Note: Descriptions are shown in the official language in which they were submitted.
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COLLECTING MANUFACTURING EQUIPMENT DOWNTIME DATA
DESCRIPTION
TECHNICAL FIELD
This invention relates generally to industrial
manufacturing processes, and more specifically to an
improved method and apparatus for collecting data relative
to manufacturing equipment downtime.
BACKGROUND ART
Known industrial manufacturing production
processes typically consist of multiple steps, or stages,
to produce a given product. Many, if not all, of the
stages include power usage for the control of each process
step. This power usage can be logged to generate a record
as to when the process step was operational, and when it
was not.
When the manufacturing equipment is not running
it is referred to as "downtime". Downtime can either be
planned (e. g., no work, nighttime, etc.) or unplanned
(e. g., mechanical breakdowns, spills, etc.). In some
situations, the cause of the downtime may be logged by
hand by the operator into batch records (where such batch
records are kept).
At other times, the cause for a given downtime
may be deciphered from the downtime pattern, if it is
distinctive. Or, the cause of the downtime may exist only
in the minds of the operations people, and subject to
their powers of recall. There is no known on-the-fly
dedicated system that exists for data gathering of
downtime causes.
Although major unplanned downtimes can be
dramatic enough to attract corrective action, cumulative
smaller downtime losses can escape unnoticed. Knowledge
of all downtime stoppages, their causes, duration and
sua~ation of this information would encourage corrective
action to be taken (or not taken), so that operating
efficiencies could be maximized. Furthermore, the
effectiveness of corrective measures could be quantified.
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DISCLOSURE OF INVENTION
The present invention provides a method and
apparatus for collecting manufacturing equipment downtime
data. Stopped manufacturing equipment is electrically
blocked from restarting (or mechanically blocked with
electric controls) until an acceptable reason has been
entered (either by code or direct verbiage identification)
and recognized by an electronic logic system. Locking out
the restart capability until the downtime cause has been
entered ensures that the causes for all downtimes are
recorded in a timely fashion.
Typically, this restart prevention consists of
controlling a process motor or device, but customizing may
be necessary depending on the situation. For instance, an
electric eye may be installed across a conveyor Zine to
detect downtime of product flow, because product can bunch
up (like on a bottle packaging line) and stop production
even though the conveyor motor is still running. This may
also include a new gate device to block movement until a
proper code has been entered. Other mechanical blocks may
be utilized, such as (but not limited to) a clutch plate
added to a drive shaft. However, the concept is the same.
Normal manufacturing operations cannot continue after
stoppage until an acceptable code for downtime has been
entered by the operator. This data may then be gathered
and recorded to measure and define explanations for lost
equipment running time. Other related data may also be
gathered.
The present invention is in essence a functional
operations meter. As such, it can be used as a comparator
to measure the benefit (or, conversely, the detriment) of
various operational conditions. Presently, for example,
raw material specification ranges, process parameters and
system procedures are largely determined by empirical
means. The present invention can be used to define peak
operational conditions more precisely and more easily than
prior methods. Provisions are included in the invention
to accept external data for comparative use.
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For example, raw material specifications are
typically set by the raw material vendor who defines
normal production standards. As best as possible the
performance range is evaluated by the purchasing factory,
but rarely are the extremes of range available for
evaluation. This method is often accepted as being
economically "good enough".
With the passage of time, raw material
specifications may drift around (within their range, or
drift in an unspecified condition). This change can
damage (or possibly even improve) the end product. If the
impact is dramatic enough for detection, the raw material
specification can be tightened back (or written in for the
first time if it did not previously exist). This can
increase the raw material cost. However. this new,
tighter range can be quantifiably compared to performance
for a more precise evaluation as described in the
following two paragraphs. This has traditionally been
determined largely by empirical estimations.
The present invention includes provisions for
adding reject counts and unit costs to determine reject
material cost. This is usually known with reasonable
accuracy before raw material specs are changed. Total
loss/unit made is equal to reject material costs/unit made
added to downtime labor costs/unit made. Since downtime
losses are known with greater precision with the method of
this invention, a more precise total loss can be
determined (or more easily determined). A curve can be
generated by plotting total losses/unit made against raw
material specification values. The integral under the
curve over any range represents the losses per units made
over the selected range.
The tighter the raw material specification
range, the more (generally) the raw material will cost.
To ascertain whether to pay a higher price for a tighter
range for a raw material the invention will support the
following format: The loss per unit made from each lot
that used the raw material within the selected narrow
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range are added together. This total is divided by the
number of lots used for data to determine the average loss
per unit made while staying within the tighter
specification. This process is repeated to determine the
(higher) average loss per unit made while operating within
the wider window raw material specification. Finally. the
ratio of the higher raw material cost per unit made
divided by the normal (broad-band) raw material cost per
unit made is multiplied times the average loss per unit
made at the tighter specification range (to account for
the price differential). The lower average cost is the
most profitable choice.
In addition to raw material issues, system
changes can impact on productivity. Presently, many
system changes are made intuitively. A simplistic example
would be to move a toolbox closer to the operator or
mechanic. It is often difficult to measure the impact of
a small system change like this amidst the amalgamation of
the "big picture" of a full production line.
The present invention allows the purported
improvement to be quantified by measuring before and after
performance. Since the invention is downtime-specific,
appropriate downtime data can be segregated to magnify
performance. In the toolbox example only repair downtimes
likely to be affected would be displayed (by total/unit
time and average time/incident) using before and after
data.
Sometimes these intuitive "improvements" are
subtly counter-productive. Because the present invention
can define downtime so specifically, other local increases
of lost productivity can be identified and reviewed for
any possible association with the initial system change.
In the toolbox example, the closer location could be
blocking the flow of material downstream. which would show
up as increased downtime at the downstream station.
Process changes can also be measured for impact.
As an example, if line speed Were increased, the curve of
actual total costs per unit made would first show the
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downward slope of reduced production costs per unit made
(due to the faster line speed): followed by a reversal of
slope direction upward of increased production losses per
unit made (due to inefficiencies of the higher speed).
5 Peak productivity occurs where the elope is minimal
(Dy/Dx=0). Presently this is determined mostly by
empirical means. This invention refines the precision,
and/or makes the determination easier to define.
Novel features of the inventive method and
apparatus include, but are not limited to, the following:
A. Forced manual prompt for downtime cause.
The method of data entry is unique.
B. Downtime reports (with causes) for normal
industrial production, as opposed to mere productivity
reports.
Everyone is aware of downtime; it's that which
reduces productivity. If downtime did not exist, nothing
would ever go wroag and total output would equal
theoretical production rate times time worked. Downtime
is the "friction" that prevents production from being
perfect. Intuitively, if one measures productivity, it
would seem that there is no apparent reason to measure
downtime, because it is simply that amount which is
missing from productivity. However, tracking downtime
allows its causes and categories to be tagged with it.
Displaying downtimes by various assorted flags is
diagnostically useful for reducing and eliminating an
appropriate portion of it. Itemized downtime reports can
be used to diagnostically reduce downtime.
C. Unlike other existing systems dedicated to
specific uses, the diagnostic solutions are not spoon-fed
to a machine over wires. This invention has a more
generic concept to make an affordable production
management system available to most all industries.
Management people (human beings) have to look at the data
produced by this invention for trends. totals, causes,
etc. Then they must decide what corrective actions they
want to take. This is the way that business has always
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been run. Industry gathers the best data they can afford
and makes the best decision they can. This invention
gives businesses better data at an affordable price. (The
cost is affordable because of its design and pre-packaged
software core.)
D. Further separation of downtime data into
subdivisions of planned and unplanned downtime events.
Pre-splitting downtime into planned and unplanned
categories enables evaluation of preventive and non-
preventive measures.
E. Allocation of downtime data sorted by
employee numbers to detect a need for additional training
and/or for best staff placement of employees (an algorithm
may be written to do this automatically).
F. Downtime causes created by human blunders
escape other systems. Because they do not lend themselves
to electrical sensor input, automation cannot cope with
this non-electrical event, yet during many production
operations human problems may account for more than half
of the outages. Of even greater significance, these
represent perhaps the most preventable of the downtime
events.
G. The key downtime data (cause) is fed
immediately to the computer as it happens.
H. The quality of productivity data will be
more accurate, because existing productivity reports can
mask downtime amounts and causes. Downtime reports
display all the "bad news". But, only if one knows what
the "bad news" is can anything be done to prevent it.
Many production rates can be "pumped up" for short bursts
to mask a downtime event. Then management does not know
that a faster rate may be possible, and they do not know
that something went wrong that might need to be changed so
it does not happen again. This does require management to
be more enlightened and less vindictive, because the
workers can often offer corrective ideas to solve
problems.
I. Planned downtimes of similar character can
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be measured against a standard (equivalent downta.mes
should be of comparable duration). Production run times
are often known, but change over (set-up) times are
accepted as is for whatever turns out. Often, substantial
equipment time can be lost during set-up time which could
have been spent productively. In most cases, this set-up
time is not comparatively monitored because real set-up
times are based not on the new set-up alone, but the
difference between the new and the previous setting. This
invention has the capability of distinguishing the various
categories of set-ups and establishing separate standards
for the nuances of each. In addition, standards for any
repetitive planned downtime can be established to monitor
this out-of-control lost time.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 (Prior Art) is a schematic view of a
typical manufacturing production control logic circuit
consisting of hardware and/or software components;
Fig. 2 is a schematic view of a motor control
logic circuit of this invention, illustrating two
modifications that may be made to the existing equipment
illustrated in Fig. 1; and
Fig. 3 is a schematic view of the conceptual
logic of this invention external to existing equipment.
BEST MODE FOR CARRYING OUT THE INVENTION
Definitions:
Downtime: Any time manufacturing
operations are not producing product.
Electronic Logic System (ELS): A PC and/or
a PLC.
Manufacturing Production Equipment: Any
electrical device, or plurality of devices, that modify a
material in such a way as to make, or contribute toward
making, a final product more marketable. (Used implicitly
throughout this specification as being equivalent to
manufacturing operations.)
Momentary Closed: Electrical contacts that
remain electrically "off" until a pushbutton is pressed by
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an operator. As long as the button is pressed in, the
contacts are closed (electrically "on"). When the button
is released the circuit reopens. In software logic this
functions as a close pulse.
Momentary Open: Reverse of Momentary
Closed. Electrical contacts that remain closed
(electrically "on") until a pushbutton is pressed by an
operator. Then the contacts open (electrically "off") and
remain open only as long as the button is held in. When
the button is released the contacts reclose. In software
logic this functions as an open (circuit-breaking) pulse.
Motor Control Starter Coil: The relay
coil, whether actual hardware or embedded in software,
that starts the device.
Motor Starter: Same as motor control
starter coil.
PC : Personal computer, the coamnon
computer.
Planned Downtime: Anticipated downtime,
such as at night, cleaning, lack of need, set-up time for
a different product, preventive maintenance, etc.
PLC: Programmable logic controller, an
electronic package that contains some or all of the
following features: internal relays, timers, counters,
logic, etc.; and external output relay contacts, analog
control signal outputs, input terminal contacts, keyboard
input interfaces, etc.
The Device: Same as manufacturing
production equipment; the entity being monitored for
downtime.
Unplanned Downtime: Unexpected downtime,
such as occurs due to equipment breakage, lack of feed
material, etc.
Referring now to Fig. l, a typical manufacturing
production control logic circuit may include the following
hardware and/or software components:
Power supply source 10. This may be 120
volts, 24 volts, 12 volts, 5 volts, etc., using either
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alternating (AC) or direct (DC) current, as long as the
voltage is compatible with the components.
Circuit completing corarton (or neutral)
return leg 12 to complete the circuit back to the source.
Stop pushbutton (switch) 14. It can be
either a single switch, ar more than one, as shown. It is
installed in series with the main logic circuit. It has
been historically installed as momentary open hardware,
but can also be built into software as safety allows. For
example, it may consist of a momentary (press & release),
normally closed style pushbutton used by the operator to
stop the motor (or other device).
Start pushbutton (switch) 16. It can be
either a single switch, or more than one, as shown. It is
installed in parallel with the motor latching relay
contacts 18 in the main logic circuit. It has been
historically installed as momentary close hardware, but
can also be built into software as safety allows. For
example, it may consist of a momentary (press & release)
normally open style pushbutton used by the operator to
start the motor (or device).
Latching Relay Contacts 18. This is a
normally open style auxiliary contact physically located
adjacent to the motor starter coil (described infra).
When the start button 16 is pressed, the motor starter
coil is activated (as long as all the safeties are
satisfied), the latching relay contacts 18 close and,
because of these contacts 18, the motor keeps running
after the start pushbutton 16 is released.
Safety Contacts 20. They can be normally
open style (as shown) or normally closed, as logic
warrants. They can be relay contacts, pressure switches,
alarm contacts, etc. They are wired in series with the
motor starter coil as shown but are typically installed in
front of the stop button to minimize the length of hot
Wires. They are functionally correct but are shown here
after the stop button 14 for schematic clarity. These can
vary from none to an unrestricted count in number
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depending on the application. They can be either in
hardware or embedded in software. They are typically used
to assure that the safety and process parameters are, and
remain, met.
5 Thermal overload protector such as a fuse
22 (shown) or circuit breaker.
Other Safety (or Operational) Devices 24:
These include proximity switches (for guard-in-place,
etc.), trip wires (to keep hands and bodies away, etc.)
10 and other miscellaneous devices to shut the equipment off,
which are not otherwise covered under safety contacts 20.
Their physical location is as described for the safety
contacts, supra.
Motor Starter Coil 26: This is a relay
coil typically sold in a package to start a motor. It has
three contacts for operating a three phase electrical
motor. It is connected to a fourth pair of contacts 18 to
latch the circuit closed for running. It occasionally has
additional auxiliary contacts for logic use, in which case
an extra coil (described infra) is not needed. The device
has been called a motor for convenience throughout this
schematic; but it can be any electrical device, such as a
heater, solenoid, etc.
When the conditions have been met to satisfy all
of the process/safety interlocks 20, 22, 24, momentary
pressing of the start button 16 completes the circuit from
power supply source 10 to common return leg 12 to turn on
the motor control starter coil 26. The motor control
starter coil 26 has multiple contacts, some of which start
the device. The pair of normally open contacts 18 in
parallel with the start button 16 are closed by the motor
starter 26 to latch in (i.e., lock to the on position)
when the start button 16 is released. These latching
contacts 18 are what keeps the device running after the
start button has been released.
A momentary (or longer) break in the circuit
from power supply source 10 to common return leg 12 by
pressing the stop button 14 or by opening any of the
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safety/process contacts (interlocks) 20, 22, 24 causes the
motor control starter coil 26 to de-energize. When motor
starter 26 de-energizes, the latching contacts 18 fall out
(open). After the cause for the stoppage has been
rectified, and all the permissive contacts (at stop button
14, safety contacts 20, fuse 22 and other safety devices
24) have been satisfied again, the device will not restart
because the latching contacts 18 (which dropped out when
the device was shut off) will remain open until the start
button 16 is pressed again. This sequence is repeated as
necessary to start and stop the device.
Fig. 2 is a schematic view of a motor control
logic circuit of this invention, illustrating two
modifications that may be made to the existing equipment
- 15- - of -Fig. 1: The present invention introduces an additional
pair of contacts as logic contacts 30 in series with the
start button 16 and in parallel with the latching contacts
18. This contact arrangement is unusual since it only
blacks the device from starting. It does not (unlike the
safety/pracess interlocks) stop the device once it is
running. Process/safety interlocks must stop the device
in the fail mode, both from running as well as to prevent
the device from starting, and are installed in series with
the main logic circuit leg as described supra. These
logic contacts 30 function as and will usually be normally
open style, but could be physically normally closed style
if logic conditions require it. Contacts 30 could be
physically placed anywhere in the circuit, but logic will
force the contacts 30 to behave as if placed where shown.
They will never stop running equipment from running; they
will only prevent stopped equipment from restarting.
Optionally, secondary relay coil 32 is a
supplement to the motor start coil 26. The motor start
coil 26 rarely has spare contacts. This new relay coil 32
merely expands the motor starter's contact capacity by two
or more additional pairs of contacts. It is active when
the motor is on. It closes the new logic contacts 30 and
opens the motor status contacts 50 (described and
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illustrated in conjunction with Fig. 3, infra) when the
motor comes on. It reverses the action when the motor
drops out.
A possible concern of management is that, during
retrofit installation of the inventive apparatus, any kind
of tinkering might shut the production down. The fact
that there are only two modifications, and both are
simple, minimizes the risk of problems to existing
equipment. Furthermore manual bypass contacts (not shown)
can be temporarily installed to bypass the contacts 30 and
keep all stations running until the system has been
debugged.
The logic contacts 30 are controlled by a
separate circuit. Fig. 3 is a schematic view of the
conceptual logic external to the existing equipment, and
includes the following components:
Decision Device 40: This may be either a
PC (personal computer) or a PLC (programmable logic
controller), depending on the situational needs.
Permissive coil 42: This coil closes the
new logic contacts 30 installed in the existing equipment
to allow the motor to start. Permissive coil 42 can also
be used to close the status indicator contacts 46, infra.
Decision Device Contacts 44: When the
decision device 40 is satisfied with the downtime cause
input via keypad 52, it closes decision device contacts 44
to activate (start) the permissive coil 42. As soon as
the motor stops, motor status contacts 50 advise the
decision device 40 that the motor is down, and the
decision device 40 opens these contacts 44.
Status Indicator Contacts 46: These
contacts activate the status circuit. They are typically
normally open style contacts as shown. They are
controlled by the decision device 40 (for logic) and the
permissive coil 42 (for hardware).
Status Condition 48: This can be as simple
as an indicator light (as shown), and/or as sophisticated
as a displayed message on a monitor or computer screen.
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It advises the operator that the inventive circuit has
been satisfied, and the equipment is ready to go if
everything else has been satisfied. It can be activated
either by the status indicator contacts 46, or else
directly from the decision device 40 itself.
Motor Status Contacts 50. These contacts
are physically closed when the motor is running, and open
when the motor stops. They can be normally closed style
(as shown) or normally open style as long as the action is
consistent with the logic.
Keypad 52: This MMI (man to machine
interface) allows the operator to provide the required
data.
Data is input by an operator via keypad 52 (or
any other appropriate input means, such as touch-screen
keypad, voice recognition, etc.). The data represents a
codified or real description for the cause of an existing
downtime. The input data is screened by electronic logic
system 40 for acceptability. If rejected, the input data
entered at the keypad may be cleared and new data entered.
If the downtime event is of long duration logic allows
multiple causes to be assigned proportionately to the
downtime interval.
If the electronic logic system 40 passes the
input data, it activates permissive relay coil 42 via a
momentary pulse closure of normally open decision device
contacts 44 in series with the permissive coil 42
(connected as necessary to hardware). Permissive coil 42
may include a pair of contacts 30 (Fig. 2) that close so
the device start button 16 can operate when pressed, and a
third pair of normally open contacts 46 that close to
energize permissive indicator 48 (by light or displayed
message).
The logic coil circuit can be completely
software-based, hardware-based, or a mixture of hardware
and software. Other related data can be entered as
appropriate, e.g., at the start of the day, at the start
of the batch, as employees change, or as keyed to process
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changes.
In its simplest format one digit (of 10) can be
used at the keyboard 52 input to the electronic logic
system 40 to indicate input cause of downtime data.
The inventive system thus provides a flip/flop
circuit that mandates that a downtime entry be given in
order to restart the device. Restarting the device clears
out the downtime entry from being reused. Stopping the
device requires another downtime entry in order to restart
the device.
All the downtime duration data and causes, along
with related data, may be gathered and sorted as per
filter screens of a spreadsheet. Then this data may be
tabulated and displayed in an appropriate database or
spreadsheet, such as EXCEL 97, SQL or ACCESS.
Typical of an information system. there are
three basic subdivisions. There is an input package, a
transmission package and an output package. Since these
packages may be utilized by various clients in various
industries, no two systems will be identical. However,
within each subdivision there are similarities. Existing
equipment will generally be modified to include one extra
set of permissive contacts to start each piece of
equipment. The contacts will latch and stay latched until
the equipment stops running by any means previously used
to stop it, and then the latching logic will drop out.
Other modifications may be necessary to gather additional
data requested by the client (such as rates of operation,
station step, etc.). However, they may follow a
generalized program as described next, but custom-tailored
to each need.
Modifications to Existing Equipment to Receive Input Data
Start Boxes
Each "Monitored Piece of Equipment", also known
as a "Unit Operation", will be referred to as a "Station"
for the balance of this system description. Each station
will receive a minimum modification, consisting of
insertion of an additional pair of permissive contacts and
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feedback from the station starter confirming start-up.
Furthermore, a new "Start Box" is connected to the "Input
Data Gathering Base", both of which are totally
independent of the client's existing system. There are
5 two basic ways (personal computer or programmable logic
controller) to provide a start station package. When PC's
(Personal Computers) are used at a station, the Start Box
and Input Data Gathering Box are likely to be together and
dedicated.
10 PC inputs offer more choices because of their
greater computing power. Typically there would be a
normal computer screen and keypad. However, PC's can be
modified to have a touch screen. Touching an area of the
screen that looks like a button or other mnemonic image
15 can often allow faster data flow. Voice recognition is an
even more elegant choice when a hands-free input is
needed.
PLC's (prograa~able logic controllers) can be
used in place of PC's, and they are generally more rugged.
PLC's are commercially available devices from Allen
Bradley, Siemens Inc., and numerous other sources that
consist of terminals for input and output data, both
digital and analog; where the input data can be logically
evaluated and processed against time, count and other
data. Another way to look at it is to consider it to be a
box of relays, timers, counters and constants that can be
wired using a PC (once it has been wired the PC is no
longer needed).
The PLC's are expected to be remote from their
Start Boxes and would generally be expected to process
data from multiple Start Boxes. The Start Box for PLC
driven stations will typically consist of a keypad and
brief display screen.
A client may request that production rates or
other information be tagged to the downtime data. This
will likely require other modifications to the existing
equipment to intercept this information most conveniently
for the operator. Other custom modifications may be
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required to meet individual customer requirements as they
arise.
There are as many Start Boxes as there are
(monitored) Stations in a factory.
Input System Package
Built into each station will typically be its
identity. It will reside in its Input Data Gathering Base
(IDGB). All data gathered from each of these stations
will be tagged with the station identification. All
downtime data will be later dividable into the tagged
categories for sorting by tagged categories. Station
identification will be built-in and will require no
operator input.
When an operator first attempts to start the
station via the new Start Box in a typical operation, he
will be prompted to enter his employee number. The IDGB
will verify each entry as eligible. Additional employee
entries are permissible up to a limit established by the
client for maximum employees/station for each station.
The next prompt is for a product code. The IDGB
will check to verify if entry is eligible. If it is
different from the previous entry, a downtime entry for
cleaning may be confirmed as a permissive if desired by
the client. A basic multi-client program may include many
provisions like this, citing these optional features for
inclusion or deletion. Deletion of these pre-written
features can occur more easily at the time of client
installation than adding custom code to a core program.
Only one entry for a product code is allowed at a time.
The next prompt is for lot number. After
checking for acceptance the standard program will query
for an "Are you sure?" response from the operator if the
lot number is not running sequentially with the previous
numbers.
The last prompt is for the cause of the existing
downtime, which at the beginning of the day is typically
the code for: "Planned/Overnight." Pressing the Start
Button now will start the equipment.
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The IDGB permissive contacts will remain latched
and the station will remain running as multiple employees
come and go (as long as at least one remains logged on),
and lot numbers may change without shutting down (if this
is consistent with client-company policy).
However, once the station stops for any reason
that it would have stopped for in the past, the latched
contacts drop out. The IDGB detaches the run-enable mode
and starts logging (off) downtime. The operator must
enter a cause for the stoppage before the equipment can
restart. The IDGB will verify the legitimacy of the entry
and latch for restart. Depending on how the Start Box is
configured, allowance can be made for custom messages to
be typed in downtime. Multiple entries for downtime
causes are allowed, but the mandate is: at least one must
be entered in order to continue.
Corrections to downtime causes may be typed in
and transmitted to the IDGH prior to restarting. Once
restarted the original data is erasable, but displayed in
a modified font.
As soon as the new feedback coil acknowledges
that the station is running again, the IDGB calculates the
time interval that the station was down (alternatively,
the differential time interval can be calculated on the
spreadsheet or database processor). It also subdivides
this interval by any other changes (staffing, etc.) that
occurred during the downtime interval. All of this data
is keyed to the start of the downtime and stored in the
IDGB for transmission to a central data base.
An exception for restart blockages will be
allowed in the set-up and related modes so as not to
impede the set-up process. Appropriate limitations will
prevent abuse of this bypass.
There are multiple Input Data Gathering Bases,
albeit not necessarily as many as the Start Boxes. since
multiple Start Boxes can be ganged onto single IDGB's.
Transmission Package
Depending on the capacity and format of the data
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18
highway used by the client, one can either install a new
independent Local Area Network (LAN) or use the existing
LAN system, or connect the input with the output
database/spread sheet processor directly if the system is
small enough. A description of some typical transmission
systems follows:
A burst-mode transmission system functions as
follows: Triggered by real clock time, midnight for
example, all of the data that has been accumulated in the
IDGH will be transferred to a storage disk for permanent
filing and a duplicate will be sent to the Master Output
Spreadsheet/Database Processor(s). A dynamic
transmission system functions on-the-fly as follows:
Conversely, the trigger may merely be a change of state at
the IDGB if the output is used as the workhorse for data
manipulation and/or the IDGB's memory is limited.
Depending on final client system capacity, the
LAN may split the output load into segments for output
processing by more than one Output Spreadsheet/Database
Processor (OSDP). The LAN will confirm the validity of
the transmission, then stagger-erase (cascade disappearing
data by holding it until verification of valid receipt
before erasing the oldest data). After the LAN is
satisfied it will command the local IDGB's to clear and
reset their input logs. It will also command the OSDP(s)
to start processing. The LAN will make one last
confirmation of the IDGB instructions to confirm proper
erasure and performance, and then it will go back to
sleep. In other words, each time data is transmitted, it
will be checked for valid transmission before erasing, and
the data at the output will be recorded on tape or
equivalent for a permanent record.
Besides the normal wake-up call of the LAN, it
will be awakened by any detectable Priority 10 (highest)
Failure of an IDGB for immediate network alarm
transmission. It will also transmit category information
(new employee names, new downtime causes, new lot numbers,
etc.) from the OSDP's to the IDGB's as needed.
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19
There is normally only one LAN required.
Output Spreadsheet/Database Processor
The Output Spreadsheet/Database Processor (OSDP)
is a coa~ercially available spreadsheet preprogrammed with
macros and other software as needed to receive the
transmitted input data, sort and organize it into a master
format, and print these reports on a prescheduled time
frame. Additionally, the structure can be organized so
that sorting of downtime data can be presented in any tag
priority sorting, on any time basis (capacity allowing).
It is preferable to leave the tag variables, and
especially the Downtime Cause Tags, to be as accessible
and free for client modification as possible.
Modem ports (controlled by the client) may allow
remote troubleshooting of future problems that may occur
to help the client reduce their maintenance costs of this
system.
Benefits of the inventive method and system
include:
1. Prior art downtime reports, such as
they exist, do not segregate planned downtime from
unplanned downtime. The present invention separates
planned and unplanned downtime (based on the cause).
2. Presently, the causes for downtime
come from operator recollections and/or scouring over
cryptic batch notations such as they exist. This is
after-the-fact data. The present invention couples entry
of a downtime cause with blockage of restarting the
device, and forces collection of timely (more accurate)
data.
3. Collection of on/off data via an
ammeter recorder or voltmeter recorder do not identify
causes of downtime because they would be limited to only
identifying causes that could be pre-programmed into them.
This precludes all human-type errors and would limit the
number of identifiable machine-caused downtimes to a
uselessly small number in most cases.
4. Data entry can be as fast as a one key
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entry (for 0 through 8 general causes, 9 preferably being
reserved for other data) for minimal delay of production
resumption. Speed of data entry is important in that slow
complicated data entries reduce the reliability of the
5 data and extend the downtime by delaying restart of the
device.
5. The data entry format, although geared
for speed, can be quickly modified in the field at the
electronic logic system for more detailed (e. g., expanded
10 digit or narrative text) entries for trouble shooting when
warranted.
6. Planned downtime, as well as the
obvious unplanned downtime, can also be broken into
categories in order to measure cleaning and set-up times.
15 While this invention has been described in
connection with preferred embodiments thereof, it is
obvious that modifications and changes therein may be made
by those skilled in the art to which it pertains without
departing from the spirit and scope of the invention.
20 Accordingly, the scope of this invention is to be limited
only by the appended claims and equivalents.
