, ,China. Keywords: CAN BUS,Environmental Factors,Data Collection,Roll Call.

Transcription

1 Advanced Materials Research Online: ISS: , Vols , pp doi: / Trans Tech Publications, Switzerland The design of artificial climate chamber environment based on CA bus data acquisition system Guozhuang Liang 1, a, Bo Zheng 1,b, Ying Zhang 1,c and Tao Ma 2 1 School of Electrical Engineering,Hebei University of Science and Technology, Shijiazhuang,Hebei, ,China troops, Shijiazhuang,Hebei, ,China a Liang_gz@sohu.com, b zhengbo @gmail.com, c zhgyg2008@163.com Keywords: CA BUS,Environmental Factors,Data Collection,Roll Call. Abstract. Introduced a kind of based on CA bus, to realization of artificial climate chamber environment data acquisition system. System adopts SJA1000, PCA82C520 as interface devices, the host through the CA bus runs around in the culture room of all CA nodes, each node through the installation of various sensors on plant growth environment factor for information collection and transmission. System has a good real-time performance, low running cost, easy to build, has broad application prospects. Introduction Artificial climate chamber is a kind of not limited by geography, seasons and other natural conditions and can shorten the research cycle, can be manually controlled illumination, temperature, humidity, air pressure and gas composition factors such as sealed isolation equipment. Plant growth state of the natural environment parameters mainly light, moderate, and temperature and CO 2 concentration, the artificial simulation of the natural environment for plant growth, used to rely on the experimenter field sampling, point by point in the climate chamber measured with instruments, or sensory judgment. Due to human factors, the time lag of measurement results is big, can't timely and accurately reflect the actual state of growth. Using real time, flexible and efficient, and safe and reliable fieldbus data communication methods as environmental condition monitoring system of data acquisition and transmission mode is very necessary. CA bus is a kind of effective support distributed control and real-time control of serial communication bus network, initially by Germany Bosch company design for auto detection and control, after being used in other departments of industry control, application range throughout the control field[2]. CA bus data communication has the characteristics of safe, reliable, real-time and flexibility[3]. System, presented in this paper is mainly used for plant grow light, humidity, temperature and CO 2 concentration of the environmental factors such as automatic collection, fault triggers to the abnormal situation of artificial climate chamber of alarm processing, simulation of human expert's information fusion ability[4], state analysis of plants to grow, to control plant growth environment temperature, humidity, light and CO 2 concentration needed for the foundation. System Overall Structure Phytotron based on CA bus data acquisition system is mainly composed of mainframe environment, communication circuit, data acquisition unit (CA node) [5], the system adopts the bus topological structure, and possesses the advantages of simple structure, low cost, the system network topology is shown in figure 1. System with PC as the host, which install Taiwan LingHua company communication card PCI By the microcontroller (P80C592), A/D converter, CA control chip SJA1000 (CA bus controller), PCA82C520 (CA bus transceiver) and related supporting chip constitute the data All rights reserved. o part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-05/03/16,04:15:18)

2 temperaturesensorhumiditylico2sensor1694 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering collector for from machine, installed in each were respectively. A host can manage 1 ~ 200 from the machine, a from the machine can be connected moderate temperature, light, CO 2 sensor 1 ~ 120. PCI Host computer CAH CA Fieldbus 120 CAL Datalogic(CA Bus odes 1) temperaturesensorhumidityligcoht2sensorsensorsensorsensorghtsensorbus odes 2) Bus odes n) htdatalogic(ca temperhumidligco2aturesensoritysensorsensorsensorculture room 1 Culture room 2 Culture room n Fig.1 The structure of network topology system System working process: firstly, the host initialize the CA communication adapter card PCI , set communication card working mode and receiving yards, accept mask and baud rate, and then enter the running state, under appropriate conditions and the data collector to communicate. Data collector for training experiment indoor temperature, humidity, light and CO 2 concentration in the sampling, data processing, and at the same time through the built-in CA interface with interrupt way sends the data to the CA bus. Host via CA bus, manages put the slave( CA node) in the 10 km range in the culture room, each slave drive, through the installation of various sensors on plant growth in the culture room environment factor for information collection and transmission. This way of serial communication with CA bus structure, has the good real-time, low running costs, convenient system set up[5,6]. The System Hardware Design The CA bus communication system.ca bus is a kind of effective support distributed data acquisition of serial communication network, it work in the form of half duplex, a node to send information, multiple nodes receive information, CA realize the distributed multi machine system, improve the reliability of data transmission in the network[5]. Information access using a CA bus as access work way of broadcasting, information CA be sent at any time by any node to the free bus, each node of the CA bus interface must receive all the information that appears on the bus, so have been set at each node a receives registers[6]. Receive register first receives the information, then according to the identifier of receiving information to decide whether to read the data in the packet, which determine whether or not to use this information[1,5]. The Characteristics of CA bus communication system.system of CA controller SJA1000 chip of PHILIPS company, it has a rudder, bus access priority and main structure group and radio message function and hardware filtering characteristics, and form a complete set of drive 82C250, it CA provide bus differential ability to send and receive, and protect the bus and the SJA1000 controller SJA1000 and 82C250 connection diagram shown in figure 2. At the same time, the system USES the SJA1000 enhancement work mode[2]. Can benefits a lot this kind of work mode, such as

3 Advanced Materials Research Vols communications double filtering method, the reliability of the communication is very high, not easy to go wrong, the double filtering way of communication is the most important feature of this system. For CA bus enhanced mode, just set the SJA1000 clock registers o. 7 bit - CDR bit is "1". Based on SJA1000 bit timing registers, BTR0 and BTR1 set to achieve different communication baud rate, CA bus communication baud rate and communication distance have close relations, the higher the baud rate, the shorter the transmission distance, and vice versa. SJA1000 AD0-AD7 TX0 TXD 82C250 CAH IT RX0 RXD CAL ALE MODE Vdd ( Intel model ) WR XTAL1 CA Fieldbus RD XTAL2 CS RST Reset Circuit Fig.2 SJA1000 connection with 82C250 The System Software Design Phytotron based on CA bus is environmental data acquisition system of the machine ( CA node) number is 1 ~ 200, they were installed in different culture room, so host must know in advance system from the machine number and address, so that the host unified management. From the machine connected to the light, moderate, and temperature and CO 2 concentration sensor, each using a sensor from the machine can connect 1 to a maximum of 128. System host also must know in advance, therefore, the number of sensors, to complete the specific experimental culture room environment factor of the data collection. Host query from the machine and the number of sensors is through the communication to achieve attendance. Star the roll call Communicate success? Send command of call Inquire the number of lower computer Communication error for 3 times Y Call End? Back to main interface Y Communicate fail Fig.3 The flow chart of the roll call system In the actual operation process, the host will command system, transmitted to the CA node through CA bus communication, and then, from the machine will according to the order of temperature, moderate, and light and CO 2 concentration data on environmental factors such as acquisition. Roll call, test, the set and radio freeze and so on four big communication module, command format is the same, as their execution order number is different, so can realize different functions. System roll call process is shown in figure 3.

4 1696 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering Roll call command is used to query ( CA node) number from the machine, and from the machine connected to the sensor number, general in the system is powered on for the first time the command to be executed. System host sends a named command format for: 0BBH +CAADD+ 0AAH +cmnd+byteh+bytel+adrh+adrl+chkxor+chksum Among them, 0BBH Host sends the command start code, namely the command. CAADD In the system the address of the CA node. 0AAH Communication between master and slave machine orders start code. cmnd The command. Byteh, Bytel Respectively to detect the data bytes. Byteh for high byte 8 bits, Bytel for low byte 8 bits, the testing data of total length = (256 + Bytel Byteh x) bytes. adrh, adrl Respectively to detect objects of sensor model and sensor number (each object has its fixed sensor models and the sensor number, which shall be prescribed by the agreement). chkxor, chksum Exclusive or calibration, and calibration respectively. Conclusion Through test proved that this data acquisition system CA collect data communication software cooperation CA be a very good the all-the-way tracking and recording technology, convenient for the user understanding of comm-unication process, and improve the ability to solve fault system. This system has been put into operation in the actual work. Running results show that the system operation is simple, reliable operation, has wide application prospect. References [1] Q. Zhang: A data acquisition system based on CA bus control technology. Control Technology.Vol. 22(2001), p. 26 [2] Y.C. Xue and J.Q. He: Industrial computer and configuration control technology principle and application(electric Power Press, China 2007). [3] M.J. Ma: Data acquisition and processing technology (Jiaoda Press, Xian 2005). [4] C.H. Zhu and J. Peng: Data acquisition and processing technology (Electronic industry Press, China 2008). [5] E. Zou: Based on CA bus intelligent ultrasonic ranging on-board system. Journal of Hunan university of technology. Vol. 3(2011), p. 69 [6] W.Lai, R.J. Ong, and X. Chen: CA bus technology and system implementtation.microprocessor Chip Technology. vol. 3(2002), p. 29

5 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering / The Design of Artificial Climate Chamber Environment Based on CA Bus Data Acquisition System /