Activity for Lundin
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #285171 |
@#54107 If not on-topic here - as you can see there's no consensus - then such questions should be fine at https://software.codidact.com/. Particularly questions regarding the higher layers and the Internet protocol suite. Questions that are specific and solely about the physical and data link layers... (more) |
— | over 2 years ago |
| Comment | Post #285198 |
@#36396 Ok then I believe you merely have to design the zener barrier after zone 0 rules but you shouldn't need to worry about things like random shorts elsewhere on your PCB. I mean as long as you have a resistor and a fuse living up to the requirements of 60079-11, then it wouldn't matter if for ex... (more) |
— | over 2 years ago |
| Comment | Post #285201 |
@#36396 The general recommendations are something like this: https://www.sensorland.com/HowPics/Zener-001.gif. For higher safety levels, multiple zeners in parallel are used. So regarding my previous note about your zeners on the supply, a similar circuit should be placed towards the hazardous zone i... (more) |
— | over 2 years ago |
| Comment | Post #285198 |
@#36396 Yes temperature limits only apply inside the zones. Since you used 3 zeners I assumed it was for zone 0/20. Generally speaking - take for example a gas station: zone 0 would be inside the fuel containers, zone 1 would be the pumps, zone 2 would be the rest of the gas station, not hazardous zo... (more) |
— | over 2 years ago |
| Comment | Post #285201 |
Actually after reading chapter 7.3 I don't think the fuse is optional either. It seems that a PTC thermistor might be acceptable though. (more) |
— | over 2 years ago |
| Comment | Post #285201 |
I believe it's the other way around: a series resistor is mandatory but the fuse is optional. From IEC 60079:11 9.1 "In level of protection "ic" safety barriers, the minim requirement is a single zener diode and a current limiting resistor". Where "ic" means intrinsic safety zone 2, the lowest requir... (more) |
— | over 2 years ago |
| Edit | Post #285198 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Flyback transformer with Intrinsic Safety Disclaimer: I'm not an expert of EX classification myself, but I once was project/product manager for such a project (a zone 0/20 intrinsic control system product). While I can't answer the question directly since my product contained no transformers nor flyback regulators, I can share some related e... (more) |
— | over 2 years ago |
| Comment | Post #285171 |
I disagree, since the OSI model is fundamental to any data communication. For example I often find myself in discussions where people ask how to send data over CAN bus or UART. Then I have to explain that how to send data isn't covered by CAN or UART, since they only specify physical and data link la... (more) |
— | over 2 years ago |
| Comment | Post #285155 |
I started a discussion regarding if these kind of questions should be on-topic here or not, see https://electrical.codidact.com/posts/285166. (more) |
— | over 2 years ago |
| Edit | Post #285167 | Initial revision | — | over 2 years ago |
| Answer | — |
A: How to treat data communication questions? I think these kind of abstract/big picture data communication questions should be on-topic here. Such as the mentioned question about the OSI model. I've been actively pushing for software.codidact.com not to accept embedded systems questions and refer such questions to this site instead, so that ... (more) |
— | over 2 years ago |
| Edit | Post #285166 | Initial revision | — | over 2 years ago |
| Question | — |
How to treat data communication questions? This question here about the OSI model was closed as off-topic. How should we treat questions about data communication? What is definitely on-topic here: - Embedded systems programming, including microcontrollers and FPGA. - Specific software or hardware questions about industry standard buses l... (more) |
— | over 2 years ago |
| Edit | Post #285140 | Initial revision | — | over 2 years ago |
| Answer | — |
A: How can we grow this community? After reading the suggestion about conferences, I came up with a loose brainstorming idea... What draws engineers to fairs/conferences (apart from free lunch)? Most definitely technical speeches/slide shows about a certain technical topic. This is well-known: try to host some embedded systems fair wi... (more) |
— | over 2 years ago |
| Comment | Post #285082 |
Curious definitions. In EU we have the "low voltage directive" which applies to everything >50VAC or >75VDC. It doesn't seem to be harmonized with the standard you mention. Generally I'd say that IEC/ISO standards are more canonical than EU directives, but this also seems like it would a source of co... (more) |
— | over 2 years ago |
| Edit | Post #285079 | Initial revision | — | over 2 years ago |
| Question | — |
Do we need tags for supply voltages? Someone just created the tags 208VAC and 230VAC. If think we need to create a policy about tag usage related to supply voltages. Clearly, stating the supply voltage is highly relevant information in most questions. However, stating it in the form of a tag may not be ideal. - Should we have tags... (more) |
— | over 2 years ago |
| Edit | Post #284983 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Asynchronous connection question Assuming you speak of UART, then the receiver must be told in advance the number of data bits, the number of parity bits and the number of stop bits. The start bit is a logic zero (low) and the stop bit(s) are logic ones (high), which is also the idle state. The data bit stream itself isn't asynch... (more) |
— | over 2 years ago |
| Comment | Post #284818 |
Most of the resistance will be in the actual wires and probes, especially so for cheap instruments that come with low quality probes. (more) |
— | over 2 years ago |
| Comment | Post #284636 |
Hmm, not really convinced... though I do have bad experience of Traco, they aren't nearly as 'premium' as they claim to be. At any rate, it sounds like a 33V TVS directly after the switch would be a good idea for spike immunity purposes. And if you are correct about the reason why the Traco blew, suc... (more) |
— | over 2 years ago |
| Comment | Post #284636 |
Is the heater really to be regarded as a resistor and not as a coil? I know very little of these and I suppose ceramic heaters are supposed to eliminate the need for a coil. But when you say that you blew the power supply and the MCU too, it sounds a lot like reverse EMF. Then the switch signal bounc... (more) |
— | over 2 years ago |
| Comment | Post #284624 |
How do you limit the current of the LEDs? Right know you are feeding them with as much as your power source can give. What makes you think it's the MOSFET that's blown? It is far more rugged than the LEDs, rated at several A, while the average LED is rated at 20mA. (more) |
— | over 2 years ago |
| Edit | Post #284570 | Initial revision | — | over 2 years ago |
| Answer | — |
A: React feature guidelines? Example of answers that should be classified as Dangerous: - "Do it yourself" Q&A where someone is fiddling around with 230VAC electronics or other such potentially lethal power sources without having much of a clue of what they are doing. - Potential fire hazards, such as modifying consumer elec... (more) |
— | over 2 years ago |
| Comment | Post #284542 |
I think safety-related applications is one of the difficult "grey areas" here. For example it's quite common on SE that some hobbyist wants to mod something on their car or bike by smacking on some Arduino that they found in a packet of corn flakes. Which is both dangerous as well as wildly illegal i... (more) |
— | over 2 years ago |
| Edit | Post #284540 |
Post edited: |
— | over 2 years ago |
| Edit | Post #284540 | Initial revision | — | over 2 years ago |
| Question | — |
Most correct term for radio switching noise? I'm wondering what's the most correct term (if any) to use for "switching noise" of a radio transceiver? By that I mean the spikes that originate from turning the power amp on/off while switching between sender and receiver. Apart from switch noise (which is easy to confuse with switching regulato... (more) |
— | over 2 years ago |
| Edit | Post #284537 | Initial revision | — | over 2 years ago |
| Question | — |
React feature guidelines? I think we should try to come up with some consensus regarding how to use the new reactions feature, more specifically the "outdated" and "dangerous" options. Which kind of posts should these be used on? Otherwise, I can see how these quickly turn subjective without some community consensus or gui... (more) |
— | over 2 years ago |
| Edit | Post #284323 | Initial revision | — | over 2 years ago |
| Question | — |
CAN "split" pin, bus termination and common mode stabilization Modern CAN transceivers like MCP2561FD that support CAN FD with high baudrates come with an optional feature called SPLIT, which is to my understanding a reference voltage output pin used to give a common mode stabilization and thereby reduce radiated emissions. It gives out 0.5Vdd so that would be t... (more) |
— | over 2 years ago |
| Comment | Post #284215 |
The larger problem is site activity, there's barely anyone posting questions. A couple of users repeatedly asking diverse questions might just be what the site needs, no matter question quality. All of these questions were perfectly on-topic, mind you. So they are already far higher quality than DIY ... (more) |
— | over 2 years ago |
| Comment | Post #283906 |
Btw depending on what battery chemistry this is, then 9V fully charged might mean 10-11V. And down to somewhere around 7V when low. Obviously it isn't a good a idea to drive a LED directly from a raw battery voltage. (more) |
— | over 2 years ago |
| Comment | Post #283906 |
@#36396 Wouldn't the worst case be the minimum voltage drop, not the maximum? The part didn't list a minimum so I used the typical value. It's better that a LED shines ever so slightly dimmer than supplying it with too high current. Also as I'm sure you know, In practice every modern LED out there ca... (more) |
— | over 2 years ago |
| Comment | Post #283904 |
Peak forward current listed below absolute maximum ratings is the stress value they promise that the diode can take for a short while. If you feed it that continuously it will eventually burn to a crisp. _Don't_ design using absolute maximum ratings! You should be looking at electrical characteristic... (more) |
— | over 2 years ago |
| Edit | Post #283906 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Select resistor for a diode You start by checking the forward voltage and rated current for the LED. 20mA is the usual industry standard for regular LEDs and the forward voltage will be specified for that rated current. In this case the datasheet says VF = 2.0V typical @ 20mA. So now we know the current and the voltage wi... (more) |
— | over 2 years ago |
| Comment | Post #283693 |
5 seems common and I've seen even more... which was also bad for soldering. (more) |
— | over 2 years ago |
| Comment | Post #283693 |
The missing hole is just me having forgotten to enable some layer in the CAD tool - I don't do any PCB layout myself. But the layout here was just plain weird and I couldn't make any sense of it. (more) |
— | over 2 years ago |
| Edit | Post #283679 | Initial revision | — | over 2 years ago |
| Question | — |
Thermal relief for through-hole on multi-layer PCB When using through-hole ("THR") connectors on a multi-layer PCB, I frequently notice problems with the ground pins, when these are connected to the ground plane(s) through various "thermal relief" layouts. When this happens, the reflow soldering job becomes mediocre and hand soldering is nearly impos... (more) |
— | over 2 years ago |
| Edit | Post #283373 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Motor Controller - What might be the purpose of these resistors? To expand on Olin's answer about power dissipation, one theory is EX/ATEX qualification for explosive environments. This is likely needed for these kind of cars, given the massive energy in those batteries. For EX qualification you are not allowed to have a thermal peak somewhere on the board in ... (more) |
— | over 2 years ago |
| Comment | Post #283244 |
Rather than drawing these by hand all the time, consider using a schematics editor. There's plenty of free ones out there, like https://www.digikey.com/en/resources/design-tools/schemeit. Or https://www.falstad.com/circuit/ which also serves as a simulator - you can run and troubleshoot digital logi... (more) |
— | over 2 years ago |
| Comment | Post #283242 |
Thanks! This further proves how tricky it is to translate such things. "Cable canal" was my literal translation from Swedish, but I could already tell that it sounded weird. "Cable duct" was something I came up with after random Google searches. Cable tray I wouldn't even have considered. (more) |
— | over 2 years ago |
| Comment | Post #283240 |
Yet another example: dump "solder flux" in Google translate and it gives me "lödflöde" in Swedish, meaning "solder flow" - which is nonsense. (more) |
— | over 2 years ago |