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Need CV HELP!!!!

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  • Member since
    February 2002
  • From: Reading, PA
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Posted by rrinker on Tuesday, November 18, 2008 9:54 PM

wjstix

Well maybe "obtuse" would be a better word. Laugh The instructions that come with a TCS decoder are very straightforward about what number to put in each CV to get the result you want re lighting options, speed control, momentum, etc. Digitrax gives you info on a few CV's and tells you to read their manual for the rest...and the manual isn't that great, I remember to get the lighting options the way I wanted with my first Digitrax decoder, I had to start with "1" in the CV and try it, then put in "2" and try it, and keep doing that until I finally stumbled into the numbers I needed (104 and 120 IIRC).

Oh, and ya I should have remembered the 256 steps are 0-255. Dunce

 104 and 120 off the top of my head sounds like Rule 17 numbers - those are given in a direct example in the Digitrax Decoder Manual. If they listed decimal numbers for every possible valid combination that chart alone would be the size of the manual. For any 8-bit number there's 255 possible combinations. Learn Hex - it's NOT difficult and makes these various CVs where each bit menas somethign MUCH MUCH easier to figure out. I'm sure most people think the decimal numbers for CV29 make liek no sense at all - because the decimal number everyone deals with has no relation to the various bits that are listed in decoder manuals.  It's really easy if you lay it out, bit 7 on the left, bit 0 on the right:

128  64  32  16  8  4  2  1

Mark each bit you need, and add up the numbers to get your decimal value. Same holds true for the lighting effects CVs, or any CV that isn't just a number value. TCS has you do this on their manuals and you don;t even realize it.

                                --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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  • From: Christiana, TN
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Posted by CSX Robert on Tuesday, November 18, 2008 7:05 PM
The numbers after the slash are hexadecimal. They are included because some of the OLD Digitrax systems required programming in hexadecimal so that you could program the full range of values with a two digit display(0 - 255 can be represented in two digits with hexadecimal).
  • Member since
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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Tuesday, November 18, 2008 5:27 PM

 Don't worry about those. The first number is all you need.

Running Bear, Sundown, Louisiana
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Dr. Frankendiesel aka Scott Running Bear
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Posted by hwolf on Tuesday, November 18, 2008 5:22 PM

Mainline Loco

Quick increase to cruising speed then 002/x02 128/x80 154/x9A

levels off to prototypical top speed.

Question. What are the numbers after the slash? The x80 after the 128.

Harold

  • Member since
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  • From: Mpls/St.Paul
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Posted by wjstix on Tuesday, November 18, 2008 12:13 PM

CSX Robert

wjstix
...

Digitrax unfortunately is a little vague in the instruction sheet that comes with their decoders, they assume you've purchased (or downloaded from their website) the full decoder instruction manual.

I don't think Digitrax is vague about this at all.  I have not looked at the instruction sheet for every one of the Digitrax decoders, but the ones I have looked at all have, as the very first sentence under "Installation Information," something to the effect of "See the Digitrax Decoder Manual for complete decoder test procedures, installation instructions, programming and technical information."

Well maybe "obtuse" would be a better word. Laugh The instructions that come with a TCS decoder are very straightforward about what number to put in each CV to get the result you want re lighting options, speed control, momentum, etc. Digitrax gives you info on a few CV's and tells you to read their manual for the rest...and the manual isn't that great, I remember to get the lighting options the way I wanted with my first Digitrax decoder, I had to start with "1" in the CV and try it, then put in "2" and try it, and keep doing that until I finally stumbled into the numbers I needed (104 and 120 IIRC).

Oh, and ya I should have remembered the 256 steps are 0-255. Dunce

Stix
  • Member since
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  • From: Christiana, TN
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Posted by CSX Robert on Tuesday, November 18, 2008 8:34 AM

wjstix

If you're looking at the CV's for start, top and middle speeds (CV 2,5,6) there would be 256 speed steps, so you could set them anywhere from 0 to 256...

The maximum value is 255, not 256.

wjstix
...

Digitrax unfortunately is a little vague in the instruction sheet that comes with their decoders, they assume you've purchased (or downloaded from their website) the full decoder instruction manual.

I don't think Digitrax is vague about this at all.  I have not looked at the instruction sheet for every one of the Digitrax decoders, but the ones I have looked at all have, as the very first sentence under "Installation Information," something to the effect of "See the Digitrax Decoder Manual for complete decoder test procedures, installation instructions, programming and technical information."

hwolf

I have 126 Speed steps. I would assume that that replaces the256 you mentioned and will then become the maximum. Am I correct?

No, these settings are independent of the speed step setting.  Each of these settings is telling the decoder what fraction of full voltage to apply to the motor. For eample, CV5(Maximum voltage) sets the voltage applied to the motor at full throttle, which is speed step 28 in 28 step mode or speed step 128 in 128 step mode.  Lets assume for this example that the maximum voltage is 12 volts.  If you set CV5 to 255, then the maximum voltage is (255/255) * 12 = 12 volts.  If you set CV5 to 128, then the maximum voltage is (128/255) * 12, or approximately 6 volts.

Although these settings are independent of the speed step setting, be aware that they are not decoder independent.  By this, I mean that not all decoders support all of these CV's and not all decoders use 0 - 255 for the settings.  As an example, The Athearn N-scale Challenger supports CV2 and CV5, but not CV6, and the range of values it uses are 0 - 32.

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Posted by Hamltnblue on Monday, November 17, 2008 5:45 PM

The Person I met was Tom.  Very helpful and loves what he does for a living.  The receptionist was very friendly and accommodating as well.

Good Luck

 

Springfield PA

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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Monday, November 17, 2008 5:29 PM

 As I said 'pickup issues'.

Running Bear, Sundown, Louisiana
          Joined June, 2004

Dr. Frankendiesel aka Scott Running Bear
Space Mouse for president!
15 year veteran fire fighter
Collector of Apple //e's
Running Bear Enterprises
History Channel Club life member.
beatus homo qui invenit sapientiam


  • Member since
    October 2003
  • 571 posts
Posted by hwolf on Monday, November 17, 2008 5:06 PM

I have 126 Speed steps. I would assume that that replaces the256 you mentioned and will then become the maximum. Am I correct?

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Posted by hwolf on Monday, November 17, 2008 5:04 PM

Guess what. When I ran the engine on a right at the turnout it stalled at the frog. Guess who is getting a call in the morning. Thanks for your help.

Harold

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Posted by Hamltnblue on Monday, November 17, 2008 3:24 PM

You might have the same problem I had.  Bachman has had a problem with shorts in the tender.  I had 2 with the problem.  The short causes a trace on the circuit board to burn off.  The engine will still run but the pickup for one side will be limited to the the tender which  is why it stutters on and off.  I hand carried the 2nd one to the bachmann repair shop in philly.  Probably the best customer service I've seen in 30 years.  They were very interested in the problem and knew the cause.  I walked out with a shiny new one.

One way you can tell if it's the same problem is run the engine over a turnout with the frog to the right. If it's the same problem, when tender's right side wheels cross the frog the engine will stall.  Also if it's the same problem you might be able to notice a burnt electronic smell from the tender.

Good Luck

 

Springfield PA

  • Member since
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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Monday, November 17, 2008 3:06 PM

 No. The CV's won't cause that problem. You have either dirty wheels or pickup issues.

Running Bear, Sundown, Louisiana
          Joined June, 2004

Dr. Frankendiesel aka Scott Running Bear
Space Mouse for president!
15 year veteran fire fighter
Collector of Apple //e's
Running Bear Enterprises
History Channel Club life member.
beatus homo qui invenit sapientiam


  • Member since
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Posted by hwolf on Monday, November 17, 2008 2:38 PM

Thanks for the Help. While I got you let me ask another question. The problem is that the Shey is running as if were on a dirty track. Jerking along. The Track is clean an my other Shay ( both Shay's by Bachmann) runs perfectly. Would the CV's be causing this problem? This is why I was going to play with the settings.

Harold

  • Member since
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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Monday, November 17, 2008 10:41 AM

 Digitrax decoders have three scaleable speed stabilyzation tables you can use. I've been known to mix and match these to get the results I want.

Switcher - Concentrated low speed control, limited top speed.
CV02=02  CV06=38  CV05=64

Road switcher - Prototypical top speed with evenly distributed speed control.
CV02=02  CV06=48  CV05=98

Mainline loco - Quick increase to cruising speed then levels off to prototypical top speed.
CV02=02  CV06=128  CV05=154

Factory defaults
CV02=00  CV06=00  CV05=00

 

Running Bear, Sundown, Louisiana
          Joined June, 2004

Dr. Frankendiesel aka Scott Running Bear
Space Mouse for president!
15 year veteran fire fighter
Collector of Apple //e's
Running Bear Enterprises
History Channel Club life member.
beatus homo qui invenit sapientiam


  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,892 posts
Posted by wjstix on Monday, November 17, 2008 9:57 AM

If you're looking at the CV's for start, top and middle speeds (CV 2,5,6) there would be 256 speed steps, so you could set them anywhere from 0 to 256. If you want to slow the engine down, set CV5 (top speed) to 120 and CV6 to 60; this will roughly cut the engine's speed in half. If you're having trouble getting the engine to start, set CV2 at maybe 5 and try it; if it needs more, go up by say 5 each time until you feel it starts OK. Keep in mind CV3 (momentum start up) is going to affect how long it takes the engine to start (and CV4 affects how it stops). I like to start by setting both CV3&4 at maybe 12-15 and see how it works - after you've got CV 2,5, and 6 working the way you want.

Digitrax unfortunately is a little vague in the instruction sheet that comes with their decoders, they assume you've purchased (or downloaded from their website) the full decoder instruction manual.

Stix
  • Member since
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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Monday, November 17, 2008 9:00 AM

 Exactly which CV# are you wanting to change?

Running Bear, Sundown, Louisiana
          Joined June, 2004

Dr. Frankendiesel aka Scott Running Bear
Space Mouse for president!
15 year veteran fire fighter
Collector of Apple //e's
Running Bear Enterprises
History Channel Club life member.
beatus homo qui invenit sapientiam


  • Member since
    October 2003
  • 571 posts
Need CV HELP!!!!
Posted by hwolf on Monday, November 17, 2008 8:55 AM

I have a Prodigy Advance Control with a Digitax decoder in my Shay. It is running poorly and I want to change the CV settings. My controler has a 3 blank spaces to put in the new setting. My questions is. Are the settings from 1-100  or are the setting 1-10? Does the higher number increase the voltage as well as the top speed? Thanks in advance

Harold

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