¿ªÔÆÌåÓý

  1. W4dccqa
  2. Topics

DCC CURRENT & VOLTAGE MEASUREMENTS

 

Hi,
I want to hard wire a panel V and A meter on my layout facia. The rrampmeter is too pricey for me.
What is the correct type of meter (not multimeter) to use for DCC and how are they wired (V vs A)?
Right now I measure the rail voltage with a multimeter on VAC. The current I can read on my Power Cab.
Thanks?
 

I haven't seen a response to you yet. But, from what I've learned with my experimenting. There is NO meter unless you spend money. An oscilloscope would be ideal, but for what you and I want, the only option I see is the RampMeter. And I am so frugal, I refuse to pay that much. I do use a regular multi-meter to check voltage. But even that is not accurate. It's only a close check. And you can forget measuring amps. I haven't found anything that works. Not even my multi-meter that measures both AC and DC amps. It simply don't work on DCC.?????????????? Morgan Bilbo, DCC since 8/18. Model PRR 1952.
 

¿ªÔÆÌåÓý

Morgan,
Thanks for that confirmation. ?
Useful to have ¡°understanding¡± confirmed.
Bill D
N&W Steam Only

On Aug 31, 2024, at 1:33?PM, PennsyNut via groups.io <fan4pennsy@...> wrote:

?
I haven't seen a response to you yet. But, from what I've learned with my experimenting. There is NO meter unless you spend money. An oscilloscope would be ideal, but for what you and I want, the only option I see is the RampMeter. And I am so frugal, I refuse to pay that much. I do use a regular multi-meter to check voltage. But even that is not accurate. It's only a close check. And you can forget measuring amps. I haven't found anything that works. Not even my multi-meter that measures both AC and DC amps. It simply don't work on DCC.?????????????? Morgan Bilbo, DCC since 8/18. Model PRR 1952.
 

I have no hard data to support this, but most boosters probably use very little current internally. Most of the DC from their power supplies probably ends up DCC current to the railroad.?

A DC ammeter connected into the power supply cable to the booster should give a reasonable approximation of DCC current to the railroad. If you note the current reading to the booster before connecting it to the railroad, you can subtract that internal current mentally, or adjust mechanical zero on some meters to cancel that and get a closer approximation.

I'm surprised a DMM that reads DCC voltage on its AC voltage ranges won't read DCC current on its AC current ranges. I'll have to check mine sometime.

Don W

--
Don Weigt
Connecticut
 

This might be of interest to you.?

?
--
Dave
Portland, OR
 

DaveH: To which I say. "Why hasn't someone made them and offer them for sale"?
We are not all able to "build" such things. How many MR's take the time to make a DCC ammeter?
It's like the Rampmeter/or however you spell it. It is available, and we as a group/MR's are grateful and love it. But not everyone can afford it.
Therefore if someone could sell the device you mention, it should sell pretty well. (Assuming of course, that it don't cost $100.)
I remember the day of DC when almost everyone had a Voltmeter and Ammeter installed on their controllers. And they were cheap enough to allow that. Our club had throttle stands located throughout the layout, about 4 or 5 as I remember. Each had it's speed, direction AND V&A meters. Before the day of walk around wireless or cable controllers.
????????????????????? Morgan Bilbo, DCC since 8/18. Model PRR 1952.
 

Something from Europe might fit...?
?
KombiMeter_(DCC)
?
One behind each booster ... they work fine.
?
Hobo
Switzerland
?
?
?
 

Morgan,
?
? You asked "Why hasn't someone made them and offer them for sale?".? Here is my
answer.
?
? First and foremost the DCC waveform is -significantly- different from most AC power.
It is much faster and it has a nearly vertical rise and fall.? And any meter you can buy
that is capable of measuring the DCC waveform itself is going to need to use much
more sophisticated (and therefore 'spendy') components.
?
? The do-it-yourself meter from MainNorth works - but it gives 'relative' current and not
actual.? That is one of the reasons for the cut out switch that bypasses the do it yourself
meter.? I know Marcus (MainNorth) personally and I'm certain he would agree with this.
? Yes, this do-it-yourself meter works well enough that you can use it and it will give?
you want you need - which is the ability to measure the amp draw of the layout or
even of an individual locomotive/train in actual operation.? But it is not likely that you
would want it to be wired in "permanently" (without the bypass switch.? But you don't
really need to have current draw showing all the time.
? But it is unlikely that anyone would manufacture this meter and sell it as a "DCC meter".
And, it is a simple and inexpensive circuit to make.
? One thing that isn't mentioned on the website is that you want one of these circuits
(DIY meters) for every booster if you have more than one booster.? Or you need to have
some way to select which booster it is measuring.
?
? I, for one, consider the RRamp meters to be worth the money.? I have one that I use
hand held and pressed down on the track to measure track voltage all around the
layout which helps me to identify any wiring errors/problems.? I have another one,
installed in the wiring just after the booster and just before all track wiring (including
before the PSX circuit breakers) that measures both amps and volts - this one is the
"equivalent" to the circuit from MainNorth - but allows it to be in the circuit at all
times with almost no voltage drop to the track (like the do-it-yourself meter).
?
? ? ? ? ? ? ? ? ? ? ? ? I hope this answers your question ... Jim in the PNW
 

¿ªÔÆÌåÓý

NCE sells a DCC meter that also connects to a computer and reads track data. ?It is not cheaper than the RRampmeter.

Allan

iPhone iTypos iAutocorrect iApologize


On Sep 2, 2024, at 11:32?AM, Jim Betz via groups.io <jimbetz@...> wrote:

?
Morgan,
?
? You asked "Why hasn't someone made them and offer them for sale?".? Here is my
answer.
?
? First and foremost the DCC waveform is -significantly- different from most AC power.
It is much faster and it has a nearly vertical rise and fall.? And any meter you can buy
that is capable of measuring the DCC waveform itself is going to need to use much
more sophisticated (and therefore 'spendy') components.
?
? The do-it-yourself meter from MainNorth works - but it gives 'relative' current and not
actual.? That is one of the reasons for the cut out switch that bypasses the do it yourself
meter.? I know Marcus (MainNorth) personally and I'm certain he would agree with this.
? Yes, this do-it-yourself meter works well enough that you can use it and it will give?
you want you need - which is the ability to measure the amp draw of the layout or
even of an individual locomotive/train in actual operation.? But it is not likely that you
would want it to be wired in "permanently" (without the bypass switch.? But you don't
really need to have current draw showing all the time.
? But it is unlikely that anyone would manufacture this meter and sell it as a "DCC meter".
And, it is a simple and inexpensive circuit to make.
? One thing that isn't mentioned on the website is that you want one of these circuits
(DIY meters) for every booster if you have more than one booster.? Or you need to have
some way to select which booster it is measuring.
?
? I, for one, consider the RRamp meters to be worth the money.? I have one that I use
hand held and pressed down on the track to measure track voltage all around the
layout which helps me to identify any wiring errors/problems.? I have another one,
installed in the wiring just after the booster and just before all track wiring (including
before the PSX circuit breakers) that measures both amps and volts - this one is the
"equivalent" to the circuit from MainNorth - but allows it to be in the circuit at all
times with almost no voltage drop to the track (like the do-it-yourself meter).
?
? ? ? ? ? ? ? ? ? ? ? ? I hope this answers your question ... Jim in the PNW
 

¿ªÔÆÌåÓý

There is a DIY DCC Ammeter I designed awhile back about halfway down the page here:

https://www.n3ix.com/pers/mr/model-railroad-projects/

Robin

Robin Becker
San Diego CA

Sep 2, 2024 12:41:15 PM Allan AE2V <bigboy@...>:

NCE sells a DCC meter that also connects to a computer and reads track data. ?It is not cheaper than the RRampmeter.

Allan

iPhone iTypos iAutocorrect iApologize


On Sep 2, 2024, at 11:32?AM, Jim Betz via groups.io <jimbetz@...> wrote:

?
Morgan,
?
? You asked "Why hasn't someone made them and offer them for sale?".? Here is my
answer.
?
? First and foremost the DCC waveform is -significantly- different from most AC power.
It is much faster and it has a nearly vertical rise and fall.? And any meter you can buy
that is capable of measuring the DCC waveform itself is going to need to use much
more sophisticated (and therefore 'spendy') components.
?
? The do-it-yourself meter from MainNorth works - but it gives 'relative' current and not
actual.? That is one of the reasons for the cut out switch that bypasses the do it yourself
meter.? I know Marcus (MainNorth) personally and I'm certain he would agree with this.
? Yes, this do-it-yourself meter works well enough that you can use it and it will give?
you want you need - which is the ability to measure the amp draw of the layout or
even of an individual locomotive/train in actual operation.? But it is not likely that you
would want it to be wired in "permanently" (without the bypass switch.? But you don't
really need to have current draw showing all the time.
? But it is unlikely that anyone would manufacture this meter and sell it as a "DCC meter".
And, it is a simple and inexpensive circuit to make.
? One thing that isn't mentioned on the website is that you want one of these circuits
(DIY meters) for every booster if you have more than one booster.? Or you need to have
some way to select which booster it is measuring.
?
? I, for one, consider the RRamp meters to be worth the money.? I have one that I use
hand held and pressed down on the track to measure track voltage all around the
layout which helps me to identify any wiring errors/problems.? I have another one,
installed in the wiring just after the booster and just before all track wiring (including
before the PSX circuit breakers) that measures both amps and volts - this one is the
"equivalent" to the circuit from MainNorth - but allows it to be in the circuit at all
times with almost no voltage drop to the track (like the do-it-yourself meter).
?
? ? ? ? ? ? ? ? ? ? ? ? I hope this answers your question ... Jim in the PNW

 

¿ªÔÆÌåÓý

Robin,
Love the disclaimer!
But thanks again for all your help to us Tam Valley product users. ?
Bill D
N&W Steam Only

On Sep 2, 2024, at 12:51?PM, Robin Becker via groups.io <rbgroups@...> wrote:

? There is a DIY DCC Ammeter I designed awhile back about halfway down the page here:

https://www.n3ix.com/pers/mr/model-railroad-projects/

Robin

Robin Becker
San Diego CA

Sep 2, 2024 12:41:15 PM Allan AE2V <bigboy@...>:

NCE sells a DCC meter that also connects to a computer and reads track data. ?It is not cheaper than the RRampmeter.

Allan

iPhone iTypos iAutocorrect iApologize


On Sep 2, 2024, at 11:32?AM, Jim Betz via groups.io <jimbetz@...> wrote:

?
Morgan,
?
? You asked "Why hasn't someone made them and offer them for sale?".? Here is my
answer.
?
? First and foremost the DCC waveform is -significantly- different from most AC power.
It is much faster and it has a nearly vertical rise and fall.? And any meter you can buy
that is capable of measuring the DCC waveform itself is going to need to use much
more sophisticated (and therefore 'spendy') components.
?
? The do-it-yourself meter from MainNorth works - but it gives 'relative' current and not
actual.? That is one of the reasons for the cut out switch that bypasses the do it yourself
meter.? I know Marcus (MainNorth) personally and I'm certain he would agree with this.
? Yes, this do-it-yourself meter works well enough that you can use it and it will give?
you want you need - which is the ability to measure the amp draw of the layout or
even of an individual locomotive/train in actual operation.? But it is not likely that you
would want it to be wired in "permanently" (without the bypass switch.? But you don't
really need to have current draw showing all the time.
? But it is unlikely that anyone would manufacture this meter and sell it as a "DCC meter".
And, it is a simple and inexpensive circuit to make.
? One thing that isn't mentioned on the website is that you want one of these circuits
(DIY meters) for every booster if you have more than one booster.? Or you need to have
some way to select which booster it is measuring.
?
? I, for one, consider the RRamp meters to be worth the money.? I have one that I use
hand held and pressed down on the track to measure track voltage all around the
layout which helps me to identify any wiring errors/problems.? I have another one,
installed in the wiring just after the booster and just before all track wiring (including
before the PSX circuit breakers) that measures both amps and volts - this one is the
"equivalent" to the circuit from MainNorth - but allows it to be in the circuit at all
times with almost no voltage drop to the track (like the do-it-yourself meter).
?
? ? ? ? ? ? ? ? ? ? ? ? I hope this answers your question ... Jim in the PNW

 

Just looked at Tony's Trains, the source of RRampmeters.
The lowest priced version is $67.95. It has no enclosure.
Here is the link:
Rob
 

What I have mentioned on one of the other chat boards is that our club is using inexpensive ($10 for 2) DC Volt/Ammeters that we bought from Amazon.? We install them between the DC supply and the command station.? While not perfect they get you most of the way there.? The command station and throttles by themselves draw very little current so almost all of the current reading shown on these meters are what your locos are using.? What we have found is that it gives a pretty good reading but remember that loco current draw is not a constant but is varying all of the time so no matter what meter you are using you will only ge an approximate reading.
?
Good Luck,
John Moonan
 

I am thinking about installing an ammeter in each of my power districts such as the one shown below (credit to Rob Paisley). I¡¯m a novice when it comes to electronics. If I hard wire the ammeter to my system do I need to worry about a voltage drop created by the ammeter which would affect the performance of my locomotives??
?
/g/w4dccqa/files/DCC%20ammeter%20Rob%20Paisley.pdf

Thanks.?
--
Dave
Portland, OR
 

There will be some voltage drop of DCC track voltage. But it may or may not affect any noticeable loco speed settings. Adding an ammeter for every booster sounds like overkill.

DonV
 

I like the circuit. The meter will need to be either analog or battery operated. The impedance of the meter at the desired amperage setting will need to be less than about 500 Ohms. I imagine that this is not a problem for a digital meter. It might be a problem for an analog mili ammeter. The cheap analog meters that would work do not specify their impedance.

Ken Harstine
413-250-8298
 

NCE has an internal supply that reduces the incoming voltage to a track voltage that is adjustable.? If the internal supply were analog than an incoming current meter would be accurate.? It is likely that a switching regulator scheme is used to produce the track voltage.? These supplies are more like constant power devices.? So if the incoming voltage and current were 16 Volts and 5 Amperes and the track voltage was set to 12 Volts than the track current would be 6.7 Amperes.
?
If your booster's track voltage is adjustable than measuring the input current would not tell you directly what the output current is.
?
Best,
Ken Harstine
 

Great info Ken and all.?

thanks.?
--
Dave
Portland, OR

1 - 18 of 18