Firmware and functional test platform developed for a smart controller

Naude, Nicolaas Hendrik (2017-12)

Thesis (MEng)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: Natural resources are important for human existence. Initiatives to manage resources effectively are exercised daily. The consumption of water and electricity increases daily in South Africa, and worldwide, thus the need for exploring new resource savings techniques. The primary electricity supplier of South Africa, Eskom, can not meet the current demand at all times. Not only is South Africa facing a shortage of electricity supply, but, at the time of writing, also a drought that could harm the economy. The Western Cape and the Eastern Cape provinces are especially under pressure by the drought. The Western Cape government implemented water usage limits and it is currently escalated to 87 L per person per day. The Nelson Mandela Bay municipality, in the Eastern Cape, was on the verge of being declared a drought disaster area in March of 2017. The necessity of saving initiatives are thus evident for South Africa. The Internet of Things is well suited to contribute to these savings initiatives. This thesis forms part of a smart controller (SC) for electric water heaters (EWHs), which allows the user to monitor water usage and set a control schedule to automatically switch the EWH on and off. The SC gathers data from EWHs, allowing research to predict optimal heating schedules. This research can also be used to implement a scheduling technique to switch an EWH on and off, depending on the national electricity grid load during peak consumption times, whilst still providing the EWH user with hot water on demand. The first development in this thesis is focused on designing and implementing firmware for a new SC hardware design. The SC communicates to a central database, with the use of an equipped cellular modem. The firmware consists of two parts, modem firmware and peripheral firmware. The peripheral firmware is responsible for correct actuator function and measuring the sensors accurately. The measurements are aggregated and concatenated into a single report string, which is sent to a cloud based database every minute. The SC forms part of a smart electric water heater controller project, which received funding from the Water Research Council to develop and install SCs in eMkhondo municipality district in Mpumalanga, South Africa. The SC used for research purposes is upgraded with new hardware, containing a new processor, which lead to the requirement of new rmware. The new hardware was tested in-house by a labourer, which required technical skills. This test required physical signal injection and result evaluation by the tester. The need to improve this test procedure lead to the second development of this thesis. An automatic test procedure is designed, which consists of test hardware and test software. The implementation of the complete test system is evaluated and the system efficacy is determined. The research objective to develop and implement firmware for the new SC hardware is achieved and is implemented on a total of 245 SCs. The data collected, by these SCs, was of such a standard that research could be done on optimisation of heating schedules and provide a means to create awareness of a household's EWH consumption patterns. The second objective to develop and implement a test system was achieved, where the accuracy of the hardware is determined and the test system efficacy showed, during the validation tests, six of the ten tests were successful. The test system would be a benefit to small scale production sectors, where uncertified test equipment suface and cost effective test solutions are required.

AFRIKAANSE OPSOMMING: Natuurlike hulpbronne is noodsaaklik vir menslike bestaan. Initiatiewe om hulpbronne effektief te bestuur, word daagliks beoefen. Die verbruik van water en elektrisiteit neem daagliks toe in Suid-Afrika, asook in die wêreld, dus word nuwe maniere ondersoek om besparings moontlik te maak. Suid-Afrika se primiêre elektrisiteitsverskaffer, Eskom, se toevoer kapasiteit is onvoldoende vir die verbruikers se aanvraag tot elektrisiteit. Nie net word Suid-Afrika in nood gestel met 'n tekort aan elektrisiteitskapasiteit nie, maar is, tydens finalisering van hierdie manuskrip, in 'n droogtekrisis. Die Wes-Kaap en Oos-Kaap provinsies word veral onder druk geplaas weens die droogte, waar dieWes-Kaap limiete op water gebruik in plek gestel het om waterverbruik te tem, die verbruikslimiet is tans 87 L water per persoon per dag. Die Nelson Mandela Munisipale Metropool, in die Oos-Kaap, was op die drempel van 'n natuur ramp area verklaar, in Maart 2017. Dus is besparings initiatiewe tans noodsaaklik in Suid-Afrika. Die internet van dinge, Internet of Things, is ideaal gepas om by te dra tot besparings initiatiewe. Dié manuskrip vorm deel van 'n slim beheerder (SB) vir elektriese warmwatersilinders (EWs), wat die verbruiker in staat stel om water verbruik te monitor asook 'n skedule te stel om die EW af en aan te skakel. Die SB versamel data van EWs, wat narvorsing toelaat om voorspellings te maak vir optimale verhitting skedules. Dié navorsing kan gebruik word om die nationale elektrisiteitsnetwerk se las te verlig deur gebruik te maak van tyddeel aanvraagsbestuur (TDAB). Hierdie las verminderings tegniek skakel die verbruiker se EW volgens die elektrisiteitsnetwerk se las af en aan. Dit verseker ook dat beide die netwerk en verbruiker positief beïnvloed word deur die netwerk las te verminder gedurende piek verbruikstye asook om te verseker die verbruiker het warmwater tydens aanvraag. Die eerste ontwikkeling in die manuskrip is gefokus om die SB se hardeware gebaseerde sagteware (harde programmatuur) te ontwikkel en implementeer vir 'n nuwe SB hardeware ontwerp. Die SB kommunikeer na 'n sentrale databasis met gebruik van 'n sellulêre modem. Die harde programmatuur word gevorm deur perifere en modem harde programmatuur. Die perifere harde programmatuur is verantwoordelik om die SB se aktueerders en sensore te beheer en akurate lesings te neem. Die gemete lesings word saamgestel in 'n enkele boodskap wat per minuut gekommunikeer word na die internet gebaseerde databasis. Die SB vorm deel van 'n slim elektriese warmwatersillinder beheerder projek, wat befondsing bekom het vanaf die Water Navorsingsraad om SBs te ontwikkel en installeer in eMkhondo munisipaliteits distrik in Mpumalanga, Suid-Afrika. Die SB wat gebruik was vir navorsingsdoeleindes, is opgradeer met nuwe hardeware. Die nuwe hardeware bevat 'n nuwe beheerder wat die vraag vir harde programmatuur laat ontstaan het. Die nuwe hardeware word binnenshuis (inhuis) getoets deur personeel wat tegnies aangelê is. Hierdie toetse benodig fisiese sein generasie en resultaat evaluering deur die toetser. Die tweede ontwikkelling se nut het onstaan om hierdie toetsprosedure te verbeter. 'n Outomatiese toetsprosedure is ontwikkel wat bestaan uit toets hardeware en toets sagteware. Die implementering van die volledige toetsstelsel word evalueer om die akkuraatheid van die berekenings-effektiwiteit van die toetsstelsel as geheel te bevestig. Die navorsingsdoelstelling om nuwe harde programmatuur te ontwikkel en implementeer was bereik en is op 'n totaal van 245 SBs implementeer. Die data, versamel deur die SBs, se gehalte is so van aard dat dit gebruik kan word vir navorsingsdoeleindes. Die tweede navorsingsdoelselling, om 'n toetsstelsel te ontwikkel en implementeer, was bereik. Die akuraatheid van die hardeware is bepaal en die berekenings-effektiwiteit van die toetsstelsel het getoon dat ses uit die 10 toetse suksesvol was, tydens die evaluasie toets. Die toetsselsel kan effektief gebruik word in kleinskaalse produksie van produkte waar die toets voldoende sal wees met koste effektiewe, ongesertifiseerde toetsgereedskap

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