Development of a Suitable Software System for a Paperboard Manufacturing Company - Case Study Example

Distributed control system design Student name: Student ID: Module Title: Module Number: Tutor’s Name: Date of submission: Abstract This paper provides detailed information on the development of a suitable software system for a paperboard manufacturing company. The company deals with production of paperboard for sale to its potential buyers. This paper highlights the location and nature of software components in the system, requirements for any data storage and the strategy used for interaction with users and operators. It explores how system designers and developers can use logical partitions to prevent problems such as unresponsive or even unusable software system when some events in the system impose heavy load on the central processing unit and enable both local and remote system access, a case study of paperboard distributed control system. List of abbreviations PC: Personal Computer RTO: Real-time Operating System TCP/IP: Transmission Control Protocol / Internet Protocol PLC: Programmed Logic Computer CPU: Central Processing Unit I/O: Input/Output System architecture This is the structure of the system, which consists of software components of the system, how those components are related and the properties of these components which are observable externally. Architectural design is done by identifying constituent modules and overall module structure and organization (Kopetz 2003). This defines relationship between major structural elements of the structure and the property of the component that constituted the model. The software to be designed will support a distributed hardware environment to facilitate all concurrent activities in paperboard manufacturing processes. This design goal will be achieved by architectural design of the paperboard distributed control system. The system is divided into three-tier architecture, namely, field layer, control layer and management layer. This is shown if figure 1 below: CPU station 1 CPU station 2 CPU station 1 Figure 1. System architecture (Zdenek 2007) Field layer From the setup above, the first layer which is the field layer consists of a Central Processing Unit (CPU), and two Input/output stations. This layer is installed in location three of programmed logic computer including other measuring and control tools (such as converter, encoder, etc) for various types of data acquisition and production line field control in paperboard production process. Other functions of layer will include the following; completion of field input and output of signals for the field, assemblage of system controllers, processing of raw data, control output basing on the given order, and finally present results of the work station. Field layer will be equipped with following stations: CPU station 1: Comprised of CPU modules. Its main usage will be for cutting and bonding machines of signal output control and signal acquirement. CPU station 2: This will also comprise of CPU modules but will be majorly used for gluing machine and coating machine current status signal acquiring, and control of signal output. CPU station 3: Its main function is for coating machine status and to control signal output. Control layer In the control layer, five industrial PC machines should be installed. These five machines will include one main operating station, one gluing machine operating station and three coating machine operating stations. The main operating station should be installed in control room, while others should be installed in production line such as control and management sections. All stations in this layer are networked by the presence of hub station local area network. Each of these stations does not depend on the other although others act as backup. This section deals with data collection for processing, data analysis, information storage, assemblage and propagation of entire control orders. When it comes to system configuration roles, production control and protection of value model occurs at these operating stations. Management layer A computer system, a printer and a server machine is setup in this layer. The printer will be used to print paperboard production report, the server machine will provide storage for a variety of real-time data forwarded from supervisory control section, and finally the computer system will be responsible for management station settings. Paperboard Company will be able to monitor the operating status of production line together with order execution; this will be achieved when managers are managing terminals using PC machine at management level. Other functions of management sections include data input management, paper order management, paper handling, staffing and shipping management. Paperboard distributed control system software The software system to be designed should be able to support a distributed environment so as to facilitate concurrent development. There should be cautious deliberation of balanced computational load so as to allow the use of common hardware to realize extensively varied control and instrumentation functions (Zdenek 2006). Figure 2 below is hierarchy architecture of software to be designed: Figure 2 : Software hierarchy The figure 2 above shows three levels of communication which are usually present in any network of distributed control system. At level one is input/output devices; these devices require real-time responses between 10 and 50 milliseconds. The next level of communication is Programmed Logic Computer (PLC) and the top most level is the human computer interface which is the interface between the software and the hardware system. In paperboard distributed control system, a field level CPU using fast anticipated real-time kernel with its cyclical time stability of work reaching 2ms should be used. The use of a CPU with such properties will ensure that exchange of data between programmed logic computer and hardware modules and fieldbus is achieved in real-time tasks. Consequently, the exchange of data in the operating system will not delay more than a few microseconds. Realtime operating systems present in level one uses a proactive, priority-based thread scheduler, which will give CPU time to the highest-priority subsystem that has some processes to execute. The readiness of a high-priority thread preempts any lower-priority process which currently runs. Users at the control level on the operator station will be able to utilize ready-made modules, do online visibility and debug the system online thus reducing the time taken by control system users performing all the above activities. To manage all complex integration issues in paperboard production system, resource partitioning should be done. This will involves separating software subsystems into different partitions and then each partition is allocated a certain portion of CPU time. In our case, the human computer interface system, PLC level and I/O devices level will each be allocated some percentage of CPU time. Doing this will ensure that each subsystem will always get its allocated CPU time hence all processes in respective components will run smoothly. This is shown the Figure 3 below: Figure 3: Partitioning paperboard software The software to be designed will be based on Windows NT plaftform and type of programming language to be used is Visual basic. The choice of this programming language is because it is easy to learn and doesn’t require a lot of coding. It also uses OPC and Activex and international standards such as TCP/IP (Plant et al. 2007, p.343). This software interface will make it easy for system users to communicate to other software components and subcomponents. The design of this software will at the end provide an interface where machine operators either at local or remote sites can monitor all machines operations, that is, gluing machine monitoring, pressing machine monitoring, coating machine monitoring all monitored by use of charts Production operations module This module will control paperboard production operations in a number of ways. To start with, it controls the speed of supplying the paperboard which is needed to complete paperboard production cycle. This will be achieved through the use of sensors and actuators. The software will also control the speed of machine (slows down from its normal operating speed of 200m/min to 60m/min) before splicing is done The system will also monitor paperboard production quantity and storage and automatically adjust the corresponding unit production speed basing on the orders made. When customer’s orders increases, the speed of operations in relevant operating stations or machines is increased so as to increase number of paperboards produced in a particular time. Managers and other responsible users will be able to enter product specifications, locally or remotely adjust cutting machine, command the machine to coat the board when a customer needs a coated board, and at the same time monitor the health of each subsystem to ensure continuous production of paperboards. Entering the product specifications will ensure that the customer receives a product that meets all the requirements he/she ordered for. Order management module This section gives detailed information on how the software will be utilized in the order management. With order management module, managers will be able to enter the date the order was made, the order number, type of customer, paper board type, paper size in terms of width and length and date of delivery. All these information will be stored under orders table in database server. It has also a feature where an authorized user can command the system to execute new orders manually. Managers will also print reports showing completion of order and all information concerning that order such as order type, date of completion, and so on. Shipping management module Shipping management module will schedule production orders to go along with shipment orders so as to ensure order deadlines are met. Shipping team will enter all information concerning shipping into the system, this will include, price of shipping, time when boards were loaded, quantity and transporters name. References L. Chen, Y. Wang. 2002. Design and Implementation of a Web-Based Distributed Control System. Proceedings of the 2002 IEEE Canadian Conference on Electrical and Computer Engineering (CCECE’02), Canada. Kopetz, H. 2003. Real Time Systems: Scheduling, Design Principles for Distributed Embedded Applications, ISBN-07923989947, Kluwer. Zdenek, J. 2006. Maximization throughput of the distributed control computer of power systemusing DMA and optimal partition. WSEAS Transactions on Power Systems, Vol. 1, No. 5, 947{952, 2006. Zdenek, J. 2007. Efficient scheduler-dispatcher software architecture of the space power facility distributed control computer. Proceeding of International Conference EPE2007, Aalborg, Denmark. Plant, Robert, Murrell & Stephen. 2007. An executive's guide to information technology.. Summary of positive issues: Visual Basic is easy to learn and widely available. Cambridge University Press. Read More