Question for Win Hill

[Rich Grise]

I've heard of ladder logic in traffic controls, but have never seen it.
I somehow don't think it would help with what I do, any more than
Greek. ;-)

As far as I understand it, it wouldn't be so much like learning Greek as
like learning Tinkertoys. ;-)

Cheers!
Rich

 

[BFoelsch]

As far as I understand it, it wouldn't be so much like learning Greek as
like learning Tinkertoys. ;-)

As I said, it's really just Visual Boolean. Vastly popular in the US PLC
market, not so popular in the European market. Like anything else, it has
its place. Like anything else, people who are comfortable with it tend to
use it even if other tools are more appropriate.

 

[Keith Williams]

As far as I understand it, it wouldn't be so much like learning Greek as
like learning Tinkertoys. ;-)

Hmm, Tinkertoys are fun!

 

[Jim Thompson]

[snip]

OK, I've gotten my computer running again, wheew! and will try to
find the time to evaluate these six interesting 2n7000 spice models.[/QUOTE]

Thanks, Win, I appreciate the help... if there's anyone here with
"hands-on" you're "the-man" ;-)

...Jim Thompson

 

[Spehro Pefhany]

As I said, it's really just Visual Boolean. Vastly popular in the US PLC
market, not so popular in the European market. Like anything else, it has
its place. Like anything else, people who are comfortable with it tend to
use it even if other tools are more appropriate.

It twists your brain around a bit if you're used to procedural
programming. Initially, I found it easier to implement a ladder-logic
processor than to write good programs for it. Then it clicked.


Best regards,
Spehro Pefhany

 

[John Woodgate]

I read in sci.electronics.design that Spehro Pefhany <speffSNIP@interlog

I found it easier to implement a ladder-logic
processor than to write good programs for it.

I am striving to resist posting a series of 'ladder-logic' jokes. I have
to let one escape to relieve the pressure.

In Germany, all ladder-logic (Leiter-logik) is based on pairs of
semiconductors (Halbleiter).

 

[Rich Grise]

I read in sci.electronics.design that Spehro Pefhany <speffSNIP@interlog


I am striving to resist posting a series of 'ladder-logic' jokes. I have
to let one escape to relieve the pressure.

In Germany, all ladder-logic (Leiter-logik) is based on pairs of
semiconductors (Halbleiter).

I don't get it. Could you explain, or give more examples?

Thanks,
Rich

 

[Spehro Pefhany]

I don't get it. Could you explain, or give more examples?

Thanks,
Rich

I fear John has gone over many of our heads with that one. I don't get
it either. Something to do with leiter = leader?

He (John) seems to have the kind of intellect that could set crossword
puzzles etc. BTW, I heard a rumor that some setters were allegedly
taking payments to incorporate certain brand names into the puzzles.


Best regards,
Spehro Pefhany

 

[Arie de Muynck]

Rich Grise ...

John Woodgate ...

I don't get it. Could you explain, or give more examples?

German "Leiter" = ladder or conductor

Leiter-logik = ladder logic (but not conductor logic)
Halbleiter = semiconductor (but not half a ladder)

You need one pair of half conductors to make one conductor.

Regards,
Arie de Muynck

 

[John Larkin]

I read in sci.electronics.design that John Larkin <jjlarkin@highSNIPland
THIStechPLEASEnology.com> wrote (in <hu6jt0ll3hqo4enlodf68jabro5u82a4jm@
4ax.com>) about 'Question for Win Hill', on Mon, 3 Jan 2005:

I didn't mean to annoy you, but it's the same as grammar and spelling,
with the difference that if you see an unfamiliar symbol, you may not
even be able to guess what it should be, unlike a wrongly-spelled word.

I was also bugged by the wrong usage of symbols in Spice (M for milli, K
for kilo, Meg for mega and Sec for second). Especially M for mill -
errors of nine orders of magnitude tend to have dramatic effects!

Yeah, but lots of Spicers don't notice the difference.

I don't bother much about spelling in newsgroup posts, and editing
often introduces grammar errors that would be caught by careful
proofreading, which I don't do here either. It's like being in a pub
and relaxing your spoken language a bit. I only write carefully when
it matters, preferably when large amounts of money are involved.

John

 

[Jim Thompson]

Rich Grise ...

German "Leiter" = ladder or conductor

Leiter-logik = ladder logic (but not conductor logic)
Halbleiter = semiconductor (but not half a ladder)

You need one pair of half conductors to make one conductor.

Regards,
Arie de Muynck

What IS "ladder-logic"?

...Jim Thompson

 

[John Larkin]

What IS "ladder-logic"?

...Jim Thompson

It's a graphical way to program PLC's, industrial programmable logic
controllers. A screen has two horizontal "voltage rails" at the top
and bottom, representing some voltage bus and ground. The user then
draws vertical rungs from rail to rail, consisting of some string of
series or parallel contact closures (representing logic states, like
maybe a pushbutton or a pressure switch) and circles representing
actuators or relay coils. Relay contacts can be named and used on
other rungs, sort of a logic fanout.

You can have nc or no contacts, time-delay relays, all sorts of stuff.
It's easy to make rs flipflops, gates, and like that. There are even
kluges for analog i/o and bus data operations and other weirdness.
I've even seen a Basic program inside a box: when power is applied,
the code runs!

This was invented in the olden days to simulate hardwired relay logic
that factory dudes were used to. They advertised "no programming
necessary!" One PLC would then replace a panel full of relays.


Here's one, except that the rails are vertical...

http://xtronics.com/toshiba/Ladder_logic.htm


John

 

[John Woodgate]

I read in sci.electronics.design that Rich Grise <[email protected]>

I don't get it. Could you explain, or give more examples?

No.

 

[Frank Bemelman]

I don't get it. Could you explain, or give more examples?

It's one of those jokes that don't translate very well, and
a play with words, not extremely funny.

Q: What is the title of the thinnest book on Earth?
A: 200 years of German humor.

 

[Clarence_A]

"John Larkin" wrote

Jim Thompson wrote:


It's a graphical way to program PLC's, industrial programmable logic
controllers. A screen has two horizontal "voltage rails" at the top
and bottom, representing some voltage bus and ground. The user then
draws vertical rungs from rail to rail, consisting of some string of
series or parallel contact closures (representing logic states, like
maybe a pushbutton or a pressure switch) and circles representing
actuators or relay coils. Relay contacts can be named and used on
other rungs, sort of a logic fanout.

You can have nc or no contacts, time-delay relays, all sorts of stuff.
It's easy to make rs flipflops, gates, and like that. There are even
kluges for analog i/o and bus data operations and other weirdness.
I've even seen a Basic program inside a box: when power is applied,
the code runs!

This was invented in the olden days to simulate hardwired relay logic
that factory dudes were used to. They advertised "no programming
necessary!" One PLC would then replace a panel full of relays.

Here's one, except that the rails are vertical...
http://xtronics.com/toshiba/Ladder_logic.htm
John

I have never seen any "Ladder Logic" where the rails were other
than vertical.

It is an extension of relay logic, which permits software to be
inserted into the flow as if the routing was a relay. I used to
program a complete system in ladder Logic right in the body of a
quote because it allowed the customer to verify with their
electrician that it was what they wanted. Basically it is Boolean
Logic for AC or DC relays!

 

[Daniel Haude]

On Mon, 03 Jan 2005 19:50:16 -0500,

I fear John has gone over many of our heads with that one. I don't get
it either. Something to do with leiter = leader?

No. Leiter = conductor. A semiconductor is half a conductor, in
German that's half a ladder, so to make a whole ladder you need two
semiconductors.

The joke really _is_ that lame, and if this is the one John couldn't
restrain himself from sharing because it's his best ladder-logic joke I
fear the worst.

--Daniel

 

[John Woodgate]

I read in sci.electronics.design that Daniel Haude
hysnet.uni-hamburg.de>) about 'Question for Win Hill/ Athlon64', on Tue,
4 Jan 2005:

On Mon, 03 Jan 2005 19:50:16 -0500,


No. Leiter = conductor. A semiconductor is half a conductor, in
German that's half a ladder, so to make a whole ladder you need two
semiconductors.

The joke really _is_ that lame, and if this is the one John couldn't
restrain himself from sharing because it's his best ladder-logic joke I
fear the worst.

Put it down to a slight excess of Cabernet Sauvignon. But my colleagues
thought it was amusing about 40 years ago when we read it in the
Christmas card drawn and sent by the Technical Director of our German
associate company.

 

[John Larkin]

I have never seen any "Ladder Logic" where the rails were other
than vertical.

Yes, I can believe that.


John

 

[Kryten]

Has anybody ever been murdered by an atheist?

Apart from God (who is arguably fictitious)?

I'm reminded Woody Allen's Raymond Chandler detective spoof -- "Mr. Big" --
in which our hero, is hired by a philosophy student to find God for her.
Well, when God turns up on a slab at the morgue, Kaiser is stumped, until he
learns that his pretty philosophy major is actually a scientist.
We join him as Kaiser returns to his client's apartment. "Something seemed
to be troubling her."

"God is dead." she says,

"The police were here. They're looking for you. They think an existentialist
did it."





A TV interviewer asked Richard Dawkins if a scientist should take the blame
for destroying the notion of God, to which he replied

"I would have thought the word 'credit' a more appropriate word than
'blame'"

 

[Charles Edmondson]

[snip]

For that matter, the universities are getting smarter as well...
high schools are ranked to qualify applicants...
one school's "A" is another school's "C".

We in the UK have a couple of independent exam boards to make ratings
uniform and independent of schools. Is it not the same in the US?

Just in the State of Arizona we have HUNDREDS of local school boards.
LOCAL control of schools is common throughout the USA.

The only things tying the country together are the College Entrance
Exams... SAT and ACT.

You must meet some real pointy-haired applicants...

Not really. Just some that are so nerdy/geeky that they're recluses.

Got any stories about the dumbest applicants you've interviewed?

I've been doing this for around 20 years, and can only recall one
really dumb one...

A girl showed up in her cheerleader uniform, chewing on bubble gum ;-)
She didn't even have a clue as to what MIT was all about... just that
someone told her she should apply.

...Jim Thompson

Way back in the dark ages, I decided to graduate from high school early.
Involved busing, my dad retiring in a year, and wanting to finish
school in Memphis and not Palm Springs...

Anyway, found out I have one big problem - most schools had you apply
for financial aid in your junior year, which I had just skipped! One
possible solution - an Army ROTC scholarship. So, I sent in the forms,
went through the hoops, and one of these was an interview before an
evaluation board. Since this had kinda become my best hope, decided to
put my best foot forward, and wore my high school ROTC uniform.

As I expected, there were at least 6 other candidates there waiting.
Was glad to see I was the only one in uniform! It was either a great
idea, or a terrible one!

A little while later, I got the letter congradulating me on receiving a
four year scholarship!

A week later, I got a form letter informing me that the medical baords
had been late, and I was disqualified due to insufficient visual
acuity... :-(

So, I could see the girl wearing her cheerleading uniform (think legally
blonde) if she wanted to emphasize that she would add welcome diversity,
but that requires that you have more to back it up...