EZ Command Controller output (track) voltages

[motrainguy]

I am wiring my HO layout. Have all track feeder leads coming from a power distribution block. I tested a set of track feeders connected to a DC transformer and got the expected DC voltage as I moved the throttle. Next I wired my EZ Command controller to the PDB and tried to get a reading at a track feeder ends and got no reading. Help... What kind of DC voltage can I expect from the EZ controller from start to full speed on the  EZ Command Command throttle??? Next I connected my multimeter directly to the EZ controller track power leads and still no reading. Is my controller dead or am I doing something wrong

[richg]

Lack of knowledge.
You do not get DC voltage out of a DCC controller. You get AC voltage. Many AC voltmeters will show around 12 VAC to 14 VAC but depends on the type of meter because of the frequency of the DCC voltage.

Ricg

[richg]

Get some DCC education. Look at the below link and store the link in Favorites. Sounds like you will need it.
Take your time. Stepping from Analog, DC, to Digital, DCC is a BIG step. Bigger than a lot of people realize.
Those of you who have never been to the site, store the link in Favorites. Do a lot of reading. With DCC, don't assume.

Rich

[NarrowMinded]

It is confusing to get no reading when voltage is there, press button 10 turn the throttle to full, your meter will now read the max output voltage of around 25vac +/-

Nm-Jeff

Ps i dont think dcc is such a big step. I look at it as a step in the right direction.

[willis]

hi richg, where is the link below?

[richg]

A properly connected DCC system will always have an AC voltage on the track.
With a system like the EZ Command, select the number for a loco with no decoder and turn up the throttle for that loco and you will see a DC voltage that depends on the throttle setting. It will reverse polarity when you reverse the throttle for the DC loco. That DC voltage will vary from 0 to max DC at full speed.
My first system was an MRC 2000 that had five throttles. Throttle 1 could operate a DC or DCC loco.
I believe there are two other brands that can do this.

Below is an explanation by Jim Banner. As usual, save the link and do a bunch of reading.

http://members.shaw.ca/sask.rail/dcc/DCC-waveforms/DCC_waveforms.html

Rich

[richg]

hi richg, where is the link below?

http://www.digitrax.com/appnote_trvolt.php

I was in a hurry to go out on my mountain bike. Sorry.

Rich

[Jim Banner]

A step in the right direction, yes, but still confusing.  That 25 volts ac that you might measure has little relationship with the voltages that are really there.  Unless your meter is capable of reading true rms voltages, it will read correctly only if the ac voltage is a sine wave with no net dc.  Address 10 is used to turn on zero stretching so that analogue locomotives will see a net dc voltage and operate on it.  Even with zero stretching turned off, the rectangular DCC waves are still far from pure sine waves.  The harmonic frequencies in the DCC waveform may have a small effect of the indicated voltage, depending on the frequency response of the meter, but the major error is the rectangular form of the fundamental.


Jim

[richg]

I have posted this fellow's site before. I suspect some are not reading all his stuff.

http://www.wiringfordcc.com/dcc_waveforms.htm

Rich

[richg]

I and some others have the cheap meters from Harbor Freight that all read quite close to each other. I have a digital scope that shows the meters are close.
Some older analog meters that have the mechanical meter movement can differ quite a lot. I have a couple older analog types that I do not use anymore.
I have taken time to do the comparisons. I learned some years ago not to trust in one meter and to pay attention to the battery in the meter.

Rich

[Doneldon]

motrain-

Don't let the peculiarities of AC/DC/DCC screw you up. DCC puts full power AC on the track but the decoders only send pulses of DC (one-half of the AC wave form) to your locos because they have DC motors. There is a fundamental difference between DC and DCC. With (conventional) DC, you control motor speed and direction by varying the current level and polarity in the track. With DCC, on the other hand, you control motor speed and direction by telling the DCC decoder what concentration of one-half of the AC power pulses (with all polarities the same among those pulses) to send to the motor. The pulses are so fast that they effectively blend together so your locomotive moves smoothly down the track. To speed up under DC you increase track power; to speed up with DCC you tell the decoder to feed a little more power to the motor. Some folks call DC "operating/running  the track" and DCC "operating the locomotive." Others describe DC as controlling how much water runs out of a hose by varying how far the supply valve is open and DCC as controlling how much water runs out by turning full blast pulses of water on and off. Although those analogies are a little simplistic, they do a pretty good job of describing the main difference between DC and DCC.
                                                                                                                                                   -- D

[jward]

i like that water comparison. and i love my new dcc shower head. it's very relaxing.

[Doneldon]

Rich-
Nice!
  D

[NarrowMinded]

Richg,
neither of my fluke Meters read voltage from my ez-command unless I press button ten and turn the voltage up, Even when a decoder equiped train will run on them.

Jim, Thank you for the explaination as to why.

NM-Jeff

Richg, I just checked out that site, Yikes... I will re-bury my head in the sand now and go back to running trains.

[poliss]

I changed from analogue DC to Digital DCC and found it to be simplicity itself. What is this BIG step?
No wonder people are put off from DCC with all this scary talk.

Take a look at Bachmann's E-Z Command videos on YouTube to see how simple it can be.
Here's a link to the first one in the series. http://www.youtube.com/watch?v=JAin_nEMHlY&;