Turning off warp speed

[milw156]

In my attempt to make my N scale locos run at sub-sonic speeds, I have been setting the forward and reverse trims to 64 (ie, 50%) before attempting any adjustment in speed tables. Then using an Accutrack II, seedometer,  I adjust the value of CV 6 to achieve 30 smph speed, and CV 5 to achieve 60 smph, although thinking about shooting for 25/50, or 20/40, but I digress(for passenger, 35 and 70 smph). Are there any disadvantages in this approach, are there any better ways to making them run at less than Lionel speeds? I have noticed very few people seem to use trim this way, do I assume that they are simply living with a speed table that ranges from 0 to maybe 50 or so??? I vaguely recall a Digitrax decoder with a CV5 of less than 50 to achieve 60 SMPH.
What am I missing?

[peteski]

With Digitrax decoder you can only either use the 3-step speed table (CV2, 6, and 5) or the full 28-speed step table.  Not both.  Which one you use is selected in CV29.

I, and many of my friends find the 3-step speed table satisfactory.  Manually setting up the 28-step table is a real chore, and if you want to have that much control over the speeds, using DecoderPro (JMRI) woudl make that fairly easy.  But as I mentioned, just using Vmin, Vmid, and Vmax trio is usually good enough.

[signalmaintainer]

In my attempt to make my N scale locos run at sub-sonic speeds, I have been setting the forward and reverse trims to 64 (ie, 50%) before attempting any adjustment in speed tables. Then using an Accutrack II, seedometer,  I adjust the value of CV 6 to achieve 30 smph speed, and CV 5 to achieve 60 smph, although thinking about shooting for 25/50, or 20/40, but I digress(for passenger, 35 and 70 smph). Are there any disadvantages in this approach, are there any better ways to making them run at less than Lionel speeds? I have noticed very few people seem to use trim this way, do I assume that they are simply living with a speed table that ranges from 0 to maybe 50 or so??? I vaguely recall a Digitrax decoder with a CV5 of less than 50 to achieve 60 SMPH.
What am I missing?

Reverse and forward trim are not enabled unless 28-step speed table is selected in CV29.

Here's a CV29 calculator that might be of use: https://www.digitrax.com/support/cv/calculators/

[milw156]

Reverse and forward trim are not enabled unless 28-step speed table is selected in CV29.

Here's a CV29 calculator that might be of use: https://www.digitrax.com/support/cv/calculators/

CV 2,6, & 5 is what I have been doing. Have been converting to ESU sound/pilot decoders, so have been using a Lok programmer in particular to get access to the braking functions on the proto-throttle .

[milw156]

Reverse and forward trim are not enabled unless 28-step speed table is selected in CV29.

Here's a CV29 calculator that might be of use: https://www.digitrax.com/support/cv/calculators/

Thnx for the reference, was not aware of its existence. found the function mapping particularly interesting

this is what i am selecting:
Speed Control=Advanced 28/128 speed step control - Use with decoders that will be run on most modern command stations
2 Digit Addressing - Use CV01 to set the address. On Digitrax throttles the display shows this as AD2. (if engine# is 2 digits*)
4 Digit Addressing - Use CV17 & CV18 to set address. On Digitrax throttles the display shows AD4 and the process is automated.(if engin# is 3 or 4 digits*)
Analog Mode Conversion =Off - Use when you do not want to run your decoder on non-DCC layouts
Normal Direction of Travel (NDOT)=Forward - Use to run decoder in the normal direction of travel defined by the loco wiring  (***usually**)
Speed Table=Disabled - Use CVs 02, 05, & 06 to set up simple 3 step speed table if desired
CV29=34

[jagged ben]

I think your method is fine, it's essentially the same as what I do.  However as others have noted you can stop bothering with trim if this is your method, because it does nothing.  Using CVs 2 5 and 6 does not allow for dealing with a locomotive that has different speeds going forward and backward.  Trim is supposed to be for that, when you use the speed table instead.   Personally I have found CVs 2, 5 and 6 adequate, and speed tables to be something I don't have time for.  YMMV.