GB2111271A - Data transmission and processing systems - Google Patents
Data transmission and processing systems Download PDFInfo
- Publication number
- GB2111271A GB2111271A GB08230489A GB8230489A GB2111271A GB 2111271 A GB2111271 A GB 2111271A GB 08230489 A GB08230489 A GB 08230489A GB 8230489 A GB8230489 A GB 8230489A GB 2111271 A GB2111271 A GB 2111271A
- Authority
- GB
- United Kingdom
- Prior art keywords
- data
- transmission
- unit
- control unit
- transmission control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q9/00—Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
- H04Q9/14—Calling by using pulses
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/42—Loop networks
- H04L12/423—Loop networks with centralised control, e.g. polling
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Small-Scale Networks (AREA)
- Selective Calling Equipment (AREA)
Abstract
A data transmission and processing system includes a central processing unit (1) coupled to a transmission control unit (2) with which any number of terminal units (6) are connected in series. Each terminal unit is coupled to data devices (4). Communication of control data between a memory in the transmission control unit and memories in the terminal units and of collected data between the latter memories and the memory in the transmission control unit is effected by transmission in a serial bit mode, control data being delivered during one portion and requested collected data being transmitted during another portion of a predetermined unit time interval. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to data transmission and processing systems
This invention relates to data transmission and processing systems and more specifically to data transmission and processing systems in which there is a transmission control unit for transmitting data between a central processing unit and a plurality of terminal units connected thereto.
There is a data transmission and processing system in which data devices such, for example, as instruments and detectors, are set up at different positions and transmit items of data to a central processing unit and are controlled by the latter under the control of data delivered from the central processing unit to said devices. This known system has the disadvantage of requiring the provision of a large number of connecting lines.
Thus the system has a plurality of terminal units coupled with the data devices and also with the central processing unit at the central processing location and there are as many separate transmission lines as there are connector lines connected between the terminal units and the data devices. Transmission lines are, of course, costly in material and construction. Although the cost of the transmission lines required can be reduced by resorting to the use of a bit serial transmission system in which the central processing unit is connected to a terminal unit through a minimum of nine transmission lines, the number of lines required still remains undesirably high. For example, if there are eight terminal units, a total of 72 transmission lines would be necessary.Also, there would be required as many transmission control units connected to the central processing unit as there are terminal units, and similar transmission control units connected to the terminal units and this involves the provision of very costly hardware.
With a conventional known data transmission system, data is collected from the terminal units or control data and is sent to the terminal units only when a request is issued by the central processing unit, so that data transmission takes a relatively long time. Because the amount of data requested is irregular, the time required for data processing varies with each processing operation. To cope with irregular requests made by the central processing unit, it is in practice necessary to allot identifying so-called physical and logic device numbers related to requested data, and it takes a relatively very long time to bring the logic device numbers representing, in coded form, device types and devices, into correspondence with physical device numbers indicative of connected terminal units.If a number of requests are made simultaneously, data transmission has to be subjected to "queuing" for the simultaneously occurring requests cannot be handled at the same time. Since the processing involved in satisfying these requirements has to be performed by the central processing unit, the said unit has to cope with a heavy working load, and is therefore expensive.
The present invention seeks to provide an improved data transmission system which does not have the foregoing defects and disadvantages and in which there is a central processing unit coupled with a transmission control unit for storing updated collected data and control data at all times for data processing at a high speed.
Another object of the invention is to provide an improved data transmission system which is such that the terminal units in the system can be of standardised uniform construction, thus reducing costs and securing a high degree of working reliability.
A further object of the invention is to provide an improved data transmission system which is such that additional terminal units can, if required, be easily inserted in a system already set up.
According to this invention in one aspect a data transmission system comprises a central processing unit; a transmission control unit connected thereto; a plurality of terminal units each having a data memory and each connected to data devices; means connecting said terminal units in series with said transmission control unit; and means for transmitting control data and collected data in the said memories in a bit serial mode in a predetermined unit time interval.
According to this invention in another aspect, a data transmission system comprises a central processing unit; a transmission control unit connected thereto and capable of transmitting and receiving data within the transmission portion of a predetermined unit time interval which includes a transmission time portion and a request time portion; a plurality of terminal units connected in series to said transmission control unit and each capable of transmitting and receiving data within said transmission time portion; a plurality of data devices connected to each terminal unit; a data memory in each terminal unit for storing control data from said central processing unit and collected data from the devices connected thereto; a data memory in said transmission control unit for storing the content of the data memories in the terminal units; and means for transmitting control data in the data memory in the transmission control unit to each terminal unit and collected data in the data memory in each terminal unit to the transmission control unit in the transmission time portion, control data being delivered from the central processing unit to the transmission control unit and requested collected data being delivered from said transmission control unit in the said request time portion.
The invention is illustrated in and further explained in connection with the accompanying drawings, in which: Figure 1 is a block diagram of one form of data transmission and processing system embodying the invention;
Figure 2 is a block diagram of the internal arrangement of one form of transmission control unit in the system illustrated by Figure 1;
Figure 3 is a block diagram showing the internal arrangement of one form of a terminal unit in a system as illustrated by Figure 1;
Figure 4 is a block diagram illustrating principal portions of the transmission control unit of
Figure 2 and the terminal unit of Figure 3;
Figure 5 is an explanatory timing diagram relating to data transmission and request processing;
Figure 6 is a diagram typifying the structure of data to be transmitted; and
Figure 7 is a diagram illustrating the manner in which data items flow.
Referring to Figure 1 , the system therein represented has a central processing unit (CPU) 1, connected by a connector line 3 to a transmission control unit 2 in which updated collected data and control data are available at all times. The transmission control unit 2 is accordingly immediately responsive to a request from the central processing unit 1. The transmission control unit 2 is connected to a plurality of terminal units (LS.1, LS.2, LS.3) 6 coupled respectively to data devices 4, for example such as data collecting instruments, or detectors by connector lines 5.
The terminal units 6, of which three are shown, through there may be any number, are connected in series by a 1-bit transmission line 7 for bit serial data transmission. This arrangement produces relatively low cost in material and construction, and results in uniform and simplified data transmission control.
Referring now to Figure 2, the transmission control unit 2 therein illustrated has a data memory 8 hereinafter called an "MFDB" serving as a second data memory and connected to a processor (microprocessor) 9 which is coupled with a request control interface 10 for the central processing unit 1 and also with a transmission control interface 11 for the terminal units 6. The interface 10 is coupled with the central processing unit 1 through the line 3 and the interface 11 is coupled with the series connected terminal units 6 through the line 7.
Referring to Figure 3 each terminal unit 6 has a data memory 12 hereinafter called an "LFDB" coupled with a processor (microprocessor) 1 3 which is connected to a transmission control interface 14 coupled with the transmission control interface 11 (Figure 2) and is also connected to a field interface from the data devices 4. The connecting or coupling lines are indicated at 5 and 7, one of the lines 7 providing input to 1 4 from the transmission control unit 2.
The data memory 8 in the transmission control unit 2 and the data memory 12 in each of the terminals 6 are constructed as shown in Figure 4.
As will be seen, the MFDB has a series of control data memories OUT.1, OUT.2, OUT.3 for delivering control data to the terminal units (LS.1--LS.3) 6, respectively, and a series of collected data memories IN.1, IN.2, IN.3 for receiving collected data from the terminal units 6, respectively. These memories have storage locations corresponding to the data devices connected to the terminal units for storing control data or collected data to or from the data devices.
In Figure 4, only the LFDB for the terminal unit
LS. 1 is shown, but the LFDB construction for the other terminal units is similar. Thus, the LFDB has control data memories OUT.1, OUT.2, OUT.3 corresponding to the control data memories
OUT.1, OUT.2, OUT.3 in the MFDB, and collected data memories IN.1, IN.2, IN.3 corresponding to the collected data memories IN.1, IN.2, IN.3 in the
MFDB. Therefore, the MFDB corresponds to the
LFDB for all the terminal units. Control data from the central processing unit 1 is written into a given storage location in one of the control data memories OUT.1, OUT.2, OUT.3 of the MFDB, and collected data is read out of a given storage location in one of the collected data memories
IN.1, IN.2, IN.3 of the MFDB and delivered to the central processing unit 1.The content of the control data memory of the MFDB is transmitted over a line 7 to each terminal unit, and the content of the collected data memory of the LFDB in each of the terminal units is transmitted over a line 7 to the collected data memory of the MFDB. A corresponding device 4 is controlled on the basis of control data stored in the LFDB. Data collected from a device 4 over a line 5 is written into a given storage location in the collected data memory
LFDB.
Timing for data transmission and request processing will now be described with reference to Figure 5, in which a unit time interval is represented by one second. The unit time interval is divided into two portions namely an earlier portion of 500 milliseconds serving as a transmission time interval Ta, followed by a later portion Tb of 500 milliseconds serving as a request processing time interval. During the transmission time interval Ta, all control data items stored in the MFDB are transmitted from the control data memories OUT.1, OUT.2, OUT.3 successively over a transmission line 7 in a bit serial transmission mode. Each terminal unit (LS.1, LS.2, LS.3) 6 takes in control data addressed to itself, and stores such control data in the control data memory of the LFDB thereof.
Then, the terminal units deliver their own collected data items from the collected data memories successively to a transmission line 7 in a bit serial transmission mode, and the delivered data items are stored in the collected data memories IN.1,
IN.2, IN.3 of the MFDB. Accordingly, during the transmission time interval Ta, six frames of data OUT.1, OUT.2, OUT.3, IN.1, IN.2, IN.3 are transmitted over a transmission line 7 as shown in
Figure 6.
During the next request processing time interval Tb, control data from the central processing unit 1 is stored in the MFDB, and requested collected data is delivered to the central processing unit 1. The data collected is updated data collected from each terminal unit 6 in the preceding 500 milliseconds, and is immediately supplied to the central processing unit 1. The control data as delivered at this time will be transmitted to the LFDB in each terminal unit 6 during the next following transmission time interval Ta.Assuming that there are one hundred data devices connected to each terminal unit (there may be any number) and that there are ten terminal units 6 connected in series by a transmission line 7 and that one element of input and output information is sent to and collected from each data device, ten frames OUT.1 to
OUT. 10 of 1000 items of control data and ten frames IN. 1 to IN. 10 of 1000 items of collected data will be transmitted during the transmission time interval Ta. Such data transmission can be satisfactorily effected, with a margin of time to spare in 500 milliseconds in a unit transmission time interval Ta of one second. If a greater amount of data is to be transmitted (as in a case in which there are more than 1000 devices), the unit time interval may be selected at a longer value e.g.
1.5 seconds, or the ratio between the transmission time interval Ta and the request processing time interval Tb may be selected at a value other than that of equality.
Operation with regard to the control of the data devices by control data issued from the central processing unit and with regard to the supply to the central processing unit of data collected by said devices will now be explained with the aid of
Figure 7.
Referring to Figure 7, assume that items A, B, C of control data for the devices 4 coupled to the terminal units 6 are delivered from the central processing unit 1 through the request control interface 10 to the processor 9, and are written thereby at given address storage locations in the control data memories OUT.1, OUT.2, OUT.3 of the MFDB, during a request processing time interval Tb-1. The control data is then transmitted from the transmission control interface 11 during a next transmission time interval Ta-2. The transmission control interface 1 4 of the terminal unit LS.1 picks up the control data A from the control data memory OUT.1, and the received control data A is stored by the processor 1 3 in a given address storage location in the LFDB.The control data items of the frames OUT.2, OUT.3 are allowed to pass through the terminal unit LS.1.
During this time, the control data for the device 4 is delivered from the field interface 15, and data is collected from the device 4, thereby performing sampling. Likewise, the terminal units LS.2, LS.3 successively receive the control data B, C from the control data memories OUT.2, OUT.3 and store the control data in their LFDBs. Sampling operation is performed between the terminal units and their devices in a period other than their own data frames. In the frame IN.1 after the frame
OUT.3, the transmission control interface 1 4 in the terminal unit LS.1 delivers the collected data from the LFDB thereof. Likewise, the terminal units
LS.2, LS.3 deliver their own collected data successively during the frames IN.2, IN.3.The terminal units effect sampling with the devices 4 after all items of collected data have been delivered and before a request processing time interval TB-2 and their own frames OUT in a following transmission time interval TA-3. During this time, the devices 4 are controlled by the control data items A, B, C, respectively, and newly collected data items A', B', C' are stored in the
LFDBs of the terminal units LS.1, LS.2, LS.3.
Thereafter, control data in the frames OUT. 1,
OUT.2, OUT.3 is collected by the LFDB of each terminal unit during the transmission time interval
Ta-3, and the collected data in the LFDB is delivered in the frames IN.1, IN.2, IN.3. The collected data A', B', C' is transmitted which serves to confirm the control data A, B, C, and is stored in the MFDB. In a next request processing time interval TB-3, the collected data A', B', C' is supplied to the central processing unit 1 in response to a request from the latter, thereby confirming the control data A, B, C. The period of time in which one set of control data is delivered and confirmed, that is, the processing time, is about 3 seconds as a maximum.For simply obtaining collected data, such updated data can be gathered in the request processing time interval Tb-l, or in the next request processing time interval TB-2 at the latest, so that the processing time will be shorter, being one second as a maximum.
The present invention has the advantage that it enables a large number of terminal units to each of which a large number of instruments, detectors or other data devices are connected, to be connected in series. This greatly reduces the number of transmission lines needed. It also enables additional terminal units to be easily inserted in the series of terminal units after a system in accordance with the invention has been set up. As will now be appreciated, the transmission control unit and the terminal units have data memories, and all control data and collected data in the memories are transmitted in a bit serial transmission mode within a predetermined transmission time interval. This has the advantage of securing uniform and simple transmission control. Since the memories store updated control data and collected data at all times, the terminal units can be standardised in their construction, resulting in economy of construction and good reliability. Furthermore, data can be processed at a high speed at the
request of the central processing unit. The central processing unit does not have to cope with each
request, and hence the working load on it is small.
The invention is not limited to the preferred embodiment hereinbefore illustrated and described, and many changes and modifications
may be made thereto without departing from the scope of the invention, as defined in the claims hereof.
Attention is directed to the specification accompanying our co-pending Application No.
(corresponding to Japanese Application
No. 173413/81 which describes related subject matter.
Claims (8)
1. A data transmission and processing system including a central processing unit; a transmission control unit connected thereto; a plurality of terminal units each having a data memory and each connected to data devices; means connecting said terminal units in series with said transmission control unit; and means for transmitting control data and collected data in the said memories in a bit serial mode in a predetermined unit time interval.
2. A data transmission system including: a central processing unit; a transmission control unit connected thereto and capable of transmitting and receiving data within the transmission portion of a predetermined unit time interval which includes a transmission time portion and a request time portion; a plurality of terminal units connected in series to said transmission control unit and each capable of transmitting and receiving data within said transmission time portion; a plurality of data devices connected to each terminal unit; a data memory in each terminal unit for storing control data from said central processing unit and collected data from the devices connected thereto; a data memory in said transmission control unit for storing the content of the data memories in the terminal units; and means for transmitting control data in the data memory in the transmission control unit to each terminal unit and collected data in the data memory in each terminal unit to the transmission control unit in the transmission time portion, control data being delivered from the central processing unit to the transmission control unit and requested collected data being delivered from said transmission control unit in the said request time portion.
3. A system as claimed in claim 1 or 2 wherein the transmission time unit is one second.
4. A system as claimed in any of the preceding claims wherein the transmission time unit is divided into two halves of which the first is a transmission time portion and the second is a request time portion.
5. A system as claimed in any of the preceding claims and having a transmission control unit substantially as herein described with reference to
Figure 2.
6. A system as claimed in any of the preceding claims and having terminal units substantially as herein described with reference to Figure 3.
7. A system as claimed in any of the preceding claims wherein the transmission control unit and the terminal units are constructed and arranged substantially as herein described with reference to
Figure 4.
8. Data transmission and processing systems substantially as herein described with reference to
Figure 1 of the accompanying drawings and constructed to operate substantially as herein described with reference to Figures 5 and 6.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17233281A JPS5873260A (en) | 1981-10-28 | 1981-10-28 | Data transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2111271A true GB2111271A (en) | 1983-06-29 |
Family
ID=15939934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08230489A Withdrawn GB2111271A (en) | 1981-10-28 | 1982-10-26 | Data transmission and processing systems |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5873260A (en) |
| GB (1) | GB2111271A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0166402A2 (en) * | 1984-06-25 | 1986-01-02 | Allen-Bradley Company | Input/output system for an industrial control system |
| EP0416235A2 (en) * | 1989-09-05 | 1991-03-13 | Mitsubishi Denki Kabushiki Kaisha | Data-communication method for loop-type network having portable slave stations connectable to addressable junction boxes permanently connected in the network |
| FR2671213A1 (en) * | 1991-01-02 | 1992-07-03 | Alcatel Espace | INSTALLATION, ON BOARD ON A SATELLITE, FOR DIGITAL DATA COLLECTION. |
| EP0380680B1 (en) * | 1988-05-17 | 1996-03-06 | Kabushiki Kaisha Komatsu Seisakusho | Series controller |
| EP1531440A2 (en) * | 2003-11-13 | 2005-05-18 | Pioneer Corporation | Data collecting system and data transmitting method |
| WO2006053567A2 (en) * | 2004-11-18 | 2006-05-26 | Nesa A/S | Compensation of simple fiberoptic faraday effect sensors |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4681346A (en) * | 1984-12-12 | 1987-07-21 | Toyota Jidosha Kabushiki Kaisha | Automatically fastening seatbelt assembly |
| US4682790A (en) * | 1985-03-29 | 1987-07-28 | Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho | Webbing retaining structure |
| JPS62117006A (en) * | 1985-11-18 | 1987-05-28 | Omron Tateisi Electronics Co | Programmable controller |
| JPS63150703A (en) * | 1986-12-16 | 1988-06-23 | Fuji Electric Co Ltd | Transmission equipment for programmable controller |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5828974B2 (en) * | 1977-01-25 | 1983-06-20 | 東京電力株式会社 | Data transmission method |
-
1981
- 1981-10-28 JP JP17233281A patent/JPS5873260A/en active Pending
-
1982
- 1982-10-26 GB GB08230489A patent/GB2111271A/en not_active Withdrawn
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0166402A2 (en) * | 1984-06-25 | 1986-01-02 | Allen-Bradley Company | Input/output system for an industrial control system |
| EP0166402A3 (en) * | 1984-06-25 | 1988-04-27 | Allen-Bradley Company | Input/output system for an industrial control system |
| EP0380680B1 (en) * | 1988-05-17 | 1996-03-06 | Kabushiki Kaisha Komatsu Seisakusho | Series controller |
| EP0416235A2 (en) * | 1989-09-05 | 1991-03-13 | Mitsubishi Denki Kabushiki Kaisha | Data-communication method for loop-type network having portable slave stations connectable to addressable junction boxes permanently connected in the network |
| EP0416235B1 (en) * | 1989-09-05 | 1997-02-26 | Mitsubishi Denki Kabushiki Kaisha | Data-communication method for loop-type network having portable slave stations connectable to addressable junction boxes permanently connected in the network |
| FR2671213A1 (en) * | 1991-01-02 | 1992-07-03 | Alcatel Espace | INSTALLATION, ON BOARD ON A SATELLITE, FOR DIGITAL DATA COLLECTION. |
| EP0494018A1 (en) * | 1991-01-02 | 1992-07-08 | Alcatel Espace | Satellite borne installation for collecting digital data |
| EP1531440A2 (en) * | 2003-11-13 | 2005-05-18 | Pioneer Corporation | Data collecting system and data transmitting method |
| EP1531440A3 (en) * | 2003-11-13 | 2006-08-16 | Pioneer Corporation | Data collecting system and data transmitting method |
| WO2006053567A2 (en) * | 2004-11-18 | 2006-05-26 | Nesa A/S | Compensation of simple fiberoptic faraday effect sensors |
| WO2006053567A3 (en) * | 2004-11-18 | 2007-11-01 | Nesa As | Compensation of simple fiberoptic faraday effect sensors |
| US9247402B2 (en) | 2004-11-18 | 2016-01-26 | Powersense A/S | Compensation of simple fiber optic Faraday effect sensors |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5873260A (en) | 1983-05-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |