4-20mA Precision Source Ideas

I used to work with a shipyard that had a "lofting room" where they did drawings of ship parts 1:1. They had huge sheets of vellum on the floor, and walked on them in their sox, and kneeled to draw. They had plenty of room to do N-ways on their schematics.

They also had a cute little robotic line follower thing, predecessor to R2D2, that was realtime interfaced to a flame cutter.

John

Larkin's mother never kissed him when she put him to bed, just, "Shut up kid!" ;-)

...Jim Thompson

PADS won't allow a 3 or 4 wire tee connection without a dot. And it won't allow near-miss connections, as Orcad and LT Spice do. A schematic wire, or pcb copper, segment must be connected on both ends or it snaps back into oblivion. We never make schematic or PCB connection errors using PADS.

But nobody does copies of copies of copies any more. Everybody prints from a PDF, if they print at all. And laser printers have phenomenal resolution and quality. Dots just don't get lost anymore.

Why follow obsolete conventions? Why not adjust to the tools that are available nowadays?

John

Your insulting my wife, and now my mother, serve only to demonstrate what a disinhibited asshole you are. That happens as people get senile. It also shows how far you'll go to avoid saying anything on topic, where your incompetance would be apparent.

Looks like you've accumulated allies: JF and AlwaysWrong. The Henhouse Trio, with apologies to Ernie Kovacs.

John

All clucking, no electronics. Nothing to say about 4-20 mA circuits.

Useless, frightened old hen.

John

And missing badly. Anything to avoid the topic here.

Done any good 4-20 mA circuits? Show us.

John

One of my favorites... only surpassed by the French movie short subject that ends with the punch line, "What woman?" ...Jim Thompson

. ^^^^^^^^^^^^ . incompetence

You're not doing too bad yourself!

There is no confusion. If there's a dot, all four wires are connected. I think it's you who are stuck in the old days of hand-drawn schematics and ratty blueline machines.

I posted a complex and highly debatable 4-20 mA schematic of an actual, recently-designed commercial product, which is on topic for this thread. You ignore all the potential circuit goodies and baddies, and fixate on the tie dots. And, of course, post nothing on topic yourself.

Keep on cluckin!

John

No surprise at all. 555s aren't especially good at precision analog current control.

John

Or "let's see if he'll post something on topic."

As if!

John