Roba66

's profile
image
engineer

Biography has not been added


Roba66

's contributions
  • 12.14.2016
  • Real world RS-485: Low power, low EMI
  • I have been using modern 3.3v RS485 transceivers with good results in the 2 to 2.5 Mbit range. Normally we use 8,N,1 serial transmission from a uart. I tested several vendors and ruled out some vendors that caused and/or detected false start bits when drivers went tristate. Nobody seems to mention the problem caused by turning off the driver, if it turns off too fast it causes glitches. The negative bias of modern receivers partially solves this problem. RS485 is designed for multidrop and devices that cause glitches when they get off the line should be avoided. I know of no specs in this regard, I had to resort to testing.
  • 05.26.2017
  • Mentor tries the low end, again, with PADS Maker
  • Mentor's "perpetual license" expires every 5 years and you have to beg for another one. You can use a wireless or wored ethernet "dongle" if you want to port to other machines. The license manager is a real pain for users, it takes a lot of time to figure out what is wrong and there always seems to be something. I hope Siemens can improve Mentor's customer and product focus, in my experience it consists of cutthroat sales people and over-priced support. Development was moved to asia and Mentor was simply allowing attrition on the US side, they did not seem to have a plan. Best to use Kicad and avoid being forced to use Windows for EDA, and avoid spending your attention span on dead-end software.
  • 02.20.2017
  • Open source is still an unpredictable option
  • My experience is almost the opposite, I went away from Microsoft products because they are the target of hackers (due somewhat to ever expanding automatic launching of whatever file they come across ;-) I have happily been using Thunderbird for 5 years and I am glad it doesn't launch everything the way Outlook does. I have used Microsoft and other proprietary products and suffered when the company dropped the product. There is no recourse for users in that case. It is the worst thing that can happen when you adopt a program. When you compare OpenOffice to proprietary products it would be fair to mention that. I have had trouble with Windows 10 updates and freezes and rejection of devices on various computers. Also the obligatory anti-malware maintenance chores are getting pretty heavy. Ubuntu is like a breath of fresh air. LibreOffice works fine, thank you. The controls are more intuitive. Yes there are issues but I have saved time in comparison to Office products because LibreOffice is just easier to use. I never liked Openoffice, it is not fair to use it as a poster child for open software. The imperative to get away from Office is greater for a Linux user and if you are locked into Windows I can see why you go with Office. But I use LibreOffice on Windows too. I produce documentation on Libreoffice and distribute PDF. I also use Framemaker for quick good looking documents, the latter is still far ahead of Word in terms of productivity, however it suffers the fate of proprietary software: expensive updates or you have to live with whatever bugs are in the version you have, then eventually the vendor will drop the product and the code base disappears forever.
  • 10.05.2016
  • Why is everything junk? (Heat-pump edition)
  • Split systems are in wide use in Japan, as are induction ranges. I do not think your problem is so obvious. I installed my own split system for my LAB and just had to get the AC guy to do the final hookup ($200). So people should not think it is a difficult thing to do. I had tried various other AC and heat solutions: portables or window mount and found them all to be noisy and inferior in many ways. The split system is just better. A BLDC will create chopper noise at 20 to 30 Khz. It may be harmonizing with the range; in my experience the inductive range created a lot of strange noises without any help and I think the frequency it works at is problematic. An inductive range is built like a tin speaker after all. For a BLDC there should be a common mode filter like a toroid to prevent high frequencies; only a big capacitor in the BLDC driver would have much effect on the 24 Khz.
  • 06.10.2010
  • An old PAL saves the day
  • I miss having PLD's, sadly nobody made them in a small formfactor and AHC to keep up with modern technology. I suppose they could not meet a reasonable cost target. I had to use 5 "multipurpose gates": 74LVC1G57 plus flipflops in a recent design.
  • 06.18.2013
  • Automotive smarts: Too much intelligence, not enough sense
  • Sounds like my Volvo, after several such events I put some Dow4 on the connector which solved the problem. But what nonsense. Here is another one: My new TDI VW has a pushbutton ignition that is so fast the glowplugs indicate a fault and the engine trouble light goes on.