USAGE OF RFID WIRELESS IDENTIFICATION TECHNOLOGY TO SUPPORT DECISSION MAKING IN STEEL WORKS. Jiří DAVID, Robert FRISCHER, Mária STRÁŇAVOVÁ

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1 USAGE OF RFID WIRELESS IDENTIFICATION TECHNOLOGY TO SUPPORT DECISSION MAKING IN STEEL WORKS Jiří DAVID, Robert FRISCHER, Mária STRÁŇAVOVÁ VŠB Technical University of Ostrava, Department of Automation and Computer Application in Metallurgy, 17. listopadu 15, Ostrava - Poruba, Czech republic j.david@vsb.cz, robert.frischer@vsb.cz, maria.stranavova.st@vsb.cz Abstract This paper deals with way how to monitor life cycle of crystallizers at continuous casting devices. There are some irregular changes where the crystallizers desks are during their life time - actual working position in continuous casting device, emergency position in continuous casting device, transport to the maintenance and diagnostic service, diagnostic and maintenance it selves. This cycle we can consider as a logistic chain and therefore it is suitable to implement some new innovative technologies in the wireless identification area. Automated monitoring of each crystallizers desks is a key process to achieve better maintenance estimation. Key words: RFID, continuous casting, RF, antenna. 1. INTRODUCTION This paper deal with the way of monitoring crystallizer s lifetime cycle, which are using in continuous casting devices. During the lifetime cycle of crystallizer s desks, there are many irregular changes of these desks. There can be a working position of the desk on continuous casting device, standby position, some transports to the maintenance and diagnostics centre and so on. This cycle can be simply consider as a logistic chain and that s why is appropriate to use an automated monitoring and localization of single crystallizer s desk. There are many innovative technologies in wireless identification area (RFID) 2. PROPOSAL OF SPECIALIZED MODULE FOR LOGISTIC SUPPORT WITH USAGE OF WIRELESS TECHNOLOGIES. Wireless identification system is based on radio frequency data transfer principle. This transfer is among sensor (base station) and moving object (person, car, palette in storage house and so on). Monitored object has to be equipped with so called transponder (RFID tag), which basically is electronic circuit, which contain transmit/receiving antenna module, power supply capacitor, memory (ROM, EEPROM) and control circuit. It s essential advantage is fact, that it don t need battery power source. In principle whole system operate as double antenna system, where one is on the transmitter side (base station) and the other one is connected to the transponder (tag). Transponders are in various types of constructions in dependence of target implementation. These tags may be in shapes and sizes of credit card, glass sticks, plastic circuit plates, cylinders and so on. Function principle of transponder is presented on (Fig. 1). The base station is continuously transmitting pulses of RF signal through the antenna to the surrounding environment.

2 Fig. 1 Basic function principle of RFID transponder. As soon as the transponder is on coverage of the antenna, it will receive the transmitting signal and through it charge up the power capacitor. This energy is sufficient to activate transponder and transmit information, stored in memory. The base station then receives transponders data to evaluate them. After that, the data are processed and stored in the database. Data can be passed to the computer immediately, or can be stored in mobile reader s memory and copy to the database system later. In our case were used passive RFID transponders. Passive transponders are dramatically cheaper than their active versions, unpretending to maintenance, climatically and environmentally resistant, they have variable working read distance from 0.5m to 10m, long life time, they are using RTF (Reader Talk First) communicating method and memory sizes from 64b to 256b. Transponders which work on highest frequency UHF, has reading radius from 1m 10m at maximum. Tags with the lowest transmitting frequency 125kHz, has only 0.5m action read/write radius. In industrial ambient may be used special RFID transponders working on 134.2kHz and 13.56MHz (Fig. 2.) kHz frequency is typical for Texas Instrument products. This RFID system is characteristic because of using frequency modulation (FM), not like others. Standard modulation in RFID communications is amplitude modulation (AM). This advantage guarantee longer working radius of reading and better interference immunity. Fig. 2 Communication channels dedicated to RFID system. Practically it means, that each part of crystallizer should be equipped with passive wireless identification sensors tags (for example cylindrical model RI-TRP-R9TD or ceramic transponder which about to be mounted on the metal). These tags will carry set of information for logistic control support. There have to be a set of base station too. These base station should be mounted on exposed spots, mostly entrance gates, train cross roads or places in large hall, where the maintenance happen (for example microreader RI-STU- MRD-1). These devices are currently under testing conditions in laboratory environment [1],[2],[3]. Suggestion of whole logistic chain is presented on visualization proposal on (Fig. 3.). During the working cycle will crystallizer pass through the monitoring station, crystallizers transponders will react and send its information to the base station. This station processes the data, add its own information header and contact the monitoring system. Testing operation in industrial environment proved itself that is necessary to use various frequency bands, by reason of disturbance caused by other devices (remote heavy load crane, traction locomotive driving and so on).

3 Fig. 3 Early suggestion of visualization of main screen Main benefit of setting up this technology may be assume in automatic gathering of information about actual position of each crystallizers desks, their working state and logistics states and stands in real time. These information than help to optimize of logistic control process of operation/maintenance state. Passing to these technologies and their usage is subjected to development of these technologies and also to making corresponding support from application side of SW equipment. Cooperation with Phobos and Sick company brought mane new possibilities, which can be used to improve this task in present time, we have two main candidates for industrial operation. The first option counts with usage of LF RFID, running on 134kHz. Problem with disturbance and low read radius is balanced by used frequency modulation. With its help and big frame antenna the read distance should extend to 2m. This is sufficient for most cases. Important thing is to verify this this technology directly in the industrial environment because of huge RF disturbance on testing spot. The second option is to use industrial reader base station from Sick company working on 868MHz band. Used directive antenna vector output power into the certain area and so it is not a major source of disturbance to surrounding wireless devices. New methods of communication allow two way operation (full duplex) and that s why other usage possibilities in logistic. 3. PRACTICAL TESTS IN OPERATION There was a testing on the model before real testing operation of reading mechanism. One of the realization conditions was a graphical expression of upcoming system. It was made to be able to exclude possible collisions with surrounding devices and in addition graphically show directive characteristics of used antenna system. To prove this detail photo documentation was made. There were choose a spots, where the RFID system should be installed. Than were made a 3D model in Rhinoceros 3D software environment. Antenna directivity than was import into the 3D model. Result roughly shows field of action of electromagnetic field generated from the antenna in guarded directions. Results of this simulations are presented on (Fig. 4.).

4 Fig. 4 3D model of industrial environment made in Rhinoceros 3D environment. Real system was disassembly onto the basic elements and modeled on PC. Created wire model serve to primary orientation in space. Next step were textures, which were piled up on the model and lights were added. Most power generated from antenna was substituted by cone. Model was rendered and incurred pictures were presented to competent person to examination. Antenna itself was identified separately. It was necessary to make detail RF coverage area. Powerful beam generated by antenna should reliably shade any RF control device in closed area. RF power is relatively high, about 20W at maximum. Antenna itself is standard panel construction. Coverage area is sector type. Measurement proceeded in lab environment and results were extrapolated on computer model. Measurements results are presented on (Fig. 5.). Antenna system was measured in horizontal and vertical polarization. Systems sensitivity were tested under several conditions. RFID transponders were shielded by various type of material and then was examined influence of the material to the reading range and system stability [4],[5]. Fig. 5 Coverage area of used antenna.

5 4. CONCLUSION Measurement in lab environment proves some supposed conclusions in context of RDIF systems. Measurements concern especially a reading distances and RF coverage area of antenna system. Low frequency systems show itself with good selectivity, but very low read distance. Even a bigger antenna didn t help. But price of these systems is very favorable and its implementation is mentioned in mass scale. High frequency RFID systems working in sub gigahertz band (860MHz) are on the contrary high appropriate to read transponder data on longer distances (12m). One disadvantage is disturbance of other RF devices in surroundings. Output RF power is in order of ones of watts and that s why can easy suppress low power remote controls of other industrial systems. So it was necessary to use high quality, sector antennas to suppress any disturbance outside of coverage area. Price of this HF RFID systems is tenth as high as LF systems. RFID technology show itself as a good alternative to other identification technologies used in industrial environment. This article can originate thanks to support of Ministry of Industry and Trade of Czech republic. Grant project TIP evidence number. FR-TI1/319 "Vývoj nových progresivních nástrojů a systémů podpory řízení spolehlivostí primárního chlazení na bramovém zařízení plynulého odlévání ocelí pro zvyšování kvality náročných plochých výrobků" and in terms of project SP2012/42. LITERATURE [1] Krejcar, O., I. Spicka, and R. Frischer Implementation of full-featured PID regulator in microcontrollers. Elektronika ir Elektrotechnika, no. 7: ISSN Database on-line. Available from Scopus. [2] Krejcar, O., I. Spicka, and R. Frischer Micro operation system for microprocessor applications. Elektronika ir Elektrotechnika, no. 8: ISSN Database on-line. Available from Scopus. [3] Krejcar, O., I. Spicka, R. Frischer, and M. Heger Incremental PIC controller with handled limit states and manual settings. In ICMEE nd international conference on mechanical and electronics engineering, proceedings V Database on-line. Available from Scopus. [4] RFID Portál. RFID Portál. [Online] [5] kol., D. a. (2011). Podpora logistiky s využitím bezdrátových identifikačních technologií. Zpráva projektu FRT 1/319, VŠB-TU OSTRAVA.