Speed Matching not working either!

[CPbuff]

My problem is a little more complicated than CudaKen  or at least I think so!

First the Basics:

2 - Athearn AC4400's purchased at the same time (new) both with Digitrax  SDH104K1A+FN04K1 combo sound decoders (also new), Both loco's have had the excess grease removed from the gears and cleaned up from top to bottom (wheels, gears etc.)   The 20' of track they are running on has been cleaned to spotless stage. I also set both loco's CV 8 to 08 to clear any oddball CV's that could cause a problem.

Using MRC Prodigy Advanced for programming etc. MRC manual says that advanced consisting can not be done unless the decoder supports the use of CV19. Which in this case of the SDH104K1A+FN04K1 it does not according to the Digitrax manual as these decoders are FX3 and FX and only FX supports CV 19.

So with this in mind MRC reccomends consisting to be in universal style programming or Old style programming to consist loco's. (Confused yet? how do you think I feel?)

Anyway to make a short story long! (Loco 1 as my golden loco)

With Step speed set at 28. (Of the 14, 28, 128 choices)

I set CV2 on both locos to 30 to match the speeds and adjusted loco 2 to 37 until loco 1 was at 30 and loco 2 was at 37 and at the low step speed of 3 the two locos matched slow speed for the 20 feet of track perfectly.  I was happy!  Until!

I set both loco's CV5 (Max voltage the same) at 180 because 255 is just to unrealistic in my space. So after much adjusting of CV5 and running the loco's at a top step speed of 14 (for me) half of maximum(28 speed step). I have the loco's almost matched but I need a little more up on the slower loco or down on the faster loco but here's the problem.

Loco 1 CV5 is now set at 35 (of a possible 255) and loco 2 (CV5) is set at 255.

 As now loco 1's start voltage CV2 is at 30 and it's Maximum voltage is at 35.

While.

Loco 2's start voltage CV2 is at 37 and it's Maximum voltage is at 255.

Just to make them almost close to perfect? I used CV 8 to 08 to clear any unwanted Values at the beginning that could cause problems. ie. CV3 and 4 or BEMF etc.

Help!!   What am I missing?

 

[Hamltnblue]

They don't have to be perfect but close.  That low high number doesn't sound right but if it's working then it's ok.  If you can't figure out the consist right away then simply program both loco's to the same address. If one loco is slightly faster put it in front to keep tension on the couplers.  After a days playing with it have some fun and then dive back into it later.

Just an fyi, you typically want to use the newer type of consist. Different vendors have different names for it but they all call the Old one by the same name.

[CSX Robert]

CPbuff

these decoders are FX3 and FX and only FX supports CV 19.

The FX3 decoders do support CV19. FX3 decoders support everything that the FX decoders support, plus the items that are specifice to the FX3.

[locoworks]

CSX Robert

CPbuff

these decoders are FX3 and FX and only FX supports CV 19.

The FX3 decoders do support CV19. FX3 decoders support everything that the FX decoders support, plus the items that are specifice to the FX3.

 i sure i read somewhere in the instructions that FX3 decoders do not support lights on when running on DC !!   i used a digitrax DH123 o 6, and when the loco went on my dads analogue layout, the lights wouldn't work. after much head scratching and CV altering i came accross a paragraph somewhere that said it wouldn't work??

[mfm37]

 Never tried one on analog but all  Digitrax FX3 decoders support advanced consisting.

CV19 is the advanced consisting address. If the decoder has CV19 it can be advance consisted. Light control analog and DCC is handled by other CV's, so their control is up to the firmware and design of the decoder.

[AlienKing]

CPbuff

I set both loco's CV5 (Max voltage the same) at 180 because 255 is just to unrealistic in my space. So after much adjusting of CV5 and running the loco's at a top step speed of 14 (for me) half of maximum(28 speed step). I have the loco's almost matched but I need a little more up on the slower loco or down on the faster loco but here's the problem.

Loco 1 CV5 is now set at 35 (of a possible 255) and loco 2 (CV5) is set at 255.

 As now loco 1's start voltage CV2 is at 30 and it's Maximum voltage is at 35.

While.

Loco 2's start voltage CV2 is at 37 and it's Maximum voltage is at 255.

Just to make them almost close to perfect? I used CV 8 to 08 to clear any unwanted Values at the beginning that could cause problems. ie. CV3 and 4 or BEMF etc.

Help!!   What am I missing?

 

You did CV2 perfectly.

At speed step 14 of 28, your locos would be using CV6 (vmid) much more than CV5 (vmax). If you want to slow your locos down at the top end, lower CV5 until you are satisfied with your speed at the top end while in speed step 28 for one of the locos. Match the other loco to the first while also running in 28.

Now put one loco on 14 of 28 and adjust CV6 until you are happy with its range of speed over each of the speed steps. This should be somewhere between 1/3 and 2/3s of speed while at 28. (1/2 for a linear speed control, 1/3 if you want better low speed control, and 2/3 for high speed). Smaller values will give you an exponential curve, larger numbers will be more asymptotic, and the average of vmin and vmax should give you something like a linear pattern.

Now adjust CV6 in the second loco until it matches the first in speed step 14 of 28. Once they matched at 14, run them through each of the speeds steps to make sure they are matched across the entire range. They should be pretty close.

[CPbuff]

Thanks you explained it perfectly and now I have three loco's matched. ( In forward direction)

1) Just a few other questions though! If I was to run one loco in reverse (Changing CV29) do I need to respeed match this reverse loco to the golden loco.

2) When I have the two locos running at the same speed in step 28 and I push emergency stop, both locos roll out for a little distance but loco 2 runs out further and almost rear ends loco1. Can anything be done?

3) When I reverse these loco's the lead loco catches the second loco, is there an adjustment now to match these in reverse , perhaps reverse trim? CV66 or CV95

4) I also found that if I tried to change and run the locos on Advanced Consisting after setting up under Universal or old style consisting that the loco again were not matched. Can speed matching be done in advanced consisting with the same results?

Thanks for your assistance!

 

 

[Hamltnblue]

They should stop right away. You probably have momentum set on them.

Set all engines acceleration and deceleration momentums to 0

I believe it's CV3 and CV4

 

[CSX Robert]

locoworks

 i sure i read somewhere in the instructions that FX3 decoders do not support lights on when running on DC !!

Close, what the decoder manual says is "In FX3 decoders, CV13 is disabled."

locoworks

i used a digitrax DH123 o 6, and when the loco went on my dads analogue layout, the lights wouldn't work. after much head scratching and CV altering i came accross a paragraph somewhere that said it wouldn't work??

The reason CV13 is disabled in FX3 decoders is because they remember the last state of the functions and use that information to control their operation on DC. In other words, if the headlight was on the last time the loco was run on DCC, the headlight will be on when run on DC, and if the headlight was off the last time it was run on DCC, it will be off when run on DC.

P.S.I know this is the case for 163 series decoders, but I am not absolutely certain about the 123 series. The 123 series has a "reduced feature set" when compared to the 163 series, the main difference other than the number of functions being the lack of Back emf compensation. Since the 123 series decoders do call there functions FX3 functions I would think that they would operate the same on DC, but I could not find a difinitive answer on it and I do not have any 123 series decoders to test it with.

[CPbuff]

No, I had set both the acceleration and deceleration to zero. Back in my first note I Reset the decoders back to factory defaults with CV8. Yet the loco rolls on, but I believe now it's just the difference from the Athearn Loco to a Kato Loco.

I am strictly using DCC and never have a need for DC settings.

[CSX Robert]

CPbuff

1) Just a few other questions though! If I was to run one loco in reverse (Changing CV29) do I need to respeed match this reverse loco to the golden loco.

There usually is not enough of a speed difference between forward and reverse to necessitate any changes, but occasionally it is necessary to use the forward and/or reverse trims on a loco to better match the forward and reverse speeds.

CPbuff

2) When I have the two locos running at the same speed in step 28 and I push emergency stop, both locos roll out for a little distance but loco 2 runs out further and almost rear ends loco1. Can anything be done?

Probably is the two locos coasting differently(Edited because of additional information in last post).

CPbuff

3) When I reverse these loco's the lead loco catches the second loco, is there an adjustment now to match these in reverse , perhaps reverse trim? CV66 or CV95

Yes. If you are satisfied with the loco's operation in forward, but it is to fast or to slow in reverse, then use CV95(Reverse Trim) to adjust it in the reverse direction. Likwwise, if you are satisfied with the loco's operation in reverse, but it is to fast or to slow in forward, then use CV66(Forward Trim) to adjust it in the forward direction.

CPbuff

4) I also found that if I tried to change and run the locos on Advanced Consisting after setting up under Universal or old style consisting that the loco again were not matched. Can speed matching be done in advanced consisting with the same results?

The problem here is that Digitrax's default settings for Bemf compensation(Scaleable Speed Stabilization) has it turned on when not in an advanced consist and turned off when in an advanced consist. If the locos are speed matched with Bemf compensation turned on, they won't necessarily be speed matched when it is turned off, and if they are speed matched with it turned off, they won't necessarily be speed matched with it turned on. If you need them speed matched both when in an advanced consist and when not, then you need to adjust CV57 so that either Bemf compensation is always on or always off(something to be aware of is that having Bemf compensation on when in a consist can cause the locos to fight each other). If you use Bemf compensation, I would advise reading the section on it in the Digitrax decoder manual for setting it up, but I will tell you that setting CV57 to 0 turns it off and setting CV57 to 102 turns it on to the default setting both when not in an advanced consist and when it an advanced consist.