GB2281132A - A process control method - Google Patents

A process control method Download PDF

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Publication number
GB2281132A
GB2281132A GB9316911A GB9316911A GB2281132A GB 2281132 A GB2281132 A GB 2281132A GB 9316911 A GB9316911 A GB 9316911A GB 9316911 A GB9316911 A GB 9316911A GB 2281132 A GB2281132 A GB 2281132A
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GB
United Kingdom
Prior art keywords
process controller
file
routing device
controller
host
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Withdrawn
Application number
GB9316911A
Other versions
GB9316911D0 (en
Inventor
Jack Walls
Dermod Ryan
Thomas O'dowd
Jack Mulvany
Nigel O'flaherty
David O'higgins
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DUNBAR Ltd
Original Assignee
DUNBAR Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by DUNBAR Ltd filed Critical DUNBAR Ltd
Priority to GB9316911A priority Critical patent/GB2281132A/en
Priority to BE9300877A priority patent/BE1005683A6/en
Publication of GB9316911D0 publication Critical patent/GB9316911D0/en
Publication of GB2281132A publication Critical patent/GB2281132A/en
Withdrawn legal-status Critical Current

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Classifications

    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00Programme-control systems
    • G05B19/02Programme-control systems electric
    • G05B19/418Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
    • G05B19/41865Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by job scheduling, process planning, material flow
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/31From computer integrated manufacturing till monitoring
    • G05B2219/31207Master sends global files to autonomous controllers, feedback of process status
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/31From computer integrated manufacturing till monitoring
    • G05B2219/31379Master monitors controllers, updates production progress, allocates resources
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/33Director till display
    • G05B2219/33182Uart, serial datatransmission, modem
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/02Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Quality & Reliability (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Control By Computers (AREA)

Abstract

A process control method carried out by a host process controller (2) and local process controllers (10, 11 and 12) is disclosed. The host process controller (2) generates a master file, and a sub-file associated with each process. The master file is transmitted initially to the relevant local process controller (10, 11 and 12). The local process controller automatically updates the file to indicate production progress. This includes updating a status code field for each record which indicates the production status of each individual product. The host process controller (2) receives allocation data via an input/output interface (3) and reads the file at periodic intervals to generate a temporary match table which includes allocation possibilities for end products to destinations. A permanent match table is generated after a pre-set time period and further input signals have been received to indicate desired matching. <IMAGE>

Description

"A Process Control Method" The invention relates to a process control method for a number of different processes carried out remotely. In particular, the invention relates to a process control method carried out by a single control system, although there may be other control systems for the processes. In the specification, the term "process control" means the partial or whole control and the monitoring of a process.
European patent specification no EP-B-33228 (Forney Int.
Inc.) describes a control system for an industrial process which includes remotely located control units, each coupled to an associated input/output device and adapted to communicate with one another through a dual channel communication link. In the system, one of the control units can assume supervisory control on a master-for-themoment basis with the other units. Thus, an integral part of the process control is that different controllers communicate with each other for control of the industrial process. There are some situations where control would not be practical such as where there are a number of controllers for a number of processes and the controllers have a largely monitoring function although they would also transmit control signals.
The invention is thus directed towards providing a process control method carried out by one of a number of possible control systems for remote processes, without the need for inter-communication.
Another object of the invention is that end products of the different processes are allocated to a correct destination in a flexible manner which takes account of disruptions in processes at any of the operations from the beginning of the processes to the end. This is to optimise the process resources.
According to the invention, there is provided a process control method carried out by a host process controller connected to a storage device, a routing device and to a bi-directional link connecting it to a set of input/output devices, the routing device being connected to a modulation/demodulation circuit for remote communication with a plurality of local process controllers linked to operation stations of an associated process, the method comprising steps of:: the host process controller generating and storing in a storage device a master file associated with the processes, the file having a plurality of records each associated with a product being produced by a process, wherein each record includes a status code field for storage of a status code indicating the current operation being performed in the process for that product, and a process identifier field; the host process controller reading process identifier fields and automatically generating sub-files of the master file, each associated with a particular process and transmitting the sub-file to the relevant local process controller via the routing device; the routing device writing the sub-file data to an associated storage device in parallel with re transmission to the relevant local process controller;; each local process controller continuously monitoring operations in the associated process and automatically updating the master file stored locally, and the master file stored at the host process controller via the routing device; the host process controller receiving allocation data from an input/output interface to indicate parameters for destinations of products being produced by the processes; at periodic time intervals, the host process controller carrying out a batch process comprising the steps of: retrieving parameter values from records associated with a set of products, retrieving the status codes for these records, and comparing the allocation data with this data in order to match an end product with a destination; feeding back signals to the relevant local process controllers to indicate allocation of products with destinations; and each local process controller controlling the associated process according to the feedback signals received.
In one embodiment, the host process controller allocates end products to destinations by carrying out the intermediate steps of: generating a temporary match file which includes a list of possible destinations for each end product selected according to essential and non essential parameter values of the associated record; and receiving signals from the input/output interfaces during a pre-set time period to cross-match the end products with destinations and subsequently generating a permanent match table according to valid selections.
Preferably, the host process controller communicates with the routing device in slave terminal emulation mode, and the communications circuit carries out parallel operations on the data in a non-invasive manner.
In another embodiment, the routing device comprises a programmable interpreter circuit and a random access memory circuit, and the method comprises the additional steps Df the communications device carrying out report generation operations according to criteria received and stored for the interpreter circuit.
In a further embodiment, the storage device connected to the routing device is dynamically partitioned into sections, there being a section associated with each process.
The invention will be more clearly understood from the following description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a diagram showing a number of processes and a process control apparatus of the invention; and Fig. 2 is a flow diagram showing a portion of a process control method of the invention.
Referring to the drawings, and initially to Fig. 1, a process control system 1 is shown for control of three remote processes, namely, process A, process 3, and process C. The processes are indicated generally by the numeral 2. The operation stations are indicated as Al, A2... Al; B1, B2... Bj; and C1, C2... Ck. The processes A, B and C have local process controllers 10, 11 and 12 respectively, each of Tich is connected by a bidirectional link 13, 14 and 15 respectively to the various operation stations.
The processes may be of any particular type and one example may be different car production processes, in which case the operation stations would include metal fabrication, engine installation, painting, chassis identifications, etc.
The controller 1 is located remotely from the processes and is provided for monitoring progress of each process, for transmitting the relevant control signals, and for allocating end products of the processes to different destinations such as purchasers of motor cars. The apparatus 1 thus has both a monitoring and a control function in that it not only monitors the progress of the process but also transmits control signals to control the manner in which the process is carried out so that supply meets demand as efficiently as possible. This is important for optimisation of process resources, and for the commercial objective of achieving customer satisfaction.
The process control system 1 comprises a host process controller 2 which has a single CPU operating at 1.9 MIPS and using a random access memory of 32 MB. There is a virtual memory capacity of 6 MB.
The process controller 2 is connected to user input/output interfaces 3 by a bi-directional link 4. The link 4 has 100 ports which are designated for communication with intelligent or slave processors, including printers. The controller 2 is programmed to activate an on-board emulation circuit which has the capability to communicate with an intelligent processor as if it where a slave device.
One of the interfaces 3 is an intelligent routing or communications device 6, which comprises an Intel 486 DXa processor operating at 25 Ez. The device 6 has 16 MB of on-board RAM and a 320 MB fixed disk 7. An important aspect of the invention is that the fixed disk is partitioned into several, Fn this case six, logical drives. Each of the drives is associated with one of the processes A, B and C, or with a separate processing function. This partitioning is dynamic because the processor assigns different sets of memory locations, depending on the extent of activity of the processes A, B and C.Another important feature is that the host process controller 2 in its emulation mode treats the device 6 as a slave terminal for communications, while transparently to the controller 2, the on-board processor has sole access to data on the fixed disk of the device 6. This limits the processing power required of the processor 2 by optimising use of processing capacity of the routing device 6 to change the data communicated with the controller 2 as appropriate.
The process controller 2 is connected to a bank 5 of fixed disks of 5 GB capacity. This stored data may only be accessed by the controller 2 because there is a direct connection by way of a link 8, and no circuits are provided for access by an interface 3, including the routing device 6. The bank 5 has a pre-set partition structure with set memory locations for each process A, B and C. This helps to ensure data access times are maintained as short as possible.
The system 1 is constructed to carry out a process control method which achieves the technical advantages of improved efficiency of the various processes, irrespective of the nature of the process, and efficient allocation of end products to their destinations with flexibility in the manner in which end products are allocated. The process controller 2 initially creates a master electronic data file with many records, there being one record for a product being produced by any of the processes. There is one electronic data file for all of the processes. The master file has a size in the range of 70 MB-80 MB, and there are 80,000 records. The three most important data fields in each record include: (a) a process identifier ie of process A, B, or C; (b) and end product identifier; and (c) a status code for the process.
The status code indicates the particular operation being carried out at the current point in real time. For example, the status code may indicate that a particular type of motor car is at stage A4 in the production process A. Initially, the fields for storage of the status codes are set to a default initial value.
The master file is stored on one partitioned section of the fixed disk bank 5. Subsequently, the controller 2 sorts the records into sub-files, there being one sub-file for each process. These operations are carried out according to field (a) above. The controller 2 then activates the emulation circuit to communicate via the device 6 with any or all of the local controllers 10, 11 and 12. Initially, each sub-file is transmitted to its associated local controller 10, 11 or 12. While doing this, the device 6 "transparently" to the controller 2 writs the data in parallel to its own fixed disk at the relevant logical drive.
During operation of a process the local controller 10, 11 or 12 automatically transmits update signals regarding the production operations to the sub-file stored locally and via a modem to the process controller 2 which, in turn updates the table in the storage device 5. The device 6 also updates its data records during the re-transmission operations. This is possible because the data transmitted is n "flat" format such as ASCII.
The important point is that the status code field is updated at a regular basis in real-time as the new operations are being carried out on the relevant product.
At regular intervals, the process controller 2 is activated by an input/output interface 3 to carry out a batch process. This process is illustrated in Fig. 2 and it involves in step 21 receiving allocation data at an interface 3 which includes values for parameters associated with the destination of the end product. The allocation data will specify required values for product parameters. For example, where the end product is a motor car, the allocation data for one particular end product would specify that the car must be of a particular make and colour, and engine size etc. Also in step 21, the process controller 2 reads the status code fields in a selected number of records. The records are selected according to the particular process involved.Finally, the step 21 involves the process controller 2 comparing the allocation data with the status code data and other data in the record from which the status codes are retrieved to generate a temporary match file in step 22.
The temporary match file is a file stored on the storage device 5 which indicates proposed end product destination allocations. These are selected according to the status codes and the record data and allocation data.
When carrying cut steps 21 and 22, the process controller 2 assigns each parameter value into essential and nonessential categories. For example, a record value for an end product would be an engine chassis number however, this would not be included in the allocation data as the end user is not interested in the engine chassis number and any number will suffice. However, an essential parameter value would be the colour of the car, which could not vary for the end user. On an on-going basis, signals are inputted at the input/output interfaces 3 to indicate cross-linking of end products with destinations in the temporary match file. This can only be done over a pre-set limited time period. Thus, the step 23 of generating a permanent match table is carried out by reference to both a real-time clock and the input signals which are received. In practice, for example, a car dealer may input a signal at an interface 3 to indicate that a certain motor car is to be allocated to a certain end user who is listed among the possibilities for that particular end product. This can only be done during a two-week time period.
The process controller 2 transmits feedback signals to the relevant local process controller 10, 11 or 12 in step 24 according to the structure of the permanent match table.
As before, these signals are trapped by the communications device 6, which updates its files as appropriate. These signals are used by the local process controllers to control the manner in which the operations are carried out and their sequence to ensure that the end products are delivered in a timely manner and in the correct order.
When the last of the operations Ai Bj or Ck has been carried out, this is signalled to the process controller 2 which automatically outputs an "allocation ready" signal via the input/output interface 3 to indicate that the processes as has been completed and the end product is ready for collection by the user.
The communications device 6 also includes a programmable interpreter circuit which Is constructed to sort all records in the master file according to variable criteria which may be inputted from another interface 3, or the keyboard of the device 6. Because of the very large random access memory capacity of the device 6, fast viewing of selected contents of the master file may take place. This is important in helping to provide information in the form of reports at an early stage regarding process status so that problems may be averted at an early stage. This processing work is of course carried out independently of the controller 2 and accordingly its operations are not delayed. Of course, the controller 2 communicates with the device 6 from time to time bypassing the emulation circuit to retrieve output files if these are required for use in process control.
The Invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims (6)

1. A process control method carried out by a host process controller connected to a storage device, a routing device and to a bi-directional link connecting it to a set of input/output devices, the routing device being connected to a modulation/demodulation circuit for remote communication with a plurality of local process controllers linked to operation stations of an associated process, the method comprising steps of:: the host process controller generating and storing in a storage device a master file associated with the processes, the file having a plurality of records each associated with a product being produced by a process, wherein each record includes a status code field for storage of a status code indicating the current operation being performed in the process for that product, and a process identifier field; the host process controller reading process identifier fields and automatically generating sub-files of the master file, each associated with a particular process and transmitting the sub-file to the relevant local process controller via the routing device; the routing device writing the sub-file data to an associated storage device in parallel with re transmission to the relevant local process controller;; each local process controller continuously monitoring operations in the associated process and automatically updating the master file stored locally, and the master file stored at the host process controller via the routing device; the host process controller receiving allocation data from an input/output interface to indicate parameters for destinations of products being produced by the processes; at periodic time intervals the host process controller carrying out a batch process comprising the steps of: retrieving parameter values from records associated with a set of products, retrieving the status codes for these records, and comparing the allocation data with this data in order to match an end product with a destination; feeding back signals to the relevant local process controllers to indicate allocation of products with destinations; and each local process controller controlling the associated process according to the feedback signals received.
2. A method as claimed in claim 1, wherein the host process controller allocates end products to destinations by carrying out the intermediate steps of: generating a temporary match file which includes a list of possible destinations for each end product selected according to essential and non essential parameter values of the associated record; and receiving signals from the input/output interfaces during a pre-set time period to cross-match the end products with destinations and subsequently generating a permanent match table according to valid selections.
3. A method as claimed in claims 1 or 2, wherein the host process controller communicates with the routing device in slave terminal emulation mode, and the communications circuit carries out parallel operations on the data in a non-invasive manner.
4. A method as claimed in any preceding claim, wherein the routing device comprises a programmable interpreter circuit and a random access memory circuit, and the method comprises the additional steps of the communications device carrying out report generation operations according to criteria received and stored for the interpreter circuit.
5. A method as claimed in any preceding claim, wherein the storage device connected to the routing device is dynamically partitioned into sections, there being a section associated with each process.
6. A method substantially as herein before described, with reference to and as illustrated in the accompanying drawings.
GB9316911A 1993-08-13 1993-08-13 A process control method Withdrawn GB2281132A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB9316911A GB2281132A (en) 1993-08-13 1993-08-13 A process control method
BE9300877A BE1005683A6 (en) 1993-08-13 1993-08-26 Process control method.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9316911A GB2281132A (en) 1993-08-13 1993-08-13 A process control method
BE9300877A BE1005683A6 (en) 1993-08-13 1993-08-26 Process control method.

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GB9316911D0 GB9316911D0 (en) 1993-09-29
GB2281132A true GB2281132A (en) 1995-02-22

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0740241A2 (en) * 1995-04-28 1996-10-30 Advanced Micro Devices, Inc. Control system for semiconductor spray process tools
WO2000036479A1 (en) * 1998-12-16 2000-06-22 Speedfam-Ipec Corporation An equipment virtual controller
EP1286289A3 (en) * 2001-08-10 2006-02-08 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US7797062B2 (en) 2001-08-10 2010-09-14 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US8417360B2 (en) 2001-08-10 2013-04-09 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US8914300B2 (en) 2001-08-10 2014-12-16 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US9729639B2 (en) 2001-08-10 2017-08-08 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0740241A2 (en) * 1995-04-28 1996-10-30 Advanced Micro Devices, Inc. Control system for semiconductor spray process tools
EP0740241A3 (en) * 1995-04-28 1998-08-12 Advanced Micro Devices, Inc. Control system for semiconductor spray process tools
WO2000036479A1 (en) * 1998-12-16 2000-06-22 Speedfam-Ipec Corporation An equipment virtual controller
EP1286289A3 (en) * 2001-08-10 2006-02-08 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US7797062B2 (en) 2001-08-10 2010-09-14 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US8126574B2 (en) 2001-08-10 2012-02-28 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US8417360B2 (en) 2001-08-10 2013-04-09 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US8914300B2 (en) 2001-08-10 2014-12-16 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US9729639B2 (en) 2001-08-10 2017-08-08 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US10581974B2 (en) 2001-08-10 2020-03-03 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization
US11507898B2 (en) 2001-08-10 2022-11-22 Rockwell Automation Technologies, Inc. System and method for dynamic multi-objective optimization of machine selection, integration and utilization

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Publication number Publication date
BE1005683A6 (en) 1993-12-14
GB9316911D0 (en) 1993-09-29

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