Schematic preferences
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From: John Larkin on 19 Jan 2010 11:30 On Tue, 19 Jan 2010 06:20:27 -0800 (PST), MooseFET <kensmith(a)rahul.net> wrote: >On Jan 18, 7:02�pm, John Larkin ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >> On Mon, 18 Jan 2010 18:39:06 -0800 (PST), MooseFET >> >> <kensm...(a)rahul.net> wrote: >> >The reference of a part encodes the page it is on. �R307 is on page 3 >> >> Yikes! Production would lynch us. After the layout is done, we >> resequence the reference designators in physical and numeric order and >> back-annotate the schematic. > >We haven't done that since the 1980s. The technicians were the ones >that >suggested the change. We used to do boards with things like RA12 >meaning >column A row 12. > We sometimes did that for classic arrays of TTL cans. One division of GE just used a number for the designator; 94 might be a resistor, 95 a capacitor. The opposite extreme is amateurs that make up prefixes... TR for transistor, RV for pot (RV actually designates a Recreational Vehicle), LED for LED even! Most annoying, especially when combined with the dreadful 2K7 notation and the accompanying bad circuits. John
From: John Larkin on 19 Jan 2010 11:32 On Tue, 19 Jan 2010 05:26:50 -0800 (PST), mpm <mpmillard(a)aol.com> wrote: >On Jan 18, 3:37�pm, D Yuniskis <not.going.to...(a)seen.com> wrote: >> Hi, >> >> Of course, this is *highly* subjective -- but, I'd enjoy hearing >> folks' "conventions" used when preparing schematics (that *others* >> will consume -- how you scribble for your own purposes isn't >> important as it depends a lot on what *you* want out of the >> drawing). > > >My main rule (a preference actually) is that the same name be used in >the callouts when a circuit involves several schematic sheets! > >I once worked for a video company that had a PLL circuit that >traversed 6 or 7 different circuit boards. >I guess each engineer / designer was responsible for his own board, >because none of the names matched up. >This made final device test & calibration very difficult. > >This device comprised roughly 75 "D-size" sheets of schematics. >I can still smell the ammonia from the Diazit copier.. I still have and use a D-size diazo copier! John
From: Jim Thompson on 19 Jan 2010 11:37 On Tue, 19 Jan 2010 08:32:48 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Tue, 19 Jan 2010 05:26:50 -0800 (PST), mpm <mpmillard(a)aol.com> >wrote: > >>On Jan 18, 3:37�pm, D Yuniskis <not.going.to...(a)seen.com> wrote: >>> Hi, >>> >>> Of course, this is *highly* subjective -- but, I'd enjoy hearing >>> folks' "conventions" used when preparing schematics (that *others* >>> will consume -- how you scribble for your own purposes isn't >>> important as it depends a lot on what *you* want out of the >>> drawing). >> >> >>My main rule (a preference actually) is that the same name be used in >>the callouts when a circuit involves several schematic sheets! >> >>I once worked for a video company that had a PLL circuit that >>traversed 6 or 7 different circuit boards. >>I guess each engineer / designer was responsible for his own board, >>because none of the names matched up. >>This made final device test & calibration very difficult. >> >>This device comprised roughly 75 "D-size" sheets of schematics. >>I can still smell the ammonia from the Diazit copier.. > >I still have and use a D-size diazo copier! > >John Gag! Reminds me I was responsible for running such a machine during a summer job when I was in high school (1957). ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: Joel Koltner on 19 Jan 2010 13:02 "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:o3nbl55g2cpeqcso7g0in089sm2hpdv700(a)4ax.com... > The opposite extreme is amateurs that make up prefixes... TR for > transistor, RV for pot (RV actually designates a Recreational > Vehicle), LED for LED even! TR and RV are arguably signs of not being familiar with industry standards. LED I could imagine someone purposely choosing even though they're well aware that normally it's just D, i.e., they believe they're creating an improvement. Whether or not that's really the case is pretty subjective, although it's pretty hard to argue that someone seeing a reference designator of LED23 wouldn't understand what kind of component it is. :-) > Most annoying, especially when combined with the dreadful 2K7 notation > and the accompanying bad circuits. 2k7 is a European thing. As with four-way intersections, historically there was some decent justification for it (the decimal point easily getting lost in mechanical reproductions), whereas today it's just a personal preference, I suppose.
From: Joel Koltner on 19 Jan 2010 13:05
"krw" <krw(a)att.bizzzzzzzzzzz> wrote in message news:1gbal51s9jie6of3ufcf6u98codr531qi3(a)4ax.com... > I really don't like prefixes (other than power) because the signal > names don't collate properly. A net and its negative should sort > together, just as diff pairs should sort together. Good point. With a few macros in your favorite text editor this is pretty easy to "fix," but I can see how that could be more hassle than it's worth. Our schematics often have many hundreds of nets (often over a thousand) of which typically fewer than 10% are actually named something meaningful (the rest just being NET0001, NET0002, or whatever the software uses by default). How about yours? |