REDUNDANT CONTROL SYSTEM FOR AUTOMATIC FORMING MACHINE

Abstract: A data processor control system (10) for controlling a machine (30) that performs various events repetitiously and sequentially at a high rate of speed.

Description: REDUNDANT CONTROL SYSTEM FOR AUTOMATIC FORMING MACHINE DESCRIPTION Technical Field The present invention relates generally to control systems for controlling various events that are performed repetitively and sequentially to manufacture large numbers of discrete products. Background Prior Art The use of computers for controlling sequences of events within a machine cycle has become common in the past decade. In the container manufacturing art, it is critical that various events in the manufacturing process be repetitive at exactly the same time to insure that the individual discrete containers are identical in every respect. The foregoing events are repetitive at a high rate of speed and it is necessary that the applicable control system provide accurate defined control of each event or function. For example, data processor control systems have been applied to a glassware- forming machine wherein a number of high speed repetitive sequence of events are necessary during each glass-forming machine cycle. A most common type of glass-forming machine is what is referred to as the Hartford I.S. Machine. In the Hartford I.S. Machine, molten glass or hot glass gobs are delivered from a feeder through a distribution system and are delivered to a plurality of independent sections sequentially into upwardly opening blank molds in each of the sections. Each mold section is a self-contained unit which includes a blank molding station and a blow molding station. The molten gob of glass is sequentially delivered to each section of the machine and is transformed into a finished bottle in two stages, respectively, in the blank molding station and in the blow molding station. Each bottle-forming section of the glassware-forming machine is identical in construction and the sequence of events for each section must be accurately controlled on a repetitive basis for each section. In the early I.S. machines, the various sequence of events were controlled by a continuously- rotating drum that had a plurality of cams at different angular points on the drum which cooperated with mechanisms that, in turn, controlled valves which supplied fluid (such as air) to various pneumatic devices that actually perform the functions or events in the desired sequence. The details of such a system and the various events that are controlled are disclosed in for example, U.S. Patent No. 3,171,729 to Andersen. More recently, numerous prior art approaches to automation with computer control of glassware-forming machines have been proposed and such control systems are exemplified in U.S. Patents Nos . 3,905,793; 3,969,703; 4,402,701. An essential common parameter in each of the prior art approaches is the utilization of a means associated with the I.S. machines to obtain timing pulses as a function of the exact position of the given machine section in its normal cycle of operation. Further development of the control systems for glassware-forming machinery resulted in considerable enhancement of the capabilities of the machine and increased productivity along with more accurate control of the various parameters. However, actual incorporation of computers or data processing system into a glassware making machine environment has presented a very real problem in that the data processor control system is susceptible to malfunction or breakdown. In high volume operations, such as the glassware making machine wherein a number of independent sections comprise a machine, a malfunction or breakdown of the data processing control system is very damaging; that is, the entire glass timing will be stopped causing numerous problems and expense. Accordingly, the prior art has disclosed systems for providing distributive data processor control systems wherein a plurality of individual data processor control systems individually control the independent sections. It is also known in the prior art to provide a system including a first or operating computer, and second or stand-by computer, the second or stand-by computer is adapted to be connected to be in-line or in an operating mode should the first computer malfunction or become disabled. In this respect, reference is made to U.S. Patent 3,303,474 discussed herein below, and incorporated herein by reference, which appears to be the closest known art. Summary of the Invention The present invention provides a redundant data processor control system for a glassware forming system which provides a high degree of protection against breakdown or malfunction of the control system. In the present inventive system, two data processors are utilized and both processors are operating concurrently; however, only the output of one data processor is utilized to control the system at any given time. Hence, an operator can continually monitor the operating condition of both processors. It is important to note that both processors are actively operating to provide control outputs, but as mentioned above, only the output of one processor is coupled to the machine or machines to be controlled. Brief Description of Several Views of Drawings The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed hereinbelow, are useful in explaining the invention wherein: The sole FIGURE is a block diagram illustrating the inventive control system. Detailed Description The inventive control system 10 comprises a supervisor subsystem 11 which controls both the bottle forming functions of one or more IS machines having multiple sections, and the machine data terminals. The supervisor subsystem 11 includes a supervisor processor 15 such as for example, such as an DEC Miσro-11 computer (manufactured by Digital Equipment Corp.) which provides intelligence to the control processor subsystem 12 and controls 5 communication with the other components of the supervisor subsystem. When machine setup or timing functions are to be changed, the supervisor subsystem 11 translates the changes into a format acceptable by the central 0 processing subsystem 12 and then communicates this information to a control or central processors or .computers 17A and 17B. Product data information is also controlled by the supervisor subsystem 11 so 5 that the user can create and maintain job setup information and product timing files. Active product files and all current timing information is stored on the system disks generally labeled 18. The system printer 19 ° provides hard copy of the data in video screens are selected and generates selected reports. The printer provides a permanent record of all management information reports and may also be used for hard copy output of video screen 5 information from the supervisors console terminal 14, such as a TI 820 (manufactured by Texas Instrument Co.) receiver terminal or similar device. The operators terminals, generally 0 labeled 16, serve as consoles for the processor 15. These units may be a DEC VT 102 video terminal (manufactured by Digital Equipment Corp.) or similar device. The operator terminals 16 allows the operator to accomplish job changes and to run the product timing functions and change them as required. The operator is also provided with a set of real time reports which allow him to monitor the performance of the machine. The control subsystem 12 provides real-time control of the I/S glassware forming machines and also provides data acquisition for machine functions which data may be included in various reports. The control processors 17A and 17B receive information/data from the supervisor subsystem 11 through suitable memory (RAM) boards generally labeled 21 and incorporates the data into the active control programs or into the machine timing tables as appropriate. The control programs provide the necessary coordination of control to operate each section of the I/S machines generally labeled 30. It should be appreciated that the control system shown in FIG. 1 can be utilized to control one or more machines. During operation, the control program obtains information from each I/S machine as to the exact operating position or status of that I/S machine. This information is then transmitted through a suitable known cable splitter board 26 to the respective associated machine interface module 25. Information or data from supervisor subsystem 11 is concurrently received. Such input information may include machine operational data for reports and status or it may be a request for a special cycle initiated by the operator. These functions are executed asynchronously by the control processors 17A and 17B using user modifiable subprograms. The timing signals for the control processors 17A and 17B may be provided as by a timing pulse transducer 32, such as a shaft encoder of any suitable known type which is mechanically driven from the shear cam shaft on the I.S. machine. For example, a shaft encoder can provide position indicating pulses at one degree intervals and a reset pulse at zero degrees. The control subsystem 12 is fully redundant to insure continuity of control in the event of equipment failure. The two identical control processors 17A and 17B, are connected or coupled in the circuit and simultaneously or concurrently execute the control software program. Processor 17A is termed the connected or in-line processor and the processor 11B is termed the redundant processor. Processor 17B might be considered as the stand-by processor, however it should be understood that both processors 17A and 17B are concurrently executing the same program and commands. However, the output from only one of the processors is electrically connected to the system, as indicated at 22A. It should be understood that the 22A electrically may consist of an electronic switch means as is well-known. The output from the other processor, as at 22B, is disconnected. In operation, the status of each of processors 17A and 17B is monitored on each I/O cycle such as by well-known watch dog timers 28A and 28B; and, if a fault is detected in the coupled or connected processor, that processor is automatically uncoupled or disconnected and the other processor is automatically coupled or connected to the respective line interface unit 23A or 23B. Also, each of the control processors 17A and 17B may include electronic switching controls 20A and 20B of any suitable known type to connect and disconnect the associated control processors from the data control paths. The electronic switching control means 20A include temperature sensors, and voltage sensors which provide an indication of the operating condition of the particular processor 17A and 17B. As stated above, both processors 17A and 17B are operating concurrently and in synchronism, an the operating condition of both processors is continually being monitored. Note that both processors 17A and 17B are normally in operation, neither processor is on a .standby mode. Assume for example that an associated sensor indicates that the temperature in the non-connected processor 17B has increased above a safe limit. An indication is visually provided of the malfunctioning non-connected processor which may then be repaired or adjusted to return to proper operating condition. Details of sensor switching circuits are well-known in the art. Likewise if a malfunction is sensed in the connected processor 17A, the switching control means 20 disconnects or opens, and also the watch dog timer 28A cause electronic switch 20A to open and the output of central processor 17A is thus disconnected from the circuit. Also, switching control means 20A causes switching control means 20B and watch dog timer 28B also closes electronic swtich 22B and thus the output of central processor 17B is connected to the glassware forming machine or machines 30 without interrupting the operation of the machines. As mentioned above, it is known in the art to provide an operating computer and a stand-by computer to assume control if the operating computer malfunctions. Also, U.S. Patent No. 3,303,472 discloses a duplexing system for controlling on-line and stand-by conditions of two computers with on computer operating on an on-line program and the other computer operating on a stand-by program. However, in patent 3,303,472, it appears that if the stand-by computer for some reason is not operating properly for the on-line condition, this may not be known. Accordingly, if the on- line computer malfunctions, and then when the stand-by computer is coupled to operate on the on-line mode, it may not adequately perform and the entire manufacturing line being controlled may be stopped or cut-off. In contrast to the foregoing, in the data processing system of the present invention, both processors or computers are operating simultaneously in an identical mode and both computers are being continually monitored. This provides improved reliability that the data processing system will continue to operate the associated manufacturing or glassware forming machine if one or the other of the control processors malfunctions or is disabled. The line interface units 23A and 23B are coupled through a cable splitter board 26, to the machine interface modules generally labeled 25. The line interface units 23A and 23B each transmits and receives data. However, as noted above, only one of the line interface units 23A and 23B is coupled into the control path at any one time. The machine interface module 25 converts the parallel communications from the line interface 23A or 23B units into control signals and distributes these signals into the I.S. machines 30. ' While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims: CLAIMS 1. A glassware forming machine having machine components operating in a repetitive process and in which a plurality of machine events take place during different phases of the machine cycle of operation, said machine including a data processing control system comprising a first control processor means, a second control processor means, means for generating electrical pulses representative of the instantaneous relative position of said machine cycle, means coupling said pulses to both said control processor means, program storage means for storing control data including the cycle position at which specific machine events are to occur, means for coupling said control data to both said processor means, said first control processor means and said second control processor being coup_ed to simultaneously operate in a similar mode to provide identical respective outputs to control said machine components, and switch means utilizing the output only one of said control processor means at any one time to controllably actuate said machine components 2. A system as in Claim 1 including means for selectrively disconnecting the output of one control processor means to said machine as the output of the other control processor means is connected to control said machine components. 3. A system as in Claim 1 wherein said switch means include interconnecting means coupling said first control processor means to said second control processor means, said interconnecting means being responsive to the operation of said control processor means, said switch means for said first control processor means being normally in an ON condition, said switch means for said second control processor means being normally in an OFF condition, said second control processor means operating concurrently and synchronously with said first control processor means, and said interconnecting means being energized to activate said switch means when said first control processor means malfunctions to open said normally ON switch means to effectively disconnect the output lines of said first control processor means to said interface and close said OFF switch means whereby operation of said machine by said second control processor means is initiated without interruption of said machine functions. 4. A system as in Claim 1 wherein system includes a watchdog timer to monitor program errors and equipment fault. 5. A system as in Claim 1 further including respective sensors for monitoring the status of each of said control processor means. 6. A data processing control system for a machine including machine components operating in a repetitive process and in which a plurality of machine events take place during different phases of the machine cycle of operation, said system comprising in combination, a first control processor means, a redundant control processor means, said control processor means and said redundant processor means being coupled to simultaneously operate in a similar mode to provide identical respective outputs to control the associated machine components, means for generating electrical pulses representative of the instantaneous relative position of said machine cycle, means coupling said pulses to said control processor means, program storage means for storing control data including the cycle position at which specific machine events are to occur, means for periodically electronically scanning the storage means to provide said control data to said control processor means, and switch means connecting the output of only one of said control processor to said machine components at any one time.

Inventors: BISHOP WILLIAM B, OFTELIE DAVID C, SELEP VICTORIA M, BISHOP, WILLIAM, B., OFTELIE, DAVID, C., SELEP, VICTORIA, M.
Applicants: NAT CAN CORP, NATIONAL CAN CORPORATION
Application year: 1986
Main classification: G06F11
IPC codes: C03B9, G05B19, G06F11