, pp.81-87 http://dx.doi.org/10.14257/astl.2017.146.16 Development of Wireless Module Test Equipment for Gas Safety Devices Performance Dong Seok Oh, Jeong Seok Oh and Jin Han Lee Institute of Gas Safety R&D, Korea Gas Safety Corporation, 1390, Wonjung-ro, Maengdong-myeon, Eumseong-gun, Chungcheongbuk-do, Korea ods500@kgs.or.kr, jsoh90@gmail.com, imhappy@kgs.or.kr Abstract. In this paper, we introduce the wireless module test equipment for certifying the performance of gas safety devices. It is the wireless module test equipment to decide whether or not gas safety devices passed the test that is measuring and analyzing wireless communications performance test items of the gas safety devices which are using the device under test (DUT). In testing performance of gas safety device receiver, the test considered environment conditions that may occur in the installation environment such as adjacent channel selectivity (ACS), blocking or desensitization and spurious response rejection is performed. As a result of test, we developed the wireless module test equipment having reliability of wireless communications data. Keywords: Wireless module, Gas safety devices, Performance test equipment 1 Introduction To commercialize a new wireless communications system, a frequency band for wireless communications should be allocated. At this time, the allocation of the frequency band may share the frequency resources allocated to the other wireless communication systems, or may allocate the unused frequency band. Such a new wireless communications system causes interference in the wireless communications system using the peripheral frequency band or the wireless communications system using the common frequency band, and it is common that a wireless communications system that has already been commercialized and operated is adversely affected by a new wireless communications system. That is, the wireless communications system is affected by the communication quality according to the surrounding noise level. If any wireless communications system increases the transmission output, the wireless communications systems using the common frequency band are more interfered, wireless communications systems using the surrounding frequency band are interfered by the effects of out-of-band radiation signals or single tone insensitivity. Therefore, before the new wireless communication system is commercialized, it is necessary to assess the interference influence between the new wireless communications system and the existing wireless communications system, and then determine what frequency band to allocate to the new wireless communications system according to the assessment result. In addition, ISSN: 2287-1233 ASTL Copyright 2017 SERSC
if the new wireless communications system is allocated frequency band, transmission parameters such as transmission power, transmission channel bandwidth, duty, and out-of-band radiation should also be determined. However, in the existing technology, there was a problem on the reliability of wireless communications data for the wireless gas safety device, because there is no a test equipment to directly test the performance of a receiver of wireless gas safety device including various wireless detectors, wireless controller or wireless interrupters capable of detecting, controlling and interrupting of gas leakage at laboratory or at site. In this paper, it is a goal to develop the wireless module test equipment for certifying performance of gas safety device. we performed test to demonstrate reliability of wireless communications data for gas safety device. To test performance of a gas safety device receiver, the test was taken into account environment conditions that may occur in the installation environment such as adjacent channel selectivity(acs), blocking or desensitization and spurious response rejection. The DUT used gas safety devices. This test is to decide whether or not gas safety devices passed the test that is measuring and analyzing wireless communications performance test items of the gas safety devices. 2 Wireless Module Test Equipment The wireless module test equipment uses a gas safety device as a DUT and evaluates various wireless communications performance tests of the gas safety device by wireless communications. Fig. 1 simply shows a wireless module test device for wireless communications performance test evaluation of a gas safety device. This gas safety device refers to various wireless detectors, wireless controllers or wireless interrupters that can detect, control or shut off gas leakage by wireless communications. Fig. 1. Schematic diagram of our test equipment Various wireless communications performance tests are to evaluate whether or not they meet the criteria for each item by measuring ACS, blocking or desensitization and spurious response rejection. The ACS measures the receive sensitivity of the gas safety device under test and the interference signal(unwanted Signal) existing in the adjacent channel to determine the level ratio (db), and then measures the selection ability of the interference existing in the adjacent channel. Blocking or desensitization is a test to measure whether the phenomenon in which a gas safety device as a device under test is to reduce the desired frequency output by interference is more than an 82 Copyright 2017 SERSC
allowable value. Spurious response rejection is a test to measure whether the ability of a gas safety device as a device under test to suppress various interference signals generated within the receiver is at least the minimum allowable value. Table 1 shows the minimum receiver performance characteristics for ACS, blocking and desensitization, and spurious response rejection. Table 1. The minimum receiver performance characteristics for ACS Characteristic Limit (db) Working frequency (MKz) Notes Adjacent channel 36 - For all bandwidths and selectivity modulation schemes Blocking or 40 ±1 In direct sequence spread desensitization spectrum system (DSSS), the 45 ±2 working frequency is the center 60 ±5 frequency Spurious rejection response 65 ±10 40 0 3 Equipment Design The wireless module test equipment includes a power unit, a communication unit, a software front panel, a vector signal generating unit, a vector signal analyzing unit, a test determination unit, a hardware panel, and an integrated control unit. Fig. 2 shows a detailed configuration of wireless module test equipment. Fig. 2. Configuration of our test equipment The power unit supplies AC power to each of the electric devices provided in the test equipment. In this case, the total usable power is 700W, the input voltage range is Copyright 2017 SERSC 83
100V to 240V, and the input frequency range is 50Hz to 60Hz. The communication unit provides an interface with the DUT to enable communication such as wire communication, wireless communications, Internet, and social network service (SNS). Fig. 3. Software panel for our test equipment In the measurement and analysis routine, when the user selects either ACS, blocking or desensitization, or spurious response rejection, the adjacent channel selectivity measurement result(db), blocking or desensitization values, or spurious rejection values measured through the vector signal generating and analyzing unit may be displayed on the panel in graphical and numerical values. The modulation signal generator modulates a continuous wave(cw) signal generated by the vector signal generator to generate a modulated signal (eg, a modulated RF signal) such as a IEEE802.15.4/ZigBee. For example, the panel may be provided with items such as signal generator parameter settings, frequency, power, modulation system, and level up step(3db). The automatic parameter setting unit may automatically set or change the parameters of the vector signal generating unit according to a communication technique through a preset batch file. The report generator makes it possible to output the final data obtained through the test determination unit, that is, various test measurement results (eg, various data and graphs), in a desired report form (eg, a pdf file). The wireless link analyzer is software that can be analyze 2.4GHz band wireless communications data packet. To implement this software, we provide a Perytons protocol analyzer capable of ZigBee/6LoWPAN/IEEE 802.15.4 network and protocol analyzer. The Perytons Protocol Analyzer provides the ability to capture, store and analyze wireless communications traffic in the actual usage environment of wireless gas safety 84 Copyright 2017 SERSC
devices. This makes it possible to perform a reliability test of the communication between the components of a wireless gas safety device. The Perytons Protocol Analyzer provides the following functions in order to perform site tests for meeting the communication loss test in ISO 7240. The vector signal generator unit generates various types of vector signals required for performance tests of gas safety devices such as adjacent channel selectivity, blocking or desensitization, and spurious response rejection. In addition, the vector signal generator unit is an NI PXIe-5673E RF vector signal generator that provides a wide instantaneous bandwidth, has an RF frequency range of up to 6.6GHz, and can generate various wireless signals in combination with software that meets user needs. In particular, it may generate AM, FM, CPM, ASK, FSK, MSK, PSK, QAM(4, 16, 64, 256), multi-tone signals and arbitrary wave forms, etc. using NI LabVIEW Modulation Toolkit. The vector signal generator unit may also generate signals such as GPS, GSM/EDGE/WCDMA, WLAN, WiMAX, DVB-C/H/C, ISDB-T, and ZigBee, etc. when it is combined with software. In this case, the vector signal generator unit meets the conditions, for example, the 85 MHz to 3.3 GHz frequency range, RF bandwidth above 100 MHz, up to +10 dbm RF power, -112 dbc/hz phase noise at 1 GHz, quickly setup into RF list mode and change possibility. The vector signal analyzer unit analyzes the vector signals generated by the vector signal generator to perform the performance tests of the gas safety devices such as adjacent channel selectivity, blocking or desensitization, and spurious response rejection. An NI PXIe-5663E RF vector signal analyzer with wide instantaneous bandwidth provides an analysis tool that integrates a high-performance PXI controller and a high-speed PCI Express data bus. The vector signal analyzer unit meets the conditions, for example, the 10 MHz to 3.4 GHz frequency range, 256 M memory size, 50 MHz instantaneous bandwidth(3db), 80 db spurious-free dynamic range(sfdr), a common noise floor less than -158 dbm/hz at 1 GHz, quickly setup into RF list mode and change possibility. Therefore, in this study, the vector signal analyzer unit may perform typical automatic measurement at a much faster speed than the existing VSA measurement. By utilizing the RF list mode, it is possible to quickly and decisively change the RF setting, thereby speeding up the multi-band measurement, thereby greatly reducing the test period. The test determination unit determines whether the wireless communications performance test for various gas safety devices used in the DUT is passed through th analysis of the vector signal analyzer unit. In the case of failure, they are analyzed and provided the factors of rejection according to test items. The hardware panel includes a rack mount kit, fan shuttle, EMC filter panel, filter panel and slot blocker, and is part of a chassis (eg, NI PXIe-1065) that forms the hardware portion of the configuration of the wireless module test equipment. The rack mount kit not only protects the internal system in harsh environment, but also monitors the internal temperature condition externally with a built-in monitoring system. Also, the cooling system automatically operates according to the set internal temperature to regulate the noise. In order to save energy, we offer an SCXI chassis in a standard 19-inch rack enclosure, and each kit has a multi-position function for recessed and ejected mounting. The fan shuttle is a measurement module for improving the cooling performance of the chassis, noise performance and the safety of the power supply. It may optimize cooling of the back plane portion of the chassis, Copyright 2017 SERSC 85
optimize cooling through a combination of fan speed control, type of the fan used, and fan mounting method, while minimizing noise emissions. The EMC filter panel shields electromagnetic waves from interfering with normal operation of the system or compromising safety. The cooling system automatically operates according to the set internal temperature to provide the optimum environment for system operation. In this case, the shielding performance is suitable from 1 MHz to 18 GHz/50 to 70 db. The filter panel covers the front and rear of unused chassis slots to protect the slots from foreign substances. The Slot blocker is a measurement module that improves system cooling by changing the flow of air from unused PXI slots to slots with modules. It is possible to be compatible with NI PXIe-1065 chassis. By mounting the slot blocker, it is possible not only to improve the long-term reliability of the entire measurement system by lowering the operating temperature, but also to extend the life of the PXI system. The integrated control unit controls the power unit, the communication unit, the soft front panel unit, the vector signal generator unit, the vector signal analyzer unit, the test determination unit, and the hardware panel. Acknowledgements. This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20172010105470) 4 Conclusions In this paper, it is a goal to develop the wireless module test equipment for certifying performance of gas safety device. We performed test to demonstrate reliability of wireless communications data for gas safety device. This test is to decide whether or not gas safety devices passed the test that is measuring and analyzing wireless communications performance test items of the gas safety devices. The wireless module test equipment includes the communication unit that provides an interface to enable communication with a gas safety device, the vector signal generator unit that generates various vector signals for testing wireless communication performance test items of gas safety device, and the vector signal analyzer unit for analyzing vector signals generated through the vector signal generator unit to test wireless communication performance test items of the gas safety device. The test determination unit for determining whether the wireless communication performance test for the gas safety device is passed through the analysis of the vector signal analyzer unit and analyzing the rejection factor for each evaluating item when it is determined that the wireless communication performance test is failed. This test device provides software for signal generation, signal collection, or test analysis result reporting in conjunction with the vector signal generator, the vector signal analyzer, and the test determination unit. The test device includes the soft front panel unit for analyzing wireless communication data packet and the integrated control unit for controlling the communication unit, the vector signal generator unit, the vector signal analyzer unit, the test determination unit, and the soft front panel unit. 86 Copyright 2017 SERSC
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