Note: Descriptions are shown in the official language in which they were submitted.
l~Z~
The present in~ention relates generally to machines for
forming glassware articles from gobs of molten glass and in
particular to electronically controlled individual section
glassware forming machines.
The individual section or IS glassware forming machine is
well known and includes a plurality of sections each having
means for forming glassware articles in a timed, predetermined
sequence of steps. Typically, the sections are fed from a
single source of molten glass which forms gobs of the molten
glass which gobs are distributed to the individual sections
in an ordered sequence. The sections are operated in synchron-
ism at a relative phase difference such that one section is
receiving a gob while another section is delivering a finished
glassware article to a conveyor and one or more other sections
are performing various ones of the intermediate forming steps.
The forming means in each section are typically operated
from pneumatic motors or actuators. In early prior art machines,
the pneumatic motors were controlled by a valve block which in
turn was controlled by a timing drum for each section driven
from a line shaft which synchronized all parts of the machine.
One of the limitations of the timing drum was the difficulty
of adjusting the timing during the operation of the machine.
One solution to this problem was to replace all the timing drums
with an electronic control means. The electronic control means
included a master unit which was responsive to a clock pulse
generator and a reset pulse generator driven by the line shaft.
The master unit generated reset signals to an individual control
circuit for each of the individual sections to synchronize the
operation of the individual circuits. Each individual circuit
included a pulse counter responsive to the clock pulses and the
master unit generated reset pulses for counting the degrees of
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the section cycle. Each individual circuit included forty-
eight, three-decade thumb-wheel switches for setting the degrees
of rotation of the machine thereon. Thus, each particular
function of the glassware forming cycle was controlled by one
of the thumb-wheel switches. Such a control system is dis-
closed in U.S. Patent No. 3,762,907.
The previously described electronic control system
utilized discrete components in its counter and gating circuit-
ry. In a later prior art control apparatus, a digital
computer with a memory and associated program storage was
utilized. Not only did such a control circuit provide a means
for automatically changing the timing values of the functions
without the manual resetting of thumb-wheel switches, but such
a circuit also provided a means for programming events, groups
of related functions, in accordance with certain boundary event
timings. The computer generated control signals through an
interface circuit to actuate solenoid controlled valve blocks.
Such a control system is disclosed in U. S. Patent No. 3,905,793.
The present invention concerns an electronic control
system for an individual section glassware forming machine.
The machine has means for forming gobs of molten glass, a
plurality of individual sections for forming glassware articles,
and means for feeding the gobs of molten glass to the
individual sections. Each of the individual sections includes
forming means for forming the glassware articles in a series
of predetermined forming steps in response to a plurality of
control signals. The machine also includes an electronic
control means for generating the control signals.
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The control means has a machine supervisory com-
puter connected to a plurality of inclividual section computers,
one for each of the individual sections of the machine. The
machine supervisory computer loads the individual section
computers with the control programs and timing data for forming
a particular glassware article. Each individual section
computer then generates the control signals required to
actuate the various forming mechanisms of the associated
section to perform glassware forming functions. A section
operator console is provided at each section to enable the
machine operator to change the on and off timing values for
any of the forming functions. The section operator console is
connected to the individual section computer which reads the
timing change value and replaces the corresponding previous
timing data with the new data.
A dwell value is associated with each machine function
and indicates that portion of a machine cycle between the on
and off timing values during which the particular machine
function is performed. A dwell reversal occurs when either
the on value is moved past the off value or the off value
is moved past the on value for a particular machine function.
A dwell reversal of a machine function could result in
mechanism collisions and disrupt the forming cycle. ~one of
the prior art devices included means for preventing a dwell
reversal. In accordance with the present invention, when an
operator desires to change a timing value, the respective
individual section computer automatically prevents a dwell
reversal from occurring and thus eliminates the problems
associated with a dwell reversal.
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It is an object of the present invention to increase
the efficiency of individual section glassware forming
machines by preventing dwell reversal of mechanism timing
values.
Embodiments of the invention will now be described
with reference to the accompanying drawings in which:
Fig. 1 is a simplified block diagram of an
individual section glassware forming machine and a control
system therefor to which the present invention is applicable;
Fig. 2 is a more detailed block diagram of the
control system and one of the individual sections of Fig. l;
Figs. 3 through 8 are simplified flow diagrams which
are representative of a portion of the programs run by the
machine supervisory computer of Fig. 2; and
Figs. 9 through 12 are simplified flow diagrams
which are representative of a portion of the programs run by
the individual section computer of Fig. 2.
There is shown in Fig. 1 a block diagram of an
individual section glassware forming machine and control
therefor to which the present invention is applicable. A
machine supervisory computer 11 receives a train of timing
pulses from a timing pulse generator 12 to establish the
timing for the machine cycle. The generator 12 typically
can be a shaft encoder or pulse generator.
The machine supervisory computer 11 is connected to
a plurality of individual section computers 13, one through
N, each of which is connected to an associated one of a
plurality of individual sections 14, one through N, of the
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glassware forming machine. Initially, the machine super-
visory computer 11 loads each individual section computer 13
with a control program and timing data for controlling the
associated individual section. Thereafter, each individual
section computer 13 generates control signals, in response to
the control program and timing pulses from the timing pulse
generator 12, to a valve block(not shown) in the associated
individual section 14 to control the glassware forming cycle.
The machine supervisory computer 11 periodically receives
current timing data from each of the individual section
computers 13 which data can be stored for use the next time
that particular type of glassware is to be formed or in the
event that one of the individual sections is shut down for any
reason.
Fig. 2 is a more detailed block diagram of the
control system and one of the individual sections of Fig. 1. The
timing pulse generator 12 generates a train of timing pulses
to the machine supervisory computer ~MSC) 11 and the individual
section computer (ISC) 13. An input/output device 15 and a data
storage device 16 are both connected to the machine supervisory
computer 11 by a pair of bidirectional lines. The machine supervis-
ory computer 11 and the individual section computer 13
typically can be LSI-II computers, the input/output device 15
typically can be a LA36 DECwriter teleprinter and the data
storage device typically can be a RXVll Floppy Disk Drive all
manufactured by the Digital Equipment Corporation of Maynard,
Massachusetts.
The timing pulse generator 12 generates a clock
signal to the MSC 11 and the ISC 13 which signal provides a
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a reference for timing the machine cycle and the sequence of
steps to be performed by the ISC. Typically, machine timing
is expressed in degrees and a machine cycle is 360 in length.
Thus, 360 clock pulses or some multiple thereof comprise one
machine cycle. The cycle for each individual section is also
360 but the cycles for all of the sections can be offset from
the start of the machine cycle by a different number of
degrees to compensate for the difference in gob delivery
time to each section. The timing pulse generator also
generates a reset signal after 360 of clock pulses which
reset signal is utilized by the MSC and the ISC to define the
end and beginning of successive machine cycles.
The MSC 11 is used to load the control programs and
timing data into the ISC 13 from the data storage device 16.
An operator uses the I/O device 15 to select the particular
timing data which is to be loaded into the ISC. It should be
noted that each ISC has a separate set of timing data for the
particular individual section which it controls.
The ISC 13 generates control signals to a valve block
17 through a section operator console discussed below. The
valve block is connected to a plurality of glassware forming
mechanisms 18 for actuating the forming mechanisms in a
predetermined timed sequence of steps to form the articles of
glassware. The valves in the valve block 17 are actuated by
solenoids (not shown) which are controlled by signals generated
by the ISC 13 in accordance with the control programs and timing
data which are currently stored in the ISC. The valve block
17 and the glassware forming mechanisms 18 together comprise
the individual section 14.
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There is also shown in Fig. 2 a blank sensor
19 which generates a signal upon the detection of a
gob at the mold in an individual section. The
blank sensor 19 includes a blank detector circuit (not
shown) for generating the signal to the ISC 13 which
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signal is ut~ ed to adjust the timing of that individual
sec-tion to th~ p~esence of the gob rather than to a position
related distribution time as was done in the prior art. The
blank sensor 19 and the blank detector circuit are the subject
matter of United States Patent 4,162,909 which issued on
July 31, 1979 to inventor Homer F. Peters and assigned to
the assignee of the present invention.
A section operator console (SOC) 21 is connected to
the lSC 13 and the valve block 17 and is used by the operator to
make adjustments to the mechanism -timing. The actuation of a
particular valve may be either advanced or retarded by the opera-
tor with the use of the SOC 21. The SOC 21 may also be used to
vary the section offset value and the reject synchronization
value as will be discussed. The SOC 21 can be provided with a
display (not shown) which enables the operator to check the cur-
rent timing value for a particular machine function.
The SOC 21 is provided with a rotary-type function
switch (not shown) for selecting the particular machine function
for timing adjustments. An on/off switch (not shown) is provided
on the SOC 21 for making adjustment in either the on timing value
or the off timing value of the selected machine function. The
SOC 21 is also provided with a spring-return type "sooner" switch
(not shown) for advancing the timing value toward -the beginning
of the cycle and a spring-return type "later" switch (not shown)
for retarding the timing value. If an operator desires to change
a timing value, he first selects the particular machine function
on the function switch and then selects whether he desires to
change the on or off timing value on the on/off switch. Next, he
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depresses the sooner switch if he desires to advance the
timing or the later switch if he desires to retard the
timing. As long as the operator continues to depress either
the sooner switch or the later switch, the ISC will automati-
cally respectively decrement or increment the timing value
one degree at a time. When the timing value reaches the
desired value, the operator releases the depressed switch.
It should be noted that the section does not have to be in
the off condition for timing adjustments, as the mechanism
timing values can be changed when the section is in the
operating condition.
As was previously discussed, each machine function
has an on timing value and an off timing value. The dwell
value of a machine function indicates that portion of a
machine cycle between the on value and the off value during
which the particular machine function is on. Thus, if a
machine cycle consists of 360, a dwell value of 0 indicates
that the function is continuously off while a dwell value
of 359 indicates that the function is continuously on. If
an operator desires to change a timing value of a function,
the timing value must not be changed so that an on value
is moved past an off value or an off value is moved past an
on value. This type of dwell value change is known as a
dwell reversal and could result in mechanism collisions
which would disrupt the forming cycle. In accordance with the
present invention, the respective ISC will not permit the
dwell value of a machine function to switch from 0 to 359
or from 359 to 0.
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The SOC 21 is also used to control the operating
condition of the individual section. When the individual
section is on, it is designated to be in the "run" condition
and, when the section is off, it is designated to be in the
"safe" condition. If the section is in the safe condition,
the operator can switch to a manual mode wherein the solenoids
of the valve block 17 can be individually controlled by a
plurality of switches (not shown) which are provided in the
SOC 21.
Although the SOC 21 is provided with start and
stop controls, the SOC 21 is located on one side of the
machine and is only easily accessible to the operator when
the operator is on that side. A remote start and stop
station 22 is provided and is typically mounted on the side
opposite the corresponding SOC. Thus, the start and stop
controls are easily accessible to the operator from both
sides of the machine.
A bottle reject control panel 23 includes a
plurality of switches (not shown) each of which corresponds
to a particular cavity of the mold in each individual section.
If an operator desires to reject a particular article of
glassware, he actuates the corresponding switch on the panel
23. The MSC 11 periodically scans the panel 23 to see if
any switches have been actuated. When the MSC 11 senses
an actuated switch, the MSC will compare the reject
synchronization value corresponding to the section of the
rejected glassware with the current machine position. If
these two values are equal, a reject signal will be supplied
to a bottle reject station 24 such that the appropriate
bottle(s) will be rejected.
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As was previously discussed with respeet to the
valve timing, the operator can utilize the SOC 21 to adjust
the rejeet synchronization value for the individual section
such that a glassware article from a seleeted eavity of
the mold is rejected when it arrives at the rejeet station 24.
The rejeet synehronization value is stored in the ISC as a
position in the maehine eyele. At a predetermined interval,
typieally every one minute, the MSC reads the rejeet
snychronization values from the ISC's and stores them. Eaeh
time there is a one degree ehange in machine position, the
MSC compares the new machine position with the reject
synchronization values and generates the reject signal when
they correspond.
Communications between the ISC 13 and the MSC 11
and between the MSC 11 and the I/0 device 15 can be aehieved
utilizing model DLVll serial input/output interfaee boards
(not shown). Input and output eontrol for the ISC 13 to the
SOC 21 and the valve bloek 17 and for the MSC 11 to the
control panel 23 and the rejeet station 24 ean be provided
by utilizing model DRVll parallel input/output interfaee
boards (not shown). If a floppy disk drive is used as the
data storage deviee 16, an RXVll floppy drive eontroller
(not shown) can be used to control data transfers between the
MSC and the floppy disk drive. The DLVll, DRVll and
RXVll are all manufactured by the Digital Equipment Corporation
of Maynard, Massachusetts.
As previously mentioned, the machine supervisory
computer 11 and the individual section computer 13 can be
LSI-ll eomputers. This partieular type of eomputer features
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hardware priority interrupts. As will be discussed, other
features of this computer are an automatic power failure
restart and user control of external task scheduling.
There are shown in Figs. 3 through 8 simplified
flow diagrams of programs utilized in the operation of the
machine supervisory computer (MSC) 11. As shown in Fig. 2,
the MSC is connected to an input/out device 15 which can be
a teleprinter having a keyboard input and a printer output
and to a data storage device 16 which can be a floppy disk
drive. The storage device stores on floppy disks both
system data, such as control programs, and job histories
which include the timing data for forming each type of
glassware article. The MSC 11 can be loaded with various
"keyboard" programs from the data storage device 16 which
programs allow the machine operator to install, change, list
or delete a job history in the storage device or to list a
directory of all job histories stored or to transfer a job
history(s) from one floppy disk to another; to set up the
machine parameters for a new job; to load a job history into
the ISC's from the storage device; to save an active job
history by loading it from an ISC into the storage device;
to reload an ISC with a control program and timing data from
any other ISC or with a test pattern; to display cavity rate
and machine speed; and to display or change the number of
cycles in which glassware articles are rejected.
The main program for the MSC 11 is shown in the
flow diagram of Fig. 3. The program is initiated at a
circle "START" and immediately enters a decision point
"KEYBOARD PROGRAM REQUEST" to check for any request to run a
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keyboard program that may have been entered by the machine
operator. If there is such a request, the program branches
at "YES" to a processing point. The processing point
"EXECUTE REQUESTED KEYBOARD PROGRAM" represents a set of
instructions drrecting the MCS toexecute the program. The
program then returns to the beginning of the main program.
If there is no keyboard program request, the main program
branches from the decision point at "NO" and returns to the
beginning of the program. It should be noted that all of
the keyboard programs run on the lowest priority and can be
interrupted by any of the programs which are shown in Figs. 4
through 8.
In addition to the keyboard programs initiated with
the input/output device 15, the MSC ll is also responsible
for running other programs all of which have a higher priority
than the keyboard programs. A clock interrupt program has
the highest priority and is shown in the flow diagram of
Fig. 4. A clock interrupt is generated each time a timing
pulse is received by the MSC ll from the timing pulse generator
12. If the MSC is running a keyboard program when the clock
interrupt is generated, the keyboard program is interrupted
and the clock interrupt is serviced before returning to the
keyboard program. The clock interrupt program is initiated
at a circle labelled "CLOCK INTERRUPT" and then enters a
processing point "INCREMENT MACHINE POSITION COUNT" to update
a count total representing the position of the machine in the
machine cycle. Next, the program enters a processing point
"CHECK STATUS OF REJECT CONTROL SWITCHES BY SECTION" which
includes instructions for checking the status of the reject
control switches on the reject control panel 23 of Fig. 2 by
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section. The program enters a decision point "ANY REJECT
SWITCHES" to determine if any bottles have been designated
for rejection. If any of the reject control switches are
actuated, the program branches at "YES" to a decision point
"MACHINE = REJECT" wherein the MSC 11 compares the current
machine position count total with the reject snychronization
value for each individual section. If they are equal, the
program branches at "YES" to a processing point "REJECT
DESIGNATED BOTTLE(S)" which includes instructions for
generating a reject signal to the bottle reject station 24
of Fig. 2 such that the designated bottle will be rejected.
The clock interrupt program then returns to the main program
at the point the main program was interrupted as is the case
when the program branches at "NO" from the "ANY REJECT SWITCHES"
decision point when no switches are actuated or when the pro- t
gram branches at "NO" from the "MACHINE = REJECT" decision
point when the machine position count total is not equal
to the reject synchronization value.
A reset interrupt program has the second highest
priority and is shown in Fig. 5. Each time a reset pulse is
generated by the timing pulse generator 12, the reset program
is initiated at a circle "RESET INTERRUPT". The program
enters a processing function "RESET MACHINE POSITION COUNT
TOTAL TO 359" which includes instructions for resetting the
machine position counter count total at the end of each
machine cycle. The reset interrupt program then returns to
the main program at the point it was interrupted. The next
timing pulse will then set the counter to zero and 359 more
timing pulses are counted to complete the machine cycle. As
the counter accumulates the last timing pulse, the reset pulse
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is again generated to correct any error which may have
occurred in the machine position count total.
As was previously discussed, the operator can
change the section timing data utilizing the SOC 21. Approxi-
mately every five minutes, the MSC 11 executes a store program
shown in Fig. 6 to update the current section timing data for
each individual section which is stored on a floppy disk in
the data storage device 16. Thus, if the operator has
changed the timing data for a section by advancing or
retarding the actuation of a valve, that timing change will be
stored in the data storage device 16 within no more than five
minutes. The LSI-ll computer is provided with a control
- over external task scheduling. For example, the operator
can schedule a program to run at an absolute time of the day,
a delta time from a clock unit synchronization or every so
many units of time, such as fivé minutes. Thus, every five
minutes, the store program is initiated at a circle "DATA
UPDATE INTERRUPT" and enters a processing function "OBTAIN
TIMING DATA FROM ISC AND PLACE IN DATA STORAGE DEVICE". After
the current timing data has been stored, the program returns
to the main program.
There is shown in Fig. 7 a reject program that is
executed by the ~C approximately every one minute to update the
reject synchronization values. Thus, if the operator has
changed any of these values to achieve a more accurate reject,
the change will be stored by the MSC within no more than one
minute. The reject program is initiated at a circle "REJECT
UPDATE INTERRUPT" and enters a processing function "OBTAIN
REJECT SYCHRONIZATION VALUE FROM ISC AND STORE" which includes
instructions for reading and storing the current reject
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synchronization values for each ISC. The reject program
then returns to the main program~ The stored values are
utilized in the comparison with the machine-position performed
at the decision point "MACHINE - REJECT" of Fig. 4.
If a power failure occurs, the volatile register contents
of the MSC and the ISCs will be lost. There is shown in
Fig. 8 a flow diagram which indicates the steps taken by the
MSC after a power failure recovery. If the MSC is a LSI-ll,
it can be programmed to execute a restart program which is
initiated at a circle "START". Next a process function
"RESTORE CONTROL PROGRAM AND JOB HISTORY TO EACH ISC" restores
the ISC memory with the control programs and timing data with
which they were loaded before the power failure. There the
restart program returns to the main program.
There are shown in Figs. 9 through 12 flow diagrams
which are representative of the operation of an ISC. The main
program is shown in Fig. 9. After ISC memory has been
restored by the MSC, the ISC performs several control program
initialization tasks such as setting the machine position
counter to 359.
The main program is initiated at a circle "START" and
enters a processing function "DISABLE INTERRUPTS AND PERFORM
INITIALIZATION TASKS". Next, the program enters a subprogram
"FUNCTION TIMING CHANGE" which includes instructions for
checking the SOC 21 to determine if the operator has requested
a change in the timing data, the section offset value or the
reject synchronization value. A more detailed flow diagram
of this program is shown in Fig. 12. Any requested changes
are stored in the ISC memory to be sent through the MSC to the
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data storage device when the store program of Fig. 6 is
executed by the MSC.
Next, the ISC main progxam enters a processing function
"ENABLE INTERRUPTS" which includes instructions to enable the
ISC to respond to the timing and reset pulses generated by the
timing pulse generator 12. The program then enters a
decision point "COMMUNICATION REQUEST BY MSC". If the MSC
has requested to either transmit data to or receive data from
the ISC, the program branches at "YES" to a processing
function "TRANSMIT OR RECEIVE DATA" which includes the required
instructions for communication between the MSC and the ISC.
The program then returns to the processing function "CHECK
SOC FOR TIMING CHANGES AND STORE ANY NEW VALUES" and continues
to loop. If the MSC has not requested communication, the
program branches from the decision point "COMMUNICATION REQUEST
BY MSC" at "NO" to return to the processing function
"CHECK SOC ....".
There is shown in Fig. 10 a flow diagram of the clock
interrupt program for the ISC. Each time a timing pulse is
received from the timing pulse generator 12 and the main
program has enabled the clock and reset interrupts, the ISC
initiates a clock interrupt since the clock interrupt program
has a higher priority. The clock interrupt program is
initiated at a circle "CLOCK INTERRUPT" and enters a decision
point "IGNORE INTERRUPT" which checks for a direction to
ignore the clock interrupt. As will be discussed below, a late
occurring reset pulse will require that at least one clock
interrupt be ignored such that the program branches at "YES"
and returns to the main program. If the clock interrupt is
not to be ignored, the program branches at "NO" and enters
a processing function "INCREMENT MACHINE POSITION COUNT"
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which includes instructions for updating a count total
representing the position of the machine in the machine cycle.
As discussed above, this count total is conveniently zero
to 359 representing 360 degrees in a machine cycle. This
corresponds to one rotation of the prior art timing drum which
utilized cams to operate the valves which actuated the
glassware forming means, the position of the cams being
defined in degrees. Next, the program enters a processing
function "SUBSTRACT SECTION OFFSET" which includes instructions
for subtracting the section offset value, if any, from the
machine position count total to obtain a count total repre-
senting the instantaneous position of the individual section
in the machine cycle which count total is stored.
Next, the program enters a processing function "CHECK SOC
STATUS CHANGE SWITCHES" which includes instructions for
checking the status of the start and stop switches on the SOC
21 and the remote panel 22 to determine if the operator has
requested a change in the status of the machine. The program
enters a decision point "RUN" to check if the section is in
the run condition forming glassware articles. If the section
is not running, the program branches at "NO" to a decision
point "START ACTUATED" to check whether either of the start
switches has been actuated as determined by the "CHECK SOC
STATUS CHANGE SWITCHES" processing function. If neither start
switch has been actuated, the clock interrupt program branches
at "NO" to a decision point "REPEAT CLOCK INTERRUPT". As will
be discussed below, an early occurring reset pulse will
require at least one extra clock interrupt such that the
program branches at "YES" back to the "INCREMENT MACHINE
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; POSITION COUNT" processing function. If the clock interrupt
is not to be repeated, the pxogram branches at "NO" to
return to the main program to await the next timing pulse.
If either start switch has been actuated, the program branches
at "YES" back to the "START" circle of the main program to
start the section.
If the section is running, the program branches from
"RUN" at "YES" to a decision point "STOP ACTUATED" to check
whether either of the stop switches has been actuated as
determined by the "CHECK SOC STATUS CHANGE SWITCHES" processing
function. If either stop switch has been actuated, the program
branches at "YES" to a processing function "STOP SECTION"
which includes instructions for stopping the operation of
the section. The clock interrupt program then enters the
"REPEAT CLOCK INTERRUPT" decision point. If neither stop
switch has been actuated, the program branches at "NO" to a
processing function "OBTAIN DEGREE VALUE OF NEXT FUNCTION FROM
TABLE" which includes instructions for looking up the degree
value of the next glassware forming function to be performed
in a table wherein the forming functions are listed in the
order they are to be performed in the forming cycle. The
program then enters a decision point "POSITION - DEGREE"
wherein the instantaneous position count total for the section
is compared with the degree value of the next function to be
performed. If the values are not equal, the program branches
at "NO" to enter the "REPEAT CLOCK INTERRUPT" decision point.
If the values are equal, the program branches at l'YES" and
enters a processing function "PERFORM FUNCTION" which
includes instructions for generating a control signal to the
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solenoid for actuating the proper valve in the valve block 17.
Next, the program enters a processing function "POINT TO NEXT
FUNCTION IN TABLE" which includes instructions for shifting
to the next function listed in the table such that the degree
value for this function is obtained as the program returns
to the "OBTAIN DEGREE VALUE OF NEXT FUNCTION FROM TABLE"
processing function. Thus, the program will perform all
functions having the same degree value before returning to
the main program.
A reset interrupt program is shown in Fig. 11. Each time
the timing pulse generator 12 generates a reset pulse and the
main program has enabled the clock and reset interrupts, the
ISC initiates a reset interrupt program which is initiated
at a circle "RESET INTERRUPT". The program then enters a
processing function "AUTO SYNCHRONIZATION" which includes
instructions for checking to see if the reset pulse occurred
between 359 and 0 of the section cycle and, if it did so
occur, no further action is required. If the reset pulse occur-
red within a range, for example, 357 through 2, instructions
are executed to modify the count of the clock pulses. If
the reset pulse was early, on the next clock interrupt the
clock interrupt program is cycled as many times as are required
to increment the clock pulse count total to place the section
in synchronization. If the reset pulse was late, the clock
interrupt is ignored as many times as are required to maintain
the clock pulse count total to place the section in
synchronization. In any of these instances, the reset interrupt
program then returns to the main program. If the reset pulse
occurs outside of the range, an emergency stop is initiated.
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the reset interrupt is lower than the clock interrupt in
priority.
There is also a line frequency interrupt program which
is similar to the reset interrupt program of Fig. 11. An
interrupt is generated by each cycle of the alternating current
power source for the ISC. Every predetermined number of cycles,
the line frequency interrupt program checks the clock pulse
count total to determine whether it has been incremented
since the last such check. If the clock pulse count total
has not been incremented for a predetermined number of these
checks, an emergency stop is initiated.
There is shown in Fig. 12 a flow diagram of the ISC
subprogràm-- "FUNCTION TIMING CHANGE" which is entered from the
ISC main program of Fig. 9 at a circle "START". As was
previously discussed, this subprogram includes instructions
for recording any timing data changes requested by the
operator. The first step is a decision point "FUNCTION CHANGE
REQUEST" which checks the SOC 21 for signals indicating that
the machine operator has requested a change in the timing data,
the section offset value or the reject snychronization value.
If no function change has been requested, the program branches
at "NO" and returns to the main program.
If a function change has been requested, the program
branches at "YES" to a decision point "TIMING DATA CHANGE"
to check for a requested change in an on or an off value for
a selected function. If the machine operator has not requested
a timing data change, the program branches at "NO" to a
decision point "REJECT OR OFFSET CHANGE" to determine if the
X
- 21 -
~Z~S~f;~
requested change is in one of those two values. If such
a change has been requested, the program branches at "YES"
to a processing function "RECORD NEW DEGREE VALUE" which
includes instructions for either incrementing or decrementing
the reject synchronization or offset degree values as required.
Since both the reject synchronization and offset degree values
are single values, there is no dwell time associated with
either and no need to check for a possible dwell reversal.
If there is no request to change either value, as in the
case of a request without depressing either the sooner
or the later switch, the program branches from "REJECT OR
OFFSET CHANGE" at "NO" back to the main program.
If the machine operator has requested a change in the
timing data, the program branches from "TIMING DATA CHANGE" at
"YES" to a processing function "OFF-ON = DWELL". This
processing function includes instructions for subtracting
the on time of the selected machine function from the off time
to obtain the dwell time for the function. Then the program
enters a decision point "DWELL = O". If the dwell time value
is equal to zero, the program branches at "YES" to a portion of
the program which only permits timing changes to expand the
dwell time. If the dwell time is greater than zero, the
program branches at "NO" to a portion of the program which
only permits timing changes to contract the dwell time to a
minimum of zero or expand the dwell time to a maximum of
359.
The "YES" branch leads to a decision point "ON OR OFF
TIME" to determine if the machine operator has requested a
change in the on timing value or the off timing value. If an
1~2See~
on change has been requested, the program branches at "ON"
to a decision point "SOONER SWITCH ACTUATED". If the sooner
switch is being depressed by the operator, the program branches
at "Y~S" to a portion of the program, beginning with a
"DISABLE INTERRUPTS" processing function for changing the
timing value since such a change would expand the dwell time
from zero. If the sooner switch is not being depressed, then
the program branches at "NO" from "SOONER SWITCH ACTUATED" to
a processing function " INDICATE CHANGE NOT PERMITTED". This
processing function includes instructions for generating a
visual indication at the SOC that no change is permitted
either because the sooner switch is not depressed or the later
switch is depressed and such a change would result in a dwell
reversal. The program then returns to the main program. If
a change in the off time has been requested, the program
branches from "ON OR OFF TIME" at "OFF" to a decision point
"LATER SWITCH ACTUATED". If the later switch is being
depressed, the program branches at "YES" to the processing func-
tion "DISABLE INTERRUPTS" since such a change would expand the
dwell time from zero. If the later switch is not being
depressed, the program branches at "NO" to the "INDICATE
CHANGE NOT PERMITTED" processing function to indicate that no
change is permitted either because the later switch is not
depressed or the sooner switch is depressed and such a change
would result in a dwell reversal. The program then returns
to the main program.
If the dwell time is not equal to zero, the program
branches at "NO" from "DWELL = O" to a decision point
"DWELL NEGATIVE" to check the sign of the dwell time. If the
1~2~Sl~
dwell value is negative indicating that the on value proceeds
the change from 359 to 0 in a cycle and the off value
follows that change, the program branches at "YES" to a
processing function "ADD 360 TO DWELL" which includes
instructions for adding 360 to the dwell time value to obtain
the dwell time as a positive value. Then the program enters
a decision point "DWELL = 359 ". If the dwell time is
already a positive value, the program branches at "NO"
from the "DWELL NEGATIVE" decision point to the "DWELL = 359 "
decision point.
If the dwell time is not equal to 359, the program
branches at "NO" from the "DWELL = 359" decision point to
the "DISABLE INTERRUPTS" processing function since such a
dwell time can be either expanded or contracted. If the dwell
time is equal to 359, the program branches at "YES" to an
"ON OR OFF TIME" decision point to determine if the machine
operator has requested a change in the on timing value or
the off timing value. If an on change has been requested, the
program branches at "ON" to a decision point "LATER SWITCH
; 20 ACTUATED". If the later switch is being depressed by the
operator, the program branches at "YES" to the "DISABLE
INTERRUPTS" processing function since such a change will
contract the dwell time from 359. If the later switch is not
being depressed, the program branches at "NO" from "LATER
SWITCH ACTUATED" to a processing function "INDICATE CHANGE NOT
PERMITTED". This processing function includes instructions
for generating a visual indication at the SOC that no change
is permitted either because the later switch is not depressed
or the sooner switch is depressed and such a change would result
in a dwell reversal. The program then returns to the main
- 24 -
1~2~5~
program.
If a change in the off time has been requested, the
program branches from "ON OR OFF TIME" at "OFF" to a
decision point "SOONER SWITCH ACTUATED". If the sooner
switch is being depressed, the program branches at "YES" to
the processing function "DISABLE INTERRUPTS" since such a
change would contract the dwell time from 359. If the sooner
switch is not being depressed, the program branches at "NO"
to the "INDICATE CHANGE NOT PERMITTED" processing function
to indicate that no change is permitted either because the
sooner switch is not depressed or the later switch is depressed
and such a change would result in a dwell reversal. The
program then returns to the main program.
The processing function "DISABLE INTERRUPTS" includes
instructions for disabling all interrupts to the ISC while the
degree value of the on or off time is being changed. The
program then enters a processing function "NEW DEGREE VALUE =
OLD DEGREE VALUE + 1 " which includes instructions for
generating a new degree value for the selected on or off time
by incrementing or decrementing the old degree value by one
degree as indicated by whether the later switch or the sooner
switch respectively is depressed. Next, the program enters
a decision point "SECTION POSITION = NEW DEGREE VALUE" which
compares the degree value of the present position of the
section in the cycle with the new degree value. If the
degree values are equal, the change is not permitted since the
ISC may miss generating an on or an off control signal, for
example, if the degree value is decremented after the clock
~ - 25 -
ll~S~
interrupt program of Fig. 10 has been executed for the
present section position but before the clock interrupt
program has been executed for the next position. Thus, the
program branches at "YES" to an "INDICATE CHANGE NOT
PERMITTED" processing function which includes instructions
for generating a visual indication that the degree value
cannot be changed at the present time. Then the program goes
to an "ENABLE INTERRUPTS" processing function.
If the section position does not equal the new degree
value, the program branches at "NO" to a "RECORD NEW DEGREE
VALUE" processing function which includes instruction for
replacing the old degree value stored in the ISC with the new
degree value. This new degree value is then read by the
MSC the next time the store program of Fig. 6 is executed.
The program then enters the "ENABLE INTERRUPTS" processing
function includes instructions for enabling the interrupts which
were disabled before the new degree value was generated. This
is the end of the function timing change subprogram and the
program returns to the main program.
In summary, the present invention concerns a control
system for a glassware forming machine. The machine has a
source of gobs of molten glass, a plurality of individual
sections for forming glassware articles, and means for
feeding the gobs of molten glass to the individual sections.
Each of the individual sections includes forming means for
forming the glassware articles in a cyclic series of pre-
determined forming steps in response to a plurality of
control signals and control means for generating the control
signals.
X - 26 -
~:~Z~i5.~5
The control means has a machine supervisory computer
connected to a plurality of individual section computers,
one for each of the individual sections of the machine. The
machine supervisory computer loads the individual section with
the control program and timing data for forming a particular
glassware article. Each section computer then generates the
control signals in accordance with the control program and the
timing data. The timing data includes an on and an off timing
value for each of the glassware forming means which timing
values define a dwell time during which the associated
glassware forming means is actuated. A section operator
console means is utilized to generate one or more signals
representing a desired change in a selected one of timing
values. The console includes means for generating a signal
representing a selected glassware forming means for which it
is desired to change one of the on and off timing values,
means for generating a signal representing a selected one of
the on and off timing values, and means for generating a
signal representing whether it is desired to increment or
to decrement the selected timing value. The section computer
is responsive to the signals for effecting the desired change
in the selected timing value unless such a change would result
in a dwell reversal, the movement of one of the on and off
timing values past the other.
In accordance with the provisions of the patent statutes,
the principle and mode of operation of the invention have
been explained and illustrated in its preferred embodiment.
However, it must be understood that the invention may be
practiced otherwise than as specifically illustrated and des-
cribed without departing from its spirit or scope.
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