I've been an electrician and electrical contractor for 40 years. I've never seen the term "ADC" used in the trade. There would be little need to, as DC is either extremely rare or extinct in the field.
I wouldn't be surprised if someone derived the subject term from "A DC". As in "1.2 A DC" That would be 1.2 amps direct current. I frequently see things like "15.2 A AC". If the voltage is already pinned down, the only variable to be discussed is the current.
Actually, if such an acronym were desired, true direct current would be referred to as "DDC", I think. It's either on, or off. You know, like a battery in a flash light. Once you vary the DC with a rheostat, you could then call it "ADC". So a power pack could be an AC/DDC/ADC converter. Seems pretty pointless.
The term seems to be an answer to a question nobody asked.
Ed
PM Railfan...ADC is rolling waves (no straightness) while DCC looks like a cityscape (lots of straightness). But BOTH are DC...
DC power for a model railroad can have different forms - it can be "straight" if it is well filtered, in which case it will still vary up and down as the throttle is varied, but for a set speed it is a flat line. It can have "rolling waves" if it is not well filtered (sometimes done on purpose to help with slow speed control of locos). It can "look like a cityscape" if it uses PWM (pulse width modulation). It can even be combinations of these, for example some throttles will use PWM or allow some unfiltered pulses through at low settings and switch to pure filtered DC at higher setttings.
DCC is NOT DC, but square wave AC.
I just waded (if that's the appropriate word) through an acronym list for ADC. Several hundred entries.
Did I find Analog Direct Current?
Uh, no.
Did I find ANYTHING similar?
I did a google search for "analog direct current".
I found it on this site. This one here. And nowhere else. In all the google world. Which is pretty much the known universe.
Now, stop wasting your time talking about something that doesn't exist. And go play with trains. Right this instant.
7j43k Now, stop wasting your time talking about something that doesn't exist. And go play with trains. Right this instant. Ed
Awh Daddy, do I haff to?
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
NP2626 7j43k Now, stop wasting your time talking about something that doesn't exist. And go play with trains. Right this instant. Ed Awh Daddy, do I haff to?
If'n you want dessert tonight, you will!
Mark R.The only reference I can find for ADC with reference to our hobby is "Analog to Digital Converter"
In the television industry ADC is Analog to Digital Converter, a device which converts old fashion NTSC signal from a video tape into a digital cable signal. So in the model railroad hobby it would be equalivant to an onboard DCC decoder. But I think the original post refers to someone thinking Analog Direct Current, confusing it with AAD and ADD which are commonly printed on music CDs to identify which part of the recording process was analog and digital with AAD standing for Analog recording, Analog mixing, Digital master.
PM Railfan ADC refers to nothing other than 'Analog Direct Current'. Not suprising most havent heard of this as 99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist.
ADC refers to nothing other than 'Analog Direct Current'. Not suprising most havent heard of this as 99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist.
Rich
Alton Junction
google turns up advanced DC thottles and advanced DC cab control besides others
I would doubt it refers to analog to digital converters (ADC) since the more common need in model railroading would be to convert a digital value into an analog (DAC) voltage to drive a motor. Every decoder includes a type of DAC to convert a digital value for the speed to a pulse width modulated (PWM) signal to drive the motor. (I guess that an ADC is needed to measure BEMF).
ADCs have been around at least as long as the phone system went digital back in the early 60s.
greg - Philadelphia & Reading / Reading
richhotrain PM Railfan ADC refers to nothing other than 'Analog Direct Current'. Not suprising most havent heard of this as 99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist. So, PM Railfan who first used this term a few weeks ago on the forum, says ADC stands for Analog Direct Current. You can read his full reply on page 1 of this thread. Rich
So, PM Railfan who first used this term a few weeks ago on the forum, says ADC stands for Analog Direct Current. You can read his full reply on page 1 of this thread.
Yes, and in my 55 years of train modeling, he's the first.
maxman richhotrain PM Railfan ADC refers to nothing other than 'Analog Direct Current'. Not suprising most havent heard of this as 99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist. So, PM Railfan who first used this term a few weeks ago on the forum, says ADC stands for Analog Direct Current. You can read his full reply on page 1 of this thread. Rich Yes, and in my 55 years of train modeling, he's the first.
In the automotive world, it stands for Analog to Digital Converter and some times referred to as a A to D converter.
Second dtc parameter from the top: Click to enlarge.
Jim
That's what it stands for in the electronic world, too.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Pretty much one and the same.
richhotrainI'm just saying, that's where the acronym, ADC, popped up and that is his definition. Rich
Your point is noted.
The problem is that he says that it is far more than "his" definition. He says that the term has "prolly" been around ever since the term "amp". And yet, it does not turn up in a Google search--not as he defines it.
So, yes, it is HIS definition. It is just not OUR definition.
In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. I spose since google is around now we can junk the old addage.... "experience wrote the book, not the other way around".
Think of all the money that will be saved when google replaces teachers, since google knows everything. Cant wait to see if google will wire my layout for me. I will go ask it right now.
PM RailfanIn glad google has been around as long as electricity has. And is the end all-be all of definitions in this world.
is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. I spose since google is around now we can junk the old addage.... "experience wrote the book, not the other way around". Think of all the money that will be saved when google replaces teachers, since google knows everything. Cant wait to see if google will wire my layout for me. I will go ask it right now.
PM Railfan99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist.
Before DCC was standardized and branded, I believe it was known simply as 'command control' and was AC powered on model railroads like the legendary V&O. The decoders were so big they had to ride in the tender or in a dummy unit.
All of the model railroaders I know are either electricians including myself or else A/V or IT geeks who think they are electricians.
gregc PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world.
You tell me? The Aristo Craft Train Engineer wireless radio throttles I use have a square wave full voltage pulse width modulated motor control output - would you call that digital?
As opposed to most variable voltage/variable current DC throttles?
All acronyms are made up by someone - My control system is partly based on one called MZL by its creator, Ed Ravenscroft - easily read about in the back issues of Model Railroader right here on this site - but Bing and Google are clueless......
Sheldon
Well, poking around the internet, it seems we have DC and AC, direct and alternating current. We also have analog and digital signals. According to http://www.researchgate.net/post/Is_DC_an_analog_signal, "if a circuit is using unidirectional (this means DC), non-time encoded current to communicate the value of a transducer, then YES - in this case it is acting as an Analog signal".
It also states "If a circuit is using unidirectional, non-time encoded current for reasons other than communication (such as providing power), then NO - it is not a signal, analog or digital." Based on these statements, it is my opinion that since we use DC to provide power, it is not a signal. Therefore analog DC is incorrect terminology in our application.
Certainly anyone who creates something can use any acronym he wishes. This does not mean that we should use non-applicable acronyms. Unless, of course, the goal is to either cause confusion or to be contrary, in which case one can do what one pleases.
Google is not "clueless" concerning MZL. I typed "MZL model railroad control" in the Google search box and got at least 10 refrences containing something about MZL, including http://www.dccwiki.com/DCC_History#MZL,
http://model-railroad-hobbyist.com/node/16475,
and http://model-railroad-hobbyist.com/node/7386
There does seem to be a conflict about what MZL actually stands for. One of the sources says "Master, Zone Layout", and the other says "Main, Zone, Local". So I'd appreciate it if someone could clear that up.
ATLANTIC CENTRALgregc PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE? You tell me?
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
You tell me?
yes it is redundant in the contexts that I can find on these pages going back to 2009 (see tomikawa TT) where "good old analog DC" is being used to emphasis its difference from DCC.
ATLANTIC CENTRALThe Aristo Craft Train Engineer wireless radio throttles I use have a square wave full voltage pulse width modulated motor control output - would you call that digital?
I wouldn't, because a digital circuit does not depend on the actual voltage, simply its state.
In a motor circuit, its not just that the PWM signal is on for 50%, but that it is on at a specific voltage for 50% of the time to provide the equivalent of a constant voltage of some value.
The control portion of a PWM circuit could be analog or digital. It could be a discrete digital circuit or a digital processor (typical DCC decoder).
If you think of digital as simply having two states, would you describe a light switch in your house as digital?
Model railroads have had AC throttles and DC throttles. Now is has DCC which puts an AC signal on the track. But you wouldn't compare a DCC throttle to an AC throttle. It's not that simple.
what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC?
gregc what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC?
I would think there is. Computers all day long use digital (non analog) DC signals both as power and control and certainly data transmission which is nothing more than massively complex streams of power itself. There IS a difference. PWM IS a 'digital' DC signal. It IS a different signal from 'analog' DC and can be measured and seen on a scope. PWM has been manipulated to produce the pulse and the width. DC is now NOT in its original, raw state (Analog!). That is what the word 'modulated' means - to change the signal (why call it pwm if its just DC?). Thus why the word "analog" is used. So you dont have to drag out a scope to see the difference in signals. Analog simply inferes pure, unchanged, unadulterated DC power. Straight off the source. PWM DOES NOT come straight off the source. The analog DC power has to be 'changed' before it can be called PWM. Now you see the difference.
I bet it would really bake your noodle to think of AC as only being alternating DC!
What makes ADC redundant is the majority of the world only thinks in AC or DC. Thats it. Who ever really worries about the power coming out of the wall when they plug in a lamp or vacumm cleaner? But as you see, there are many forms of DC. ADC refers to its natural, raw state, in a distinct pattern (wave form). Thats it. Only meant to be a distinquishing aspect amongst the other related DC terms.
If DC is just DC no matter its form, then why was PWM and DCC coined as terms when we all could just be saying DC? Analog, however redundant, is no different in meaning as a term. It just describes DC in a particular form. This is what i was taught. Has served me fine for years and never have i ever seen it questioned like in this thread.
Heck from now on i will just say DC and let the reader wonder what type.
Put it to you this way, if there wasnt a difference in DC power (analog vs digital) then the screen infront of you would be an etch-a-sketch instead of a nice monitor! There IS a difference.
Direct Current is what you get from a cell (or several, which is a battery.)
Alternating Current is created by a rotating machine.
DC can be created artificially from an AC sinewave.
A series of binary pulses is not Direct or Alternating Current. It is a pulse train, created by switching the signal state as needed.
Both AC and DC are used for analog control, by varying the voltage and current to change speeds, brightness, or whatever.
Analog DC is almost as silly as Digital Speakers or Headphones. Speakers are analog transducers, they don't work well (or last long) on a digital waveform. Just because some some audio equipment uses Class D or worse amplifiers to achieve high power outputs cheaply doesn't mean it is a digital signal either.
PM Railfangregc what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC? I bet it would really bake your noodle to think of AC as only being alternating DC!
don't understand why you would think this.
But it makes the point I tried to make, which is if there is a term, Direct Current (DC), is there something that is not direct. Indeed there is, Alternating Current (AC). Alternating Direct Current (ADC) doesn't make sense.
but these are just one way of classifying electrical signals. Analog and digital are another way.
PM RailfanThus why the word "analog" is used. So you dont have to drag out a scope to see the difference in signals.
There are hundreds of ways to describe electrical signals. We don't say PWM DC and I've never seen signals for communication (e.g. FSK, PSK, QPSK, OFDM, CDMA, ...) which are almost always AC described as something AC (e.g. CDMA AC).
If you have the background, the differences between these signals can be describe precisely.
PM RailfanAnalog simply inferes pure, unchanged, unadulterated DC power. Straight off the source.
I disagree. Almost all modulated waveforms (radio and communication) are considered analog even if they are carrying digital data.
But if i understand your point in the context of a model railroad throttle, I think your trying to say that a DC throttle which simply controls a constant voltage on the rails should be described as analog DC
and a more advanced throttle that injects pulses or use PWM could not be described as an analog DC throttle, which I disagree with.
PM RailfanPWM IS a 'digital' DC signal. It IS a different signal from 'analog' DC and can be measured and seen on a scope. PWM has been manipulated to produce the pulse and the width.
I understand why you think it is digital. And based on your description of analog DC signals as having a relatively constant voltage, I can see why you think PWM can't be analog. But I wouldn't consider PWM as digital just because it has two states.
PWM is simply a different type of analog signal that is driving a purely analog device, in our case a motor.
PM RailfanPWM has been manipulated to produce the pulse and the width. DC is now NOT in its original, raw state (Analog!). That is what the word 'modulated' means - to change the signal (why call it pwm if its just DC?).
If the current flow in the signal does not change direction, no matter how complicated the voltage changes, it is not AC and therefore DC.
while PWM can be DC (i.e. on/off vs V+/V-), DC is only one characteristic of a PWM signal
PM RailfanIf DC is just DC no matter its form, then why was PWM and DCC coined as terms when we all could just be saying DC?
DC only describes one small aspect of the signal.
The DCC signal carrying both power and communications over the rails is AC. But that is only one characteristic.
Is DCC PWM? It uses PWM to control the motor voltage, but PWM doesn't describe the control part of DCC
Is DCC digital? it uses a digital processor.
PM RailfanWhat makes ADC redundant is the majority of the world only thinks in AC or DC.
I doubt this is true.
PM RailfanHeck from now on i will just say DC and let the reader wonder what type.
there is a large vocabulary of terms used to describe electrical signals which can be used to avoid confusion. There's no need to make up new ones.
While DC and AC mean direct and alternating current, in model railroading they tend to refer to the type of throttle. It would make sense to me to describe a digital DC throttle as using digital technology to control the analog voltage on the rails to a DC locomotive, just as describing a more common DC throttle using analog control circuits as an analog DC throttle.
The problem is in combining two things that aren't really related. AC and DC are two forms of current (or an Aussie band). Analog and Digital are two types of signaling. Selection of current type does not preclude selection of signalling system. Most computers are digital, and happen to use DC current, however there's nothing stopping you from doing digital signalling with AC. There are also analog computers that use, well, analog signalling. Nothing says you can't use AC current in an analog computer, or DC current.
Likewise - we have analog control systems that in some manner vary the voltage that appears to the loco motors. We have digital control systems that send a digital signal to a decoder that controls the voltage that appears to the loco motor. You could have 60hz standard sine wave AC on the rails and still transmit a digital signal over that. You cna have fixed DC to the rails and transmit a digital signal over that - that's how many of the earlier comand control systems worked. You can have varying AC voltage on the rails to control trains - Lionel anyone?
In a nutshell analog does not always mean DC, digital does not always mean DC, digital does not always mean DCC, but DCC is always digital. ANd DC does not always mean analog.
Wow, Randy, you mean acronyms may have multiple meanings? How can that be?
Because no one of these wonderful standards bodies that exists for just about everything ever made a standard for TLAs. Across diciplines, the same acronym means different things. In engineering, ADC is analog digital converter. It could also be the Art Directors Club in advertising, or the Association of Diving Contractors
My point is, AC and DC are types of current. Analog and Digital are types of signals. This back and forth about "well if there is analog direct current, there must be digital direct current" is completely meaningless because the two sets of descriptors do not go together. That's it. We've now had 3 pages of an pseudo-acronym that is not commonly if ever seen in the discipline to which it is being applied.
To answer a question that was asked, and then ignored:
MZL - as originally envisaged and implemented by Ed Ravenscroft:
The key feature of MZL control is that electrical sections which would be separate blocks in traditional cab control are end-connected by contacts on the devices that move switch points. A train moving through something as complex as the throat of Grand Central Terminal needs power to only one section of track, probably the platform track at which it originates or terminates. The contacts that move with the switch points take care of the rest of the route.
I will admit that a knowledge of Boolean algebra is handy for designing the circuitry...
As for the Analog in Analog DC - pure DC has a continuous, constant voltage and polarity (as from a lead-acid battery, 2.2 volts.) We vary the voltage and sometimes reverse the polarity to control our miniature locomotives. Hence, the controls we use are an analog of the controls on a 1:1 scale locomotive...
I rest my case.
Chuck (Modeling Central Japan in September, 1964 - analog DC, MZL)
tomikawaTTTo answer a question that was asked, and then ignored: MZL
Chuck, thank you.