Development of an Automatic Mini-Conveyor System for Product Monitoring

This thesis presents the development of an automatic mini-conveyor system for product monitoring. It is aimed at solving relative industrial and manufacturing problems such as product pilferage, inefficient supervision, monitoring and workmanship. It is also to improve production management system, using ICT based platform to enhance monitoring control and data acquisition (MCDA) system in manufacturing process. ASSEMBLY programming language was used on a programmable logic controller (Atmel 89C52) microcontroller for control and monitoring protocol. The method includes; simulation, hardware development; to include; sensing, counting and signalling wireless system containing sensors and a wireless radio frequency transmitter and receiver. Design calculation analysis, fabrication and operational tests were carried out on the developed mini-conveyor. The operational and test result shows that, the time the product travels along the conveyor through a distance of 0.8m between entrance and exit point sensors was between 15.7sec to 16.3sec. At a distance of 0.096metres between sensors, the response to display time on LCD is approximately 1.0 second. The developed mini-conveyor system is able to remotely monitor a product on a communication distance of 22 metres in which the required information is displayed on computer screen on a telnet hyper-terminal platform, through a baud rate of 1200. Therefore, the developed machine has open opportunities for product monitoring control and data acquisition in material handling systems in the industries for more accountability.


Introduction
Material handling is a field involving the transportation, storage, and control of goods and products throughout the processes of manufacturing, distribution, consumption and disposal of all related materials [1]. The focus of the material handling industry is on the methods, mechanical equipment, systems and related controls used to achieve necessary functions. The use of conveyors in material handling has been in practice since the early 20 th century and is known to be the back bone of material handling [2]. Conveyors is commonly known as a piece of equipment that moves material from one place to another and are specifically for quick and efficient transportation of wide variety of materials of all shapes and sizes [3,4]. In a production system where, large quantities of products are produced with high production rates, the products are to be transported with material handling system that is sophisticated yet safe and reliable. According to [5], "material handling looks at the problems of moving, transporting, storing materials and product; improvement of handling methods". Automated materials handling can be referred to as the management of material handling system by use of automated machineries and electronic equipments to reduce or eliminates the need for humans to do certain or all the activities in a material handling process manually. It also helps to increase the efficiency and speed by which materials or products are shipped, stored, and handled. This can significantly cut down on costs, human error or injury, and lost man hours [6,7]. Wireless network may be referring to any type of computer network that is connected without cables of any kind. Nevertheless, Wireless telecommunications networks are adopted and administered using a transmission system which is called radio waves [8].
This work explores the adoption of ASSEMBLY programming language instead of C++, JAVA, and FORTRAN on a Programmable Logic Controllers (PLC); Atmel 89C52 (AT89C52) microcontroller for control and monitoring protocol for the mini-conveyor. The system is developed on the back drop that in the future many production systems will need to adopt ICT in its operations with a choice to pick and adopt monitoring, control and data acquisition systems (MCADS) in the mist of diverse ICT base wireless production monitoring system that is effective, efficient and at low cost of implementation. A conveyor machine is developed on which products can be monitored during production run. There are several literatures concerning belt design with more focus on structural modification, maintenance efficiency, safety and some other research focuses on the automation area of maintenance, inspection and monitoring using different wireless sensor network (WSN) system and programmable logic controllers (PLC) structure and devices [13,14]. There are many WSN system, PLC algorithm structural unit design and devices that are yet to be fully tested within a semi or full automated conveyor system as an alternative to the already implemented ones [20,21]. The emphasis in recent time is on the application of ICT in manufacturing and industrial process to help improve production process and increase productivity.

Materials
The materials used for this work includes: Mild steel square pipes, angle iron, flat sheet, sprockets, chain and steel rollers. Other materials are PVC flexible (leather), electrical sensors, infra-ray (IR) transmitters, photodiodes, and quarter wave whip antennas.

Method
In this project, consideration was made concerning the program language adopted and the basic essential electronic and electrical devices for the development of the wireless systems used. The conveyor is developed using essential mathematical engineering models, equations, design data from belt conveyor manuals and required material properties.
The development of this project involves the following methods; 1. Electrical-electronic circuit design for the automatic counting system.

Design analysis
The design analysis of the major components of the mini belt conveyor to achieve a functional structure as shown in Figure 1, were considered and hereby presented.

Conveyor Belt Design
The following are design parameters needed for conveyor machine development.
Belt capacity, C is obtained from equation (1).
1 Where Al = Load cross section perpendicular to belt; Vb = Belt speed; ρb = Density of conveyed material.
The belt width (Wb) as given by [14] is: 2 Where T1 = belt carrying side tension σb = (allowable design stress of belt material) The belt thickness (tb) is as given from equation (3 and 4) by [13] as:

Belt Friction and Tension
The frictional and tension factors on the conveyor belt are obtained from effective tension (Te) from equation (4) as given by [13]  Where Fe = total empty friction; Fl = load friction. Similarly, the return side friction (Fr) [14] is given as: Fr= ( y ) kN 6 Where: = 0.020 (for horizontal conveyor equipment friction factor) = Mass of moving parts per metre length Lcd = Centre to centre distance of rollers g = acceleration due to gravity Therefore, total empty friction (Fte) is: Fte = ( )) kN 7 Where Fe = 0.020 (for horizontal conveyor equipment friction factor) = 45 (Fenner Dunlop conveyor manual, 2009) Also the load friction (Fl) is given as [14]: Where Ft = 0.025 for horizontal and elevating conveyor C = Transport or capacity of the belt conveyor Load slope tension (TLS); The slope tension is the product of the belt weight and the vertical lift and has its maximum value at the highest point (height) of the conveyor.
TLS can be calculated thus as [14]: TLS = kN 9 The effective tension from equation (4)

Design of Chain Length
The length (L) of chain for an open chain drive connecting two sprockets is obtained from the equation (11)

Analysis of Effect of Distance between Sensors on power Density between Sensors
Sensors distance analysis is based on power transmitted and/or power density across sensors and magnitude of the incident current generated at the photodiode. The table 1 below shows the data obtained for the effect of distance between sensors on power density between sensors.

Figure 2: Distance between sensors
Pt is the power transmitted by the IR sensor, which comes with the manufacturer specification. The data for Pd is gotten from the formula; Pd = [18] for charge carrying points 16

Effect of Distance between Sensors on Response Display time on LCD
Test was carried out to know the shortest time to display on LCD 2 as the product between the IR and photodiode sensor at the exit sensors point with reference to distance between the sensors, before signalling the data to the computer. Data obtained were tabulated and analyzed.

Simulation of Designed Circuit
Simulation was done on the ISIS professional animation platform, using a virtual circuit designed containing AT89C52 PLC microcontroller, on proteus 7.0 shown in figure 3 [19,20]. The components in the designed circuit layout are shown in figure 4.

Design Results Used in the Development of the Mini-conveyor
The table1 shows essential parameters obtained from design calculations and used for the development of the mini-conveyor.

System Performance Results
Plate I and II shows the conveyor on off and on mode. Plate III shows product between sensors at the entrance point, at this point the product block the photodiode from the light emitted by the IR sensor, this blockage is seen as an interruption by the photodiode sensing system and it is transformed into counting sequence by the micro-controller and is reflected as a number on the LCD 1(yellow coloured).
Plate IV shows the object or product in between the sensors at the exit point. At this point also, the product blocks the photodiode from the light emitted by the IR sensor, this blockage is seen as an interruption by the photodiode sensing system and it is transformed into counting sequence by the microcontroller and is reflected as a number on the LCD 2 (blue coloured). At this point the second microcontroller compares the count between the two sensors, and sends the count data or count imbalance error data (inform of a code number 5) through the data transmitting wireless signalling unit to the MAX 232 interfacing wireless data receiver modem.

Plate I: conveyor after fabrication and finishing
Plate II: conveyor with counting electronic un with power on and Product on takeoff tray on conveyor Plate VII shows the hyper terminal monitoring dialog box initiated and Plate VIII shows the modem connected to computer system with count data being displayed in monitoring dialog box. The pattern of data display on the product monitoring display dialog box is show below in figure 5. The 00000 count is displayed when the modem is turned on and it is not receiving data or information from the signalling system on the conveyor. Immediately the modem connects wirelessly to the conveyor system, connection code 15 is displayed continuously on the monitoring dialog box, but immediately product or object passes between the sensors, the actual numbering begins, such as; 0000100020000300004000050006 etc, extracted from the dialog box on the screen in plate IX, and is shown in Figure 5. The computer receives this information on a telnet wireless protocol, on baud rate of 1200. The baud rate 1200 is the frequency at which the computer receives information and displays it.

Plate VII: The monitoring display dialog box initialized
Plate VIII: MAX 232 data receiving wireless modem turned on and laptop receiving data Plate IX: Product monitoring display dialog box screen extracted from computer on plate VIII Figure 5 shows the data display before counting begins, when the modem is connected to the conveyor counting and signaling unit 0001500015and when the counting data begins, showing 00001 00001 00002 00002 00003 00003 etc.  Table 2, shows the data obtained by studying the effect of distance between IR and photodiode sensors on power density generated between the sensors. The graph obtained reveals that as the distance between sensors increases the power density deceases. This result gives a guide as to how far apart the sensors must be positioned in order to obtain optimum sensitivity when placed in their line of sight. Figure 6 reveals that power density has a great effect on magnitude of the incident current generated.

Effect of distance between sensors on Response display time on LCD
The Table 3 shows the values of the response display time on LCD 2 obtained by varying the distance between the IR and photodiode sensor. The graph was plotted sing MATLAB and is shown in Figure 7. This result reveals that at the of 0.096m the time it takes the system to sense the object and display the count on the LCD is approximately 1.0second. Also determined is the time it takes the product to move from sensor at entrance to sensor at exit point and was measured to be between 15.7sec to 16.3sec depending on the power in the motor from the power source. The distance between the entrance sensors and the exit sensor is 0.8m; it therefore means that the product is moving at the speed of 0.05m/s. This is the speed at which the conveyor belt is moving.

Test Distance
During the test, the modem placed on the computer and connected to it was moved away from the conveyor machine and far away from the building in which the conveyor machine is stationed. The maximum distance at which there is no loss of connection signal was measured using tape. The distance measured is 22metres. This test reveals that, the wireless system developed will be operational at a maximum distance of at least 22metres between the factory location and the management or administration departments were the monitoring and collection of production data is carried out. It was pointed out by [21], that SCADA was developed on an internet based protocols to enable monitoring and optimization of the process through the web system. However, the main objective of establishing an internet based system is to enhance rather than to replace computer based process control systems. Also, though SCADA and other systems shown in Table 4, are been used as solutions in controlling and managing processes in a wide range of industrial application. This X-system developed is a typical MCDA system and is more advantageous, because of the adoptability of an RFID module architectural structure with counter system in its wireless protocol design platform and is for a typical manufacturing based sector for monitoring, data acquisition and feedback, to reduced error in human intervention, theft reduction and elimination.

Comparison of MCDA System and other Data Acquisition Systems
The features of X-System developed with a typical MCDAS and other data acquisition systems are presented on Table 3.  Table 3: Comparison of X-System developed and a typical MCDA system and other data acquisition system Table 4, shows a simplified comparison of few data acquisition systems renowned with the MCDA system developed. SCADA is widely known to provide monitoring and data acquisition system; it is mostly adopted in the gas and piping industry. BARCO, is known for supplying system monitoring to the industries especially for carpet manufacturing company, it uses the Bluetooth technology and has limited accessibility communication distance of about 15metres. The MCDA system is more flexible, robust and gives room to both software and hardware modification, lower cost, longer range of distance of communication and operates on a web base internet protocol using WSN system and embedded RFID than other known monitoring system. The communication distance tested for the wireless monitoring system developed X-system is 22metres. It is greater than the communication distance recorded for BARCO system. Although, the distance is less than that recorded for a typical MCDA system, it is still a typical MCDA system due to similarity in feature adaptation production line output monitoring system application in the industries.

Conclusion
This wireless-based monitoring control, data acquisition system, MCDAS, enable immediate update of the detail of production line activities as the production runs are being initiated from one production shift to another. For every production run, information is gathered, therefore, with this system there is no downtime in data reporting and transmission and this data can be printed at the end of every production shift. And also has data log, where previous data can still be assessed. It was also found from experimental analysis that the time it takes the product to move from the entrance sensor to the exit sensor covering a distance of 0.8m is between 15.7second to 16.3second. At a distance of 0.096metres between IR and photodiode sensors the response time to display on LCD is approximately 1.0 second. Therefore, showing that the belt round the rollers is running at a speed of 0.05m/s, which is the designed speed. Therefore, with rapid advance in wireless information technologies, many solutions are emerging and its application in industries have been researched and developed. It can be concluded that this system which merges four technology that is; mini-conveyor, sensing and counting and signalling wireless network system into one solution is highly compatible and suitable to meet the requirement of any production line layout output monitoring system application in the manufacturing industries.

System
Embedded Web-based Low Automatic monitoring M2M wireless communication flexible design, adding Name RFID and system cost monitoring compared communication range modification of WSN standard time, target software and hardware SCADA x