I'm building a new layout, to be powered with an NCC ten amp system through breakers to create power districts.
I'd like to put meters on a panel to monitor system performance, broken down by districts. What kind of meters should I use?
Of course, I'm interested in low cost. If you know suppliers for those you recomment I'll appreciate that ifo too! Thanks!
Amps or voltage?
Actually knowing both is an advantage with DCC. A volt meter will show you a defective feeder in a section if something develops.
The only commercial I know of is the Rampmeter.
I have made my own amp meter and voltmeter a few years ago. Two separate meters.
Both use the Harbor Freight multimeter and are accurate.
The NCE 5 amp systems shuts down at about 4.9 amps. Close enough for me.
Cost for the amp meter was about ten dollars total. Meter, few passive components and two three terminal chips, plus a PC board.
Maybe couple dollars for the voltmeter.
Initially I made a small circuit to convert the HF meter to an RMS meter but found out my other HF meter worked very well on my DCC layout that uses the NCE system. Shows about 13.6 VAC and my converted meter was maybe tenth of a volt different.
I used a couple PNP transistors and a few caps and resistors. I found the circuit online in a search.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Found the info. The difference between the meter with the adapter is not much different than just using the meter on the AC scale. Again, results of experimenting, not opinion. I borrowed a RMS meter and I came out close.
Voltmeter
Amp meter. I used the ZXCT circuit. http://home.cogeco.ca/~rpaisley4/DCCvolts.html Rich
Amp meter. I used the ZXCT circuit.
http://home.cogeco.ca/~rpaisley4/DCCvolts.html
I recall back when I was researching DCC that meter reading of track power in DCC is not the same as track power in DC - so if thats true, the information you get from meters may be totally different and may not tell you what you are used to in conventional volts and amperage terms. Something to keep in mind.
Rio Grande. The Action Road - Focus 1977-1983
I am speaking from experience, not opinion. Look at the circuits.
DCC is a form of AC with digital info.
The Harbor Freight showed 13.6 VAC on the tracks. That is about normal for NCE DCC systems. About the same for the NCE Power Cab and NCE 5 amp system. Have not looked at any other systems.
The three terminal ZXCT device is made for monitoring this type of siganl.
The Power Cab and 5 amp systems trip when the max current for the systems is reached. I used a high wattage rheostat across the track to simulate an increase in current until the systems trip.
Can't argue with success.
Not sure what measuring DCC track or rectified track voltage reading woud provide that a lamp or led would indicate.
DCC track voltage varies with the data being trackmitted. So what's the correct voltage? Rectified dcc track voltage should be the output voltage of the power supply and shouldn't vary my much except for dropping a little under heavy load.
being able to measure the current draw ofeither a DC or DCC single locomotive may usefu to determine if it's excessive which may be fixable with neodymium magnets or a new motor. But once one the layout, wouldn't a circuit breaker be all that's needed?
greg - Philadelphia & Reading / Reading
gregc...DCC track voltage varies with the data being trackmitted...
Not true.
The downside of using a bridge rectifier to measure DCC voltage is that it would read low due tot he diode drops in the rectifier. The bridge to measure current works, except you then have lower track voltage due to the diode drops. The ZTC circuit is effectively what is in the RRAmpmeter for the amp side - if you want digital instead of hooking up an existing multimeter, you can find chead LED meters on eBay and just wire it all up permanently - clone of the RRAmpmeter.
Current draw should not matter, DCC or not. If there are two locos running, each drawing .5 amp, then you should see a 1 amp load on the booster. No different than 2 locos running on DC, each drawing .5 amp.
I said it before - having a set of meters on each booster sure would look cool - it would REALLY look cool to have one massice power panel, except that totally defeats the purpose of multiple boosters and distributing them to keep the bus runs short. At best, I may put jumpers in at each booster panel so that a meter can be inserted on a temporary basis. Unless I find or build some sort of remote indicating meters, where the 'meter' is local to the booster but the display for it can be remotely located in said power panel.
However, I have model railroaded for 47 years and apart from an occasional test for curiosity, I have never had any sort of meters hooked to my system permanently. I remember lusting after the (I think) Controlmaster XI way back when, the one with the two big lighted meters, 5 position brake, adjustable pulse, adjustable momentum, and adjustable top voltage - every control under the sun. I think it retailed for around $100 at the time - far beyond what my 10 or 11 year old self could ever afford. Never had panel meters, or a pack with meters when runnign DC, and I haven't purchased anything since going DCC. Main thing I've used my meter for is actually just to test resistor wheelsets as I make them. But a panel full of glowing meters - yeah, that would be cool....
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
richg1998Again, results of experimenting, not opinion. I borrowed a RMS meter and I came out close.
Did the true RMS meter show a higher or lower value than the adapter circuit?
Jim
Hi guys
About the only use a meter would be is to tell you data is moving maybe, as a meter will fluctuate with the data movement back and forth.
It would be better to have something digital that says the data is moving back and forth
Is it a good or bad message and is it going where it is suposed to be going
has something failed and there is no message.
This kind of information with recognisable codes is far more usefull when things stop working.
The only time you would need Volts and Amps is during initial set up and catastrophic failure when the unit shuts down, and you have lost everything and the first thing you need to know is do I still have power.
The next thing would be Ohms for any fuse testing
regards John
i think the current measurement on the NCE PowerCab for one locomotive is very useful.
and I was wrong. Since the DCC waveform is symetrical, even the DC (average/rms) voltage should be zero. It wouldn't depend on the data.
John BusbyAbout the only use a meter would be is to tell you data is moving maybe, as a meter will fluctuate with the data movement back and forth.
Out of curiosity, where does this come from? I have never read any place where it suggests that there is a variation of volts and/or when data moves back and forth.
There are any number of Youtube videos showing the RRAmpmeter in use and you can see that the volts and amps do not fluctuate while a loco is running - if they do, it usually means you have really dirty track and the loco is loosing contact. The voltage should stay constant, maybe dipping slightly as the load approaches the booster's maximum, unless there is a short and/or power is cut off. If it drrops excessively, it could be a sign that the input power source to the booster is not adequate for the load. Current will vary constantly as locos are started and stopped, or go from running light to hauling a significant train.
rrinker There are any number of Youtube videos showing the RRAmpmeter in use and you can see that the volts and amps do not fluctuate while a loco is running - if they do, it usually means you have really dirty track and the loco is loosing contact. The voltage should stay constant, maybe dipping slightly as the load approaches the booster's maximum, unless there is a short and/or power is cut off. If it drrops excessively, it could be a sign that the input power source to the booster is not adequate for the load. Current will vary constantly as locos are started and stopped, or go from running light to hauling a significant train.
Alton Junction
richhotrainIf your feeder wires are too far apart, you will see a voltage drop on the RRampMeter. Rich
That depends on where the meter is. If it is close to the load, you will see a drop, but if it is close to the source, you won't. Since this thread is about using panel mounted meters, I'm pretty sure Randy was talking about having them close to the source.
CSX Robert richhotrain If your feeder wires are too far apart, you will see a voltage drop on the RRampMeter. Rich That depends on where the meter is. If it is close to the load, you will see a drop, but if it is close to the source, you won't. Since this thread is about using panel mounted meters, I'm pretty sure Randy was talking about having them close to the source.
richhotrain If your feeder wires are too far apart, you will see a voltage drop on the RRampMeter. Rich
Well, we were talking about panel meters..
but yes, if you have inadequate feeders or bus, or just way too long of a bus run, if you connect the RRAmpmeter at the far end away from the booster, then there may be a noticable difference vs connecting it right next to the booster. With no load on the layout you might not see any difference, but if you put a load on the rails, a couple of running locos, or even a resistor, you would see the drop. Anything a half volt or less is generally not noticeable, much more and you would see the locos slow down, a key giveaway that there is inadequate power feed. And even if everything looks ok, the quarter test is cheap verification that everything is working ok - lay a quater on the rails (no pressing down) at various locations and in every case, the circuit breaker, either in the booster or if you use external breakers, should trip. If there are places that you put the quater and no breakers trip - that's another sign of inadequate power feeds to that area.
rrinker Well, we were talking about panel meters..
The RRampMeter is essentially a panel mounted meter that can be disconnected from its primary location and carrried around the layout in portable fashion, adding to its functionality.
In my case, strongly suspecting that in one remote location the feeders were insufficient, I was able monitor the voltage drop from the RRampMeter's primary location, confirming my suspicion.
I gotta say that the one thing that is sometimes disappointing about this forum is nitpicking about some replies as if they warrant deletion. In my opinion, there is nothing off-topic about my previous replies which were submitted with the thought that they would be helpful to the 'non-expert' readers who could benefit from the experience of others.
You're nbot wrong, and it probbaly is a better use of a RRAmpmeter to not attach it somewhere permanently, they are a little too expensive for that. Should I ever get my still plannion glayout built, I suspect I will need 4 boostrs for adequate covereage (command station will be dedicated - I use Digitrax so in reality the two functions are combined in the DCS100 and DB150 products, but best practice is to not use the track output of the DCS100 to power trains. I may use it to power accesory decoders, which worked out well on my last layout with my Zephyr as the command station and a DB150 booster, the Zephyr drove my Singlet accessory decoders and the DB150 drove the rails). I am strongly considering building my own accessory decoders for controlling servos, so those only need a DCC signal and draw miniscule power from the DCC bus, the power for the servos and the circuit all comes from an external power supply. My plan ther was to maybe use one large one, like a computer power supply, and make individual bus runs, each fused down to a reasonable level. Luckily for a basic power supply like that I don;t need RRAmpmeters, the cheap digital meters from ebay will suffice for monitoring those. But that's still 4 or 5 RRAmpmeters. Not cheap. A few of Rob Paisley's circuits plus either the cheap ebay meters or some Harbor Freight multimeters would be a lot cheaper - just got another coupon to get a free one, except I will be out of town for the next couple of weeks.
As i mentioned, since unless I make a radical change, most of my stuff will be mounted on swing down boards up under the layout, and most definitely not centralized, so dedicated meters would be kind of a waste anyway. I may leave a jumper in the booster output and also in each breaker output that I could unplug and connect a meter if I'm having trouble, and just use one RRAmpmeter or Paisley circuit and switch it around as needed.