| ??? 06/01/08 09:20 Read: times |
#155341 - why do you use WD then? Responding to: ???'s previous message |
Kai Klaas said:
Jan said:
...that EMI sufficiently strong to throw the micro out of way, never occurs. Jan, CE standards are so demanding, that your product is immune against 99.9% of all strange effects. Oh, it's never 100% then, is it? What if it's the 0.1% on which the renome of your product and the future of your company depends? Kai Klaas said:
Jan said:
And how did you come to the conclusion that Alex's case is not due to unforeseeable situations? Because he talked about "lightning". And CE complying products are immune against lightning, as they are "surge" tested, which is a very harsh test by the way. If you design your power supply unit properly, lightning on mains is totally filtered out of your supply voltage. (I do not talk here about a direct hit, of course, but which is very very seldom.) He also talked about "unstable" power. When being designed properly, then only power downs and power up can be critical and these aren't cured by the help of a watchdog, but by a proper supervisory/reset controller. Oh, and what if due to unstable power (mains) as the consequence of unstable grid in a thunderstorm a factoryful of contactors jump wildly up and down, for example? Alex might quite well be in the situation where he can not influence the environment in which his box has to operate. I have already mentioned the case of a box, otherwise operating flawlessly many hours in many installations, failing when placed in a room next to powerful transmitters used in car racing. I was also told by an outdoor lights control box, which after years of flawless operation went crazy randomly about twice a day, when, as it turned out, a new powerful radar has been installed on the nearby airport, and the beam hit the box inadvertently from time to time... These might sound like extreme cases, maybe the 0.1%; but again, how do you know this is not Alex's case? Why do you refuse to answer his original question - maybe including a line saying "make your desing sound first", why not? Jan |
