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Hello All:
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Is there any good reason to plumb the ground net (node 0) out of a hierarchical schematic block?
Inside the block, the hierarchical label could be called RTN and outside the block, the hierarchical label could be connected to ground (node 0).
Assuming it is always connected to node 0 outside the block, it appears to me that there is no good reason to do the plumbing.
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I understand that if the reference inside the block is not connected to node 0 outside the block then of course that inside reference would have to be plumbed to the outside of the block.
Node 0 is the only universal node.
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Any horror stories either way?
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All for now
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On Mon, Feb 3, 2025 at 08:26 PM, eewiz wrote:
Is there any good reason to plumb the ground net (node 0) out of a hierarchical schematic block?
Inside the block, the hierarchical label could be called RTN and outside the block, the hierarchical label could be connected to ground (node 0).
Assuming it is always connected to node 0 outside the block, it appears to me that there is no good reason to do the plumbing.
There are actually some "tricks" going on, when a subcircuit (or lower-level schematic) has a "ground" net that comes out on a .subckt pin.? Some years ago I spent some time documenting this, but did not finish.
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When a subcircuit has its "ground" pin brought out to the higher-level, and if that pin is not connected to node 0 / ground at the higher level, then the internal "ground" is no longer ground.? It becomes whatever that pin connects it to.
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This is particularly useful when you inherit a subcircuit model from someone else, which has internal points connected to ground, but you don't want to use it that way.? Say that you have an IC that is "normally" powered by +5 V and ground.? The guy who made the SPICE model might have written it so that the "ground" pin goes to node 0 inside their subcircuit model.? But you might want to use it powered by +2.5 and -2.5 V.? In the old days, what we had to do was re-write the vendor's SPICE model, changing all their node 0 netnames to something else, so that it could be NOT connected to ground.? What LTspice allows you to do, is just bring that net out on a pin, letting you use it as if it was not node 0.
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This looks wrong, because the lower-level schematic (or .SUBCKT block) seems to be using node 0, but it actually isn't.? LTspice handles the net name translation automagically.
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By the way, I am not sure if everyone here understands your use of the words "plumb" or "plumb out".? Honestly, I am not sure that I know exactly what you mean either.? Remember that a sizable percentage of?the members of this group are not in North America and do not know our slang.
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Node 0 is the only universal node.
Except when it isn't.
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If I remember correctly, LTspice uses "GND" as an alias for node 0, but not "ground", and not nodes 00 or 000.? The fact that node "ground" is not the ground node (node 0) can be a little confusing, because LTspice displays that both of them are ground if you hover over them, but one is "ground" while the other is "node ground".
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Andy
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On Mon, Feb 3, 2025 at 07:45 PM, Andy I wrote:
Assuming it is always connected to node 0 outside the block, it appears to me that there is no good reason to do the plumbing.
There are actually some "tricks" going on, when a subcircuit (or lower-level schematic) has a "ground" net that comes out on a .subckt pin.? Some years ago I spent some time documenting this, but did not finish.
Piqued my curiosity. I'd like love to see this.?
By the way, I am not sure if everyone here understands your use of the words "plumb" or "plumb out".? Honestly, I am not sure that I know exactly what you mean either.? Remember that a sizable percentage of?the members of this group are not in North America and do not know our slang.
“Electronics is just plumbing,” is universally idiomatic, no?
--
Michael Stokowski
LTspice Team
Analog Devices Inc.
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I must say I'd like a translation? pof plumbing in the realm of
electronics.
Le 04/02/2025 à 17:20, mstokowski via
groups.io a écrit?:
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Show quoted text
On Mon, Feb 3, 2025 at 07:45 PM, Andy I wrote:
Assuming it is always connected to node 0 outside
the block, it appears to me that there is no good
reason to do the plumbing.
There are actually some "tricks" going on, when a subcircuit
(or lower-level schematic) has a "ground" net that comes out
on a .subckt pin.? Some years ago I spent some time
documenting this, but did not finish.
Piqued my curiosity. I'd like love to see this.?
By the way, I am not sure if everyone here understands
your use of the words "plumb" or "plumb out".? Honestly, I
am not sure that I know exactly what you mean either.?
Remember that a sizable percentage of?the members of this
group are not in North America and do not know our slang.
“Electronics is just plumbing,” is universally idiomatic, no?
--
Michael Stokowski
LTspice Team
Analog Devices Inc.
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Le 04/02/2025 à 17:20, mstokowski via groups.io a écrit?: “Electronics is just plumbing,” is universally idiomatic, no? Certainly not. Never heard of it in 50 years of contact with english and american electronic designers. Honest, I fail to understand what it means.
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Not really. Simple DC circuits can use
plumbing analogies, as can EMI shielding, but AC circuits
require little-known fluid dynamics, so that plumbing analogies
are not helpful.
On 2025-02-04 16:20, mstokowski via
groups.io wrote:
“Electronics is
just plumbing,” is universally idiomatic, no?
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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DC circuits can be modelled as the flow of
water along pipes of different diameters and lengths, but
modelling AC circuits becomes very complicated and usually not
useful.
On 2025-02-04 16:30, Jerry Lee Marcel
via groups.io wrote:
I must say
I'd like a translation? pof plumbing in the realm of electronics.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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On Tue, Feb 4, 2025 at 11:30 AM, Jerry Lee Marcel wrote:
I must say I'd like a translation? pof plumbing in the realm of electronics.
Maybe I'm dumb, but I don't know what eewiz meant in this context.? Some things that came to my mind are these:
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To "plumb" might mean to bring something straight to ground.? I'm thinking about a "plumb line", which is a carpenter's tool, not related to plumbing or what a plumber does.
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To "plumb" might mean to direct or re-route something to somewhere else, through some other path.? This is what a plumber does with pipes.
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Electronics is somewhat similar to the second version.? The wires are like pipes that move the electrons around.? That is the kind of thing you might hear once, and then never again, so it is no surprise if you never heard that.
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Andy
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There's always a good reason to start a new topic on a different
subject, rather than hijack existing one that's completely
unrelated. It may not matter to you, but it messes things up for
people that read messages in threads.
Please don't do this!
--
Regards,
Tony
On 04/02/2025 02:26, eewiz via
groups.io wrote:
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?
Is there any good reason to plumb the ground net (node 0) out
of a hierarchical schematic block?
Inside the block, the hierarchical label could be called RTN
and outside the block, the hierarchical label could be connected
to ground (node 0).
Assuming it is always connected to node 0 outside the block,
it appears to me that there is no good reason to do the
plumbing.
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What Tony is saying is that you (eewiz) started this topic by replying to a message in another topic and changing the Subject line.? Please don't do that.
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To those who do not use email programs like Thunderbird that properly thread replies, you probably can't tell the difference.? But to others, your message displays in the wrong place, as a reply to someone else's topic.? You hijacked their topic.
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New topics must start by clicking "New Topic" (on the web) or "Start new message" or "Compose" or whatever in your email program.
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This group's email address is simple enough to remember: LTspice (at) groups.io .? Add it to your Address Book.
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Andy
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Oof, forgot the tongue in cheek. Mistakes were made. Apologies.
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As noted by others, plumbing is used sometimes to explain basic DC electronics, not much beyond that.
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That said, I liked the poetic (incorrect) use of plumb as a verb in this case, but agree it does not easily translate.
--
Michael Stokowski
LTspice Team
Analog Devices Inc.
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The only things that you can plumb in English
are 'the depths'.
On 2025-02-04 21:43, mstokowski via
groups.io wrote:
Oof, forgot the tongue in cheek. Mistakes were made.
Apologies.
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As noted by others, plumbing is used sometimes to explain
basic DC electronics, not much beyond that.
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That said, I liked the poetic (incorrect) use of plumb as a
verb in this case, but agree it does not easily translate.
--
Michael Stokowski
LTspice Team
Analog Devices Inc.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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That's just plumb silly.?
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I'm surprised no one has worked with the origins of plumb. Plumbum
is the latin name for lead (hence the chemical symbol Pb). The
English word "Lead" is, of course,? a heteronym - a multi-functional
word with different pronunciations.
--
Regards,
Tony
On 04/02/2025 22:46, John Woodgate
wrote:
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The
only things that you can plumb in English are 'the depths'.
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Which leads us to plumb the depths of the language issues with a
lead-weighted line, with which we might find a true ground.
(FWIW, I don't believe in "ground" - most nodes labelled "ground"
are actually nets that return current to some reference node.)
Donald.
On 2/4/25 17:45, Tony Casey wrote:
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I'm surprised no one has worked with the origins of plumb. Plumbum
is the latin name for lead (hence the chemical symbol Pb). The
English word "Lead" is, of course,? a heteronym - a
multi-functional word with different pronunciations.
--
Regards,
Tony
On 04/02/2025 22:46, John Woodgate
wrote:
The
only things that you can plumb in English are 'the depths'.
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And if the weighted line is too short at 12 feet, do we shout, “mark TWAIN”?
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From: [email protected] <[email protected]>
On Behalf Of Donald H Locker via groups.io
Sent: Tuesday, February 04, 2025 4:02 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Any Good Reason to Plumb Ground Out of Hier. Schem.
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Which leads us to plumb the depths of the language issues with a lead-weighted line, with which we might find a true ground.
(FWIW, I don't believe in "ground" - most nodes labelled "ground" are actually nets that return current to some reference node.)
Donald.
On 2/4/25 17:45, Tony Casey wrote:
I'm surprised no one has worked with the origins of plumb. Plumbum is the latin name for lead (hence the chemical symbol Pb). The English word "Lead" is, of course,? a heteronym - a multi-functional word with different pronunciations.
--
On 04/02/2025 22:46, John Woodgate wrote:
The only things that you can plumb in English are 'the depths'.
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Did someone say short? What are the real and virtual impedances?
No real grounds; no real shorts. (JMNSHO)
Donald.
On 2/4/25 19:13, Bell, Dave via
groups.io wrote:
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And if the
weighted line is too short at 12 feet, do we shout, “mark
TWAIN”?
?
?
Which leads us to plumb the depths of the language issues
with a lead-weighted line, with which we might find a true
ground.
(FWIW, I don't believe in "ground" - most nodes labelled
"ground" are actually nets that return current to some
reference node.)
Donald.
On 2/4/25 17:45, Tony Casey wrote:
I'm surprised no one has worked with the
origins of plumb. Plumbum is the latin name for lead (hence
the chemical symbol Pb). The English word "Lead" is, of
course,? a heteronym - a multi-functional word with
different pronunciations.
--
On 04/02/2025 22:46, John Woodgate
wrote:
The only things that you can plumb in
English are 'the depths'.
?
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Le 04/02/2025 à 23:45, Tony Casey a écrit?: I'm surprised no one has worked with the origins of plumb. I have. Being french, I have no merit. The french name for lead is plomb. But I still fail to understand the relevance to ground. I understand the analogy between current flow and circulation of fluids, though. In particular "plumbing out"...
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On Wed, Feb 5, 2025 at 12:07 AM, Jerry Lee Marcel wrote:
But I still fail to understand the relevance to ground.
I think eewiz now made it clear there that wasn't any relevance to ground.? That was something going through my mind, and I guessed wrongly.? I was imagining a plumb-line, which takes the shortest, most direct path straight to earth.
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For eewiz, the comparison was to plumbing, by routing the Node 0 signal out of a subcircuit.
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Andy
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OK. Still I don't understand the meaning of "plumbing out". Is it
meant to replace "disconnect"?
Le 05/02/2025 à 06:23, Andy I via
groups.io a écrit?:
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Show quoted text
On Wed, Feb 5, 2025 at 12:07 AM, Jerry Lee Marcel wrote:
But I still fail to understand the relevance to
ground.
I think eewiz now made
it clear there that wasn't any relevance to ground.? That
was something going through my mind, and I guessed wrongly.? I
was imagining a plumb-line, which takes the shortest, most
direct path straight to earth.
?
For eewiz, the comparison was to plumbing, by routing the
Node 0 signal out of a subcircuit.
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Andy
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eewiz
John Woodgate
Tony Casey
thutches
Bell, Dave