S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications                       (IJERA) I...
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  1. 1. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp. Embedded Web Server Based on DAC System Using ARM S.A.N.Sandeep P.Malyadri M.Tech Student Assoc Prof PKSK College PKSK College ECE Dept ECE DeptAbstract: Now a days we are using many in a central server and has all the applications. ANetworked embedded systems for monitoring person that needs to access any data must firstand control the home or industrial devices.With access the server. An indirect access to the data-the scalable networking solution The server acquisition unit makes the system unattractive forenables Web access to distributed real-time control applications, where directmeasurement/control systems and provides interaction with the system may be required. Theoptimization for educational laboratories, need to maintain an additional server will alsoinstrumentation, Industrial and home increase the setup costs and the costs to maintain theautomation. In this paper , we present the acquisition systems, such as regular maintenanceprinciples and to design a system for Internet- costs, system updates, etc. Therefore, the centralbased data-acquisition system and control by server has to be eliminated for a real time system.using Advanced RISC Machine i.e ARM The closest to this idea is published in [5]. In thisprocessor and in-build web server application system, a reliable bidirectional Point-to-Pointwith General Packet Radio Service (GPRS) Protocol (PPP) link for real-time control andtechnology. The main core of the system is an surveillance via a GSM network is formed.embedded hardware running on a NUT OS, a However, there is still no effort to minimize theindustrial grade RTOS for hard time operational costs. In addition, this system is basedapplications. The embedded device on an industrial PC, thus making it an expensivecommunicates through General Packet Radio solution. Interaction with the embedded unit is alsoService (GPRS),and also help us to communicate an important issue. In [6], an embedded PC cardwith the GSM as most of us were communicating placed on the Internet allows limited interactionwith GSM which makes it accessible from through commands sent through Transmissionanywhere in the world through a web server Control Protocol/IP (TCP/IP) and User Datagrambuilt into the embedded device.The proposed Protocol. In this paper, we propose a GPRS basedsystem eliminates the need for server software portable low-cost data-acquisition system, whichand maintenance. The proposed system can establish a reliable bidirectional connection forminimizes the operational costs while operating data acquisition. The proposed system uniquelywith a large amount of data. reduces the Costs occurring from frequentlyKey Terms: GPRS, GSM, Real Time Processing, requested data and eliminates the need for a well-Dataacquisition. established server. The system uses a dummy server for static information, thus optimizing the transfer ofI. INTRODUCTION large data. The user can directly log in and interact DATA-ACQUISITION systems are in with the embedded device in real time without thegreat demand in industry and consumer applications. need to maintain an additional server. The system isIn some applications, human beings have been modularly built, allowing different modules to bereplaced by unmanned devices that will acquire data added. In addition, it is flexible to accommodate aand relay the data back to the base [1]. There are wide range of measurement devices withdata-acquisition and control devices that will be a appropriate interfaces.substitute for a supervisor in a multisite joboperation. A single person can monitor and eveninteract with the ongoing work from a single basestation. An acquisition unit designed to collect datain their simplest form is detailed in [2], which isbased on Linux [3], which is a popular choice forembedded PC systems. A similar system in [4]provides data acquisition with no concern for remoteaccess. In these applications, data are compiled in acentral server and are then served to the clients viathe Internet. The client framework is In Section II, we will introduce the details of the 1|Page
  2. 2. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.aforementioned system. In Section III will describethe Testing of Embedded Web Server. In Section IVdata acquisition sensors are connected to theembedded system to demonstrate its operation andthe results are presented. Section V presents theconclusion.II. INTERACTIVE DATA- ACQUISITION SYSTEM Interactive Internet-based systemsprovide a way to monitor and adjust using standardweb browsers and a PC. The target systems can bemonitored and controlled independent from thelocation and the platform since standard webbrowsers can be used on the client side. A typicaldata-acquisition system is connected to web clientsvia the Internet, as shown in Fig. 1. The dataacquisition system needs to relay the acquiredinformation to the requesting clients. Digitally A. Establishing a Direct Communication Linkacquired data are stored in web server’s data base. between the Client and the EmbeddedWhenever the client wants to access data, it sends Device:the request to server; this request is taken by the The use of GPRS is well known torouter, which is connected to the internet. The web everybody and almost all service providers on GSMprocesses the request made and finally connects to are giving this service. GSM and GPRS [8] arethe desired web server, access the requested data developed for cellular mobile communication.and sends the data to the client. Hence it is very much easy to be getting connected to the Internet world. Once a GPRS connection hasEmbedded Web Server Architecture: been established queried data can be relayed to the An embedded web server is an ARM client via a central server[8]. Using a central serverprocessor that contains an internet software suite as to relay the acquired data has some disadvantages.well as application code for monitoring and First, a central server needs a client interfacecontrolling machines/systems. Embedded web framework. An additional data transfer correspondsservers are integral part of an embedded network to time delays before the data are made available to[7]. Fig 2. Shows the proposed concept of DACS the client. In addition, since the server acts as awith embedded web server on a single chip module. relay, no direct bidirectional communicationThis is a single hardware it contains RTOS portable between the client and the embedded system can beARM processor. ARM processor is the responsible established. This makes the system unsuitable forpart for measuring signals and controlling the real-time control applications.devices remotely. Measurements can be done by The basic idea behind real-time processingDACS mode and the data are shared with clients is that the embedded system is expected to respondthrough embedded web server by embedded web to the queries in time. Real time should be fastserver mode. The real time operating system enough in the context in which the system ismanages all the tasks such as measuring signals, operating and reliable as well. Real-time systemconversion of signals, data base up-dation, sending correctness depends not only on the correctness ofHTMLpagesandconnecting/communicating with the logical result of the computation but also on thenew users etc., result delivery time [9]. This method also increases The RTOS manages all the required tasks the data transfer cost as the number of clientsin parallel and in small amounts of time. Web based increases due to the access amount of data transfersmanagement user interfaces using embedded web via GPRS. Direct communication, on the otherserver have many advantages: ubiquity, user- hand, enables access to only relevant information infriendly, low-development cost and high the embedded system by pre processing the data.maintainability. Embedded web server has different The embedded system should also handle the webrequirements, such as low resource usage, high services. This eliminates the need for a centralreliability, security, portability and controllability server and reduces the amount of data sent from thefor which general web server technologies are remote unit since only the queried data will beunsuitable. transferred. In the proposed system, the GPRS architecture and protocols are compliant with [8]. This system is configured to be virtually online at all times in a GSM network. An admin script is 2|Page
  3. 3. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.executed after the boot of the operating system, This process is illustrated in Fig. 4. Theinitiating the GPRS connection software module. A DHCP approach is more flexible and works betterPPP connection is established by a GPRS modem compared with the static approach as a cost-that works at 900/1800/1900 MHz operating effective solution, despite the necessity for a scriptfrequencies. A PPP daemon (PPPD) is used to running on the embedded server, one-timemanage the PPP network connections between the broadcasting its IP to the FTP server. The hypertextclient and the embedded module. file placed on the FTP server by the embedded The PPPD is responsible for setting up the system and queried by the client is shown in Fig. 5.GPRS parameters, such as the connection speed and With this mechanism in place, the embedded systemcompression. To directly access an embedded updates it IP information on the FTP server uponsystem, the IP address of the embedded device every reboot, which causes an IP refresh from theshould be made available to the client side. There GSM service- providerare two choices available. A static (hard-coded) IPcould be used, or the remote device should initiate a B. Data Management in the Systemconnection by reporting its IP. This choice is quite The Internet server is used to decrease thestraightforward and simple. Although the usage cost management costs by sending all the pictures (logo,remains unchanged, it requires a static IP setup by picture, bar graphics, etc.) to the client through athe service provider and involves monthly recurring server on the Internet. Text data such as coordinates,costs. The static IP is preferred for its simplicity in temperature, and altitude are served from thedesigning a system; however, its overhead may be embedded system. If bulky data are going to be sent,impractical. The other choice is to use a dynamic IP the embedded module is set to send the image onlyassigned through a Dynamic Host Configuration once via GPRS and placed on an FTP server. ThisProtocol (DHCP) server of the GSM provider for approach eliminates the transfer of large dataevery connection established. However, this IP through GPRS more than once, thus reducing theneeds to be known by any client requesting an transfer costs, particularly if more than one client isaccess to the embedded server. One solution is to involved or multiple requests to the same data arebroadcast this IP to a dummy FTP server. The FTP needed, as shown in Fig. 6.server is a dummy server and does not requireregular software updates or maintenance. The folderstructure of the FTP server is shown in Fig. 3. Ascript on the embedded device is configured toupdate its IP address on the FTP server in HypertextMeta-Language as an index.htm file, under a folderuniquely named by its hostname. This script simplyparses the current IP for that embedded device andsends an html file with the IP information of theembedded device to the FTP server. Once this file is in place, a directconnection can be established with the desiredembedded device by a simple query. An exampleembedded system, named DAS (Fig.3), can bequeried from the FTP server by a simple command.The web browser processes the (index.htm) file inthe specified folder as default; therefore, a file nameis not needed for referencing. 3|Page
  4. 4. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp. D.Software and Operating System Choice Nut/OS [10] is an embedded open-source operating system for microcontrollers, licensed byC. Hardware egnite software [11] under the BSD license. It is The general hardware structure of the allowed to modify the source code and chip binaryremote I/O data acquisition and control system software, as long as the original copyright notice isbased on ARM processor is shown in Fig 7. The included. Nut/OS offers many features to theremote I/O data acquisition and control system programmer like dynamic memory allocation,based on embedded ARM platform has high threading, formatted output and many more. But touniversality, each acquisition and control device ease portability of the stack itself as few Nut/OSequipped with 24-way acquisition/control channels specific features as possible were used. Theand isolated from each other. Each I/O channel can operating system also offers a modular design, soselect a variety of electrical and non electrical that only needed parts are linked together and nosignals like current, voltage, resistance etc., Digital unneeded parts are loaded into the limited programacquisition are done by special ADC. The measured space of the host. Another advantage is the supportdata are stored in external memory in which the for cooperative multi threading. The applicationmemory is act as a data base during web server itself runs in a separate thread and there is no needmode. The ARM processor directly supports the for the application programmer to cope with events,Ethernet service and RS485 communication. Hence dispatching and other confusing techniques.the data has been stored and controlled by some Multiple threads can wait on a queue and block untilother PCs or network via RS485 and Ethernet. ARM an event is posted to this queue. Then either one orprocessor has internal I2C module. So it has the all threads wake up. Nut/OS also supports dynamicability to communicate with any other peripherals. memory management to allocate and free memoryA Data acquisition module, and a GPRS are on the heap, although this is not used to easeintegrated into the embedded board to form a portability. Timer support and stream I/O functionssample application, as shown in Fig. 8. DAS are also supported. In the Nut/OS part serial device drivers and a PPP stack is included. Additionally Nut/OS features a Nut/Net part, including a fully functional TCP/IP stack providing ARP, IP, UDP, ICMP and TCP protocol, automatic configuration via DHCP, a HTTP server with CGI functions and TCP and UDP socket API for the application programmer. 4|Page
  5. 5. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp. III. RESULTS AND DISCUSSIONS Fig 10 and 11 shows execution results of ARM Embedded web server based on DACS system.III.TESTING EMBEDDED WEB SERVER Initially, the target is tested for the workingof operating system. This is done by booting thetarget using the hyper terminal. After the target issuccessfully booted with Nut/OS, it is tested overthe network using ping command. Now theembedded web server is responding to the clients,request is made to the server, embedded web server,by typing the IP address of the server in the client’sbrowser. The user has to enter IP to access theserver. This request is taken by the operating systemof the client and given to the LAN controller of theclient system. The LAN controller sends the requestto the router that processes and checks for the Above showed web pages are requested bysystem connected to the network with the particular the client and served by the embedded web serverIP address. If the IP address entered is correct and which is ported on ARM9 processor. Client canmatches to that of the server, a request is sent to the interact with the machine through its own browserLAN controller of the server and a session is via these embedded web pages. Every client’sestablished and a TCP/IP connection is establishes control has been executed in industry via theand the server starts sending the web pages to the embedded web server.client. IV. CONCLUSION In this application, a low-cost, Internet- based data acquisition and control system has been designed and implemented that should find interest from researchers. The application possibilities are virtually unlimited by attaching modules with appropriate interfaces, although the usage of the system is demonstrated with only a few sample devices. Compared with other applications, this system has advantages in terms of allowing direct bidirectional communication and reducing overhead, which can be vitally important for some real-time applications. The operational costs have been reduced by relinquishing the storage of large data to an FTP server on the Internet. The system is designed to support both static and dynamic IPs. A method to distribute the IP information has been developed. This cost-minimization effort is a big concern for mobile systems using wireless communication methods and has not been discussed 5|Page
  6. 6. S.A.N.Sandeep, P.Malyadri / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.before. The overall cost advantage of the system in Packet Radio Service GPRS: Architecture,terms of the components used makes it an attractive protocols, and air interface,‖ IEEEchoice for data-acquisition applications. The power Commun. Surveys Tuts., vol. 2, no. 4, pp.demand of the device is still in the process of being 2–14, Third Quarter 1999.improved by putting the attached devices into sleepmode at times when they are not in use to conserve [9] RTOS Evaluation Project, ―What makes apower. good RTOS,‖ Dedicated Systems Experts, 2001. [Online].REFERENCES Available:http://www.dedicatedsystems.co [1] C. E. Lin, C.-W. Hsu, Y.-S. Lee, and m C.C.Li, ―Verification of unmanned air vehicle flight control and surveillance [10] www.ethernut.de/en/firmware/nutos.html using mobile communication,‖J. Aerosp. Comput. Inf. Commun., vol. 1, no. 4, pp. [11] www.egnite.de/en/software/nutos.html 189–197, Apr. 2004.W.-K. Chen, Linear Networks and Systems (Book style). Belmont, CA: Wadsworth, 1993, pp. 123– 135. [2] K. Jacker and J. Mckinney, ―TkDAS—A data acquisition system using RTLinux, COMEDI, and Tcl/Tk,‖ in Proc. Third Real-Time Linux workshop 2001. [Online]. Available: The Real Time Linux Foundations: 2001/papers.html [3] E. Siever, A. Weber, S. Figgins, and R. Love, Linux in a Nutshell. Sebastopol, CA: O’Reilly, 2005. [4] Q. Zhou, W. Wu, and Y. Ma, ―The embedded data acquisition system for Mössbauer spectrum,‖ in Proc. Third Real- Time Linux Workshop Embedded Linux Expo Conf. Real-Time Embedded Comput. Conf., Milan, Italy, Nov. 2001, pp. 26–29. [5] C. E. Lin, C.-C. Li, A.-S. Hou, and C.- C.Wu, ―A real-time remote control architecture using mobile communication,‖ IEEE Trans. Instrum. Meas.,vol. 52, no. 4, pp. 997–1003, Aug. 2003. [6] T. Motylewski, ―The industrial data- acquisition system with embedded Rt- Linux and network server technology,‖ in Proc. Third Real-Time Linux Workshop, 2001. [Online]. Available: The Real Time Linux Foundation: http://www.realtimelinuxfoundation.org/ev ents/rtlws-2001/papers.html [7] Klimchynski, ―Extensible embedded Web server for internet-based data acquisition and control,‖ in Proc. 3rd IEEE Int. Conf. Sensors,Vienna, Austria, Oct. 24–27, 2004, vol. 1, pp. 52–55. [8] C. Bettstetter, H.-J. Vögel, and J. Eberspächer, ―GSM phase 2+ General 6|Page

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