Digitrax BackEMF

[WC3026]

So I have been thinking about upgrading from the dh123d decoders and going to the dh163d decoders. the reason why is they have backEMF. Can anyone tell me if it does what they say???? I have one hill on my small layout and it gets hard running two trains and not letting them rear end each other. so is it worth it to get it or not???

 

[Espeefan]

According to the decoder data sheeet and the digitrax manual if your DH-123D is an Fx3 version you should already have Back EMF. You may just have to turn it on. Not all decoders ship with it enabled. Look at the instruction sheet that came with your decoders, and if it says FX3 you're in business. CV's 55, 56, and 57 control it. Directions are in the Digitrax decoder manual, starting on page 58. You can download it from their site if you don't have a copy. Yes, it does do what they say, however depending on your DCC system when you consist locomotives you should turn it off on all locos except the lead unit. I beleive Digitrax's command station does this for you, but some other brands don't. There is a really good Digitrax discussion group on Yahoo if you have detailed questions.

 

[WC3026]

OK Yes I have fx3 decoders but I am lost. I am using MRC prodigy adv2 for my controls and what I am confused by is the number for programing. what does 005/x05 mean when I go to program I can only put one number in and not two......

 

[Cjcrescent]

IIRC, the first number indicates the CV to be changed. The second number is what it is to be changed too. This indicates that CV 005 should be changed to whatever the number is you need. The numbers would be in the CV tables in the Digitrax decoder manual, which if you don't have a copy is available as a free download from Digitrax.com.

The reason I can't remember is I haven't used a throttle to program a decoder in years. I use JMRI's DecoderPro. You don't have to go thru the trouble of looking up what CV does what with what number. The computer does it in plain language.

 

[WC3026]

How to set up a loco with Scaleable Speed Stabilization (Back EMF)
1. Install the decoder.
2. Program CV57 (Intensity) to a CV value of 005/x05. This will turn on
speed stabilization.
3. Put the loco on level track and run it at about 20% of full speed.
Beginning with the default value of 128/x80 in CV55 (Static), repro-
gram the CV value to increasingly higher values until you observe
the loco jumping as speed steps increase when you run the locomo-
tive. Finish this step by reprogramming CV55 to the CV value just
before the jumping started. Ops Mode programming on the main
line works very well here.
4. Follow the same procedure with CV56, beginning with the default
value of 048/x30 and increasing it until you notice the loco oscillat-
ing, faster-slower, faster-slower, as speed is increased. Finish this
step by programming CV56 to the CV value just before the oscilla-
tion started.
5. Follow the same procedure with CV57, beginning with the value 05 as
programmed in step 1. Increase the CV value in this CV until the
speed when going up hill is roughly equivalent to the speed on level
track. This will yield a best intensity consistent with the locomotive
characteristics.
6. Keep notes about the values you program for these 3 scaleable speed
stabilization control CVs so that you can use them as a starting point
for setting up scaleable speed stabilization in similar locomotives.



That is what it tells me to do #2 and #3 is where i get lost with the numbers it dont make sense since it tells me to put in two numbers and I can only put in the CV # and the first number.......

 

[CSX Robert]

According to the decoder data sheeet and the digitrax manual if your DH-123D is an Fx3 version you should already have Back EMF...

The DH123 is an "Economy" series 3 decoder, meaning that it has FX3 functions but does NOT have Bemf compensation.

...what does 005/x05 mean when I go to program I can only put one number in and not two......

That is not two separate numbers, but two representations of the same number. Some of the very early Digitrax throttles used hexadecimal for programming because they could only display two digits(CV values can be 0-255, which can be represented in two digits in hexadecimal), so the decoder manual has always shown decimal and hexadecimal representation. In the example above, 005 is the decimal representation and x05 is the hexadecimal representation.

 

[WC3026]

I believe they actually do have it because when I was going through the steps it was doing exactly what the directions say jumping and what not. now my one loco runs up and down at the same speed as on flat

 

[scroggin]

I believe they actually do have it because when I was going through the steps it was doing exactly what the directions say jumping and what not. now my one loco runs up and down at the same speed as on flat

Ok so that digitrac decoder must switch off the Back EMF when operating in a consist

 

[CSX Robert]

I believe they actually do have it because when I was going through the steps it was doing exactly what the directions say jumping and what not. now my one loco runs up and down at the same speed as on flat

Actually, I do now remember some people saying that they had decoders that were labeled and sold as DH123's but they had Bemf. At least some of them also had four functions while the DH123 is supposed to only have two. I don't know if they were actually labeled wrong from Digitrax or if maybe Digitrax was low on the proccessor used for the DH123 and substituted another more feature rich proccessor. Regardless, with a DH123 you may get lucky and have Bemf, but I would not count on it(the Digitrax website even has an added note to all of the DH123 pages specifically stating that the DH123 series does not have Bemf).

 

[Cjcrescent]

Robert,

I was looking at DecoderPro, and under the Digitrax entries for the DH-123, it shows 2 versions, the regular 2 function, and a 4 function. I use the DH-123's in the majority of my steamers, and I've never seen a 4-function one. I believe that people are confusing Digitrax Transponding with BEMF. The DH-123's do have transponding, but not BEMF.

This merely shows a signalling/auto-controlling system where the locomotive is on the layout. Kinda like a GPS for trains.

 

[Espeefan]

I've never seen a four function 123 either. I should have looked at the 163 data sheet. It says that the 163 has back EMF. The 123 data sheet does not say this and the data sheet (on the site, not the sheet in the package) says it isn't available in the enconomy decoders. Their manual seems to say that all FX3 decoders have it, but this isn't so. Digitrax has data sheets and instruction sheets, and you need both to see what you're getting. This is one of the things I don't like about them. Too many places to chase information. The bulk of my installed decoders are Digitrax, but I also have used NCE and TCS. Those companies put everything you need with regards to features and how to program it right in the package with the decoder. What a neat idea!!!