Design of Automatic Identification and Sorting System for Parcels Based on Plc Control

International Journal of Research in Engineering and Science (IJRES)
ISSN (Online): 2320-9364, ISSN (Print): 2320-9356
www.ijres.org Volume 5 Issue 3 ǁ Mar. 2017 ǁ PP.22-30
www.ijres.org 22 | Page
Design of Automatic Identification and Sorting System for
Parcels Based on Plc Control
Fu Chengcheng1
, Jin Xiaoyi1
, Cai Wenfeng1
1(
College Of Mechanical Engineering, Shanghai University Of Engineering Science, Shanghai, China)
ABSTRACT:With the rise of the electricity industry, to the logistics sorting industry caused great pressure to
design a PLC (programmable logic controller) based on control, combined with Kingview software, and the
application of bar code recognition technology, automatic identification and sorting system. According to the
structure of the system, the working principle of the system is analyzed, the control requirements are put forward,
and the hardware design, software design and configuration process design of the control system are carried out.
Using PLC as the next bit machine to improve the acquisition signal and control signal accuracy, and can be based
on functional requirements on-site modification and commissioning procedures at the same time easy
maintenance. Application configuration Wang as the host configuration software, users can easily adapt to their
own needs to adapt to the data acquisition system, real-time monitoring system operating status, protection of
information flow, very consistent with the needs of modern production.
Keywords: PLC, Barcode, automatic identification, automatic sorting
I. INTRODUCTION
With the continuous development of society, online shopping has become an indispensable part of the
current life of a way of consumption, but thus the logistics industry has a huge pressure to express the package
sorting a new request, the urgent need a package sorting system to improve labor efficiency and speed up logistics
[1]
. The so-called package sorting is a lot of parcels in accordance with the destination assigned to the
corresponding area of the work, generally can be divided into manual sorting, mechanical sorting and automatic
sorting.
Manual sorting business is heavy, continuous operation time is long, error and other issues, so more and
more sorting tasks are used automatic sorting system. The most critical step in the design of the system is to read
the bar code of the goods [2]
. The design of the current selection of the more popular one-dimensional code to
achieve the storage of information, so the goods to read the label is equivalent to how to convert the
one-dimensional code to the problem, so the main problem of system design is how to use The specific instrument
reads the one-dimensional bar code[3]
. Due to the powerful, easy to use, high reliability of the PLC, it is often used
as a controller for field data acquisition and equipment. Kingview software as a user can customize the function of
the software platform tools, can be easily on the PC can develop a friendly man-machine interface, through the
PLC on the automation of intelligent control equipment. So the use of PLC technology, configuration software
technology, bar code recognition technology to achieve the design [4]
.
II. SYSTEM DESIGN
The system consists of two parts of the design: the hardware part of the selection, the software part of the
design. Which part of the software, including PLC software design, configuration software design of these two
parts. The PLC software part of the design is the core content. As the system site has a charged bar code reader and
the number is not a lot of other controlled objects, therefore, select a medium-performance PLC can achieve all the
control functions. In addition, in order to facilitate the user to use, you need to use Kingview software design
corresponding man-machine interface, using the system shown in Figure 1 design.

Design Of Automatic Identification And Sorting System For Parcels Based On Plc Control
Control
panel
module
barcode
scanner
Alarm
module
S7-200
PLC
Motor
drive
module
Photoelec
tric
sensor
module
Set parameters
identifying
information
Alarm
Signal
Detect package
Start/End
Fig.1 system structure
1) PLC controller: the control core of the system. The digital and analog signals of the objects, such as the motor,
the bar code reader and the cargo position, are first input to the registers of the PLC. The PLC converts and
processes the various signals, and outputs the signal to the monitored object and uploads the key information
in real time The host computer, while the implementation of the host computer to send control instructions to
complete the real-time and on-site equipment and automation control.
2) control panel: the control panel is equipped with a configuration of Wang software, industrial computer as the
host computer. Host configuration monitoring system to complete the following three aspects of the task:
First, the host computer from the serial port to read the value of the PLC register, these values are displayed in
the human-computer interaction interface, followed by real-time to the PLC to send the corresponding control
instructions, Machine to PLC to upload the value of a certain deal, the information in the form of historical
data stored in the system database to report the form of storage, to facilitate future inquiries.
3) information collection module: the main use of bar code reader to collect the bar code information on the
goods, and through the serial port to the data sent to the PLC, followed by the operation of the PLC. Abarcode
is a symbol of certain information that consists of a set of bars, empty, and corresponding characters in a
particular rule. Barcode recognition technology is the photoelectric scanning equipment to obtain the bar code
symbols for collection and processing, on the basis of the use of machine identification of goods, and accurate
and quickly transfer the converted digital signal to the PLC.
4) photoelectric sensor module: photoelectric sensor is the use of light detection object sensor collectively, by
the transmitter part of the launch of the optical signal and the object is detected by the reflection, block and
absorption, and then accept the part of the detection and conversion to the corresponding electricity The
signal is used to detect whether the area is wrapped.
5) motor drive module: through the PLC out of the control signal to achieve the movement of the load motor
control.
6) alarm module: through the sound and light equipment on the system is not the normal operation of the state
alarm.
III. INFORMATION RECOGNITION SYSTEM DESIGN
2.1 Barcode recognition method and principle
Barcode is divided into one-dimensional bar code and two-dimensional bar code. One-dimensional bar code is
only in one direction (usually horizontal) to express information, and in the vertical direction does not express any
information [5]
. A complete one-dimensional bar code is composed of blank spaces on both sides, starting
characters, data characters, check characters (optional) and terminating characters and characters for people to
read. Different types of bar codes, there are different code systems and coding methods. There are two bar code
coding methods:
1) width adjustment method: bar code bar (empty) wide width set different, wide unit that binary "1", narrow
unit that binary "0". The so-called 39 yards, Kudba bar code and cross 25 yards are part of the width
adjustment method coding.
2) module group with the law: bar code symbols in each bar code characters of the strip and the air were

composed of a number of modules, a module wide bar that binary "1", a module wide empty said binary " 0
". General merchandise bar code (EAU code and UPC code), 93 yards, EANl28 code belongs to the module
group with the law encoding [6]
.
128 code in 1981 after the launch, has been rapid development and application. 128 code consists of a set of
characters whose length is not fixed and the continuity is unknown [7]
. The main structure is divided into the
starting code, data code, termination code, check code and other four parts, the four parts of the check code can be
omitted. Code 128 code that includes ASCII 0 to ASCII 127 total 128 symbols, so referred to as 128 yards. 128
code to support the number of characters than the number of one-dimensional code to be more, in addition to
different encoding can be cross-use, so the use of flexibility is also more flexible. Figure 2 is an example of 128
yards and results.
Fig. 2 code128 code basic structure
128 code has three different types of digital coding (see Table 1), for the choice of what kind of coding, it
depends on the contents of the start code. Termination code Whether it is A, B, C what coding, 128 yards of the
termination code are fixed for a performance, the logical type are 1100011101011. The current implementation of
the 128 yards is EAN a 128 yards, EAN a 128 yards is based on EAN / UCC a 128 yards as a standard to convert
the data into bar code symbols, and 128 logics, with integrity, tightness, connectivity and high Reliability of the
characteristics. The coding of EAN-128 is shown in Table 2.
Table 1 1128 code encoding
Start code Coding category Logical form relative value
CODE A 11010000100 103
CODE B 11010010000 104
CODE C 11010011100 105
Table 2 EAN-128 coding instructions
Code number length Description
A Application identification code 18 00 The contents of the subsequent
documents for the transport container
serial number
B Packaging performance indicator 1 3 Represents an undefined wrapper
code
C Prefix code and company code 7 9 Represents the EAN preamble and
company code
D Compile serial number on its own 1 Specify the serial number by the
company
E Check the code 4 Check the code
F Application identification code On behalf of the subsequent
information content for the

distribution of postal code
G Delivery post code On behalf of the distribution of postal
code
2.2 Ommunication Method of PLC and Bar Code Scanner
Siemens S7-200 series PLC is a small programmable controller, with a small structure, multi-functional,
low price, itself integrated CPU, I/O points, power, while providing a simple, open communication. Cost-effective,
communications and real-time advantages, is the development of more complex automation system solutions
ideal [8]
.
The system uses Siemens CPU226. It integrates two serial ports, port0 port as the connection between the
man-machine interface and CPU interface, the other end port1 used to connect bar code scanning gun. As the bar
code scanning gun for the 232 interface, two free communication port for the 485 port, so the need to use 232-485
conversion module to achieve communication.
2.2.1Special registers
(1) Control word register SM130: Port1 communication mode The protocol is set by SM130. The system set
SM130 00001001 as a free port protocol, baud rate of 9600, the data length of 8, no parity.
(2) communication to accept the character buffer SMB2: SMB2 is a transient register, used to store in the free
mode to receive the current characters, in the next step should be removed from the contents of which,
through the programming control will receive the characters one by one Move to receive buffer.
(3) Communication test result flag SM3.0: PLC according to SM130 specified parity mode to check the received
data. If the check is wrong, then SM3.0 set 1, no error is set to 0. If an error occurs, send this error message to
the barcode and request a retransmission.
(4) Working mode flag SM0.7: S7-200 series PLC in the RUN state to carry out free port mode communication,
STOP state can only use PPI mode communication. When the PLC is in RUN state SM0.7 = 1, otherwise
SM0.7 = 0, it can be used to determine the status of free port communication.
2.2.2Receiving data and communication procedures
S7-200PLC communication port port0 port has three interrupt events: to accept the character 8 interrupt,
send and receive 9 interrupt, receive signal 29 interrupt. The global interrupt can be enabled by the ENI instruction
in the user program. All interrupts are disabled with the DISI instruction. A single interrupt can be opened and
disabled independently by the ATCH and DTCH instructions. Communication port 1 port has 24, 25, 26 three
interrupt events [9]
. The system calls the 24th interrupt to receive characters, communication procedures shown in
Figure 3.
Fig. 3 communication procedures

III. DESIGN OF PLC CONTROL SYSTEM
3.1 PLC hardware
The control system has the following requirements: economical and practical, able to adapt to the scene,
improve the reliability of equipment; to facilitate the modification of on-site data, with a certain degree of
flexibility; to ensure accurate data collection, improve productivity; improve equipment automation rate. Based
on the above requirements, the system uses Siemens S7-200 series PLC, which integrates the power unit, CPU
unit, basic I/O unit, special function unit and communication unit.
According to the input and output points and functional requirements, PLC port wiring as shown in Table 3, Table
4 shows.
Table 3 Input Assignment Table
input name function
I0.0 run/stop system run
I0.1 code scanner sensor control code scanner
I0.2 sensor 1 detect whether the goods in channel1
I0.5 sensor of conveyor detect
I0.6 Manual control switch 1 Manual control drive belt
I0.7 Manual control switch 2 Manual control motor 2
i1.2 Manual control switch 5 Manual control motor 5
Table 4 Output Assignment Table
output name function
Q0.0 Motor 1 drive belt
Q0.1 Motor 2 control motor 2
Q0.5 Sound and light alarm system alarm
3.2PLC software
3.2.1Software architecture
Software overall structure of the main program, calibration procedures, data conversion procedures, mechanical
sorting subroutine, hand automatic conversion procedures. The overall flow chart shown in Figure 4.
1) mechanical sorting subroutine: mainly according to the host computer to deal with the corresponding cargo
information, according to the bar code to provide the basic information in accordance with the corresponding
rules of the goods for different treatment. The design is mainly reflected in the different goods through the
conveyor belt sent to different channels, so that the next unit for other operations.
2) alarm processing subroutine: the main completion of the system failure and communication anomalies and
cargo identification failure alarm.
3) hand automatically switch subroutine: According to the design function requirements, when the system fails,
cannot be completed in the automatic control mode, the manual will be selected according to the specific
circumstances of manual control.

Start
Automation?
Barcode
scanning
Communication
normal?
Receive
data
Normal
receiving?
Read data
Data check
legitimate
Data
transformation
Data interpretation
and recognition
Automatic mechanical
control subroutine
End
Alarm
processing
subroutine
Manual control
subroutine
N
Y
N
N
N
Y
Y
Y
Fig. 4 System program flow chart
2.2.3 Mechanical sorting program specific process
The core part of the software is the mechanical sorting subroutine, in order to achieve the correct sorting
parcels, as shown in Figure 5. The specific process is as follows:
1) detection system communication is normal, if normal, then open the system, the implementation of
initialization procedures.
2) When the package is in a low power state, the package is detected and the package is transported to the
scanner for scanning.
3) The scanner sends the processing result to the PLC for information matching.
4) If the match fails, then the package is not the area, the sorting device will not perform the sorting action, the
parcel continues along with the conveyor belt.
5) If the match is successful, then the package in this area, the matching results will be sent to the PLC input, the
corresponding area of the sorting device will perform sorting action, the package into the appropriate area.

Start
Communication
normal
Initialization
Belt running
Scanner work
Comply with the
requirements for
sorting
Perform sorting action
End
Y
N
Y
Fig. 5 Control subroutine
IV. CONFIGURATION INTERFACE DESIGN
"Configure" means "configuration", "set", "set" and so on, refers to the user through similar "building
blocks" in a simple way to complete their own software needs, without the need to write Computer program, that
is, the so-called "configuration". In short, the configuration software can achieve the automation process and
equipment monitoring and control. It can extract all kinds of information from the automation process and
equipment, and display the information in a way that is easier to understand, such as graphics, and transmit
important information in various ways to the relevant personnel, carry out the necessary analysis and processing
of the information, Issue control instructions and so on.
Commonly used configuration software InTouch, WinCC, MCGS, etc., here use the more popular
configuration King software to develop configuration interface, it has a strong adaptability, openness is good, easy
to expand, the economy, the development cycle is short and so on. Usually the king development system can be
divided into control layer, monitoring layer, management three levels of structure [10]
. The monitoring layer is
connected to the control layer, on the connection management layer, which not only realizes the real-time
monitoring and control of the scene, and in the automatic control system to complete the upload and release, the
important role of configuration development. According to the design requirements and the actual production
needs, the system operation, mining
The data is integrated, and four function modules are set up: parameter setting module, data dictionary
setting module, page setting module and authority setting module.
The specific steps are as follows:
1) Select the correct PLC driver, refer to the communication protocol to set the communication parameters.
2) in the browser inside the hardware device configuration. details as follows:
First, according to the different means of communication in the configuration of the king to set the
corresponding. Kingview software has five main types of communication: serial communication, data acquisition
board communication, networking communications, man-machine interface card communication, DDE or OPC

communication.
Second, the network node communication settings need to select the corresponding node name in the
"Device" outline. When the communication mode of the lower computer is "network node", the "network node"
needs to be selected. If the other communication mode is adopted, all communication modes other than "network
node" can be used.
Third, set the I / O device parameters. System PC control interface will be real-time production status
display in the human-computer interaction interface, this time the host computer control can replace the basic
hardware control console based traditional control. Monitor all the operating buttons on the main interface and the
goods feedback signal are input through the PLC digital signal, and the host computer driven by the PLC device is
driven by auxiliary relay.
Fig. 6 monitoring system main interface
Figure 6 shows the monitoring system configuration screen, mainly used to display the cargo
identification control effect. The left side of the screen indicates the connection between the computer and the
PLC, the PLC and the controlled device. The main part of the picture is the movement of the pallet in the conveyor
belt. The pallet is placed on the pallet, and a barcode is hung on the gantry. Through the goods information, the
right side of the screen will be real-time display of the current scan cargo number, destination, the number of
goods to be scanned and other information, while the system shows the current state of operation, the
implementation of the operating elements and so on.
V. CONCLUSION
The system combines the programmable controller and the configuration software to study the cargo
identification process and designs a set of effective automatic identification control system. The design mainly
from the PLC main program, the host computer, configuration monitoring, and RS232C communication to
complete the design task.
The main work to complete the following work:
1.introduced a low cost, stable and reliable serial communication, that is, the use of small programmable
controller S7-200 free communication interface to achieve communication with the serial device, but also gives
a bar code scanner to achieve communication programming Examples, providing a viable solution for low-cost
communications.
2.PLC control system design. Combined with the control requirements given the PLC input and output ports of
the distribution and wiring, and according to the operation process design procedures, including the main
program, calibration procedures, data conversion procedures, mechanical sorting subroutine and automatic
conversion procedures.
3.real-time monitoring of the screen design and implementation process. Based on the combination of software
and PLC on the upper and lower computer, not only can real-time in the human-computer interaction interface
to collect and display data information, but also to achieve the real-time monitoring and automatic control of the
goods pipeline, save system data and fault information and other functions.

The automatic identification and sorting system designed in this paper has good scalability and flexibility
in mechanical and control systems. Here only three areas as an example, the actual application can be extended to
the needs of more areas, or even greater areas. This system makes use of the existing PLC technology, combined
with the configuration king development monitoring screen, so that the courier company's sorting process
becomes unmanned, automated, greatly increased the company's operational efficiency, with further promotion
and research significance.
REFERENCES
[1]. Jin Zhe. Automatic identification of bar codes. Beijing: National Defense Industry Press, 1991.
[2]. Sun Xianming, Jin Lijun. Realization of PIE Data Acquisition and Recognition Based on Bar Code
Reade application design. Automation Technology & Applications, 2007 (5): 12-18.
[3]. Tan Guili Configuration software control technology. Beijing: Beijing Polytechnic University Press,
2007.
[4]. Liu Weichang. Application of Automatic Recognition Technology in Circulation Field. Information and
Computers, 2008 (10)
[5]. Yang Ping, Yang Ji. Two - dimensional bar code and its application. Henan Science and Technology,
2000 (15): 67-69.
[6]. Yang Dong, Huang Yonghong, Zhang Xinhua, Ji Jinghua. Using PLC basic instructions to achieve
automatic motion positioning control. Microcomputer Information, 2010, 26 (2-1): 62-64.]
[7]. Chen ChangJuan, XueKai.Implementation of Single and Double Axis Motion Control of Stepping Motor
Based on PLC. Mechanical Design And manufacturing. 2009 (3).
[8]. LIU Jing-ting, MA Fan-jin, ZHOU De-jian, et al.Application of PC and PLC master-slave monitoring
system in rolling machine
[9]. Li Minghe. Principle and Application of Programmable Controller [M]. Hefei: Hefei University of
Technology Press, 2010.
[10]. Siemens AG.Working with STEP7 V5.2 Getting Started.2002

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