Method and apparatus for analyzing machine control systems

A diagnostic system analyzes conditions of critical points in a production line. The diagnostic system generates an operator message based on the conditions it analyzes. A sensor senses the conditions of the critical points in the production line and generates critical point signals representative of the conditions of the critical points. An isolator receives the critical point signals and generates logic signals representative of the critical point signals. The isolator isolates the logic signals from the critical point signals. A controller receives the logic signals and generates an operator message based on the logic signals.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus and method for diagnostic machines 
in a production line. More particularly, this invention relates to 
analyzing critical points in production line machines. 
2. Description of the Prior Art 
Many industrial production lines are comprised of a plurality of processing 
machines which are tied together. One example is an industrial production 
line for producing corrugated paper. Corrugated paper is generally 
produced by using three webs of paper. One web is fluted (the flute) and 
is glued between two other flat webs of paper. This process can be done 
using anywhere from 5 to 25 different machines which are mechanically and 
electrically coupled to one another. 
All of the machines used to produce corrugated paper are collectively 
called a corrugator. A corrugator can be 300 feet long or longer. At one 
end, paper enters the corrugator from large rolls which are nominally 8 
feet wide. The three webs of paper (including the flute) are then glued 
together, sheared, slitted and scored, and cut to the proper length. 
Finally, the paper is stacked. 
Usually, corrugators are made up of dual machines which can run two or more 
orders at the same time. Since the paper rolls generally come in 8 foot 
wide rolls, several orders are set up to best utilize that dimension. For 
example, one order requiring six foot wide sheets of corrugated paper is 
run along with an order requiring two foot wide sheets. After being glued, 
the paper is slit to the proper width. Therefore, it is economically 
efficient to run more than one order at the same time. 
The machines in a corrugator come from a wide variety of vendors and are 
not precisely matched. Sometimes machines are all manufactured by the same 
vendor. Corrugators typically run at a speed of approximately 600 feet of 
paper per minute and the paper tension in the corrugator is important for 
proper production. Since the machines run at a high rate of speed and 
since proper paper tension is important throughout the corrugator, the 
machines must be synchronized with one another. 
Also, each machine has its own individual safety interlocks. Since the 
operation of the entire corrugator depends on the operation of each 
individual machine in the corrugator, when one machine is shut down by a 
safety interlock, the other machines should also be shut down. Therefore, 
the electrical interlocks of the machines are tied to one another so that 
all machines stop when one interlock is tripped. 
Typically, a corrugator takes a crew of 5 members to operate. Each crew 
member operates one portion of the corrugator. When a problem exists in 
one machine in the corrugator, a safety interlock may shut that machine 
off or the operator may push a stop button. When this happens, the entire 
corrugator is shut down. 
When a safety interlock stops a corrugator, confusion among the crew 
members results because none of them knows which machine has stopped the 
corrugator or what caused the stop. This can result in what should have 
been a 30 second stop turning into a ten minute or longer stop which 
substantially decreases production. For example, where the corrugator is 
running at 600 ft/min., nine extra minutes of downtime means a loss of 
more than one mile of corrugated paper production. 
When one of the operators pushes a stop button, the corrugator usually 
coasts to a stop. While the corrugator is coasting, a second problem can 
arise (such as a jam in one of the machines). The operator of the jammed 
machine will think that the jam is the problem which caused the corrugator 
to stop initially. Upon clearing the jam, the operator will restart the 
corrugator not realizing that the initial condition which stopped the 
corrugator was that another operator pressed a stop button. This also 
results in confusion and time delays in getting the corrugator running 
again. 
Another problem which causes the corrugator to stop is an intermittent 
problem. For example, a relay contact can temporarily open up causing the 
corrugator to stop but while the corrugator is coasting to a stop, the 
relay contact could automatically reset itself. Machines in the corrugator 
don't stop at the same rate, so during the time the corrugator is coasting 
to a stop, another problem may arise. The operator will see the apparent 
problem and erroneously determine that it caused the corrugator to stop 
initially. The intermittent problem having temporarily remedied itself, 
the corrugator will be restarted and the intermittent problem will never 
be identified. However, if the intermittent problem is recurring, the 
corrugator stoppages can be very timely and costly. Typically, corrugators 
are in dusty, extremely humid and hot environments which contribute to 
causing intermittent component failures. 
Because of the large number of machines (typically from different vendors) 
and the intertwined safety interlocks involved in a corrugator, finding 
the exact problem which caused the corrugator to stop running can be very 
difficult. Each of the different machines has many operator's manuals, 
schematics and other diagrams which are used to fix the machines. 
Therefore, when the corrugator stops and the crew does not know which 
machine has caused the stop, it can take a repairman or serviceman 
minutes, hours or even days to wade through the necessary documentation to 
find the problem. Since the corrugated paper industry usually strives for 
"just-in-time" operation, these delays in finding problems are very 
expensive. 
Another problem which causes corrugators to stop running is that jams can 
occur when the corrugator shifts from producing corrugated paper for one 
order to producing another dimension or another quality of corrugated 
paper for another order. These order changes require adjustments in 
various machines in the corrugator. When the order change begins and the 
adjustments have not been made, machine jams and other problems can result 
in corrugator stoppage. These stoppages are extremely costly in a short 
order plant where small quantity orders are produced. Corrugators in this 
type of plant may typically run for only 4 or 5 minutes between order 
changes. With no warning as to the problems that accompany the order 
change, operators cannot make the necessary adjustments in time and 
corrugator downtime is drastically increased. 
Until now, manufacturers in the corrugated paper industry have concentrated 
on making each of the individual machines in the corrugator more 
technically advanced. However, as yet, no one has addressed the problem of 
finding the reasons that these highly automated machines fail, fixing the 
problems and restarting the machines. Therefore, some of the major costs 
in the corrugated paper industry are those costs which are associated with 
downtime of the corrugator. One of the primary costs is lost business. The 
just-in-time nature of the corrugated paper industry requires producers to 
supply orders on very short notice. If the corrugator is down for a period 
of hours or days, corrugated paper purchasers will take their business 
elsewhere. 
Another major cost is overtime payments. When the corrugator is down, in 
order to provide the purchasers with the corrugated paper they have 
ordered, the producers must run overtime to make up for the corrugator 
downtime. Yet another cost is the cost of repair and service personnel 
which are required to find the problems in the corrugator. Due to the 
complex nature of the machines in the corrugator, it can take service and 
repair persons weeks to find the problem. All this time will be charged to 
the producer and that can be very costly. 
Several existing diagnostic systems are on the market today. However, they 
generally simply tie into the programmable controllers of each of the 
machines in a production line. Therefore, they only provide the 
diagnostics capability which the programmable controller in each machine 
provides in the first place if it provides any at all. None of them are 
able to isolate problems which cause stoppage of the production line down 
to a component level. 
Also, the diagnostic systems on the market today do not provide an operator 
with the cause of a current downtime period along with a most critical 
condition keeping the production line from being restarted. 
SUMMARY OF THE INVENTION 
The diagnostic system of the present invention analyzes conditions of 
critical points in a corrugator and generates an operator message based on 
the diagnostics. Sensing means sense the conditions at the critical points 
in the corrugator and generate critical point signals representative of 
the conditions. Isolator means receive the critical point signals 
generated by the sensing means and generates logic signals representative 
of the critical point signals. The logic signals are isolated from the 
critical point signals by the isolator means. Controller means receive the 
logic signals generated by the isolator means and generates a diagnostic 
based on the logic signals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a block diagram of the diagnostic system S of the present 
invention, which diagnostic operation of corrugator 10. As shown in FIG. 1 
corrugator 10 includes wet end 12, rotary shear 14, slitter/scorer 16, 
cut-off 18 and downstacker 20. Diagnostic system S also includes isolator 
station 22, fault latches 23, controller 24, display/printer 26, data 
entry terminal 27, reporting system 28, and conductors 30, 32, 34, 36, and 
38. 
For simplicity of illustration and discussion, not all of the machines in 
corrugator 10 are shown. Large rolls of paper are fed into corrugator 10 
at wet end 12. When one roll of paper runs out, another is spliced onto 
the end of the first roll and the paper feed is continuous. Three webs of 
paper are fed into corrugator 10 at wet end 12. One web is fluted and has 
starch and water applied to it creating a glue. This web, called a flute, 
is then glued between the other two webs of corrugated paper and steam 
cured. The corrugated paper is then fed into rotary shear 14 where the 
paper is cut width-wise to remove scrap and create a gap in the paper for 
order changes. The corrugated paper then enters slitter/scorer 16 where it 
is split lengthwise typically into two webs of corrugated paper which are 
run through the remainder of corrugator 10 as two separate orders. 
Slitter/scorer 16 also slits and scores the corrugated paper to the 
specifications of a particular order. Corrugated paper is typically made 
into boxes which require these slits and scores. After leaving 
slitter/scorer 16, the corrugated paper is fed into cut-off (knife) 18 
where it is cut to the proper length. Then, the corrugated paper enters 
downstacker 20 where it is stacked for shipment or delivery. After leaving 
corrugator 10, the corrugated paper is usually removed to another plant or 
a different portion of the production facility where it is formed into 
boxes and glued. 
The machines in corrugator 10 are often not from the same vendor and 
therefore do not precisely match one another. They are often linked by 
tables or rollers. The machines move the corrugated paper through 
corrugator 10 at a rate of approximately 600 feet per minute or more. 
Corrugator 10 is typically at least 300 hundred feet long and it takes 
approximately 5 crew members to operate it. 
The diagnostic system S of the present invention analyzes several critical 
points on each machine in corrugator 10. The critical points which are 
analyzed range from simple circuit breakers and emergency stop buttons to 
steam level monitors, water flow rate monitors and starch viscosity 
monitors. The critical points which are analyzed in corrugator 10 are 
substantially anything which, when not in the proper condition, is capable 
of stopping corrugator 10. 
Each of the sensors on each machine in corrugator 10 produce a signal which 
is representative of the current state of that particular critical point. 
For example, where a circuit breaker on slitter/scorer 16 is monitored, 
the presence of 120 volts AC indicates that the circuit breaker is closed 
and the absence of 120 volts AC indicates that the circuit breaker is 
open. The signals representative of the current states of the critical 
points which are analyzed are critical point condition signals and are 
provided to isolator station 22, in this preferred embodiment, by being 
hard wired via conductors 30, 32, 34, 36, and 38. For simplicity, 
conductors 30, 32, 34, 36 and 38 are shown as single lines in FIG. 1, but 
each typically contains multiple lines--one line or set of lines (twisted 
pair) for each point within the machine which is analyzed. 
Isolator station 22 optically isolates the critical point condition signals 
received from corrugator 10 and produces logic signals representative of 
the critical point condition signals. When a fault condition exists and 
causes corrugator 10 to stop, the logic signal associated with the 
critical point causing the fault condition changes states and is latched 
in fault latches 23. Isolator 22 provides the logic signals and latch 
outputs from fault latches 23 to controller 24. The optical isolation 
performed by isolator station 22 not only protects controller 24 from 
electrical transients, accidental short circuits and high voltages, but 
also prevents controller 24 from interfering with the performance of the 
machines in corrugator 10 which are being analyzed. 
Controller 24 periodically polls the logic signals produced by isolator 
station 22 (e.g. approximately once every 0.25 sec.) and analyzes that 
information to determine the current state of the critical points in 
corrugator 10. Controller 24 determines that a fault condition exists when 
the condition of any critical points which are analyzed in corrugator 10 
have caused corrugator 10 to stop. For instance, if an electrical 
interlock in downstacker 20 has caused a circuit breaker to open thereby 
shutting down corrugator 10, the logic signal associated with that circuit 
breaker will change state and be latched in fault latches 23 at isolator 
station 22. Therefore, controller 24 will "see" which circuit breaker has 
tripped, will generate a corresponding operator message and will provide 
it to the operator at display/printer 26. The information is also uploaded 
to reporting system 28 and is processed and analyzed and included in one 
of a number of report formats. 
Similarly, where a crew member in charge of rotary shear 14, for instance, 
sees a jam and manually pushes an emergency stop button bringing 
corrugator 10 to a stop, the logic signal associated with the emergency 
stop button will change states and be latched in fault latches 23 at 
isolator station 22. Hence, controller 24 will "see" that this particular 
emergency stop button has stopped corrugator 10. Controller 24 will then 
generate an operator message on display/printer 26 thereby eliminating any 
confusion resulting from the stoppage among the crew members along the 300 
foot production line. In that case, the crew member which pushed the 
emergency stop button will enter a reason at data entry terminal 27 
indicating why the stop button was pushed. This allows controller 24 to 
upload the operator's reason to reporting system 28 to be included in a 
production report. 
Table 1 shows one particular example of machines used in a corrugator. 
Also, Table 1 contains a list of operator messages associated with each 
point analyzed on the double backer and upper knife in the corrugator. 
Note that there are two messages listed. One message is displayed if the 
corresponding critical point has caused an initial fault and the other is 
displayed as a current condition message. 
TABLE 1 
______________________________________ 
Machine Manufacturer 
______________________________________ 
Double Backer S & S 
Rotary Shear Marquip, Inc. 
Auto Auxilliary Scoring 
Marquip, Inc. 
Section 
Slitter/Scorer Marquip, Inc. 
Lower Knife Marquip, Inc. 
Upper Knife Marquip, Inc. 
Lower Downstacker Marquip, Inc. 
Upper Downstacker Marquip, Inc. 
Machine Interface Alliance Technical 
Services, Inc. 
______________________________________ 
DOUBLE BACKER OPERATOR MESSAGE 
A001C 
The double backer start will not start due to a Failure to the dynamic 
brake contactor or TD delay. 
Contact maintenance! 
The double backer dynamic brake contactor or T.D. Failed. 
A002C 
Fault message only 
Double backer [cr] relay failure caused stop 
A003E 
Fault message only 
Double backer belt-lifter switch was switched to [MANUAL] 
A004E 
The double backer belt-lifter switch is set on [manual]. in order for the 
Double backer to start, The switch must be in [auto]. 
If the switch is not in [manual], contact maintenance! 
The Double Backer belt-lifter switch was turned to [manual] 
A005P 
The line is ready to start, press the double backer Start button. If the 
line won't start, the fault Message should indicate why. 
Contact maintenance if the double backer won't start. 
This fault should never be logged - - - A005P 
A006C 
The double backer belt lifter auto-manual selector Switch has failed. 
Contact maintenance! 
This message should never be logged - - - A006C 
A007C 
The double backer start button has been pressed. the Double backer should 
start when the belts are nearly Down. if the double backer does not start, 
contact Maintenance! the fault message should indicate Component failure. 
if the double backer does not Start, lss could be defective 
A008C 
The double backer mainline drive motor thermal is Tripped. contact 
maintenance immediately! 
The double backer mainline drive motor thermal Tripped. 
A009C 
The double backer drive control relay (cr) has failed. 
Contact maintenance immediately! 
The double backer drive control relay (cr) failed. 
A010C 
The double backer jog button at the glue machine is Defective. the normally 
closed contact is open. 
Contact maintenance! 
The double backer job button at the glue machine Failed. 
A011C 
The double backer job button at the main belt head Pulley stand is 
defective. the normally closed Contact is open. contact maintenance! 
The double backer job button at the head pulley stand Failed. 
A012C 
The double backer low speed relay (lsr) contact is Open. this diagnostic 
should appear if Single Machine analysis is used while the Double Backer 
is Running. 
The double backer low speed relay (lsr) contact Failed. 
A013C 
The double backer is not ready to start because the Dry-end ready contact 
in the double backer stop Circuit is open. 
This message should appear only when single machine Analysis is used. 
This message should never be logged - - - A013C 
A014P 
The double backer stop push button at the c flute Operator stand is open. 
if the button is not Depressed contact maintenance! 
Double backer stop button at c flute station was pressed. 
A015P 
The double backer stop push button at the b flute Operator stand is open. 
if the button is not Depressed contact maintenance! 
Double backer stop button at b flute station was Pressed. 
A016P 
The double backer stop push button at the glue Machine stand is open. if 
the button is not Depressed contact maintenance! 
Double backer stop button at glue machine stand was Pressed. 
A017P 
The double stop push button at main belt head pulley Stand is open. if the 
button is not depressed Contact maintenance! 
Double backer stop button at head pulley stand was Pressed 
A018C 
The double backer is not ready to start because the Dry-end e-stop contact 
in the double backer e-stop Circuit is open. this message should appear 
only When single machine analysis is used. 
This message should never be logged - - - A018C 
A019P 
The double backer e-stop push button at the glue Machine stand is open. if 
the button is not Depressed contact maintenance! 
Double backer e-stop at the glue machine was pressed. 
A020C 
A double backer belt lifter motor thermal (lnol) is Tripped. contact 
maintenance! 
A double backer belt lifter motor thermal (lnol) Tripped 
A021C 
A double backer belt lifter motor thermal (lnol) is Tripped. contact 
maintenance! 
A double backer belt lifter motor thermal (lnol) Tripped 
A022C 
The double backer control circuit fuse (cfu) has Blown. contact 
maintenance! 
The double backer control circuit fuse (cfu) blew 
A023C 
No power is sensed at the double backer drive control Circuit. check to see 
if the drive is on. if the Drive will not start, contact maintenance! 
double Backer drive was turned off or failed while running 
A024P 
The double backer e-stop push button dry-end contact Is open. if the button 
is not depressed, contact Maintenance! 
The double backer e-stop push-button dry-end contact Opened 
A025P 
The double backer is being jogged. 
The double backer was jogged while ready to start 
A026C 
The Double Backer BELT NEARLY DOWN limit switch (LSS) Or MAIN CONTROL RELAY 
(CR) has failed. The belts Will not latch down. 
Contact maintenance! 
The Double Backer belts won't stay down, contact Maintenance! 
A027C 
The double backer glue station is turned off. The Glue station must have 
power in order for the line to Power up If the disconnect is on, contact 
maintenance! 
The double backer glue station lossed power. 
A028C 
The Double Backer is coasting to a stop. 
This message should change when the Slow Speed limit Switch is tripped. 
This message should not be logged - - - A028C 
UPPER KNIFE OPERATOR MESSAGES 
F001C 
The power feeding the upper control circuit is off. Check the main 
disconnects of the knife. Contact the maintenance if disconnects are on. 
The 480 v. supply to the control circuit transformer was lost.-upper 
F002C 
The circuit breaker (CB-7) of the UPPER level has tripped. The breaker is 
located in the right hand knife cabinet. 
Contact maintenance. 
The circuit breaker (CB-7) of the upper level tripped. 
F003C 
The Upper Knife is not ready. 
The Knife computer interlock relay (CR-80) has failed. 
Contact maintenance! 
The Knife computer interlock relay (CR-80) failed. 
F004C 
The Upper Knife velocity monitor card is preventing control power from 
enabling. Contact maintenance! 
The Upper Knife velocity monitor card caused an E-stop. 
F005P 
The control lockout keyswitch on the knife computer console is turned to 
LOCKOUT. 
The control lockout on the knife console was turned to LOCKOUT. 
F006P 
The control lockout keyswitch at the knife (Operator Side) is turned to 
LOCKOUT. 
The control lockout at the knife was turned to lock-out. 
F007P 
The knife's emergency stop pushed button is pressed. 
If the button is not depressed, contact maintenance. 
The knife's emergency stop push button was pressed. 
F008C 
The knife's customer e-stop contact of the upper level is open. 
Contact Maintenance! 
The knife's customer e-stop contact of the upper level opened. 
F009P 
The knife's normal stoppush button is pressed. 
If the button is not depressed, contact maintenance. 
The knife's normal stop pushbutton was pressed. 
F010P 
The Upper Knife control power push-pull button contact is open. 
If the button is not depressed, contact maintenance. 
The Upper Knife control power pushbutton was pressed. 
F011C 
The Upper Knife computer controlled E-stop relay (CR-89) is open. 
This contact should open after any E-stop but should close again. 
If this message does not change, contact maintenance. 
The Upper knife computer controlled E-stop relay (CR-89) opened. 
F012P 
The Upper Knife control power is not on. 
Control Power should enable. 
If control power will not enable, contact maintenance. 
Upper Knife control power turned off when CR-1 failed. 
F013C 
The SENTINEL is in single machine analysis of the upper knife and upper 
auto will not come on because the upper stacker ready input is off. 
This message should never appear - - - F013CF014E 
Upper Knife auto will not turn on because the upper rolls are raised. 
If the rolls are not raised, contact maintenance. 
This message should never appear - - - F014E 
F015C 
The Upper Knife is not ready. 
A jam is sensed at the exit rolls. 
Contact maintenance if no jam is present. 
A jam in the upper knife caused the stop. 
F016C 
Upper Knife Auto is off. There is no Air Flow sensed through the Upper 
Knife. 
Contact Maintenance! 
The Upper Knife Auto turned off due to NO AIR FLOW condition. 
F017C 
The Upper Knife Auto is not on, the Oil Level is low!!! 
Contact maintenance! 
The Upper Knife Auto turned off due to Low Oil condition. 
-F018C- 
The Upper Knife Auto is not on. The excessive line speed output is on! 
Contact Maintenance! The Upper knife excessive speed was on too long 
causing the stop. 
-F019C- 
This current condition should never appear - - - F019C. 
The upper knife auto disabled. Too many cyl. racks may have disabled. 
F020P 
This current condition message should never appear - - - F020P. 
The upper knife auto disabled when the pushbutton was pressed. 
F021C 
The Upper Knife power supply (P.S.-1310) has failed. 
Contact maintenance! 
The Upper Knife power supply (P.S.-1310) failed. 
F022C 
There is no power coming from the upper knife power supply 136. 
Contact maintenance! 
The upper knife power supply - 136 lost power. 
F023C 
There is no power coming from the upper power supply - 134. 
Contact maintenance! 
The power from the upper power supply - 134 was lost. 
F024C 
The Upper Knife Auto is off. Auto should enable when the button is pressed. 
Contact maintenance if Auto will not come on. 
Upper Knife Auto turned off, Rack #5 failure or computer failure. 
F025E 
Upper B.E.C. failure/crash. 
The Upper Knife manual interlock was pulled while running in MANUAL. 
F026E 
This current condition should never appear - - - F026E 
The Upper Knife manual interlock was pulled in while running in MANUAL. 
F027E 
The CRT/Manual switch contact is open and the Switch is in MANUAL. 
Check the position of the switch, ensure it is firmly in position. 
The Knife's CRT/Manual switch opened, knife was not ready for CRT.F028C 
The Upper Knife computer E-stop relay (CR-61) contact is open. 
This contact remains open after an E-stop for approximately 20 seconds. 
If this message never changes, contact maintenance. 
The Upper Knife computer E-stop relay (CR-61) contact opened. 
F029C 
The Knife Ready circuit is open due to a failure of relays CR88 and/or 
CR98. Contact maintenance! 
The Knife Ready contact (Relays 88 and 98) failed. 
F030C 
The Knife's door sense relay (CR 90) is not energizing even though all 
limit switches are made. 
Contact maintenance. 
The knife's door sense relay (CR 90) failed. 
F031C 
The knife right hand (looking downstream) top cover, farthest from the 
stacker, is open or the limit switch is tripped. 
The Knife downstream right hand top cover was opened. 
F032C 
The Knife left hand (looking downstream) top cover, farthest from the 
stacker, is open or the limit switch tripped. 
The Knife upstream left hand top cover was opened. 
F033C 
The Upper Knife infeed rollout section is pulled out or is not closed all 
the way. 
The Upper Knife infeed rollout section was pulled out. 
F034C 
The Lower Knife infeed rollout section is pulled out or is not closed all 
the way. 
The Lower Knife infeed rollout section was pulled out. 
F035C 
The knife's left hand (looking downstream) top cover closest to the stacker 
is open or the limit switch is tripped. 
The knife's upstream left hand top cover door was opened. 
F036C 
The knife's right hand (looking downstream) top cover closest to the 
stacker is open or the limit switch tripped. 
The knife's upstream right hand top cover door was opened. 
F037C 
The Knife right hand side (looking downstream) left door, is open or the 
limit switch is tripped. 
The Knife right hand side (looking downstream) left door opened. 
F038C 
The Knife left side (looking downstream) right door is open or the limit 
switch is tripped. 
The Knife left side (looking downstream) right door opened. 
F039C 
The Knife left side (looking downstream) left door is open or the limit 
switch is tripped. 
The Knife left side (looking downstream) left door opened. 
F040C 
The Knife right side (looking downstream) right door is open or the limit 
switch is tripped. 
The Knife right side (looking downstream) right door opened. 
F041C 
The Knife is not ready due to a blown fuse. 
Fuse 53FU in the sense doors circuit has failed. 
Contact maintenance! 
Fuse 53FU of the knife failed. 
F042C 
The Knife is not ready due to a blown fuse. 
Fuse 52FU in the sense doors circuit has failed. 
Contact maintenance! 
Fuse 52FU of the knife failed. 
F043C 
The Knife air conditioning interlock relay (CR BOA) is open. 
The relay has failed. 
Contact maintenance. 
The Knife air conditioning interlock relay (CR BOA) failed. 
F044C 
The Knife air conditioner interlock circuit is preventing the Knife from 
being ready. The circuit breaker CB-2 has failed. 
Contact maintenance. 
The Knife Air Conditioner circuit breaker tripped. 
F045C 
The Knife air conditioner interlock circuit is preventing the Knife from 
being ready. There is no power sensed to this circuit. 
Contact maintenance! 
The Knife Air Conditioner incoming power was turned off. 
F046E 
The Knife is in MANUAL mode, switch to CRT if desired. 
To continue in MANUAL, either push in the Upper Interlock or turn on Upper 
Control Power and Auto. 
This message should not be logged - - - F046E. 
F047C 
Single Machine Diagnostic. 
The Upper Knife is ready (Control Power and Auto are on). 
This single machine diagnostic should never be logged - - - F047. 
F048C 
spare message 
F049C 
The Upper Knife Ready output is off but all conditions are met. 
Call maintenance! 
The Upper Knife Ready output failed. 
FIG. 2a is a flow chart showing one preferred embodiment of the operation 
of controller 24 when executing a diagnostic routine. The first 
determination made by controller 24 is whether corrugator 10 is running or 
whether it has been stopped. If it is running, controller 24 goes to a 
warning routine where various warning points are analyzed. This is 
indicated in blocks 100 and 102. If corrugator 10 is not running, 
controller 24 determines the previous state of corrugator 10. If 
corrugator 10 was previously running then an initial fault condition has 
just occurred which has stopped corrugator 10 and which must be 
identified. Controller 24 turns off any alarms which are on and reads the 
state of fault latches 23 at isolator station 22 as indicated in blocks 
104, 106 and 108. After reading the state of fault latches 23, controller 
24 jumps to a machine analysis subroutine (which will be described in more 
detail later) to analyze the data retrieved from fault latches 23 to 
determine what the initial fault was which stopped corrugator 10. This is 
shown in block 110. After analyzing the initial fault, controller 24 jumps 
out of the diagnostic routine. 
If corrugator 10 was not previously running, then the initial fault 
condition has already been identified on a previous run through of the 
diagnostic routine. Controller 24 next determines whether corrugator 10 
was ready to start before this run through of the diagnostic routine by 
checking a previous condition variable which was set by controller 24. If 
it was ready, controller 24 determines whether corrugator 10 is presently 
ready to start. If corrugator 10 is presently ready to start, controller 
24 reads the current state of the critical points which are analyzed at 
isolator station 22 then jumps to a machine analysis routine to analyze a 
current condition of corrugator 10 for any fault conditions. Once the 
analysis is complete, controller 22 jumps to the end of the diagnostic 
routine. This is indicated in blocks 112, 114, 116 and 118. 
However, if corrugator 10 was ready to start before this run through of the 
diagnostic routine, and corrugator 10 is no longer ready to start, then 
corrugator 10 has gone from a running condition to a stop condition to a 
ready to start condition and back to a stop condition. This is defined as 
a subsequent fault. A subsequent fault is one which occurs after an 
initial fault has caused corrugator 10 to stop running and after 
corrugator 10 has returned to a ready to run state. Therefore, controller 
24 reads the state of fault latches 23 for a subsequent fault. Next, 
controller 24 jumps to a machine analysis routine to analyze the data 
retrieved from fault latches 23 to determine the nature of subsequent 
fault conditions. Then, controller 24 jumps to the end of the diagnostic 
routine. This is shown in blocks 112, 114, 120 and 122. 
If the previous condition variable indicates that before this run through 
of the diagnostic routine, corrugator 10 was not ready to start, then the 
current state of the critical points is keeping corrugator 10 from being 
restarted. Therefore, controller 24 reads the current state of the 
critical points (as opposed to fault latches 23 which are read to 
determine initial and subsequent faults) at isolator 22. Next, controller 
24 jumps to a machine analysis subroutine to analyze the current state of 
the critical points in order to determine what must be done for corrugator 
10 to be restarted. There may be a number of critical points which have a 
current state that is keeping corrugator 10 from being restarted. However, 
many of these may depend on only one critical point located upstream of 
them. Therefore, controller 24 filters through the current states of the 
critical points to determine a current condition which is the most 
critical condition which must be remedied to restart corrugator 10 (i.e., 
the logical first step to be taken in restarting corrugator 10). After the 
machine analysis subroutine is run, controller 24 determines whether 
corrugator 10 is now ready to start. If it is, fault latches 23 are 
cleared and controller 24 jumps out of the diagnostic routine. If 
corrugator 10 is not ready to start, then there is yet another current 
state of the critical points which is keeping corrugator 10 from being 
restarted. Therefore, controller 24 comes to the end of the diagnostic 
routine which will be rerun in approximately 0.25 sec. at which time the 
current state keeping corrugator 10 from being restarted will be 
identified. These steps are shown in blocks 124, 126, 128 and 130. The 
effect of these steps is to give the operator an updated indication of the 
current condition of corrugator 10 and the next step to take in restarting 
corrugator 10. 
FIG. 2b shows a flow chart for the machine analysis routine discussed in 
conjunction with FIG. 2a. The machine analysis routine analyzes 
information retrieved from isolator station 22 and fault latches 23 and 
returns a fault code identifying and pinpointing the reasons for stopping 
corrugator 10. After controller 24 enters the machine analysis routine, it 
first determines whether it is looking for an initial or subsequent fault, 
or whether it is looking for the current condition of the critical points. 
This is done by determining whether it has been through the machine 
analysis routine since the initial fault has caused corrugator 10 to stop 
running and been remedied. If it has, it has already identified the faults 
and is looking for current conditions. If not, it is either looking for 
the initial fault or a subsequent fault. The difference is that if it is 
looking for faults, it reads fault latches 23. If, on the other hand, it 
is looking for the current condition of the critical points, it reads the 
current state of those points at isolator station 22. This is shown in 
blocks 132, 134 and 136. 
After determining whether it is looking for fault or current conditions, 
controller 24 analyzes the critical points of one machine (e.g., machine 
A) in corrugator 10. Then, based on the machine logic, controller 24 
determines whether there are any faults in machine A. If there are, 
controller 24 displays an operator message describing the fault and then 
jumps out of the machine analysis routine. This is shown in blocks 138, 
140, 142. 
If there are no faults in machine A, controller 24 isolates the fault to a 
portion of corrugator 10. For instance, the wet or dry end of corrugator 
10 (e.g. the end of corrugator 10 where the paper is glued or the end 
where it is cut and stacked). Next, controller 24, based on the machine 
logic, isolates the fault to a particular machine in corrugator 10 and 
then analyzes the critical points of that particular machine to determine 
the exact critical point causing the fault condition. After pinpointing 
the fault condition, controller 24 again displays an operator message at 
display/printer 26 describing the fault and how to remedy the fault. This 
is shown in blocks 142, 144, 146 and 148. 
Controller 24 may also be set to run the machine analysis routine for 
particular machines in corrugator 10 ignoring the other machines. This is 
useful when one machine is stopped for routine maintenance and the 
operator desires to troubleshoot another machine. 
FIG. 2c is a flow diagram showing the warning routine which is briefly 
discussed in conjunction with FIG. 2a. In the diagnostic routine of FIG. 
2a, controller 24 first determines whether corrugator 10 is presently 
running. If it is, controller 24 jumps to the warning routine. Controller 
24 determines whether corrugator 10 was previously running. If not, then 
corrugator 10 has just been restarted and fault latches 23 are cleared. If 
corrugator 10 was previously running, controller 24 checks an order change 
status to determine whether machine adjustments must be made for an 
upcoming order change. This is shown in blocks 150, 152 and 154. 
After the order change status is checked, controller 24 reads conditions of 
critical points in corrugator 10 which constitute warning points. These 
points are anything which could cause an operator to stop corrugator 10 if 
their condition is not changed. Based upon the condition of the warning 
points, controller 10 determines whether any warnings are necessary. If 
not, controller 24 turns off any alarms which may be on, removes any 
message for the operator which may be present indicating that warnings are 
present and jumps out of the warning routine. This is shown in blocks 156, 
158, 160 and 162. 
If the conditions of the warning points indicate that warnings are 
necessary, controller 24 determines whether any new warnings have been 
generated. If not, controller 24 simply displays a warning message for the 
operator and jumps out of the warning routine. However, if new warnings 
are required, controller 24 turns on corresponding alarms, if they are not 
already on, and then displays a warning message for the operator and jumps 
out of the warning routine. This is shown in blocks 162, 164 and 166. 
FIG. 3 shows one preferred embodiment of an operator message format 
displayed at display/printer 26 when controller 24 has detected a fault 
condition and corrugator 10 has been stopped. Time and date displays 40 
and 42 display the current time and current date, respectively. Duration 
indicator 44 shows the duration of time that corrugator 10 has been down. 
This time is stopped when corrugator 10 is restarted. 
Fault indicator 46 shows the nature of the initial fault which has caused 
corrugator 10 to stop. 
Subsequent fault indicator 48 displays a subsequent fault condition which 
has occurred after that displayed by fault indicator 46. 
Current condition indicator 50 displays the current condition of corrugator 
10. To analyze initial and subsequent fault conditions, controller 24 
reads the state of fault latches 23. To analyze the current condition of 
corrugator 10, controller 24 reads the current condition of the critical 
points at isolator station 22. Where multiple fault conditions exist, and 
are preventing corrugator 10 from being restarted, the most critical 
condition is displayed at current condition indicator 50. Therefore, as 
the operators or servicepersons are fixing the faults, current condition 
indicator 50 will be updated to display the next most critical fault 
condition which is keeping corrugator 10 from being restarted. Current 
condition indicator 50, therefore, is particularly helpful in stepping an 
operator through a logical progression of steps which must be taken to 
remedy the fault conditions keeping corrugator 10 from being restarted. 
The combination of current condition indicator 50 and fault indicator 46 is 
particularly helpful, when an intermittent problem causes corrugator 10 to 
stop. For example, where a relay contact in a safety interlock temporarily 
opens, causing corrugator 10 to stop, and then immediately recloses, while 
corrugator 10 is coasting to a stop and before the operators have noticed 
that it has been stopped, a jam in downstacker 20 could occur causing an 
operator to push an emergency stop button. Without diagnosticing system S 
of the present invention, the operator would expect that the jam in 
downstacker 20 caused corrugator 10 to stop, would clear the jam, and 
would try to restart corrugator 10. Where the relay contact fault which 
originally stopped corrugator 10 is an intermittent problem, it may be 
weeks or months before the operators or maintenance crews locate that 
problem. This can result in very costly downtime in the interim. 
However, with diagnostic system S of the present invention, the relay 
contact fault, even though it is intermittent, is latched in fault latches 
23 at isolator station 22 when its corresponding logic signal changes 
states. Consequently, it is "seen" by controller 24 and is also displayed 
at fault indicator 46. Any current condition keeping corrugator 10 from 
being restarted, such as a jam at downstacker 20, would be displayed in 
current condition indicator 48. Therefore, the operators waste no 
unnecessary time restarting corrugator 10 until the intermittent problems 
are fixed. 
Reason indicator 52 displays an operator-entered reason why corrugator 10 
was stopped. Since standard operator control shutdowns most commonly stop 
corrugator 10 or keep it from being restarted, it is important to know why 
the standard operator control shutdowns occur. For example, where an 
operator has a plant meeting, goes on break or notes bad or low quality 
paper entering his or her machine and presses an emergency stop button, 
the operator enters a two digit code in reason indicator 52 at data entry 
terminal 27. The two digit code is representative of the operator defined 
reason for the downtime. This information is particularly helpful in 
generating production reports. 
Downtime indicator 54 displays the cumulative total downtime of corrugator 
10 for the entire day and also the total downtime for each shift during 
the day. Downtime display 54 is updated each time corrugator 10 is 
restarted. 
Last downtime display 56 displays the duration of the most recent downtime 
of corrugator 10. Last downtime display 56 is updated when corrugator 10 
is successfully restarted. The fault condition which caused the most 
recent previous downtime is displayed at fault indicator 58. Fault 
indicator 58 is also updated when corrugator 10 has been successfully 
restarted. Similarly, reason indicator 60 indicates the operator-entered 
reason for the last downtime of corrugator 10 and is updated when 
corrugator 10 is successfully restarted. 
Controller 24 not only produces the operator message shown in FIG. 3 when a 
fault condition is detected, but it also gives the operator access to help 
screens which are selectable by the operator. The help screens are 
comprised of information which is relevant to the fault condition 
surrounding the downtime of corrugator 10. Typically the help screens are 
schematic diagrams showing the circuitry causing the fault condition, 
pictures or sketches showing the physical location of the fault condition, 
part numbers and print numbers corresponding to parts or document prints 
associated with the fault condition and tutorial text describing how to 
remedy the fault condition. 
In this preferred embodiment, when the operator message shown in FIG. 3 is 
displayed, the help screens for the fault condition indicated in fault 
indicator 46 will be displayed when the operator presses "F3" at data 
entry terminal 27. Also, if the operator has further questions concerning 
the problem displayed in current condition indicator 50, the operator can 
retrieve the help screens associated with the current condition displayed 
in current condition indicator 50 by pressing "F5". Controller 24 can be 
programmed to display these help screens when any convenient command is 
given at data entry terminal 27. 
If the operator enters "F1", in this preferred embodiment, the previous 7 
fault conditions, subsequent fault conditions and operator-entered reasons 
will be displayed on display/printer 26. The help screens for these fault 
conditions are also retrievable. Also, an editing function allows the 
operator to edit the operator-entered reasons but not the faults. 
When corrugator 10 has been successfully restarted, and when the operator 
has entered the two digit code in reason display 52 for the last downtime, 
controller 24 displays the operator message shown in FIG. 4 at 
display/printer 26. Time display 40, date display 42, downtime indicator 
54, last downtime display 56, fault indicator 58 and reason indicator 60 
are identical to those shown in FIG. 3 except that they have been updated 
accordingly. 
Warning indicator 62 will warn the operator about any condition at a 
critical point which is being analyzed in corrugator 10 which could result 
in the operator stopping corrugator 10 if it is not remedied. For example, 
where slitter/scorer 16 is set up to run a particular order, and an order 
change is approaching in which slitter/scorer 16 needs to be adjusted in 
order to run properly, warning indicator 62 will warn the operator of this 
potential problem. If the operator adjusts slitter/scorer 16 properly 
before the order change, there will be no resulting excess downtime and, 
hence, no loss of production. Also, in this preferred embodiment, when a 
warning is displayed at warning indicator 62, controller 24 also causes an 
audible alarm to be triggered to assure that an operator realizes that 
corrugator 10 will go down unless some adjustments are made. 
If more than one warning is generated by controller 24 at one time, that 
will be indicated in warning display 62. Then, by pressing "F2", in this 
preferred embodiment, the operator will see a display of any other 
warnings. 
When corrugator 10 is up and running properly, speed display 64 displays 
the speed at which corrugator 10 is producing corrugated paper. In FIG. 4, 
speed indicator 64 shows that corrugator 10 is producing corrugated paper 
at a rate of 639 feet per minute. Wet end 12 provides an analog reference 
voltage for controlling the speed of downstream machines in corrugator 10. 
This reference voltage is converted to a digital value at isolator station 
22 and provided to controller 24. Speed display 64 is constantly updated 
by controller 24 to display the speed of corrugator 10 based upon the 
digital value of the analog reference voltage. 
All of the information displayed in the operator messages shown in FIG. 3 
and FIG. 4 is capable of being transmitted by controller 24 to reporting 
system 28. In this preferred embodiment, reporting system 28 is a data 
base in a computer which is in the same plant as controller 24 but which 
is remote. Reporting system 28 can be any controller at any location so 
long as it is at least periodically linked with controller 24. 
There are essentially three things which cause corrugator 10 to stop or 
which keep it from being restarted. The first, and most frequent, is a 
standard operator control stop. This is where an operator merely pushes a 
stop button to stop corrugator 10. The second is a nonoperator control 
stop. This is a limit switch of any type operating properly to stop 
corrugator 10. The third is a component failure stop. This results from a 
faulty component such as a motor overload or a faulty circuit breaker. As 
previously discussed, the diagnostic system is capable of detecting all of 
these. Also, these can all be included in various report formats generated 
by reporting system 28. 
FIG. 5a shows a summary report format which is generated by reporting 
system 28. The report shows the total downtime in hours, total number of 
stops, total number of standard operator control stops, total number of 
non-operator control stops and the total number of other component failure 
stops. 
FIG. 5b is a more detailed report format generated by reporting system 28. 
This report contains the fault code for each fault condition detected by 
controller 24, the operator enteredreason for the fault condition, a brief 
description of the cause of the fault condition, the time that corrugator 
10 stopped and the duration of the downtime. 
FIG. 5c is a frequency format report generated by reporting system 28. This 
report shows the operator entered reason that corrugator 10 stopped, the 
corresponding description and the number of occurrences. 
FIG. 5d shows a severity report format generated by reporting system 28. 
This report contains the same information as the report in FIG. 5c except 
that instead of the number of occurrence of the fault conditions, the 
total time in hours is shown. 
FIG. 5e shows another form of frequency report format. This report shows 
the fault code associated with each fault condition detected by controller 
24, the corresponding description and the number of occurrences. 
FIG. 5f is a severity format report. This contains the same information as 
the report in FIG. 5e except, instead of the number of occurrences of each 
fault condition, the total hours of downtime caused by each fault 
condition is shown. 
In addition, other combinations of information can be combined by reporting 
system 28 into report formats which are useful to management personnel. 
These reports can be used to allocate maintenance and to pinpoint machine 
problem areas. Also, they can be used to determine operator problems such 
as where additional training is required. 
CONCLUSION 
Diagnostic system S of the present invention analyzed the current condition 
of critical points in each machine in corrugator 10. It is capable of 
diagnostic substantially all points which could cause corrugator 10 to be 
stopped. Controller 24 periodically polls the critical points which are 
analyzed and the state of fault latches 23 and determines when potential 
stoppages are arising. Controller 24 then warns the operator through using 
an operator message at display/printer 26. If a fault condition does 
arise, controller 24 provides an operator message at display/printer 26 
telling the operator what caused the fault condition, any subsequent 
faults which occurred and the current condition of corrugator 10 (i.e., 
what needs to be done to the machines in corrugator 10 in order to 
successfully restart corrugator 10). Controller 24 accomplishes this by 
supplying brief descriptions of the components causing the fault 
conditions and current conditions and help screens which include 
schematics, pictures, tutorials on how to remedy the fault conditions and 
current conditions and any other relevant documentation such as part 
numbers or print numbers which are associated with the fault condition or 
current condition. 
Since controller 24 is periodically polling the logic signals received by 
isolator station 22 at a fast rate, and since any change in state of logic 
signals is latched at fault latches 23, controller 24 will "see" even 
intermittent problems which cause corrugator 10 to go down. These 
intermittent problems will be indicated to the operator in an operator 
message displayed at display/printer 26. Additionally, when corrugator 10 
is stopped, controller 24 analyzes current condition of the critical 
points. Controller 24 keeps the operator apprised of what must be done, 
and in what order, to restart corrugator 10. 
All the information provided by diagnosting system S of the present 
invention helps operators and repair or service personnel to quickly 
locate the reason why corrugator 10 has been stopped, to fix it and to 
successfully restart corrugator 10. This provides large savings in 
downtime and waste which results in higher business retention and less 
overtime and service pay. 
All of the information acquired by diagnostic system S of the present 
invention has the capability of being uploaded into another system to be 
stored in a database. This information is analyzed and used, in this 
preferred embodiment, by reporting system 28 to produce production reports 
which are helpful in allocating resources and pinpointing problems. 
Additionally, diagnostic system S of the present invention has the 
capability of being networked with other diagnostic systems or other 
controllers. 
Although the present invention has been described with reference to 
preferred embodiments, workers skilled in the art will recognize that 
changes may be made in form and detail without departing from the spirit 
and scope of the invention.