Dammit. I _distinctly_ remember saying "oh, I don't need to make a special Kelvin connection package on that -- I'll just remember it in layout".
Crap. Crud. Etc.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Nothing like the daily aw shit moment ;-) ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
I'm down to the point now of "how can I bodge this so I can test the rest of the circuit, pending a new, correctly laid out circuit board".
But the new, correctly laid out circuit board does have a kelvin- connected current sense resistor, dammit!
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Yeah. I know, the hard way, that if I leave something "for later" and don't make explicit notes about it where I cannot possibly ignore them, I *will* forget the Later.
Have had to do a bunch of reworks of various sorts (hardware and software) and enjoy the tangy taste of corvid-burger a few times because of that.
No! (being mostly a bear of little brain.) I always feel I've gotta make X number of mistakes on a project, and the sooner I get them over with, the faster it's done. :^)
George H.
exacto knife, and bits of wire.
George H.
The only way to avoid repeating mistakes is to make them the first time. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| 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.
You might consider having a formal checklist of gotchas for the layout. Schematic notes are limited, and I remove layout-related notes before releasing the schematic, so at some point in the process they disappear.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
You mean implement ISO9001 ?
;D
Cheers
No, do something that actually improves quality.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I'm sure that you could implement ISO 9001 and in a way that didn't improve quality, but most people manage to fit something useful into the bureaucratic straight-jacket.
-- Bill Sloman, Sydney
I can see most managers see it as a waste of time, but there are some aspects that would solve a lot of problems.
Cheers
mostly the problem of other businesses requiring you have it ;)
-Lasse
One of our customers dings our quality scores because we aren't ISO9000. But they aren't either.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
can't you assign a special footprint for that part while you're entering the schematic.
-- \_(?)_
Kelvin connection is often just a matter of routing. You can usefully do 4-wire Kelvin to a conventional surface-mount resistor. All you need to do is remember.
Our software doesn't deal with footprints in the schematic entry program. Schematic decals are distinct from PCB decals, and the PCB program handles those.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
What!?! You can't assign specific PCB footprints to various schematic symbols? What package do you use?
--
Thanks,
- Win
PADS.
PADS has "parts", and each part references a schematic decal (optionally with gates or some alternate decals) and a PCB decal. The Logic program creates schematic decals, and the Layout program creates pcb decals.
A zillion different resistor parts can share the general "resistor" schematic decal but can have different PCB decals. We do have a special 4-wire resistor decal, which has 4 pins instead of two.
We create a lot of different parts because a part can have added attributes, like a Highland stock number, which is handy for automatic BOM generation. So we have a zillion different SOT23 nfet parts, and D9 connectors, and opamps, and such that reference a relatively few decals.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Den torsdag den 17. marts 2016 kl. 23.57.28 UTC+1 skrev John Larkin:
but nothing prevents you from sticking a part on the schematic and then manually changing its footprint attribute to something else with the right number of pins, it'll still work just the BOM will be messed up
-Lasse
In the Layout program, we can enter ECO mode and do hacks, like changing PCB decals or adding/deleting parts or connections. We discourage that because it confuses the documentation trail and can make the schematic differ from the layout, a long-term time bomb.
I recently had a d-sub connector that has two plastic alignment pins, with corresponding drill holes in the pcb footprint. They were disturbing my power pours, so I went into ECO mode and grounded them. Those pins aren't even on the schematic decal.
We do commonly edit pad stacks at layout time, like drill sizes or something. I recently rounded the corners on all the pads on a high-voltage board, which is not a conflict with the schematic, now or on future revs.
PADS can output (or input!) everything in ASCII, so we can get ASCII files from both the sch and pcb programs, and run checks. I've written some PowerBasic programs that do that.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.