Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [functional-safety]

9 questions
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Household appliances commercial project EU certification

I got a job to do a household appliances with wireless remote control. I’m working as embedded developer in current company, but we haven't had to certificate our solutions and I'm looking for advice. The first level of this job is to make a…
martin_embed
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Detecting hardware fault in safety critical system

I have recently been introduced to the IEC61508 and the ISO 26262 and trying to get my head around how to make a hardware design safe. This question is related to article "Four Steps To ISO 26262 Safety Mechanism Insertion And Validation" written by…
gyuunyuu
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Coin battery for powering the RTC while MCU power down: is safe for ATEX ZONE 2 or DIV2 in hazardous environment? The Box is heavy duty IP67 sealed

I wish to use RTC which keep powered by a coin battery (i.e. CR1225) while disconnected from +5V power. The box is heavy aluminum diecast with IP67 sealed. I was concerned about using coin batteries (non-recharagable) within Div2 or Atex Zone 2…
Riscy
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Do residential smoke alarms monitor their sounders? If so, how?

This is an open question, and wondered if someone out there might have the info on a typical fire alarm architecture, such as for this generic alarm: Image source : LABChomeowners Obviously as much as the detection of smoke is critical, it is no…
midnightBlue
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Manufacturing precautions for voltage multipliers

I've been watching YouTube: https://youtu.be/YYKlfFYTl-8. Can you tell me is this dangerous or not to do at home? So I've been watching this video, and I've wanted to do it myself, but to the number 67000V is scary. I looked up what is the upper…
Tesla
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What is the safest way to control another circuit?

From my custom board with an MCU I need to connect to an Interlock Pin of another circuit. I have a lot of options, but I don't know what is better. Using an optocoupler, but I'm afraid the output will be shorted (the transistor is shorted) and I…
Knowledge
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Thick Film Resistor FIT rate for Hardware FMEDA

I am currently working on a hardware FMEDA as per IEC 61508 and I am using thick film resistors such as AC0402FR-071K5L and I want to calculate/find the FIT rate of the thick film resistors according to SN29500. According to the SN29500 document…
Clyasenth
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Safety-Critical Diagnostic Signaling

I need to (extremely) reliably detect the status of a normally-closed DPST momentary switch at the end of a short distance of cable (max. 3m, 22 AWG). I propose to do this with two entirely independent circuits, driven with arbitrary pulse-trains…
foxtrot
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Form C (SPDT) Relay Failure Modes and Detection

This is a question about the failure modes of an SPDT (i.e. form C) relay. Specifically, I am interested in electromechanical relays for an automotive application. I understand that either contact could be stuck open or stuck closed. But is it…
benpro
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