4-20mA Precision Source Ideas

Did you get a degree? Did they teach you schematic drawing conventions?

Looking at some various Tektronix schematics, I see 4-way junctions done both ways, sometimes on the same sheet. They didn't seem to be too rigid about it, but mostly use the offset method. And they decorated schematics with guys on skis, race cars, all sorts of stuff that I'm sure you wouldn't approve of.

John

Or with anonymous idiots who claim to have a degree...

You can't fix stupid. You can't even put a Band-Aid? on it, because it's Teflon coated.

It would have been removed by the store selling the set, or the first one to crack the case open. A few shops used to brag about removing and destroying the Sears & GE documentation that was shipped with their TV sets. Sears was in an envelope stapled to the back of the cabinet, and GE had a small plastic cover that was part of the neck cover for the CRT that popped open. No one sold a TV in a sealed carton back then. At one time Hitachi had their TV schematics available online for free download for registered repair shops.

--- Me???

I posted a schematic several hours before you did, and commented on a better way to show connections than the way you choose to.

You, then, were the one who went "ballistic" with your outrage at having been rightly corrected and have tried, with your malicious lying chicanery, to get off the hook.

As for the rest of it, I'll bet Will Rogers never met _you_.

-- JF

Well, I think electronics is cool; unfortunately, I've been leapfrogged by the advances in technology that have taken place while I was distracted by stuff like doing the housework while my Mom's job was changing Dad's diapers.

How about this - is VHDL "electronics?" ;-)

Cheers! Rich

Yes, idiot.

Drafting was years earlier. Several years worth. Schematics came with Electronics courses in High School. The same course they were teaching at XU (Xavier).

Drawing conventions were also taught in college. Currently, the CAD packages all handle most drafting requisites, so they barely touch on these elements any more. Sad, that, as dolts like you are the result.

That does not mean that all the variable elements in a drafting package are there for you to pick what you think "looks nice" from.

This is all krw is reduced to.

He makes no contribution, just pokes and prods. He wouldn't like the poke he'd get at arms length. I'd turn your jaw, boy. You'd be sippin' through a straw for a year if I ever met you and gave you what you deserve to get.

He fantasizes importance because his initials match that of a great company.

You are not important.

Folks need to know what to expect when they look at Company B's schematic. Company B needs to know what to expect when they look at company A's schematic.

The STANDARD that has been in place for a VERY LONG NUMBER OF YEARS (at least two decades) is that a line crossing another line is to ALWAYS be considered NOT connected. That way, there is NEVER ANY confusion. THAT IS THE RULE.

So whenever you look at a schematic, you should be able to note that all the lines that cross over another never connect.

THAT IS THE INDUSTRY WIDE ASSUMPTION, and any time you see a dot there, the person that drew it made a mistake.

Any engineer worth his salt would catch it immediately. He would also attempt to instruct the errant conveyor.

That is what started to happen here, but everybody got on their "stab at George" bandwagon.

There are a number of folks here that are incapable of accepting instruction from others.

That would be John. Since you only qualify as a slug, you cannot accept instruction either, but for different reasons. You're just plain dumb.

Zero is for your contributions. Clucking noises don't count.

John

Whatever it was in, it doesn't seem to have involved much math.

Of course it does.

John

The fact that you wonder how a schematic would represent a physical configuration is quite a tell about you.

There is no need for all of such a group of physically tied conductors to be represented by a single node on the schematic. There is no such requisite anywhere in the industry.

So a single ground stud with ten wires stacked on it, in your precious "star ground" termed manner would show on a schematic as a string of single node ties along a single conductor with a single ground symbol.

o___o___o___o___o___o___o___o___o_______o | | | | | | | | | | | | | | | | | | | | device| device| device| device| device ----- | | | | --- device device device device -

You are an idiot. I have had Eagle and have ran it, likely under more Operating Systems than you ever did as well.

A layout package will let you make a mistake, you are the boss of your end product.

That does not change the fact that it is a mistake. Non-compliance IS error.

I was always taught that, "the nice thing about standards is that there's so many to choose from!"

But seriously... I was taught that the standard you follow is the one your boss or customer tells you to, because they're the one writing your paycheck! ...But that in the very common situation where none is specified, while it's important to understand the available standards, they all have various pros and cons, and there's no reason to think that you aren't just as insightful as the guys who designed the standards, and hence can't make a rational decision as to which standard you're going to follow, or if you just want to do something completely difference.

I'll grant you that there can be a grey area between, "I'm not using a standard because I'm confident it doesn't really apply to my situation or just doesn't matter, and my own homebrew standard here is better than the extant options" and, "I'm clueless and overestimate my own abilities and am going to do things my own way even though pretty much all of my more-experienced peers would suggest this is really a bad idea," but for cying out loud -- this country is all about encouraging people to try out new ideas and letting people vote with their feet and dollars, you know? Apple is a prime example of a company that is phoenomenally successful for purposely breaking with many standards, and even though I personally find only a small fraction of their products interesting and others seem quite distasteful to me (and I wish they would have stuck with more established standards), I have respect for the success that Jobs brought to the place and his abilities to know what a huge number of people are going to find "insanely great" and flock to his stores with their wallets wide open...

Do people ignore standards when, in practice, they probably shouldn't have? Yes, all the time.

Does that apply to John's decision to draw his schematics the way he does? No, I don't think so.

Do people just blindly following standards sometimes negatively impact their own productivity and competiteness? Yes, absolutely.

But hey, as I allude to, if you care to employ John to design you somethng, I fully expect that for the right price he'll draw schematics however you'd desire. Just open your wallet...

---Joel

Wrong. I don't sell schematics, and nobody is going to tell me how to draw.

It's absurd that some people here seem to think that this matters.

John

How was it you didn't end up with that task? :-)

I suppose, at least a bit... although it's digital electronics, which perhaps isn't quite as interesting as analog stuff. :-)

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You get pickier when you have sorted out production problems that can be traced back to a drawing error, and start getting enthusiastic about drawing conventions that eliminate as many source of potential ambiguity (no matter how implausible) as possible.

Maybe people who get to pick their employees and co-workers don't get motivated quite as often.

-- Bill Sloman, Nijmegen

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Only sloppy designers or beginners make primitive mistakes like that. That never happens in our products. We check everything before we release it to production. And what's ambiguous about two wires that cross, with a big fat dot at the intersection? We use 75 mil dots on equivalent D-size drawings, usually printed B-size on a laser printer. Impossible to miss.

The more subtle problems are things like oscillation, digital crosstalk, latchups, and transmission line effects. We check for those too, but once in a while one will sneak up on us.

We've had a couple of cases where we never understood a problem; we just had to fix it. On one of my boards, a Xilinx FPGA wouldn't configure all the time. No amount of probing spotted anything unusual, and the pcb layout looked fine. Adding a cap to the CCLK pin fixed it.

I don't pick employees as much as they pick me. And other people in Engineering are more agressive than I am about enforcing schematic, library, and PCB standards. But none has cared about dots at 4-way crosses, because none of them are rulebound idiots.

The big 4-20 circuit I posted should offer numerous opportunities for substantive whining, and the best you guys can do is harp on dots.

John

^^^^^^^ Benicia

You used to work there and still live close by and can't spell it right. Shameful.

I only spent a few hours there, in a supertanker that was unloading, and almost blew it up. And probably the town with it. And I nearly ripped a LASH ship off the dock into the Mississippi, turning a trimpot too far. Field service is not high in my skill set, I suppose.

I did spend 20 hours dead in the water, in the Gulf, on a sea trial run full of tech reps and owners and a bunch of Coast Guard folks, when my throttle control system locked up. But it wasn't my fault.

So give me a C- in spelling. Write to your congresswoman. Whatever.

John