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Programming CV 29 for 28/128 Speed Steps on Bachmann High Boiler 4-6-0 w/DCC & Sound

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Posted by akriggm on Saturday, August 18, 2018 11:28 AM
Henry, I did a forum search on changing to 128 speed steps and found the other thread, so I asked the question there. I didn't realize/remember that there was a button for SPD STEP on my MRC throttle, but found it by searching a .pdf of the manual for "128". Still learning...… Thanks again, akriggm
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Posted by BigDaddy on Saturday, August 18, 2018 10:56 AM

You posted in a different thread asking how to set 128 speed steps.  Like posting a picture in this forum, DCC is not necessarily intuitive.   A manual is essential and your answer is on page 2-2 of the manual. 

I use my loksound manual all the time and even then, I sometimes can't figure and ask questions here or the Yahoo loksound group. 

 

Henry

COB Potomac & Northern

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Posted by akriggm on Saturday, August 18, 2018 10:46 AM
Thanks! akriggm
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Posted by rrinker on Saturday, August 18, 2018 10:42 AM

Starting voltage and CV2 are the same thing - CV2 is defined as the starting voltage. 

                                   --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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Posted by akriggm on Saturday, August 18, 2018 9:40 AM

Henry,

I read out CV 2 which actually showed a value of "0" (which matches my previuos input).  I then reset CV 2 to "1" and increased CV 3 to "75".  The starting speed may have decreased slightly (it still starts with a bit of a leap forward) and the acceleration is much smoother in reaction to the throttle which is a definite imprivement.  Is there any difference between programming SV (starting voltage) and resetting CV 2?  I suspect it is 2 different ways to do the same thing, but I'm trying to minimize assumptions......

Thanks,

akriggm 

 

 

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Posted by rrinker on Friday, August 17, 2018 11:26 PM

 One thing that will really help with the running properties of a bachmann loco is to remove the capacitors that are paralleled with the motor. These mess up the PWM drive signal from the decoder, and interfere with BEMF, if the decoder has it. Even the cheap no-sound Bachmann decoders work a little better without those capacitors.

                                             --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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Posted by RR Baron on Friday, August 17, 2018 11:01 PM

akriggm

Big Daddy,

You are correct about the CV value of 34 - it didn't match the short loco address of 3.  I just set CV 29 to 2, CV 2 to 0 & CVs 3 & 4 to15 as recommended above and the loco still operates, but it doesn't seem to perform any differently than the factory defaults.  Perhaps the Bachmann just doesn't allow nice, slow operation......

Thanks,

akriggm

 

akriggm,

The locomotives equipped with the old SoundTraxx Tsunami decoder and its OEM versions are notorious for not running well at slow speeds. Beyond CV 2, 3 and 4  --  The decoder has CVs available that a modeler with basic DCC knowledge can use to significantly improve slow speed running.  There are several procedures that can be used.  Search “tsumani slow speed running”  ---  Example,   Mark Gurries website covers several of the procedures  https://sites.google.com/site/markgurries/home/decoders/decoder-motor-tuning/soundtraxx

 

Because the procedure is time consuming, most just live with what they have or install different decoder utilizing newer technology. 

 

RR Baron

 

 

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Posted by rrinker on Friday, August 17, 2018 10:48 PM

I like this calculator:

http://www.2mm.org.uk/articles/cv29%20calculator.htm

because it can work both ways. Frankly, I can do the decimal/binary conversion in my head faster than I can usually type things on a web page, but having a calculator handy is useful as well. The one I linked allows you to put in a value and it shows you which options are selected, as well as the usual capability of choosing what options you want and it telling you what CV29's value should be.

Most any modern DCC system takes care of most things for you, although not always the 'extra' things like analog on/off or Railcomm on/off. 

 If you count the bits correctly - the calculatoor app that coomes with Windoows can do this for you as well - there is a "programmer" mode in addition to the basic and scientific, and you can entery values in binary and it will tell you the decimal (and hex and octal, but that's not important) value, or you cna put in a decimal value and it will show the binary, so you can look at it and see bit 1 and bit 5 are turned on.

                                   --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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Posted by RR Baron on Friday, August 17, 2018 8:39 PM

 

 

Henry and all,

 

Sorry for the misinformation about the Digitrax calculator. I have edited the post.  In a hurry and never tried to use the Digitrax calculator, only glanced at it. My focus was on CV 29 can be 34. 

I calculate any CV by its Bits being 1 or 0 and the Bit position value.

RR Baron 

 

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Posted by BigDaddy on Friday, August 17, 2018 7:08 PM

No fat fingers, I missed the analog.  I hate posting wrong information for folks, but thanks for pointing that out. 

I will edit my posts.

 

Henry

COB Potomac & Northern

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Posted by rrinker on Friday, August 17, 2018 7:00 PM

 There is not. CV29 is a NMRA standard, there ar enot multiple calculated values. Someone fat fingered a value. I just tried the linked Digitrax oonline calculator and if you select 28/128, no analog, long address the value shown is - 34! 36 is long address, analog on, 14 speed steps.

 34 is long address, 28/128 steps, no analog. Always. Anything that says different is incorrect. I tried 2 different online calculators, both give the same result. So does the Digitrax toolbox app.

2 is short address, 28/128 steps, no analog.

38 is long address, 28/128 SS, analog on.

6 is short address, 28/128. analog on.

About the only "it can vary" CV29 option is for Railcomm, which if turned on adds 8 to the above values. Only decooders that actually have Railcomm will support that bit being set.

Some decoders take a 0 in CV2, 3, and 4, others like TCS and ESU the minimum value is 1, but typically if you put it to 0 and then read back it will show a 1.

                                    --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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Posted by BigDaddy on Friday, August 17, 2018 5:43 PM

Given that we just discovered that multiple calculators give multiple results for CV 29, I don't know that my loksound can speak for your situation but the minimum CV for CV 2 is 1 not 0.  The maximum for the acceleration CV 3 is 255 with a default of 16 and the default for the midrange CV 6 is 64 which is also the max.

I'd say go up on CV 3 to extend the time to acceleration.  Report back please, we are all learning here.

Henry

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Posted by akriggm on Friday, August 17, 2018 5:26 PM

Big Daddy,

You are correct about the CV value of 34 - it didn't match the short loco address of 3.  I just set CV 29 to 2, CV 2 to 0 & CVs 3 & 4 to15 as recommended above and the loco still operates, but it doesn't seem to perform any differently than the factory defaults.  Perhaps the Bachmann just doesn't allow nice, slow operation......

Thanks,

akriggm

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Posted by BigDaddy on Friday, August 17, 2018 5:11 PM

I just looked at the Advance 2 manual.

First they caution you not to monkey with CV29, then the give examples.

  • CV 29 for long address and the default setting is 34.
  • For long address and 14 steps it is  32.

That's different than both Baron's calculation and the Digitrax calculator.   So there must be some proprietary leeway in the calculation of CV 29

So if you were originally running the loco as an address of 3 and you changed CV 29 to 34, you told it to use a long address without actually giving it a long address and it did not respond.

Henry

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Posted by wjstix on Friday, August 17, 2018 5:06 PM

RR Baron
 
wjstix

I'm assuming this is an engine with a factory-installed Soundtraxx decoder - "Sound Value" or "Ecomomi", not Digitrax?

 

 

 

 

It was established in another post the locomotive is equipped with SoundTraxx OEM Bachmann feature set using Tsunami technology. Thus the decoder installed is not "Sound Value" or "Ecomomi".

 

RR Baron 

 

 

Well you can't use a Digitrax settings calculator with a Soundtraxx decoder. The CV settings aren't the same from one company to another.

Stix
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Posted by akriggm on Friday, August 17, 2018 5:05 PM

My MRC system uses long addresses when I plug in 4 digit engine numbers.  However, the 4-6-0 in question is undecorated, so I have left it as "3" per the default.  My system does not ask if I want to use long addresses, so I assumed it does so automatically; that may not be the case.  If so, then per the CV 29 calculator I listed above, the value should be "2" using a short loco address. I'll try that out.  Also, the MRC system manual doesn't say anything about cycling power after programming when using a program track (which is what I have been doing) or on the main,

Thanks,

akriggm

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Posted by selector on Friday, August 17, 2018 4:49 PM

akriggm

Henry,

The loco is set to the default address 0003 (# shown on throttle display after I input "3" in loco selection), so I assume the MRC system automatically uses long addressing.  Is that a bad assumption?

 

As I read the quote of yours above, yes, it's an erroneous assumption.  You must select, or know already if, the address is (to be) a 'long' one.  Then, if it's not the cab number decaled on the locomotive, you must record it someplace for when you want to go use it again after months.  This is for those of us who have several locos we use in a long rotation.

According to Randy in a post about four months ago or so, the ESU decoders have a different cut-off point for long addresses, but pretty much all the rest use 127 as the point from which you must enable action to a long address on your system. But the point is, the system should ask.  It should prompt as it does in the Digitrax systems with a 'y' or a 'n' when it flashes 'enable long address?"

I might be wrong because I only have experience with reading here over the years and with my own Super Empire Builder, an old Digitrax system using the early DT400 encoder twin throttles, but our screens do ask if we enter a long address.

One other thing Randy likes to drum into us is that you must complete the addressing by actually shutting off power to the rails momentarily.  Digitrax, again that horrible system, does this automatically when you press the final enter to complete the address change.  You must manually press to restore track power, and then your newly addressed loco should NOT respond on ADD '03', but on whatever you pressed and entered.

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Posted by BigDaddy on Friday, August 17, 2018 4:30 PM

Not really automatic.

Locos come from the factory with an address of 3.   A reset returns it to 3, if it has been changed.  I don't know MRC but DCC systems allow you to change the address to another short address or a long address. 

How to do that should be in your manual and if you don't have one, you should download one.

Henry

COB Potomac & Northern

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Posted by akriggm on Friday, August 17, 2018 3:24 PM

Henry,

The loco is set to the default address 0003 (# shown on throttle display after I input "3" in loco selection), so I assume the MRC system automatically uses long addressing.  Is that a bad assumption?

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Posted by RR Baron on Friday, August 17, 2018 3:15 PM

wjstix

I'm assuming this is an engine with a factory-installed Soundtraxx decoder - "Sound Value" or "Ecomomi", not Digitrax?

 

 

It was established in another post the locomotive is equipped with SoundTraxx OEM Bachmann feature set using Tsunami technology. Thus the decoder installed is not "Sound Value" or "Ecomomi".

 

RR Baron 

 

 

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Posted by BigDaddy on Friday, August 17, 2018 3:05 PM

RR Baron
You cannot get CV = 34 using that CV 29 calculator. But programming CV 29 to 34 will set only CV 29 Bit 1 and Bit 5 CV 29 Bit 1 -- 28/128 speed steps, Bit value = 2 CV 29 Bit 5 -- Extended Address, Bit value = 32

I believe you but if the calculator says 36, is there that much...elasticity, slop, tolerance in setting CV 29?

To the OP, much of what has been posted here in the past about 14 speed steps is that it gives you less control and more abrupt changes.  That's why people are suggesting changing starting voltage and the like.  Keep a record of what you try, because if you will forget that you tried something before that didn't work.

We haven't explained why he lost the engine by setting it to 34, unless the loco was on short address.

Henry

COB Potomac & Northern

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Posted by akriggm on Friday, August 17, 2018 3:00 PM

BigDaddy,

I got 34 by assuming that my MRC DCC system uses long addresses, so using this calculator http://www.2mm.org.uk/articles/cv29%20calculator.htm with the box for long addresses and DCC-only operation checked, I got a value of 34 (which didn't work).

akriggm

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Posted by RR Baron on Friday, August 17, 2018 2:53 PM

BigDaddy

Here is a CV calculator and I'm not sure how you get to 34.  I can't

http://www.digitrax.com/support/cv/calculators/

CV's 2-6 are where the start, mid range high voltage and acceleration and deceleration lives.  That is where I would look to change things.

 

** Edit in bold **

You cannot can get CV = 34 using that CV 29 calculator.

Change

Addressing - select 4 Digit Addressing 

Analog Mode Conversion - select Off


Programming CV 29 to 34 will set only CV 29 Bit 1 and Bit 5 

CV 29 Bit 1   --  28/128 speed steps, Bit value = 2

CV 29 Bit 5   --   Extended Address, Bit value = 32

 

RR Baron

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Posted by akriggm on Friday, August 17, 2018 2:50 PM

I believe the loco has the factory Soundtraxx sound decoder and I'm trying to get it to start smoother (it takes off fairly abruptly similar to the Bachmann 2-8-0 reviewed in the September 2018 edition of MR; unfortunately I misremembered the review thinking it was set to 14 speed steps rather than the 28 stated in the article).  I'm fairly new to DCC (obviously) and getting this 4-6-0 to operate smoothly has baffled me thus far.

akriggm

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Posted by wjstix on Friday, August 17, 2018 2:34 PM

I'm assuming this is an engine with a factory-installed Soundtraxx decoder - "Sound Value" or "Ecomomi", not Digitrax?

Stix
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Posted by BigDaddy on Friday, August 17, 2018 1:49 PM

Here is a CV calculator and I'm not sure how you get to 34.  I can't

edit I couldn't because I didn't choose analog off

http://www.digitrax.com/support/cv/calculators/

CV's 2-6 are where the start, mid range high voltage and acceleration and deceleration lives.  That is where I would look to change things.

Henry

COB Potomac & Northern

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Posted by wjstix on Friday, August 17, 2018 1:47 PM

I believe CV29's default value of 6 creates a situation with no speed tables, analog mode OK, 28/128 speed steps, normal direction, and short address only.

I think changing it to 34 only changes it to allow long addresses, and to turn off analog mode (so it won't work on DC). Rest is the same.

I'd suggest checking to make sure CV2 is at zero (start speed) and set the momentum (CV3-4) to say 15 or 20 and see how it starts and stops then.

Stix
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Posted by RR Baron on Friday, August 17, 2018 1:32 PM

 

 

Bachmann factory install sound decoder default setting is 28/128 speed steps.

 

What address are you trying to use?  CV 29 = 34 configures in part the decoder to respond to the Extended Address in CV 17-18.

 

RR Baron

 

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Programming CV 29 for 28/128 Speed Steps on Bachmann High Boiler 4-6-0 w/DCC & Sound
Posted by akriggm on Friday, August 17, 2018 1:04 PM

I have a Bachmann high boiler 4-6-0 w/DCC & sound that starts at a fairly high speed and I'd like to get better starts & slow speed operation.  I assume it is factory set for 14 speed steps and I've been trying to reprogram CV 29 to a value of "34" (based on reading here on the Forum) with my MRC Prodigy Advance 2 throttle, but after doing so the loco won't respond to any inputs (default sounds still play).  I have to reset the decoder to the factory defaults (CV 8 = 8) to get it to respond again.  What am I likrly doing wrong?

Thanks,

akriggm

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