IES940031A2 - A process control system - Google Patents

Abstract

A process control system (1) has an automatic workstation 5 (25) which is driven directly from a flag file (5) to a databank (2). A pre-processor (7) automatically updates the flag files (5). The first workstation (25) generates command signals in an efficient manner by direct access to the flag file (5) and operations sequences are efficiently 10 s

Description

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................. The invention relates to a system for process control whereby several different workstations or operations devices generally are controlled to carry out tasks for completion of jobs or processes. An example of the operations carried out may be the linking of communication nodes in either a local or a wide area network. Various operations associated with a particular process in this case may include the printing of documents, the automatic interconnection of communication nodes, the output of screen displays or tracking various operations. The invention relates in particular to process control where the operations carried out at each workstation are carried out in batch sequences, and an example is the automatic moulding of casings for electronic devices.

Where there are several different workstations, each carrying out its own set of tasks in sequence, these tasks being related, it is very important to ensure that failure of one workstation does not cause disruption of the other workstations. The invention is thus directed towards providing a process control system whereby although each workstation is driven by command instructions related to a common set of data records, the command instructions for different workstations are isolated from each other as much as possible to ensure that failures are localised.

It is another object of the invention to provide for a fast response when command instructions are requested for activation of a particular workstation and a related object is that data processing for generation of command instructions be carried out efficiently.

British Patent Specification No. GB 1,429,467 (Chubb) describes a system for transaction control. As is clear from Fig. 1 of this specification, the various items of r 040031 ~ equipment such as an enciphering unit, a modem, a printer, a tape reader, a recognition unit are all interconnected in a permanent manner to provide control instructions. While such a system is apparently quite efficient, it does not appear that it would be particularly versatile in that it would be difficult to adapt the system for different workstation control uses. Further, it appears that there would be difficulty in providing versatility in the manner in which the workstations are controlled for particular processes .

According to the invention, there is provided a process control system comprising : at least one automatic workstation constructed to be driven by control signals generated from a sequence of data records; a video controller connected to a video screen for outputting data according to viewing templates for data records; a printing/communications workstation connected to a data retrieval processor constructed to generate command signals for the workstation; a databank comprising a plurality of data files, each file comprising a plurality of records, records of different files being linked in hardware by interconnected data and address buses and in software by a microprocessor identifying relational fields within the records; - 940031 Ζ a pre-processor constructed for automatic retrieval of data from records within the databank and for generation and storage of a flag file comprising a plurality of records, each record having a set of flag values being related to a plurality of other records within the databank to provide data relating to an individual process to be carried out by the process control system; a command signal generator connected for reception of flag file inputs and connected to the automatic workstation for transmission of command signals for the automatic workstation; a digital filter connected to the databank for filtration of data records; a primary allocation processor for reception of the output of the filter and generation of an extraction file for a second workstation, records not written to the extraction file being transmitted to a secondary allocation processor constructed to monitor the filtered records to create a secondary extraction file in which records are grouped into a current dataset and a future dataset, said video controller and retrieval processor being connected to the secondary extraction file;and a databank update circuit comprising means for reception of interactive inputs from the workstations for updating records within the databank. k 0 0 3 i 3 In one embodiment, the databank update circuit comprises: means for retrieving each of a plurality of master data records from the databank; means for determining storage device locations for a process update field within each master data record; means for carrying out read and write operations to effectively shift all data values within the locations of the field in one direction; and means for writing a current parameter value to the first memory location.

Ideally, the filter is constructed for automatically retrieving parameter values from pre-set sequences of the locations in the process update field of the master records to determine filtration thresholds.

In another embodiment, the first workstation comprises a command signal generator for generation of command signals on one output line and interface signals on another output line, said signals being generated from a sequence of data records retrieved from the flag file of the databank, the signals on the two output lines being synchronised together, and wherein the first workstation further comprises an emulator connected to a feedback interface for automatic updating of relevant records within the databank while in emulation mode, and also for automatic modification of the command signals according to the feedback. 940031 - 5 Preferably, the system further comprises a data processor for automatically updating a workstation driver field within a plurality of data records, the values being written to the workstation driver field being associated with sequences for operation of the workstation, and wherein the first workstation comprises means for reading the field value and writing the value to a sequence if a sequence already exists, or alternatively creating a new sequence if one does not already exist, and means for generating command signals according to each sequence of records .

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings in which :Fig. 1 is a diagram showing a process control system of the invention; Fig. 2 is a diagram showing the manner in which memory device locations are utilised for fast retrieval of data to indicate job status; Fig. 3 is a diagram showing synchronisation and emulation features of a workstation; and Fig. 4 is a diagram showing the manner in which a workstation is driven for sequential operations.

A process control system 1 is shown in Fig. 1. In this diagram, various arrows are used to indicate the data and command instruction flows between parts of the system 1.

At the core of the system 1, there is a data bank 2 having hundreds of data files, each containing many records. The 940031 - 6 files are interconnected by relational links 3 formed by address and data buses connected to a microprocessor operating according to various parameters linking the records. The files may be broken down into a group of data files 4 including a master file for each job. In this specification, the terms job and process refer to processes which are carried out by the process control system 1, each process comprising a number of operations carried out by different workstations forming part of the system 1. Indeed, a particular job or process may involve a set of, say, four workstations carrying out operations over a prolonged period of time.

There is a set of flag files 5 in the general case and in the particular case illustrated there is only a single flag file 5, construction of which is described below. Finally, there is a set of process history files 6. Data relating to each job or process is stored in a large number of records and files of the databank 2, the records being linked by relational fields. This provides for easy expandability and also for versatility in retrieval of data .

The system 1 also comprises a pre-processor 7 which operates primarily to process the data files 4 and to monitor the value of fields within the data files and to automatically determine a flag value for associated records within the flag file 5. The generated flag values are written to the flag records on the file 5. A processor 7 usually operates in batch mode before the carrying out of the major processing for updating of the system 1.

The system 1 also comprises a digital filter 10 which operates according to two different sets of criteria. The first set is a set of hard-coded filtration parameter 940031 - Ί values which indicate the memory locations to be read by the microprocessor in order to determine flag and data values from records which are retrieved from the databank 2. The other set of criteria is a set of variable inputs which are freshly stored before each batch process of the system 1 and these relate to the manner in which filtration should be carried out. In other words, the fixed inputs determine which data or flag values are to be filtered and the variable inputs define the threshold values for any particular batch process of the system 1. A primary allocation processor 11 receives the output of the filter 10 and generates two different files. The first file which is generated is an extraction file 13 which comprises a set of records from which command instructions are generated for operation of a workstation 14. A major aspect of operation of the system 1 is outputting a set of records from which command signals may be generated for operation of a particular workstation. Most of the workstations of the system 1 operate in sequential mode whereby the operations which are carried out are repetitive, being similar in nature for each data record in succession. What is important is that the system 1 provides the correct records for each workstation at the correct time. The primary allocation processor 11 also automatically provides feedback signals 12 to the databank 2. In particular, the feedback signals are routed directly to the flag file 5 so that the flag files may be reset according to the extraction file generated, in addition, however, the data files 4 may also be updated. Records which are not written to the extraction file 13 are automatically written to a secondary allocation processor 16 which carries out further processing of the records according to the filtration output. These records are used in generation of an extraction file 17 having records grouped into a current data set 18 and another set into a future data set 19. 940031 ί Records in both data sets are broadly similar in that they are required for generation of command signals for workstations which are not necessarily automatic in operation and may be networks for outputting of data on paper, tape, disk and/or video screens. Such data is retrieved by a retrieval processor 22 which generates command signals for a workstation 23 which may, for example, be a printer. However, a primary aspect of the extraction file 17 is that a video controller 20 which is constructed for viewing of certain fields of the records provides signals for a video screen user interface 21. While these particular outputs are not automated and do not directly carry out physical operations, they do provide instructions for personnel to carry out certain tasks which are of necessity manual. A typical example is a set of instructions of a quality control inspector for monitoring output of various workstations according to statistical analysis.

An important feature of the system 1 is the manner in which feedback is provided from various workstations . The screen 21 and the workstation 23 provide data which is used for interactive inputting by users using an interface 24. The feedback signals are indicated by the numeral 27. However, in addition, automatic feedback is provided on a signal line 15 from the workstation 14 connected directly to the databank 2. Finally, the system 1 comprises an automatic workstation 25 for automatic carrying out a sequence of tasks, each task being driven from an individual data record. An important aspect of operation of the workstation 25 is that records are retrieved directly from the flag file 5 which has been updated by the pre-processor 7 .

Referring now to Figs. 2 to 4 inclusive, various aspects of the system 1 are now described in more detail. In Fig. ί Η 3 1 '3 2, there is shown the manner in which the data files 4 are updated either automatically on the signal lines 15 and 26, or using interactive inputs 27. Each master record has at least one field 20 which is a mapped set of memory locations on magnetic disks for reception of data or dates. As each master record relates to a particular job which may take place over a lengthy period of time, the recordal of data updates is extremely important. An operations parameter value 30 is inputted and is written to Byte 0 of the field 28 and is indicated by the arrows 31, and each parameter value is written to the next successive memory location Byte 0,1,2, ..... n. This is a very simple feature and involves relatively few read/write operations to a set of memory locations each time it is carried out. It has the major advantage in that every time the master file 4 is accessed to retrieve a current operations parameter value, the processor reads Byte 0 to obtain the correct value. In addition, where process status information is required, the processor as indicated by the arrow 32 reads any desired set of the Bytes 29 to retrieve a pattern of parameter values indicative of status of the process over the period of time represented by those Bytes. A data retrieval processor 33 performs these operations. It will be appreciated that while this is a very simple feature, it does provide extremely fast retrieval of data both for updates of current status, and also for status of a process in general over a period of time.

Another important aspect of the system 1 is the manner in which the automatic workstation 25 operates. The workstation 25 as indicated in Fig. 3 comprises a command signal generator 40 which automatically generates command signals according to the data records which are retrieved directly from the flag file 5, and possibly from other linked files, where necessary. There are two parallel λ η η 3 ί - 10 outputs from the command signal generator 40. These are a machine control signal output 42 and a machine interface output 43. These outputs are synchronised so that the interface simultaneously prints or displays information representing a control signal being outputted on the line 42. Where the automatic workstation is for the interconnection of communication nodes, the signals on the line 42 perform the actual switching operations, while the interface line 43 provides information to an operator as to which communication nodes are being connected. Feedback may be provided on a line 44 and this feedback may be either manually or automatically generated, depending on which output line 42 or 43 it is in response to. An important aspect of the feedback line 44 is that it is directly connected to an emulator 41 forming part of the workstation 25. The emulator 41 allows direct routing of the feedback signals to the databank 2 so that not only is the workstation 25 updated so that it can where necessary modify the command instructions, but in addition, the databank 2 is updated on-line. This is important as the databank 2 forms the core of the system 1.

Regarding the manner in which the command signals are generated on the line 42, reference is now made to Fig. 4. The data records which are downloaded from the databank 2 are indicated by the numeral 50 in Fig. 4 and each record 50 includes a workstation driver field 51. The driver field is a set field within each record to which a value is written by a data processor 52 before the activation of the workstation 25. The data processor 52 may be easily configured interactively by a user to write different values to the field 51 according to various criteria in processing of the records 50. ζ η Μ ι - 11 The flow chart 55 of Fig. 4 shows the manner in which the workstation 25 uses the value of the field 51 to generate command sequences. The field value is read in step 56 and in step 57 the workstation command signal generator determines if a sequence already exists for that particular value. If so, in step 58, the command signal generator 40 writes the record to the sequence. However, if the sequence does not exist, the generator 40 creates a new sequence and writes the record to it. As indicated by the decision step 60, this set of operations is repeated for each field value 56 which is downloaded from the databank 2. In the step 61, the workstation 25 operates according to command signals generated from each sequence of data records. As indicated by the decision step 62, operations of the workstation 25 are ended when all sequences have been used for generation of command sequences. However, if there is another sequence of data records, further command signals are generated and the workstation 25 continues to operate.

It will be appreciated that the invention provides for separation of command signal and data flows for different workstations in the manner which provides reliability by virtue of the fact that the signal and data flows are isolated to a large extent. For example, the data and signal flows to the workstation 25 are directly from the flag file 5 with only a small amount of additional data being retrieved from other records in some instances. The workstation 14 is driven directly from an extraction file 13 wherein the screen 21 and the workstation 23 are driven by an activation file 17 generated from a separate secondary allocation processor 16. It has been found that by distributing the data flows in this manner, reliability is achieved. 940031 - 12 It has also been found that by updating the master records using the shifting operations described above, data may be retrieved very quickly for fast response times. This is particularly important where workstations are operating in real-time and command signals must be generated in realtime. The risk of data corruption is considerably reduced by the manner in which feedback signals 2 are provided in the vast majority of cases directly to the flag file 5. The combination of this feature with the relational nature of the various files associated with each process, minimises the risk of data corruption occurring.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims (5)

1. A process control system comprising : at least one automatic workstation constructed to be driven by control signals generated from a sequence of data records; a video controller connected to a video screen for outputting data according to viewing templates for data records; a printing/communications workstation connected to a data retrieval processor constructed to generate command signals for the workstation; a databank comprising a plurality of data files, each file comprising a plurality of records, records of different files being linked in hardware by interconnected data and address buses and in software by a microprocessor identifying relational fields within the records; a pre-processor constructed for automatic retrieval of data from records within the databank and for generation and storage of a flag file comprising a plurality of records, each record having a set of flag values being related to a plurality of other records within the databank to provide data relating to an individual process to be carried out by the process control system; 940031 7 a command signal generator connected for reception of flag file inputs and connected to the automatic workstation for transmission of command signals for the automatic workstation; a digital filter connected to the databank for filtration of data records; a primary allocation processor for reception of the output of the filter and generation of an extraction file for a second workstation, records not written to the extraction file being transmitted to a secondary allocation processor constructed to monitor the filtered records to create a secondary extraction file in which records are grouped into a current dataset and a future dataset, said video controller and retrieval processor being connected to the secondary extraction file;and a databank update circuit comprising means for reception of interactive inputs from the workstations for updating records within the databank. A system as claimed in claim 1, wherein the databank update circuit comprises: means for retrieving each of a plurality of master data records from the databank; means for determining storage device locations for a process update field within each master data record; 040031 3 means for carrying out read and write operations to effectively shift all data values within the locations of the field in one direction; and means for writing a current parameter value to the first memory location.

2. 3. A system as claimed in claim 2, wherein the filter is constructed for automatically retrieving parameter values from pre-set sequences of the locations in the process update field of the master records to determine filtration thresholds.

3. 4. A system as claimed in any preceding claim, wherein the first workstation comprises a command signal generator for generation of command signals on one output line and interface signals on another output line, said signals being generated from a sequence of data records retrieved from the flag file of the databank, the signals on the two output lines being synchronised together, and wherein the first workstation further comprises an emulator connected to a feedback interface for automatic updating of relevant records within the databank while in emulation mode, and also for automatic modification of the command signals according to the feedback, and preferably the system further comprises a system as claimed in claim 4 further comprising a data processor for automatically updating a workstation driver field within a plurality of data records, the values being written to the workstation driver field being associated with sequences for operation of the workstation, and wherein the first workstation $40031 - 16 comprises means for reading the field value and writing the value to a sequence if a sequence already exists, or alternatively creating a new sequence if one does not already exist, and means

4. 5 for generating command signals according to each sequence of records.

5. A system substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings .