Načrtovanje merilnih poti naprave za testiranje varnosti medicinskih aparatov

Fortuna, Žiga (avtor), Jankovec, Marko (mentor)

V magistrskem delu je predstavljeno načrtovanje in izvedba več-funkcijske naprave za preskušanje varnosti medicinskih naprav in sistemov. Najprej smo predstavili osnovne pojme in izvlečke standardov IEC 60601 in IEC 62353, ki opisujeta zahteve za preskušanje medicinskih naprav. Predstavljeni so osnovni pojmi in koncepti meritev ter ostale informacije merjenih električnih veličin. Dobro poznavanje relevantnih standardov je namreč izrednega pomena za začetek načrtovanja merilnega dela inštrumenta. V drugem delu so podrobneje predstavljena merilna vezja oz. vhodna prilagoditvena vezja. Namenjena so zajemu merjenih veličin – napetosti in toka. Vhodnemu prilagoditvenemu vezju sledi ustrezno načrtovana ojačevalna stopnja za digitalni zajem in nadaljnjo digitalno obdelavo opazovanega signala. Najpogosteje merjena veličina pri preskušanju naprav je uhajavi tok. Ob prisotni prvi napaki na preskušani napravi se namreč na dotakljivem prevodnem delu lahko pojavi nevarna napetost. Ob dotiku tako izpostavljenega dela bo skozi človeka stekel določen tok. Za zaznavanje toka, ki bi od dotiku stekel skozi človeško telo se uporablja t.i. standardni model človeškega telesa. Ko torej povežemo merilne sponke inštrumenta z aktualnimi deli preskušane naprave, inštrument s tako načrtovanim vhodnim delom ustrezno zazna, obdela in prikaže uhajavi tok. Pri načrtovanju sklopov merilnega inštrumenta so v veliko pomoč različna razvojna orodja. Pri načrtovanju relejne matrike, ki povezuje merilne sponke inštrumenta z notranjimi merilniki in signalnimi izvori, je ključnega pomena celoten zapis vseh merilnih funkcij v odvisnosti od stanja relejev ali obratno. Sistematičen pristop ne omogoča le lažjega razvoja, temveč močno poenostavi kasnejše odkrivanje in odpravljanje napak ali spreminjanje že obstoječih merilnih poti. Pri več-funkcijskem inštrumentu imamo opravka z več različnimi signali oz. merilnimi območji teh signalov. Nujen je popis vseh signalov in zahtevanih merilnih območij, da ustrezno določimo vhodno prilagoditveno stopnjo signala in ojačevalno stopnjo med vhodnim prilagoditvenim vezjem in analogno-digitalnim pretvornikom. Kompleksnost relejne matrike in množica električnih veličin sta narekovala razvoj preproste aplikacije, ki jo je možno nadgraditi, kjer so na enem mestu pregledno zbrani načrtovalski postopki inštrumenta. Tako je nastala aplikacija v okolju MS Excel, ki omogoča zbiranje postopkov za več različnih inštrumentov.

• Jezik: Slovenski jezik
• Ključne besede: standardi, preskušanje medicinskih naprav, uhajavi tokovi, merilne poti
• Vrsta gradiva: Magistrsko delo/naloga
• Organizacija: FE - Fakulteta za elektrotehniko
• Leto izida: 2024
• PID: 20.500.12556/RUL-154704
• COBISS.SI-ID: 186770691
• Datum objave v RUL: 23.02.2024

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Designing Measurement Paths of the Safety Tester for Medical Devices

Izvleček

In the master's thesis, the design and implementation of a multi-functional device for testing the safety of medical devices and systems are presented. First, we introduced basic concepts and extracts from the IEC 60601 and IEC 62353 standards, which describe the requirements for testing medical devices. Basic concepts and measurement concepts, as well as other information on measured electrical quantities, are presented. A good understanding of relevant standards is crucial for initiating the design of the measuring part of the instrument. In the second part, the measurement circuits or input adaptation circuits are presented in more detail. They are designed to capture measured quantities - voltage and current. The input adaptation circuit is followed by an appropriately designed amplification stage for digital acquisition and further digital processing of the observed signal. The most commonly measured quantity in device testing is leakage current. In the presence of the first fault in the tested device, a dangerous voltage may appear on the touchable conductive part. When such a part is touched, a certain current will flow through the human body. To detect the current that would flow through the human body from touch, the so-called standard model of the human body is used. Therefore, when we connect the measurement clips of the instrument to the actual parts of the tested device, the instrument with the designed input section appropriately detects, processes, and displays the leakage current. In the design of measurement instrument circuits, various development tools are highly beneficial. When designing the relay matrix that connects the measurement clips of the instrument to internal meters and signal sources, it is crucial to have a comprehensive record of all measurement functions depending on the state of the relays or vice versa. A systematic approach not only facilitates easier development but also greatly simplifies the subsequent detection and correction of errors or the modification of existing measurement paths. In the case of a multi-functional instrument, we deal with several different signals or measurement ranges of these signals. It is necessary to list all signals and required measurement ranges to appropriately determine the input adaptation stage of the signal and the amplification stage between the input adaptation circuit and the analog-to-digital converter. The complexity of the relay matrix and the multitude of electrical quantities dictated the development of a simple application that can be upgraded, where design procedures for the instrument are clearly collected in one place. Thus, an application in the MS Excel environment was created, allowing the collection of procedures for multiple different instruments.

• Ključne besede: standards, medical device testing, leakage current, measurement paths