with a very small influence even if MMI is repeated offline and online.

[Configuration of the Invention] (Means and Actions for Solving the Problems) In order to solve the above problems, the present invention provides a plurality of portable MMs.
A logical token ring is formed between each other, and
Each portable MMI has a token ring configuration change command processing means for wirelessly transmitting a token ring configuration change command at the second channel frequency when switching off-line or online, and wireless data communication for communicating data at the first channel frequency. A processing means is provided, while the control system reorganizes the token ring configuration already held based on the content of the token ring configuration change command transmitted from the portable MMI. Means and always use the first channel frequency to transfer the data required for the control system to each portable
A wireless communication processing unit is provided for sequentially exchanging wirelessly with each other to the MMI based on the token ring system and transmitting the recognition data of the token ring configuration after the reorganization to each portable MMI. When switching from online to offline or from offline to online,
When the token ring configuration change command processing means transmits a token ring configuration change command to the control system side using the second channel frequency, the control system side:
Based on the contents of the token ring configuration change command in the token ring configuration reorganization means, that is, offline or online, the offline or online portable MMI is deleted or participated in the reorganization. Save the token ring configuration after organization. Here, the wireless communication processing means,
After transmitting the recognition data of the token ring configuration after reorganization on the first channel frequency to each portable MMI, the data is exchanged with each portable MMI for process control based on the token ring configuration after reorganization It is a thing.

In another invention, in the case of a distributed control system, when any of a plurality of stations on a data highway goes offline or online, the station sends a ring configuration change command to the station in the token, The stations in this token reorganize the token ring configuration and send it to each station.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. That is, in this system, a plurality of control stations 12 for controlling the plant are provided on the data highway 11.
... and a plurality of operator stations 13, ... having a man-machine interface function are distributed and arranged, which is the same as the conventional one. Especially, the difference is that the fixed station 14 and the child station, which are the master stations installed in the data highway 11, are installed. Data communication with a plurality of portable MMIs 15a, 15b, 15c, ... serving as a station using the logical token ring communication 16 and the token ring configuration change command communication 17 independently of the logical token ring of the distributed control system It is in.

As shown in FIG. 2, the fixed station 14 is based on the control system communication processing means 141 for exchanging data with the control system and the token ring communication 16 for each MMI 15a, 15b ,.
And the second channel frequency transmitted from the portable MMI wireless communication processing means 142 for exchanging data at the first channel frequency, the data transmitting section 143, the data receiving section 144, and each portable MMI 15a, 15b ,. Token ring configuration change command communication unit 17
145, a token ring configuration reorganization unit 146, a token ring configuration data holding unit 147, and the like.

Each of the portable MMIs 15a, 15b, ... Specifically, as shown in FIG. 3, is an MMI that stores data for requesting necessary data from the control system side after token acquisition and received data from the control system side. Functional means 151, wireless data communication processing means 152 for exchanging data at the first channel frequency, data transmitting section 153, data receiving section 154, and token ring configuration change for transmitting a token ring configuration change command at the second channel frequency. Command transmission unit 155, token ring configuration change command processing means 156, online command unit 157on
And an offline command unit 157of and the like.

Next, regarding the operation of the system configured as described above, (1) the fixed station 14 and each portable MMI 15a, 15b,
Data communication with ..., (2) Broadcast communication, and (3) Station configuration change command communication will be described in this order.

(1) Fixed station 14 and each portable MMI 15a, 15b, ...
About data communication with.

First, these fixed stations 14 and each portable MMI 15a, 1
5b, ... Independently of the system-side logical token ring, wirelessly performs data communication by the logical token ring communication 16. This wireless logical token ring
The portable MMIs 15a, 15b, ... wirelessly form a ring in a fixed order and sequentially circulate a signal or frame called a token at fixed time intervals, and the portable MMI that acquired the token at this time is the parent of the communication. , And communicates with the fixed station 14 on the system side and with other MMIs. Communication of data regarding processes is normally performed with a fixed station, but communication between MMIs is also possible.

So, a portable MMI that got the token and performed the parent's right
Is the wireless data communication processing means 152 determines whether the token is in its own station, and if it is in its own station, specifies the address of the communication partner side, for example, the fixed station 14, and
The data to be transmitted is fetched from the MMI function means 151 and sent to the data transmission unit 153. Here, the data transmission unit 153 specifies the fixed station 14 and wirelessly transmits the data from the wireless data communication processing unit 152.

On the other hand, on the fixed station 14 side, the data receiving unit 144 receives data from the portable MMI and sends the received content to the portable MMI wireless communication processing means 142. Here, it is judged whether or not the received data, especially the address, is for the own station, and when it is judged to be a data request to the own station, the request content is passed to the control system communication processing means 141. The control system communication processing means 141 accesses the control station 12 or the operator station 14 according to the request content, collects necessary data, and sends it to the portable MMI wireless communication processing means 142. Therefore, the communication processing unit 142 specifies the request source and transmits the data to the request source portable MMI via the data transmission unit 143.
Here, the requesting MMI receives the data transmitted from the fixed station 14 at the data receiving unit 154, and passes the received data to the wireless data communication processing means 152. Here, the wireless data communication processing means 152 determines whether or not the contents are addressed to its own station.
It is sent to the I function means 151.

(2) About broadcast communication.

From the fixed station 14 to multiple portable MMIs 15a, 15b,…
On the other hand, when it is desired to communicate the same data, the fixed station 14 uses the address (broadcast address) so that each portable MMI 15a, 15b, ... The data is transmitted through the transmission unit 143. Here, each of the MMIs 15a, 15b, ... Receives the data from the fixed station 14, determines that the wireless data communication processing means 152 is the broadcast communication, and performs necessary processing or monitoring based on the received data.

(3) About station configuration change command communication.

The communication methods (1) and (2) described above are the same as the data transmission / reception of the conventional wired token bus method, but in general, in a logical token ring having a plurality of portable MMIs 15a, 15b, ... If the electrodes 15b, ... Are frequently turned on and off, the ring configuration must be changed each time.

At this time, in the conventional token bus system, when there is no response to the MMI, it is judged as a failure, the configuration of the logical token ring is reorganized, and it is constantly monitored whether or not the MMI is restored.

On the other hand, in the method of the present invention, reorganization of the ring configuration is positively performed from the operational aspect of MMI. Specifically, the MMI having the token outputs the offline command from the offline command unit 157of after the power-off operation command and before being actually turned off. Then, the token ring configuration change command processing unit 156 converts the offline command into appropriate command data, and then the token ring configuration change command transmission unit 155.
To the fixed station 14 which is the master station.

On the other hand, in the fixed station 14, the token ring configuration change command receiving unit 145 receives the command and sends it to the token ring configuration reorganizing means 146. The token ring configuration reorganizing means 146 includes the token ring configuration data holding means 1
With reference to the ring configuration data stored in 47, the logical token ring is configured again with only the remaining MMIs, excluding the MMIs that were powered off this time and left the ring system. Then, the newly reorganized result is stored in the token ring configuration data holding means 147 and the portable M
Send to MI wireless communication processing means 142. Here, the MMI wireless communication processing means 142 transmits the recognition data of the new logical token ring to each MMI via the data transmission unit 14. Also, M
After that, the MI wireless communication processing unit 142 refers to the ring configuration of the holding unit 147, and each MMI that is currently online.
In response, necessary data is transmitted via the data transmission unit 14.

The MMI that leaves the logical token ring configuration is actually turned off after transmitting the token ring configuration change command to the fixed station 14. On the other hand, when the remaining online MMI receives the own station recognition data of the new logical token ring from the fixed station 14, the MMI function means 151 stores the recognition data, and thereafter performs data communication with the new ring configuration.

When the offline MMI participates in the token ring, the online command unit 157o after the power-on operation command is issued.
An online command is output from n. Here, the token ring configuration change command processing means 156 converts the online command into appropriate command data, and then, via the token ring configuration change command signal 155, the fixed station 1 serving as the master station.
Send to 4.

In this fixed station 14, the token ring configuration change command receiving unit 145 receives the command and sends it to the token ring configuration reorganizing means 146. The token ring configuration reorganizing means 146 stores the token ring configuration data holding means 147.
While referring to the ring configuration data stored in
This time, the power will be turned off and a logical token ring including the MMI that will newly join the ring system will be configured. The result of this new reorganization is the token ring configuration data holding means 147.
And stores it in the portable MMI wireless communication processing means 142. Here, the MMI wireless communication processing means 142 transmits the new logical token ring recognition data to the MMI via the data transmitting unit 14.

Here, the MMI newly participating in the token ring, after transmitting the token ring configuration change command to the fixed station 14, waits until it receives new logical token ring configuration data and its own identification data from the fixed station 14. ing. Then, after receiving such data, data communication is started by the new ring configuration.

Therefore, according to the configuration of the above embodiment, the number of frequency channels for data communication between the fixed station 14 and the portable MMIs 15a, 15b, ... Can be realized with only two channels at most. Even if the total number of portable MMIs increases, as long as it is within the maximum number of stations in the logical token ring configuration, the data communication between the slave station-master station and the slave station-slave station can be secured reliably and in real time. it can. In addition, since the MMI is actively notified of departure and participation from the MMI token ring configuration, and based on this, the fixed station 14 side performs the reorganization of the token ring by interrupt processing. As described above, it is not necessary to constantly monitor the recovery state, and it is possible to suppress an increase in transmission load and, in turn, improve transmission efficiency. Further, the wireless system has lower reliability of data transmission than the wired system.
For example, a certain object may be hidden and unable to communicate for a certain period of time. However, in this case, by forcibly removing the MMI from the token ring and joining the MMI again when the MMI makes a request, the data transmission efficiency due to the existence of the MMI that cannot communicate is increased. You can avoid the deterioration.

The present invention is not limited to the above embodiment. That is, the MMI side automatically issues the online and offline operation commands when the power is turned on and off, but it is also possible to manually output the online and offline operation commands, for example.

In the above embodiment, the method of forcibly reconfiguring the token ring configuration for the wireless logical token ring method has been described. However, for example, for a local area network (LAN) of the original wired token bus method, The idea of reorganizing the compulsory token ring configuration can be easily applied. In this case, each station 1
1, ..., 12, ... Have functions corresponding to those in FIGS. In the case of a cable, the problem is how to put the reorganization request data on the same line as a normal data signal. For example, the fluctuation of the base voltage of a digital signal and the wavelength modulation in the case of optical communication. Can be dealt with.

Therefore, by using the function of forcibly reorganizing the token ring configuration in the LAN using this token bus system, the following various points are improved.

In the conventional token bus system, when a certain station fails, the LAN that does not reorganize the token ring performs a process to pass the token to the failed station every time, which increases the load on the bus.

In the conventional token bus system, when a station fails, the failed station is detected and the token ring is reorganized, and the recovery of the station is constantly monitored, and the token ring is reorganized when the station recovers to the normal state. In a functional LAN, the recovery of stations is constantly monitored, which increases the load for monitoring.

On the other hand, if this method is applied, the token ring is reorganized when a failed station is detected, and the process of passing the token to the failed station is not performed. Also, since the token ring is reorganized by the restoration / token ring participation command from the failed station, the restoration is not always monitored. As a result, the communication load on the bus can be significantly reduced compared to the conventional method.

When a station becomes unable to communicate, the station that cannot communicate is detected by the same method as the conventional token bus method. After detecting the incommunicable station, the token ring is reorganized so as to remove this station from the token ring. When the station that has become unable to communicate with itself detects that it cannot communicate with other stations, it performs processing to leave the token ring and has an online command from the operator. When it becomes possible to communicate again with the online command from the operator, a token ring reconfiguration request is output. In this way, processing can be made to wait when communication is impossible.

In addition, the present invention can be modified in various ways without departing from the scope of the invention.

[Effects of the Invention] As described above, the present invention has the following effects.

First, according to the first aspect, the control system can exchange necessary data with a large number of portable MMIs at a low channel frequency, and can ensure the reliability and real-time property of data transmission among a large number of MMIs. Also, when the MMI is offline or online, the token ring configuration change command is transmitted from the MMI, and the control system side receives the command to reconfigure the ring configuration, so data communication is performed without waste to the online MMI. Therefore, the efficiency of data transmission can be improved.

Next, in claim 2, data communication can be efficiently performed between the stations in the distributed control system to online stations, and the efficiency of data transmission can be similarly improved.

[Brief description of drawings]

1 to 3 are shown for explaining one embodiment of a data communication system of a control system according to the present invention. FIG. 1 is a schematic configuration diagram to which the system of the present invention is applied, and FIG. FIG. 1 is an internal configuration diagram of the fixed station shown in FIG. 1, FIG. 3 is an internal configuration diagram of the portable MMI shown in FIG. 1, and FIG. 4 is a schematic configuration diagram of a conventional general distributed control system. FIG. 3 is a configuration diagram illustrating a data communication method of a conventional distributed control system. 11 …… Dataway, 12 …… Control station, 13
...... Operator station, 14 …… Fixed station, 15a, 15b, ……… Portable MMI, 16 …… Logical token ring, 17 …… Token ring configuration change command, 141
...... Control system communication processing means, 142 …… Portable MMI
Wireless communication processing means, 146 ... Token ring configuration reconstructing means, 147 ... Token ring configuration data holding means, 151
...... MMI function means, 152 …… Wireless data communication processing means, 15
6 …… Token ring configuration change command processing means, 157on ……
Online command section, 157of …… Offline command section.

Claims (2)

[Claims] 1. A data communication method of a control system for wirelessly performing data communication between a control system and a plurality of portable man-machine interfaces, wherein a logical token ring is formed between the plurality of portable man-machine interfaces. And, each portable man-machine interface is provided with a token ring configuration change command processing means and a wireless data communication processing means for wirelessly transmitting a token ring configuration change command at a specific frequency based on offline or online. On the other hand, the control system includes a token ring configuration reorganization means for reorganizing the token ring configuration already held based on the content of the token ring configuration change command transmitted from the portable man-machine interface, and normally The frequency different from the specific frequency Data required for the control system to each portable man-machine interface by wirelessly exchanging data by using the channel frequency based on the token ring system, and the recognition data of the token ring configuration after the reorganization is transferred to each portable man. A data communication method for a control system, which is provided with a wireless communication processing means for transmitting to a machine interface, and forcibly reorganizes the token ring configuration when each portable man-machine interface is offline or online. 2. In the case of a control system in which a plurality of stations are distributedly arranged on a data highway, a wired token bus system is adopted between the plurality of stations, and each station is offline or offline. Token ring configuration change command processing means for transmitting the sent token ring configuration change command and token ring configuration reorganization means for reorganizing the token ring configuration already held based on the contents of this token ring configuration change command The data communication system of the control system according to claim 1, which is provided.