Model Train Forum banner

21 - 40 of 49 Posts

·
Registered
Joined
·
2,515 Posts
You don't need a True RMS meter, you only need a simple meter that will read A/C and DC, many have suggested Harbor Freight as they have a cheap (sometimes free) VOM. I use a couple of meters from China (Banggood.com) . Right now they have this one on sale //usa.banggood.com/Flashdeals.html?pid=1296230&rmmds=home-flashdeal&bid=35139 which has a nice big readable display, or if you want a nicer one that display the track on an oscilloscope type display (way overkill) try the Mustool MT8206 as it has one of the easiest to read displays. GunrunnerJohn I think just got a MDS8207 which is an upgraded version, but these meters that have some very basic oscilloscope function while great as multimeters are very basic in their waveform display capability.

Make sure you don't put a non-DCC equipped (DC only) Locomotive on a DCC system. It may talk about some capability to run a DC locomotive but I would avoid doing it as there is far to much risk of doing permanent damage to motor!

Measure the voltage on the DCS210+ from rail A to Rail B not to ground. And I think you may need to connect the throttle up to turn on the rail power. The DCS has LED's on it that indicate if the rail power is on.
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #22 ·
The locomotive will only begin to move when the decoder gets information packets that says it is to move....OR....because the throttle or command station still has information about the last throttle commands stored and is continuously re-issuing that command. It's like placing a locomotive on unpowered rails, putting power through to the rails, and the locomotive either takes off like a jackrabbit or the bells rings...or the horn/whistle won't stop. Those are all indications that the throttle still has those commands working from the last session. If one looks at the throttle display, it should show the active locomotive and will probably show one or two functions in action. The jackrabbit start problem is well documented for some decoders who, when the power gets applied to the rails initially, sense the inrush as maximum DC voltage and take off accordingly, too often with horrible consequences. That's a simple CV29 fix.

I can't help with the voltage disparity...I think Digitrax will help you to trouble-shoot whatever is the issue, but that's only if there isn't a simple explanation. Many years ago, they took my call and held my hand for a few minutes over the long reaches of wires to help me through a crisis with my brand new DB150. Once it all clicked, it has become second nature and that Super Empire Builder has never given me a whiff of a problem, now 15 years.

To put yourself at ease, both with your enjoyment of your trains and to keep your days happy as we move into summer, give them a call and explain your circumstances. It may take a day or two for them to call back, or someone might have you up and running inside of five minutes. Life's too short to be pondering a complex problem, or a simple one that seems intractable, when there's no shortage of help at the other end of a phone line.

That'll be two cents, please. :p
thanks much !!!
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #23 ·
You don't need a True RMS meter, you only need a simple meter that will read A/C and DC, many have suggested Harbor Freight as they have a cheap (sometimes free) VOM. I use a couple of meters from China (Banggood.com) . Right now they have this one on sale //usa.banggood.com/Flashdeals.html?pid=1296230&rmmds=home-flashdeal&bid=35139 which has a nice big readable display, or if you want a nicer one that display the track on an oscilloscope type display (way overkill) try the Mustool MT8206 as it has one of the easiest to read displays. GunrunnerJohn I think just got a MDS8207 which is an upgraded version, but these meters that have some very basic oscilloscope function while great as multimeters are very basic in their waveform display capability.

Make sure you don't put a non-DCC equipped (DC only) Locomotive on a DCC system. It may talk about some capability to run a DC locomotive but I would avoid doing it as there is far to much risk of doing permanent damage to motor!

Measure the voltage on the DCS210+ from rail A to Rail B not to ground. And I think you may need to connect the throttle up to turn on the rail power. The DCS has LED's on it that indicate if the rail power is on.
OK,I did that ! The track status light is red & I get 6.5 volts DC rail to rail ! Is that good ?
 

·
Registered
Joined
·
9,014 Posts
The DPDT momentary toggles and the latching relays will work
but it's a shame we didln't get to refer you to the Stapleton 751D
toggle for twin coil turnouts. In addition to throwing the points.
it controls your panel and/or track side LED signals. It also
has a built in Capacitor Discharge Unit that protects the
turnout motor coils for accidental burnout.


Don
 

·
Registered
Joined
·
2,245 Posts
thanks much !!!
I don't know that I have helped much, but one last bit of advice that was pounded into us by the recently deceased DCC guru over at Model Railroad, Randy Rinker (yes, COVID): before you end a session by turning off the power, double-check your throttle display(s) to ensure there are no speed steps left on the throttle, and that all unwanted functions are off. It used to be that the QSI decoders could be put into a coma by successive double-presses of F9. People would come back to the train room after a few weeks away and wonder why their relatively new Challenger doesn't seem to respond to any throttle inputs. Someone on a forum would ask if they had tried successive presses of F6 to see if they had put it to sleep earlier. Bingo. So, that's an example of things we forget and that come back to bite us. Zero your throttle!
 

·
Registered
Joined
·
4,604 Posts
You don't need a True RMS meter, you only need a simple meter that will read A/C and DC,...
Digitrax procedure:

Method 1: Rail to Chassis Ground
This is the method recommended by Digitrax.

The measurements will be made between one rail and a common reference point. On a Digitrax booster, there is a "GND" or ground terminal which is used as the reference. It is also possible to use the metal case/chassis as the reference point.

Measurements are made using the DC Volts (DCV) mode, on the 20VDC range, if the meter does not autorange.

Ensure that Address 00 (analog) is set to a speed of 0.
  1. Measure from Rail A to Ground. Record this value
    1. Ignore the sign, as DCC has no polarity.
  2. Measure from Rail B to Ground. Record this value
  3. The track voltage is the sum of the values found on Rails A and B


Using this method you definitely won't need a true RMS meter since you don't need it for measuring DC.
 
  • Like
Reactions: Stejones82

·
Registered
Joined
·
2,245 Posts
"...the sum of the values..." Well, that tidies things substantially. This is solid information, and Digitrax supplied it on line. I hope this soothes the fret of our OP when he does the measurements and the sum. :p
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #28 ·
Digitrax procedure:

Method 1: Rail to Chassis Ground
This is the method recommended by Digitrax.

The measurements will be made between one rail and a common reference point. On a Digitrax booster, there is a "GND" or ground terminal which is used as the reference. It is also possible to use the metal case/chassis as the reference point.

Measurements are made using the DC Volts (DCV) mode, on the 20VDC range, if the meter does not autorange.

Ensure that Address 00 (analog) is set to a speed of 0.
  1. Measure from Rail A to Ground. Record this value
    1. Ignore the sign, as DCC has no polarity.
  2. Measure from Rail B to Ground. Record this value
  3. The track voltage is the sum of the values found on Rails A and B


Using this method you definitely won't need a true RMS meter since y
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #29 ·
I just did that. On rail A I get 7 volts....on rail B i get .5 volts ! I get the same readings right off of the 210+ terminals !
 

·
Registered
Joined
·
2,515 Posts
I've never used that method and always use the meter on AC and and read the voltage between the rails, that what the decoder would see.
At this point I suggest calling Digitrax and let them determine if the 210+ is working correctly. According to their method 1, rail be should be a 7 also and its not.
 

·
Registered
Joined
·
4,604 Posts
I received an email from NCE about this DCC voltage meter. They claim it will accurately measure DCC voltage on the rails which is really closer to a digital / PWM AC computer signal at about 10Khz.

I might have to get one of the panel mount meters.

This is not an NCE product.

RRampMeter by DCC Specialties
 

·
Registered
Joined
·
2,245 Posts
I've never used that method and always use the meter on AC and and read the voltage between the rails, that what the decoder would see.
At this point I suggest calling Digitrax and let them determine if the 210+ is working correctly. According to their method 1, rail be should be a 7 also and its not.
Yes, agreed, and I do the same. Press the button to switch between DC and AC, turn the voltage range knob to 20 volts, and probe each rail. Should get a voltage of between 13.5 and 14.5V in AC. At least, that's what my meter tells me my DB150 is putting out.
 

·
Premium Member
Joined
·
2,346 Posts
Since I have both meters I decided to do a test.

I have a Digitrax DCS51 base station.
It's advertised output is 14.3 Volts I believe.
Reading across Rails A & B.
With the multimeter it showed 15.4 VAC.
It's an old one but not a cheepy, Snap-On.

With the RRampMeter it showed 14.6VDCC.
0.08 Amps with one sound loco running at low speed.

There is a difference of about 1 Volt, not that big a deal.

Doing the Digitrax test, multimeter.
Rail A to ground 7.72 VAC
Rail B to ground 7.5 VAC.
Total 15.22 VAC. Pretty much what the reading was across two rails.

Rereading the test again it said use DC so I did.
Rail A to ground 7.2VDC.
Rail B to ground 6.6VDC.
Total 13.8 VDC. About a half a Volt from what the advertised 14.3 VAC.

Magic
 

·
Registered
Joined
·
2,515 Posts
Well Magic my curiosity was tweaked and I had to look at my voltages. I have a DCS240 powered by a 15 volt Jamco power supply (picture 1).
DC_PowerSupplyVoltage-120022.jpg

Picture 1

I powered everything up an used the DS602D to turn on the track power (note that in picture 1 the Track Status light is not Green as the track power was not on yet. The next picture (2) is the AC voltage across rail A and Rail B which shows 16.5 volts AC.
AC_RailAtoRailBVoltage-120023.jpg

Picture 2

Picture 3 is the waveform across rail A and rail B.
AC_RailAtoRailBVoltageWaveform-120025.jpg

Picture 3

Pictures 4 and 5 show the DC voltage from rail A to ground (7.33 VDC) and its waveform.
DC_RailAtoGroundVoltage-120001.jpg

Picture 4
AC_RailAtoGroundWaveform-120026.jpg

Picture 5

Pictures 6 and 7 show the DC voltage from Rail B to ground (7.33 VDC) and its waveform.
DC_RailBtoGroundVoltage-120002.jpg

Picture 6
AC_RailBtoGroundWaveform-120027.jpg

Picture 7
Summing Rail A + Rail B to ground measurements I get 14.66 while the AC voltage across Rail A to B was 16.5 VAC.
Note that the meter in graphics mode indicates 8.08 and 8.11 peak to peak and summing these voltage I get 16.19 and from picture 2 the graphics output display a 16.54 peak to peak voltage.

Summary - it's easier to just read the Rail A to Rail B voltage as an AC voltage, but Digitrax may want the ground to rail voltages for some sort of fault isolation.
 

·
Registered
Joined
·
9,014 Posts
All of this is true, but far above the understanding of the
average modeller. Very, very few of us would ever have
need of a precise track voltage reading. The simple multimeter
AC probes on the rails reading of 'around' 14 volts
is sufficient to prove ample track power.

Don
 

·
Registered
Joined
·
62 Posts
Discussion Starter · #38 ·
Well Magic my curiosity was tweaked and I had to look at my voltages. I have a DCS240 powered by a 15 volt Jamco power supply (picture 1).
All of this is true, but far above the understanding of the
average modeller. Very, very few of us would ever have
need of a precise track voltage reading. The simple multimeter
AC probes on the rails reading of 'around' 14 volts
is sufficient to prove ample track power.

Don
All of this is true, but far above the understanding of the
average modeller. Very, very few of us would ever have
need of a precise track voltage reading. The simple multimeter
AC probes on the rails reading of 'around' 14 volts
is sufficient to prove ample track power.

Don
I am just way to frustrated at this point ! I spent hundreds of dollars for all of this Digitrax stuff because I wanted to go DCC with a walk around controller ! It said I will be up & running in an hour !!!!!! Well it's been2 months and I'm nowhere yet ! Yesterday I tried programing an Athearn road switcher that I installed 126 decoder in. Watched a video and when I thought I was done the screen says "program track empty" So I failed at that too !!!! So this morning with the booster still hooked up to the program track i checked the voltage at the main line terminals and I get terminal A to ground 7 volts & B to ground 2 volts. (DC) .........Across A&B I get 2 volts (AC) At this point I am going to take a break ! I'm way to frustrated to continue. I realize that I'm in way over my head for an old guy !!!!!!!
View attachment 559462
Picture 1

I powered everything up an used the DS602D to turn on the track power (note that in picture 1 the Track Status light is not Green as the track power was not on yet. The next picture (2) is the AC voltage across rail A and Rail B which shows 16.5 volts AC.
View attachment 559459
Picture 2

Picture 3 is the waveform across rail A and rail B.
View attachment 559460
Picture 3

Pictures 4 and 5 show the DC voltage from rail A to ground (7.33 VDC) and its waveform.
View attachment 559463
Picture 4
View attachment 559458
Picture 5

Pictures 6 and 7 show the DC voltage from Rail B to ground (7.33 VDC) and its waveform.
View attachment 559464
Picture 6
View attachment 559461
Picture 7
Summing Rail A + Rail B to ground measurements I get 14.66 while the AC voltage across Rail A to B was 16.5 VAC.
Note that the meter in graphics mode indicates 8.08 and 8.11 peak to peak and summing these voltage I get 16.19 and from picture 2 the graphics output display a 16.54 peak to peak voltage.

Summary - it's easier to just read the Rail A to Rail B voltage as an AC voltage, but Digitrax may want the ground to rail voltages for some sort of fault isolation.
 
21 - 40 of 49 Posts
Top