Ping John Larkin: Question on MAX
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From: John Larkin on 28 May 2010 22:42 On Fri, 28 May 2010 16:12:55 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Just one word of caution. Be careful with Purchasing generating parts. >Usually that should be an ECO process, or at least close. While they are >certainly experts in electronic parts it is easy to overlook something >that normally never matters. Example in one of the cases I was involved: >A (too quick) decision was made to replace a resistor with another that >looked like a perfect form-fit-function match. Well, it was, almost. >Except that it wasn't low inductance ... tsssss ... *PHUT*. Then there >were those caps that looked identical, except that they didn't have an >AC rating. The bang was a lot louder, with stuff flying about. We have a form for creating parts, and we include the mfr's and mpn's that are acceptable buys. Bonnie will sometimes need to find a new one, but she's pretty good about checking with engineering before doing it. She knows when it's safe, too, like simple resistors and such. I've worked for companies where engineering had no control over this, no real visibility as to what was being stuffed into a stockroom bin. I quit my first job in California, partly because they refused to get this under control. The purchasing manager was the President's wife. Besides, Fremont sucks. John
From: Nico Coesel on 29 May 2010 08:43 "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Nico Coesel" <nico(a)puntnl.niks> wrote in message >news:4c004c6d.892986843(a)news.planet.nl... >> "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >>>We have ORCAD CIS and no, it doesn't, AIUI: If you want to change, e.g., a >>>resistor's value only (but it's still the same old 0603 generic resistor >>>otherwise), you can to use "change database part" and go find the new, e.g., >>>1.12k, 0603 resistor. In most cases that's a lot more mouse clicks that >>>double-clicking one on the part's value, entering the new value, and calling >>>it good. >> Yes, but you'll have a lot of work afterwards to edit and check the >> BOM. At lot of chances to introduce errors a well. > >The idea is that you don't have to check the BOM -- you're guaranteed that if >all you did was change a "generic" resistor's value from 220ohms to 470ohms, >your new BOM is correct. Yes, but the internal/external order codes are still missing. How about tolerances and package sizes? >> Make sure you can add parts yourself. > >Ho, ho... yeah, well, that isn't going to fly at many places I've been. At >one place, even after demonstrating that on average something like 1 in 10 >parts had errors in them (albeit many of them minor, such as incorrect >electrical pin types, lack of overbars, etc. -- perhaps 1 in 40 had "board >killer" errors such as the wrong footprint or wrong pin numbers), management I don't know where you are from, but over here it is customary to simply ignore management when it comes to obvious mistakes. Anyway, if for some reason the parts database contains errors then its useless. You'll need to do the work yourself one way or the other (either maintaining the parts database or editing the BOM by hand). Perhaps management can be enlightened by showing them how many hours you lose by having to do tedious administrative tasks over and over again. IMHO the actual profit from a parts database comes from having to deal with tolerances, footprints, order numbers, etc only once for each part. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Joerg on 29 May 2010 09:54 John Larkin wrote: > On Fri, 28 May 2010 16:12:55 -0700, Joerg <invalid(a)invalid.invalid> > wrote: > > >> Just one word of caution. Be careful with Purchasing generating parts. >> Usually that should be an ECO process, or at least close. While they are >> certainly experts in electronic parts it is easy to overlook something >> that normally never matters. Example in one of the cases I was involved: >> A (too quick) decision was made to replace a resistor with another that >> looked like a perfect form-fit-function match. Well, it was, almost. >> Except that it wasn't low inductance ... tsssss ... *PHUT*. Then there >> were those caps that looked identical, except that they didn't have an >> AC rating. The bang was a lot louder, with stuff flying about. > > We have a form for creating parts, and we include the mfr's and mpn's > that are acceptable buys. Bonnie will sometimes need to find a new > one, but she's pretty good about checking with engineering before > doing it. She knows when it's safe, too, like simple resistors and > such. > > I've worked for companies where engineering had no control over this, > no real visibility as to what was being stuffed into a stockroom bin. > I quit my first job in California, partly because they refused to get > this under control. The purchasing manager was the President's wife. > > Besides, Fremont sucks. > Yesterday the news said that the first bridge (Golden Gate?) staretd charging carpoolers, too. And if you don't buy into Fastrack it's the full six bucks. How are people doing that who aren't engineers but closer to min wage? For them it eats up a whole work hour of net income. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: John Larkin on 29 May 2010 10:44 On Sat, 29 May 2010 06:54:58 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Fri, 28 May 2010 16:12:55 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >> >>> Just one word of caution. Be careful with Purchasing generating parts. >>> Usually that should be an ECO process, or at least close. While they are >>> certainly experts in electronic parts it is easy to overlook something >>> that normally never matters. Example in one of the cases I was involved: >>> A (too quick) decision was made to replace a resistor with another that >>> looked like a perfect form-fit-function match. Well, it was, almost. >>> Except that it wasn't low inductance ... tsssss ... *PHUT*. Then there >>> were those caps that looked identical, except that they didn't have an >>> AC rating. The bang was a lot louder, with stuff flying about. >> >> We have a form for creating parts, and we include the mfr's and mpn's >> that are acceptable buys. Bonnie will sometimes need to find a new >> one, but she's pretty good about checking with engineering before >> doing it. She knows when it's safe, too, like simple resistors and >> such. >> >> I've worked for companies where engineering had no control over this, >> no real visibility as to what was being stuffed into a stockroom bin. >> I quit my first job in California, partly because they refused to get >> this under control. The purchasing manager was the President's wife. >> >> Besides, Fremont sucks. >> > >Yesterday the news said that the first bridge (Golden Gate?) staretd >charging carpoolers, too. And if you don't buy into Fastrack it's the >full six bucks. How are people doing that who aren't engineers but >closer to min wage? For them it eats up a whole work hour of net income. Carpoolers can share the toll anyhow. The GG Bridge would have been paid off long ago, so they stopped being a "bridge" and became a "transit agency" so they could waste gigabucks and keep raising tolls. Yeah, we have Fastrak. It removes the immediate pain of paying tolls. It even works for airport parking. Some day everything will be charged to your cell phone. And it will be a universal password, door opener, transit pass, drivers license, passport, everything. "You have no privacy. Get used to it." John
From: krw on 30 May 2010 10:51
On Fri, 28 May 2010 16:30:12 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Nico Coesel" <nico(a)puntnl.niks> wrote in message >news:4c004c6d.892986843(a)news.planet.nl... >> "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >>>We have ORCAD CIS and no, it doesn't, AIUI: If you want to change, e.g., a >>>resistor's value only (but it's still the same old 0603 generic resistor >>>otherwise), you can to use "change database part" and go find the new, e.g., >>>1.12k, 0603 resistor. In most cases that's a lot more mouse clicks that >>>double-clicking one on the part's value, entering the new value, and calling >>>it good. >> Yes, but you'll have a lot of work afterwards to edit and check the >> BOM. At lot of chances to introduce errors a well. > >The idea is that you don't have to check the BOM -- you're guaranteed that if >all you did was change a "generic" resistor's value from 220ohms to 470ohms, >your new BOM is correct. Our "value" and "P/N" fields are separate so that only the value is printed on the schematic, not the entire P/N. It would help immensely if all the parts had the value encoded in the P/N, but some nitwit about 1600 parts back decided to divorce them and start numbering all parts from 00000001. :-( >> Make sure you can add parts yourself. > >Ho, ho... yeah, well, that isn't going to fly at many places I've been. At >one place, even after demonstrating that on average something like 1 in 10 >parts had errors in them (albeit many of them minor, such as incorrect >electrical pin types, lack of overbars, etc. -- perhaps 1 in 40 had "board >killer" errors such as the wrong footprint or wrong pin numbers), management >was not convinced that adding parts should be in the purvue of design >engineering. We *can* add parts, but leave it to the "component engineer", who also is the layout guy. I'll make OrCad symbols and put them in my own library. He pulls them from there and checks all the information before putting it in a "standard" library. >We even had one guy quit his position as "parts librarian" >because he said there were too many correction requests coming in from >engineering -- even though he didn't dispute that any of the correction >requests were invalid! Amazing... He was likely given the position without the time or perhaps authority to do the job properly. Management is often does things like that. |