Note: Descriptions are shown in the official language in which they were submitted.
CONVEYING SYSTEM AND METHOD OF ASSOCIATING DATA TO AN ITEM
BEING TRANSPORTED BY THE CONVEYING SYSTEM
[0001]
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to conveying systems and methods, and in
particular
to conveying systems and methods of associating data to items being
transported by the
conveying system.
Description of Related Art
[0003] Conveying systems are conventionally used in a number of applications,
such as
packaging systems, order fulfillment systems, manufacturing systems, shipping
sortation
systems, and returns processing systems. Some of these conveying systems use
centralized
multi-horsepower AC motors to drive shafts, belts or chains that in turn move
banks of rollers
to transport items throughout the conveying system. Others are based on
rollers with internal
DC "micro-horsepower" motors that drive a localized segment of rollers. The
latter systems
include brushless DC roller conveying systems. A brushless DC roller conveying
system is
built around several components and features, including drive rollers with
self-contained
brushless DC motors, intelligent local controllers and networking between the
controllers
based on bidirectional communication protocols,
[0004] One methodology for controlling brushless DC roller conveying systems
uses the
local controllers to control local functions in each zone of the conveying
system but uses a
centralized controller to track "items" (such as corrugated boxes, plastic
totes, or pallets) as
they are transported throughout the conveying system. This tracking occurs by
using the
centralized controllers to uniquely identify items at decision points in the
conveyor system.
These decision points include, for example, diverts, transfers, merges, order
picking zones,
weighing, sortation, and printing.
[0005] To uniquely identify the items, the conveyor systems use bar codes,
usually printed
on adhesive labels that may be adhered to the items. Alternatively, when
reusable totes to
hold the items, a permanent bar code label is assigned to the item(s)
contained within the tote.
The bar code ID associated with the permanent label is re-used or re-assigned
as the tote
contents are changed.
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[0006] As items are transported throughout the conveyor system, bar code
scanners are
positioned at decision points to read the bar codes. At each decision point,
the bar code
inforination is electronically sent to the centralized controller, and that
centralized controller
determines what needs to be done with the item or what data for that item is
required at that bar
code scan location. This methodology has a few negative aspects. Firstly, bar
code scanning
and related equipment capable of reading bar codes on moving items is
expensive and can
represent a large percentage of the cost of a typical automated conveyor
system. Secondly, the
bar code scanners must be tied electronically to the central control system,
resulting in
extensive and expensive data communication networks and associated cabling.
Thirdly,
information required at decision points is stored in a central database, and
thus access to that
database in a timely manner can become challenging on large automated conveyor
systems, as
the central controller must service all decision points simultaneously.
[0007] Usually, the bar codes used in automated conveyor systems are one-
dimensional
bar codes that uniquely identify the item. However, the one dimensional bar
codes do not
contain any additional data about the item. Instead, the data that is needed
to determine the
functions to be performed by the conveying system is stored remotely in a
database
associated with the centralized controller. This data can be a route the item
must take on the
conveyor system, order data, sort point, return point, etc.
[0008] The use of two-dimensional bar codes has allowed some of this
additional data to
be passed along with the item, but the data within the bar code cannot be
updated. These
two-dimensional bar codes can simplify some sortation systems by including
data about a
predefined route of a specific item within the automated conveyor system.
However, the data
on the two-dimensional bar code cannot be updated.
SUMMARY OF THE INVENTION
[0009] A method of associating data to an item being transported by a
conveying system,
according to an embodiment of the present invention, comprises the steps of:
receiving an
item into a first zone of a conveying system; receiving data associated with
the item and
storing the data into a first storage memory associated with the first zone;
transporting the
item into a second zone of the conveying system; and transferring the data
stored in the first
storage memory into a second storage memory associated with the second zone.
[0010[ The step of receiving data associated with the item may include reading
data from a
data tag associated with the item using a data reader associated with the
first zone. The data
read by the data reader may be stored into the first storage memory, or the
data read by the
data reader may be sent to a central database, and wherein data received from
the central
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database is stored into the first storage memory. The data reader may include
at least one of a
bar code reader and a RFID reader.
[0011] The method may further include the step of sensing a property of the
item using a
sensor associated with the second zone. The step of sensing a property of the
item using a
sensor associated with the second zone may include sensing a weight of the
item using a scale
associated with the second zone. The data associated with the sensed property
may be stored
into the second storage memory.
[0012] The method may further includes the steps of transporting the item into
a third zone
of the conveying system and transferring the data stored in the second storage
memory into a
third storage memory associated with the second zone. The transferred data
into the third
storage memory may include the data transferred from the first storage and the
sensed
property data stored into the second storage memory.
[0013] The method may further include processing the item in the third zone
based on the
sensed property data stored in the third storage memory. Processing the item
may include
transporting the item into a fourth zone of the conveying system if the data
associated with
the sensed property meets a predetermined standard and transporting the item
into a fifth zone
of the conveying system if the data associated with the sensed property fails
to meet the
predetermined standard. The sensed property may be a weight of the item, and
the
predetermined standard may be a prescribed tolerance within an expected weight
of the item.
[0014] The processing the item may include printing a label using a label
printer associated
with the third zone based on the sensed property data stored in the third
storage memory.
[0015] A conveying system according to an embodiment of the present invention
may
include: a plurality of zones, each comprising: a conveyor section that
transports an item; a
driver that drives the conveyor section; a storage memory that stores data
associated with the
item; and a controller that communicates with a controller of an adjacent
zone, controls the
driver to transport the item into the adjacent zone and controls the storage
memory to transfer
the stored data into the storage memory of the adjacent zone.
[0016] One of the plurality of zones may include a data reader that reads data
from a data
tag associated with the item. Thee data reader may include at least one of a
bar code reader
and a RFID reader.
[0017] One of the plurality of zones may include a sensor that senses a
property of the
item. The sensor may be a scale that senses a weight of the item.
[0018] The plurality of zones may include first, second and third zones, and
wherein the
controller of the first zone controls the driver to transport the item into
the second zone if data
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stored in the storage memory associated with the first zone meets a
predetermined standard
and controls the driver to transport the item into the third zone if the data
in the storage
memory associated with the first zone fails to meet the predetermined
standard.
[0019] One of the plurality of zones may include a processor that processes an
item based
on the data stored in the storage memory. The processor may be a label printer
that prints a
label for the item based on a property of the item.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates a conveying system and method of associating data to
an item
being transported by the conveying system, using a bar code;
[0021] FIG. 2 illustrates a conveying system and method of associating data to
an item
being transported by the conveying system using an RFID data tag;
[0022] FIG. 3 illustrates a conveying system and method of associating data to
an item
being transported by the conveying system according to an embodiment of the
present
invention; and
[0023] FIG. 4 illustrates a first and second example of a conveyor system, the
first example
being without the storage memory and the second example including the storage
memory.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 illustrates a conveying system and method of associating data to
an item 1
being transported by the conveying system, wherein a one-dimensional bar code
2 is affixed
to the item 1. As shown, the conveying system includes a first zone 10 and a
second zone 20.
Each zone includes a conveyor section 11, 21 that transports the item 1, a
driver 12, 22 that
drives the conveyor section 11, 21, a data tag reader 13, 23 (in this case, a
bar code reader)
that reads the data encoded in the one-dimensional bar code 2 and a local
controller 14, 24.
The first zone 10 further includes a scale 16 and the second zone 20 further
includes a label
printer 27. The conveying system further includes a centralized controller 40
and a
centralized database 41.
[0025] In a method of FIG. 1, the item 1 having a one-dimensional bar code 2
is received
into zone 10, wherein the data tag reader 13 reads the one-dimensional bar
code 2 and sends
the data associated with the one-dimensional bar code 2 to the local
controller 14, which
sends the data to the centralized controller 40. The centralized controller 40
then retrieves an
expected weight of the item 1 from database 41 and sends the expected weight
data to local
controller 14. Meanwhile, the scale 16 weighs the item 1 and sends the data
associated with
the actual weight of the item to the controller 14, which compares the weight
from scale 16
with the expected weight received from the centralized controller 40. If the
local controller
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14 determines that the actual weight is not the same the expected weight,
within a prescribed
tolerance, then the local controller 14 will divert the item 1 to another zone
(not shown).
Otherwise, local controller 14 queries local controller 24 to determine if the
second zone 20
can accept the item 1 currently occupying the first zone 10. If the second
zone 20 is clear
(has no item), the second zone 20 will control driver 22 to turn on conveyer
section 21, and
the second zone 20 will notify the first zone 10 that the second zone 20 can
accept the item 1.
Upon receiving the notification from the second zone 20, the first zone 10
will control driver
12 to turn on convey section 11, causing the item 1 to be transported into the
second zone 20.
Meanwhile, the data associated with the weight sensed by scale 16 is sent to
the centralized
controller 40 and stored in database 41. In the second zone 20, the data tag
reader 23 reads
the one-dimensional bar code 2 and sends the bar code data associated with the
one-
dimensional bar code 2 to the local controller 24, which then sends the data
to the centralized
controller 40. After accessing the database 41 to retrieve the weight data
associated with the
one-dimensional bar code, the centralized controller will then send the weight
data to the
local controller 24, which then instructs the label printer 27 to print an
appropriate shipping
label 28 based on the item weight. A problem of the system and method of FIG.
1 is the
nature of the one-dimensional bar code 2 that merely includes a single number
or code that
represents the item 1 but does not include actual data, such as estimated
weight, related to the
item 1. Another problem is the static nature of the one-dimensional bar code 2
that does not
allow the weight data to be passed from the first zone 10 to the second zone
20 along with the
item 1.
[0026] The use of two-dimensional bar codes can allow for some of the actual
data, such as
estimated weight, to be included in the bar code, but does not allow for
updating of the actual
data included in the bar code.
[0027] FIG. 2 illustrates a conveying system and method of associating data to
an item 1
being transported by the conveying system, wherein a RFID tag 3 is affixed to
the item 1. As
shown, the conveying system includes a first zone 10 and a second zone 20.
Each zone
includes a conveyor section 11, 21 that transports the item 1, a driver 12, 22
that drives the
conveyor section 11, 21, a data tag reader 13, 23 (in this case, an RFID
reader) that reads the
data encoded in the RFID tag 3 and a local controller 14, 24. The first zone
10 further
includes a scale 16 and the second zone 20 further includes a label printer
27.
[0028] In a method of FIG. 2, the item 1 having a RFID tag 3 is received into
zone 10,
wherein the data tag reader 13 reads the RFID tag 3 and sends the data
associated with the
RFID tag 3 to the local controller 14. If the data includes expected weight
data, then it is not
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necessary to access a centralized controller to retrieve an expected weight of
the item 1.
Meanwhile, the scale 16 weighs the item 1 and sends the data associated with
the actual
weight of the item to the local controller 14, which compares the weight from
scale 16 with
the expected weight. If the local controller 14 determines that the actual
weight is not the
same the expected weight, within a prescribed tolerance, then the local
controller 14 will
divert the item 1 to another zone (not shown). Otherwise, local controller 14
queries local
controller 24 to determine if the second zone 20 can accept the item 1
currently occupying the
first zone 10. If the second zone 20 is clear (has no item), the second zone
20 will control
driver 22 to turn on conveyer section 21, and the second zone 20 will notify
the first zone 10
that the second zone 20 can accept the item 1. Upon receiving the notification
from the
second zone 20, the first zone 10 will control driver 12 to turn on convey
section 11, causing
the item 1 to be transported into the second zone 20. Meanwhile, the data
associated with the
actual weight sensed by scale 16 is written onto the RFID tag 3. After the
item is transported
to the second zone 20, the data tag reader 23 reads the RFID tag 3 and sends
the data
associated with the RFID tag 3 to the local controller 24. After retrieving
the actual weight
data from the RFID tag 3, the local controller 24 will then instructs the
label printer 27 to
print an appropriate shipping label 28 based on the item weight.
[0029] The benefit of the system and method of FIG. 2 is that the RFID tags
allow the data
to move with the item and also be updated with new data created after the RFID
tag was
assigned to the item. However, RFID tags are expensive and not an option for
applications
where items are inexpensive or where the item is shipped and not returned.
This problem can
be overcome to some extent by attaching the RFID tags to reusable totes, where
the RFID tag
is assigned to the item(s) contained within the tote, and the RFID tag is
reused or reassigned
as the tote contents are changed. However, in this case, another problem is
that RFID are
write limited, meaning they can only be written on a limited number of times
before they fail
to operate reliably. Another problem is that RED data tag readers are needed
at each
decision point in the conveying process. Yet another problem is that the speed
at which
RFID tags can be accessed while an item is moving is limited, with is
especially a problem
when large amounts of data are being read.
[0030] According to an embodiment of the present invention, FIG. 3 illustrates
a conveying
system and method of associating data to an item being transported by the
conveying system,
wherein a storage memory is associated with each zone of the conveying system.
As shown,
the conveying system includes a first zone 10 and a second zone 20. Each zone
includes a
conveyor section 11, 21 that transports the item 1, a driver 12, 22 that
drives the conveyor
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section 11, 21, a data tag reader 13, 23 (in this case, a bar code reader)
that reads the data
encoded in a one-dimensional bar code 2 associated with the item 1, a local
controller 14, 24
and a storage memory 15, 25. The first zone 10 further includes a scale 16 and
the second
zone 20 further includes a label printer 27. The
conveying system further includes a
centralized controller 40 and a centralized database 41.
[0031] In a method of FIG. 3, the item 1 having a one-dimensional bar code 2
is received
into zone 10, wherein the data tag reader 13 reads the one-dimensional bar
code 2 and sends
the data associated with the one-dimensional bar code 2 to the local
controller 14, which
sends the bar code data to the centralized controller 40. The centralized
controller 40 then
retrieves an expected weight of the item 1 from database 41 and sends the
expected weight
data to local controller 14. Meanwhile, the scale 16 weighs the item 1 and
sends the data
associated with the actual weight of the item to the controller 14, which
compares the weight
from scale 16 with the expected weight received from the centralized
controller 40. If the
local controller 14 determines that the actual weight is not the same the
expected weight,
within a prescribed tolerance, then the local controller 14 will divert the
item 1 to another
zone (not shown). Otherwise, local controller 14 queries local controller 24
to determine if
the second zone 20 can accept the item 1 currently occupying the first zone
10. If the second
zone 20 is clear (has no item), the second zone 20 will control driver 22 to
turn on conveyer
section 21, and the second zone 20 will notify the first zone 10 that the
second zone 20 can
accept the item 1. Upon receiving the notification from the second zone 20,
the local
controller 14 of the first zone 10 will control driver 12 to turn on conveyor
section 11,
causing the item 1 to be transported into the second zone 20. Meanwhile, the
data from the
one-dimensional bar code 2 and the weight data from the scale 16 that was
stored in the
storage memory 15 of the first zone 10 is transferred to storage memory 25 of
the second
zone 20. In the second zone 20, after retrieving the actual weight data from
storage memory
25, the local controller 24 instructs the label printer 27 to print an
appropriate shipping label
28 based on the item weight.
[0032] According to FIG. 3, data is allowed to move with the item and also be
updated
with new data created after the one-dimensional bar code was assigned to the
item. Also, a
data tag reader at each decision point in the conveying process can be
avoided, and the time
needed for reading physical data tags, such as bar codes or RFID tags, can be
avoided and the
time needed for accessing the centralized controller 40 can be avoided.
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[0033] It will be understood that the above described system method is one
exemplary
embodiment and that the system and may include variations from the above
description as
well as additional features, some of which are described below.
[0034] As shown in FIG. 3, the item is encoded with a one-dimensional bar code
that
merely includes a single number or code that represents the item but does not
include actual
data, such as estimated weight, related to the item. The one-dimensional bar
code was chosen
for FIG. 3 to show that the benefits of using the two-dimensional bar code or
RFID data tag
could be achieved by the system and method of FIG. 3 even using the one-
dimensional bar
code. However, any data tags could be used, including one-dimensional bar
codes, two-
dimensional bar codes and RFID data tags. Also, as shown in FIG. 3, the data
tag is affixed
to the item. However, the data tag could be affixed to a container holding the
item or be
integrated with the container holding the item, or otherwise associated with
the item.
[0035] As shown in FIG. 3, the first zone includes a scale and the second zone
includes a
label printer. These functions of the first zone and second zone were chosen
for illustrating
benefits for the system and method, which could apply to any number of
circumstances that
benefit from allowing data to move through the conveying system with the item,
such as at
decision points in the conveying system, which may include diverts, transfers,
merges, order
picking zones, weighing, sortation, and printing.
[0036] The conveying system may use rollers with internal DC "micro-
horsepower"
motors that drive a localized segment of rollers, including brushless DC
roller conveying
systems. The brushless DC roller conveying system may include drive rollers
with self-
contained brushless DC motors, intelligent local controllers and networking
between the local
controllers based on bidirectional communication protocols. These types of
conveyor systems
may segment long runs of conveyor into zones that hold a single item in a
"Zone". Each zone
may have its own powered/motorized roller and can be started and stopped
independently of
the other zones on the system.
[0037] The local controller, in addition to driving the brush-less motor, also
may also have
the capability of communicating with external control components through
digital I/O (Inputs
and Outputs). These devices include but are not limited to photo eye sensors,
limit switches,
operator interfaces, solenoid valves, motor contactors, etc. Each controller
may also contain a
microprocessor and storage memory. Compared to using a rewritable RFID tag,
storage
memory may have much more storage capacity, and does not exist as a physical
device that
travels with the item, and instead acts a virtual data tag that travels with
the item. Also, since
the data tag is virtual, there is no cost for the tag itself or the
reader/writer devices that are
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conventionally required throughout conveying systems to read and write RFID
tags. Also, since
the data is transferred electronically, there are no speed issues relative to
the transfer of the data.
[0038] The conveyer system may include a motor driven roller conveyor line,
which is
basically a series of individual conveyors (zones) connected end to end to
create longer
lengths of conveyor. Each section of conveyor may contain its own drive roller
which is
coupled to the other rollers in that zone. Typically, as an item is conveyed
on a conveyor
line, each local controller communicates with the controller(s) adjacent to it
to move an item
from one zone to another. The storage memory may reside on a zone controller
card of each
local controller. When an item enters or is placed onto the conveyor line
(inducted), specific
data relating to that item may be extracted from a central database and is
transferred
electronically to the controller and onto the storage memory of the zone
controller card.
[0039] The following description compares, in more detail, a first example
wherein a bar
code is associated with an item to be transported in a conveyer system without
the storage
memory and a second example wherein the storage memory is included.
[0040] According to the first and second examples, a shipping manifest system
generally
takes a completed customer order in a box or tote and weighs the item to
determine if the
item is the correct weight and then either diverts the box to a reject lane or
continues on and
prints a shipping label specific to that order.
[0041] According to the first example, illustrated in FIG. 4, a box (the item)
enters Zone 1.
A bar code scanner reads a bar code on the item and identifies it as Item
12345. Item 12345
ID is sent to the central database (Host) to indicate to the Host that the
item is being processed
and has entered the system.
[0042] Once the data is captured and sent to the Host, Zone 1 queries Zone 2
to determine
if Zone 2 can accept the item currently occupying Zone 1. If Zone 2 is clear
and has no Item,
Zone 2 will turn on and notify Zone 1 it is clear. Zone 1 then turns its motor
on and drives the
Item into Zone 2. As the item is being transferred from Zone 1 to Zone 2, a
bar code scanner
at Zone 2 reads the identifying bar code on the item.
[0043] Now, the item resides in Zone 2. In this example, Zone 2 is equipped
with a scale
function. Zone 2 weighs the item and then sends the weight of the item to the
Host. Zone 2
then queries Zone 3 to see if it is available to accept the item currently in
Zone 2. Zone 3
turns on and indicates to Zone 2 that it is free to accept an item. Zone 2
powers up and
transfers the item to Zone 3. As the item is being transferred from Zone 2 to
Zone 3, a bar
code scanner at Zone 3 reads the identifying bar code on the item. The bar
code ID is then
sent to the Host to determine if the items actual weight gathered in Zone 2 is
the same as the
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expected weight stored in the central database on the Host. The Host compares
the expected
weight with the actual weight. If the Host determines that the actual weight
is not he same as
the expected weight, within a prescribed tolerance, it will tell Zone 3 to
divert the item to
Zone 6, a reject conveyor for orders that may have picking errors. To
accomplish this divert,
Zone 3 queries Zone 6 to see if it is available to accept the item. If Zone 6
has no item, it will
notify Zone 3 that it is available while turning on its drive motor. Zone 3
then transfers the
item to Zone 6.
[0044] If the actual weight matches the expected weight, the Host tells Zone 3
to transfer
the item to Zone 4 in the same manner that the transfers occurred in the
previous descriptions.
Zone 4 then attempts to transfer the item to Zone 5 in the same manner.
[0045] As the item is being transferred from Zone 4 to Zone 5, a bar code
scanner at Zone
reads the identifying bar code on the item. When the item arrives at Zone 5,
the label printer
at that zone needs to print a shipping label for that order. The bar code ID
for the Item is sent
to the Host, which retrieves the required information from its central
database to create the
shipping label. The Host then sends the label information to the label printer
and notifies the
conveyor when the label is ready to print. Zone 5 then powers up its rollers
to transport the
item past the label printer.
[0046] This methodology requires central processing at each decision and many
bar code
scanners, one for each control point.
[0047] According to the second example, also illustrated in FIG. 4, a box (the
item) enters
Zone 1. A bar code scanner reads a bar code on the item and identifies it as
Item 12345.
Item 12345 ID is sent to the central database to retrieve specific
inforination about the order
(single database record). The information would typically include the
customers address
information required to print the label, the expected weight of the order, the
desired shipping
method (USPS,UPS, Fed-x, etc.), and possibly the detail of the SKUs and
quantities that are
in the order. This data from the database, in its entirety, is sent to the
storage memory on
Zone l's control card.
[0048] Once the data is written to the control card, Zone 1 queries Zone 2 to
determine if
Zone 2 can accept the item currently occupying Zone 1. If Zone 2 is clear and
has no Item,
Zone 2 will turn on and notify Zone 1 it is clear. Zone 1 then turns its motor
on and drives the
Item into Zone 2. As the item is being transferred from Zone 1 to Zone 2, Zone
1 send the
entire data record it is storing in its storage memory to Zone 2 and clears
its own storage
memory.
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[0049] Now, the item resides in Zone 2 and all the data associated with the
item has been
electronically transferred to Zone 2's storage memory. In this example, Zone 2
is equipped
with a scale function. Zone 2 weighs the item and then writes the weight to
the storage
memory in the appropriate field. Zone 2 then queries Zone 3 to see if it is
available to accept
the item currently in Zone 2.
[0050] Zone 3 turns on and indicates to Zone 2 that it is free to accept an
item. Zone 2
powers up and transfers the item to Zone 3 and sends the data associated with
the item,
including the actual weight, to Zone 3. Zone 3 then compares the expected
weight with the
actual weight using the data record in its storage memory. If Zone 3
determines that he actual
weight is not he same as the expected weight, within a prescribed tolerance,
Zone 3 will
divert the item to Zone 6, a reject conveyor for orders that may have picking
errors. To
accomplish this divert, Zone 3 queries Zone 6 to see it is available to accept
the item. If Zone
6 has no item, it will notify Zone 3 that it is available while turning on its
drive motor. Zone
3 then sends Zone 6 the data associated with the item while it transfers the
item to Zone 6.
[0051] If the actual weight matches the expected weight, Zone 3 attempts to
transfer the
item to Zone 4 in the same manner that the transfers occurred in the previous
descriptions.
Zone 4 then attempts to transfer the item to Zone 5 in the same manner.
[0052] When the item arrives at Zone 5, the label printer at that zone needs
to print a
shipping label for that order. Since all of the data required to ship the item
exists directly in
the Zone 5 storage memory, the control card for that zone simply prints the
label directly and
marks the order shipped. The completed order information including the
shipping tracking
number, weight, time shipped, etc. is then sent back to the main controller
database.
[0053] This is a small example, but shows how many conveyor functions that
require item
specific data are accomplished without the aid of a bar code scanner or other
identifying
device at each point where data is either required or generated. Another
benefit is that this
method requires fewer bar code scanners. Fewer scanners means less initial
cost, but also
proportionally reduces the chances of "No-Reads". -Whenever a scanner cannot
properly
decode a bar code, the item must be handled differently and sent to special
lanes on the
conveyor system to be inspected, relabeled, or re-inducted. This represents an
ongoing cost
as well as an increased initial cost for the subsystems to handle no-reads.
[0054] Another benefit of this invention is that there is no need for the
central controller
(Host) to react quickly to decisions required by the conveyor system, as each
controller
makes its own decisions locally and requires no real-time data from the Host.
Systems
configured like the first example rely on timely responses from the Host to
requests. When
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WO 2013/116652 PCT/US2013/024349
the Host receives several rcque4sts from throughout the system simultaneously,
system
throughput can suffer because items may be held up waiting for responses from
the Host.
[0055] Since the control card for each Zone also has serial data communication
capability,
wiring and associated costs related to connecting bar code scanners, scales,
printers, etc. to
the system is greatly reduced. Instead of having to cable these "data" devices
to a remote
Host, each of these data devices is wired directly to the local Zone
controller.
[0056] Although the invention has been described in detail for the purpose of
illustration
based on what is currently considered to be the most practical and preferred
embodiments, it
is to be understood that such detail is solely for that purpose and that the
invention is not
limited to the disclosed embodiments, but, on the contrary, is intended to
cover modifications
and equivalent arrangements that are within the spirit and scope of the
appended claims. For
example, it is to be understood that the present invention contemplates that,
to the extent
possible, one or more features of any embodiment can be combined with one or
more features
of any other embodiment.
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