Industrial Water Level Measurement and Control System Based on
Contents
1. 5 Hardware Minde Zhou Microcumputer amp Software application Tsinghua University publishing company p 175 1772. Alarm processing module Alarm processing module includes voice alarming and vision alarming as well as the function of alarming data retrieving Voice alarm module joins alarming flash lamp in water control display through the output of ADAMS5510 When water level rises and exceeds the upper limit level alarming lamp begins to flash and voice alarm makes a noise alarm Same thing will happen when water level is lower than the lower limit level Both the water upper limit and the lower limit can be set by operator according to the real situation 3 Communication module Communication function actually is realized by both the instrument driver program and the I O interface software The data acquired by Programmable controller and their control information is transferred to the host PC through twisted pair wire bus 4 Database management module Data acquired is saved and analyzed by this module Water level and other situation may be seen through the trend curve And history data may be retrieved from the database 5 Report module It processes data within database reporting and printing The user may query any data record with excel format report forms A variety of featured VIs are built according to their different functions The procedures are following Front panel Select the objects required from the control palette place them on front panel and then the VIs may be designed one by one The objects include input out
3. 11 IMEKO TC 4 Symp Trends in Electrical Measurement and Instrumentation September 13 14 2001 Lisbon Portugal INDUSTRIAL WATER LEVEL MEASUREMENT AND CONTROL SYSTEM BASED ON VIRTUAL INSTRUMENT TECHNOLOGY Tianshu Huang IEEE member Zheng Zhang Qingzhen Ren Jidong Xiang Department of Electronic Information Wuhan University Wuhan 430072 P R China Tel 86 27 67803897 Fax 86 27 67803410 e mail tshuang wuhee edu cn Department of Electronic Information Wuhan University Wuhan 430072 P R China Tel 86 27 67803896 Fax 86 27 67802125 e mail zzhang wuhee edu cn Department of Electronic Information Wuhan University Wuhan 430072 P R China Tel 86 27 67803897 Fax 86 27 67803410 e mail qzren wuhee edu cn Department of Electronic Information Wuhan University Wuhan 430072 P R China Tel 86 27 67803896 Fax 86 27 67802125 e mail jdxiang wuhee edu cn Abstract This paper discusses the implementation of a new industrial water level measurement design and and control system Virtual Instrument technology is employed to construct the and hardware framework The modularized system features high flexibility and expandability The system provides with parameter software display data testing alarming storage and printing The system is opening and compatible Keywords Virtual instrument communication water level control 1 INTRODUCTION With the development of DCS field bus
4. M5510 In the end it sends the result to the PC in the way of ADAM5000 in order to implement the control and data collection For example change the ADAM5000 into ADAM5510 without changing other configuration When LabVIEW needs to acquire the data from the module ADAM5017 LabVIEW sends 01S1 to ADAMS5510 and the user s programs in it judges the sent command to see if received command corresponding with instruction set of ADAM5000 485 like 01S1 CRY If it is true then it returns an answer in the format of command gt 1 4567 1 4852 1 6661 1 6321 1 6459 2 989 1 7768 1 1623 CR and LabVIEW accepts the ADAM5510 as ADAM 5000 4 SYSTEM SOFTWARE DESIGN System application software is the pivotal segment of the whole water location control system Its tasks include system initialization measuring parameter display data testing data storage control information output alarming and printing etc Taking advantage of design concept and method of LabVIEW s modular and layer programming a layered application software is designed from top to bottom Its functional modules is shown in Fig 3 and its function may be described as following 1 Real time data monitoring module Including pressure and flux s data monitoring and parameter setting up The water level control system operation status is displayed intuitively in measuring results and graph At default instance data acquisition executes automatically 2
5. ile it also carries out data acquisition and other functions such as data processing data storage alarming trend curves printing etc System application software faces directly to operators so it requires friendly man machine interface and picture etc The whole system may be divided as five parts instrument module instrument hardware interface I O interface software instrument drivers and system application It is shown as Fig 2 Application software Windows API RS 232 interface RS 232 interface Programmed control Programmed control System software i ADAM5510 programmable controllers are controlled by host microcomputer It works not only as an independent unit but also as a part of the whole distributed control system The communication is important because remote file downloading to ADAM5510 is necessary for its operation Data and information transferring is also needed RS 232 port must be initialized before ADAM5510 communicates to host computer it makes both ADAM5510 and computer communication has same format The initial parameters include baud rates start bit stop bit and checksum It can be realized by programmed by Turbo c 2 0 ADAM5000 485 is a serial communication mode it has RS 485 a synchronism communication serial interface Its communication protocol is ASCII command response protocol It is either in receiving or sending modes PC sends out a command that includes a special address to the s
6. ith virtual instrument technology It is used for measuring temperature pressure flux and signal of valves PLC communicates with the upper host computer in series communication y 7 o o 2 g 2 2 g 5 3 3 Fig 1 System Construction System uses virtual instrument graphics programmable software LabVIEW Based on virtual instrument technology system may be described as following 1 Instrument Module It is hardware level and is directly faced to object It is the base of water level control system It implements functions of data acquisition adjustable control etc Input message of ADAM5510 module is faced to transducers signals such as flux pressure and water level etc 2 Instrument Interface RS 232 is used to implement communication between ADAMS5510 and host PC 3 YO interface software I O interface is a series of canonical and programmed functions in advance which has been provided by software developer LabVIEW uses a kind of standard application program I O programmable interface API named VISA to implement the communication VISA is a high level API LabVIEW provided many ready made VISA for application 4 Instrument Driver Program It realizes communication with ADAMS5510 through I O interface to drive hardware to execute data acquisition and equipment control etc 5 System application software It realizes the operation of hardware through instrument driver program and I O interface Meanwh
7. put controls indicators and so on One VI may consist of some subVIs that will accomplish a variety of tasks Block diagram To construct data flowing block diagram is one of the key procedures Select necessary functions from the functions palette shown by icons and place them on block diagram Then connect the correct terminals of the function or VI to let the data to transfer Terminals are regions on a VI or function through which data passes VI Hierarchy A good way for creating an application is to start at the top level VI and define the inputs and outputs for the application Then construct subVIs to perform the necessary operations on the data as it flows through the block diagram 147 Parameters set Fig 3 Top to bottom function modules 5 CONCLUSION Utilizing LabVIEW technology and its modular design ways a water level control system is designed in the top to bottom design way Because it adopts the idea of virtual instrument this system structure is clear and simple The canonical protocols are used between their internal levels The system provides interfaces for both hardware and software for further development The system holds the advantages of opening and expanding REFERENCES 1 Instrumentation Reference and Catalogue 1998 National Instruments 2 LabVIEW users manual National Instrument Corp 3 ADAMS5510 Series User s Manual unpublished 4 ADAM5000 485 User s Manual unpublished
8. technology etc automation measurement and control systems are applied widely in a variety of industry fields Water level measurement and control system is a typical application Recent years virtual instrument system has got noticeable development It is a great breakthrough for conventional instrument technology The virtual instrument is a result that computer combines with instrument technology It breaks through the restriction of traditional instrument in data processing display storage etc which makes it easier for users in maintenance expanding and upgrading their instrument systems By utilizing latest computer technology virtual instrument technology makes it easier to realize and expand the functions of the conventional instrument This paper designs a real time and automatic M amp C measure and control system based on the virtual instrument technology The system is opening and compatible 2 SYSTEM STRUCTURE DESIGN ADAMS5510 is programmable aptitude controller that can be used in data acquisition and control it has four I O modules 64 channels provides a serial port RS 232 485 to communicate with other devices ADAMS5510 may directly connect many kinds of transducers to measure temperature pressure flux etc The input may be standard industrial voltage current or various digital signals It is suitable in water level measurement and control system ISBN 972 98115 4 7 2001 IT Fig l is the system constructed w
9. ystem and waits system s response for a certain time If there is no response the process is interrupted and the PC returns a control command The command format is depart character address slot channel command data checksum carriage return Each command begins with a partition character There are four valid characters and The partition character is followed by two hexadecimal address characters that specifies the target system The address followed the System hardware Fio Svstem I evel Frame 3 COMMUNICATION 146 two characters specifies the module channel and slot Based on the command an optional data segment may follow the command string An optional two bit checksum character may also be appended to the command string Every command is terminated with a carriage return Because the LabVIEW doesn t support the ADAM5510 driver user has to develop the communication program between ADAM5510 and LabVIEW So he must be clear of the interior address distribution of ADAM5510 system which is a little difficult to a developer In this paper an easy method is introduced It is available to imitate the ADAM5000 485 in programming the communication drivers because LabVIEW supports the driver of ADAM5000 485 Thus sending and receiving of commands may be done in the command format of ADAM5000 485 ADAM5510 receives the commands then unscramble them carries out corresponding functions of ADA
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