Activity for Lundinâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #291085 |
I have the transceivers failing during production and I doubt the cause is ESD. I suppose hot-plugging during testing could be a culprit, but then the type of connectors used means the ground is always there before voltages. (more) |
— | about 1 year ago |
| Edit | Post #291080 |
Post edited: |
— | about 1 year ago |
| Comment | Post #291082 |
I guess the TVS values were picked because we already have the same ones elsewhere on the BoM protecting 24V on/off and the like. That and taking a bit of the blow in case someone shorts the supply against data lines. We have already considered adding TVS suitable for RS-485, I noticed there are some... (more) |
— | about 1 year ago |
| Comment | Post #291082 |
Oops yes this is a typo. Since the design is propriety, I cannot share it as-is, so I just quickly redrew the relevant parts in an online schematic program. (more) |
— | about 1 year ago |
| Comment | Post #291080 |
@#53661 It can be hot-plugged, yeah, but I don't see it related to the failures. The PCB ground will be sitting close to the chassis ground potential - it will be grounded to chassis from where the PCB is connected, as well as at a few other places where shielded connectors are attached to the chassi... (more) |
— | about 1 year ago |
| Edit | Post #291080 | Initial revision | — | about 1 year ago |
| Question | — |
MAX485 transceivers breaking, Pi filter generating spikes? Problem description & speculation about causes I've having a problem with MAX485 transceivers breaking intermittently, passing our production tests but later failing. The error phenomenon is wrong signal voltage levels on the RS485 lines, as well as the transceiver failing to return the signals to... (more) |
— | about 1 year ago |
| Comment | Post #290874 |
The slightest scratch will mean that the solder mask is leaking however. Solder mask is literally what it says: a means for preventing solder to end up on top layer traces. Using it for anything else (including isolation) is questionable practice. Anyway, the standard practice for anything in tough e... (more) |
— | about 1 year ago |
| Comment | Post #290874 |
How would the signals get to the SMD connector without vias? Some sort of blind vias? Are they waterproof and who says so? Anyway, to be honest this is such a bad idea from the start. Not just because of water, but because of salt, galvanization and probably a bunch of other problems too. Separate th... (more) |
— | about 1 year ago |
| Comment | Post #290774 |
I still think this question would be more suitable for Power Users, where computer hardware questions are [explicitly on-topic](https://powerusers.codidact.com/help/faq), whereas here on EE the question is [explicitly off-topic](https://electrical.codidact.com/help/topics) since it is still about "hi... (more) |
— | about 1 year ago |
| Comment | Post #290541 |
@#52935 Regarding availability I don't think you can look at the Covid component crisis, since pretty much every silicon vendor's logistics chains were broken. I couldn't get plain schottky diodes of any brand with less than 30 weeks... same deal with any Cortex M of pretty much any brand. ST and Inf... (more) |
— | about 1 year ago |
| Comment | Post #290541 |
@#52935 I will use a modern standard transceiver like MCP2562FD which has great voltage tolerances and good ESD protection. Then TVS, common mode EMI filter etc etc on top. Not worried about protecting the actual bus, we've passed similar nasty EMC testing before when using RS485, but we didn't use g... (more) |
— | about 1 year ago |
| Comment | Post #290541 |
Thanks for your reply! Though I'm not following your concerns about CAN. The isolator, no matter type, will have to be placed between the MCU and the transceiver ("CMOS levels"). The Tx and Rx signals there are not bidirectional. The isolator I linked and intend to use is 2 channel, so there's one ch... (more) |
— | about 1 year ago |
| Comment | Post #290533 |
@#52987 Both primary and secondary will be supplied with old school LDOs and we'll also encapsulate the whole PCB with screens. Decoupling caps on all supply pins naturally. I don't think there's a risk that the supply traces etc pick up substantial currents from radiated EMI that way? Maybe it's wis... (more) |
— | about 1 year ago |
| Edit | Post #290533 | Initial revision | — | about 1 year ago |
| Question | — |
Most reliable galvanic isolation technology for extreme EMI environments? I'm working on another project with extreme EMC requirements as per various notorious military EMC standards. Civilian product but for military use, and as such subject to the toughest levels of conducted/radiated susceptibility, 200V/m fields across an 2MHz-18GHz range, peak pulses of far higher ene... (more) |
— | about 1 year ago |
| Edit | Post #290532 |
Post edited: |
— | about 1 year ago |
| Edit | Post #290532 | Initial revision | — | about 1 year ago |
| Article | — |
How to introduce or port my microcontroller project to MISRA C? MISRA C has become a de facto standard for all embedded systems firmware, no matter if it is safety-related or not. C comes with a lot of freedom, which makes it powerful yet dangerous. MISRA C is a safe subset of the C language, acting as a filter to block poorly-defined or otherwise dangerous parts... (more) |
— | about 1 year ago |
| Edit | Post #290434 |
Post edited: |
— | over 1 year ago |
| Comment | Post #290423 |
Either solution sounds over-engineered IMO. If you have a CAN bus, you have a MCU, so why not use the MCU? (more) |
— | over 1 year ago |
| Edit | Post #290434 | Initial revision | — | over 1 year ago |
| Answer | — |
A: CAN BUS monitoring with a LED I've done similar things on UART lines, but for significantly lower baudrates (9600 etc) than traditionally used on most CAN buses. It's also easier to do when you have 5V guaranteed to be well-over the LED Vfwd, which the CAN lines do not necessarily live up to. For instance there are 3.3V suppl... (more) |
— | over 1 year ago |
| Edit | Post #286121 |
Post edited: |
— | over 1 year ago |
| Comment | Post #290231 |
Also this could mean anything. We have high voltage regulation (>1000VAC, >1500VDC) , we have "low" voltage regulation (50-1000VAC, ~75-1500VDC) and "extra low" voltage regulation (<50VAC, < ~75VDC). These categories can in turn be divided into many sub-categories: isolated regulators, transformers,... (more) |
— | over 1 year ago |
| Edit | Post #286121 |
Post edited: |
— | over 1 year ago |
| Edit | Post #286121 |
Post edited: Minor spelling and fortmatting |
— | over 1 year ago |
| Edit | Post #289867 |
Post edited: |
— | over 1 year ago |
| Edit | Post #289867 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Will shorting a lithium ion battery cause an explosion? It depends on how you define "battery". I guess the definition is different depending on if you are a chemist, an engineer or a consumer. When electrical engineers speak of batteries, they typically mean a battery cell - a component. Then there's the end user application with a cell + electronics emb... (more) |
— | over 1 year ago |
| Comment | Post #286035 |
I think I've seen this app note before, I use the very Silabs parts that they use as example. But most of it is generic ESD and the figure 19 didn't really bring anything new other than "take care about the parasitics of the selected TVS diode", which was already mentioned in the question here. Figur... (more) |
— | over 1 year ago |
| Comment | Post #289688 |
Which part is the Darlington, more specifically? One of the classic ULNs I take it? These are notoriously brittle and shouldn't be used in industrial applications. Consider some "smart" MOSFET driver instead, with plenty of built-in protection. (more) |
— | over 1 year ago |
| Edit | Post #289623 |
Post edited: |
— | over 1 year ago |
| Edit | Post #289623 | Initial revision | — | over 1 year ago |
| Answer | — |
A: What residential wiring questions are on-topic here? The reason I left that comment is because determining the quality of a coaxial cable involves electrical engineering more so than an electrician, let alone some DIY. The rule of thumb "would you ask this to an engineer or electrician" is good. However, in this case you are unlikely to get a good ... (more) |
— | over 1 year ago |
| Comment | Post #289574 |
And well, trouble-shooting PSUs on the product level is probably off-topic here. We'd expect questions to rather be about how to trouble-shoot them on the component level. Rectifier bridges, transformers, regulators, isolation, filters etc etc. (more) |
— | over 1 year ago |
| Comment | Post #289574 |
You won't ever get to the bottom of the cause of the "spark noise" unless you dissect the PSU, do some light reverse-engineering and see what may be the cause. However, please note that disassembling these can be dangerous even with power disconnected since the internal caps can hold high loads for q... (more) |
— | over 1 year ago |
| Edit | Post #289515 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Professional vs Hobbyist advice and potentially dangerous projects The main problem with a question along the lines of "how do you design a product for medical applications" is that it's way too broad. You cannot reasonably write a somewhat complete answer because it would be a very long one. The general approach of all these Q&A sites is that in case an answer ... (more) |
— | over 1 year ago |
| Comment | Post #289423 |
I deliberately picked PID because it has only one sensible definition in the context of Electrical Engineering. Process ID is (arguably) not a term used in EE, so therefore the term which _is_ used, established and well-known too, should be the one that get the tag as well as the abbreviation. Otherw... (more) |
— | over 1 year ago |
| Edit | Post #289416 |
Post edited: |
— | over 1 year ago |
| Comment | Post #289348 |
@#52991 Ok so I tried to compile a draft for some sort of general policy here: [Tag creation/deletion crieria](https://electrical.codidact.com/posts/289416). And yeah this might mean that tags such as `voltage` are free to delete. Any feedback is appreciated. (more) |
— | over 1 year ago |
| Edit | Post #289419 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Tag creation/deletion criteria Draft for a tag creation/deletion criteria A tag must fulfill all of the below requirements or it may get renamed or deleted: 1. A tag must be named appropriately, considering Tag naming guidelines. 2. A tag must be on-topic, meaning it has to be related to Electrical Engineering. 3. A tag m... (more) |
— | over 1 year ago |
| Edit | Post #289417 | Initial revision | — | over 1 year ago |
| Answer | — |
A: Tag naming guidelines. Additions: - Do not use company names in tags. Questions should be about specific products, not about companies. Furthermore, silicon companies merge/split and purchase each other all the time, so company tags will quickly become outdated. For example, questions about STM32 should be tagged... (more) |
— | over 1 year ago |
| Edit | Post #289416 | Initial revision | — | over 1 year ago |
| Question | — |
Tag creation/deletion criteria Because of recent discussions regarding whether vague terms like `voltage` and `ground` should be valid tag names or not, it is clear that we have no consistent rules here. These terms are about on-topic matters, but they are vauge and ambiguous and cannot "stand alone" without other tags. In comp... (more) |
— | over 1 year ago |
| Comment | Post #289348 |
@#52991 But if we look at more specific tags, you also propose to delete `PTC`, which stands for positive temperature coefficient. This term is (almost?) exclusively used in the context of thermistors, at least as far as I know. Therefore `PTC` is a clarification of a question tagged `thermistor` in ... (more) |
— | over 1 year ago |
| Comment | Post #289348 |
But also **we should not make it harder to change tags than to invent them**. If we allow everyone and their mother to create tags, which is usually the case, I don't think we can regard tags as something "holy" as on SE but let trusted users/moderators change them without too much meta debating. I t... (more) |
— | over 1 year ago |