Programming Acceleration and Deceleration Values in Your DCC Decoders


Greg@mnrr

Greg@mnrr

Section Hand
How many of you DCC users program locomotive acceleration and deceleration in your locomotives? What values for the CV's do you find to be the best choice for road and switchers?

I don't like to over do either value, but like to achieve more prototypical locomotive operation.

Thanks.

Greg
 
I never programmed decoders to do that. In my opinion it is better to have immediate response and let the command station handle the acceleration (IIRC power cub can have inertia setting)

Just my .02 worth
Regards!
 
Values for the rate of DCC acceleration and deceleration are stored in the decoder, not in the command station. Per the NMRA specification, CV3 is for acceleration rate, CV4 is for deceleration rate. When you change a locomotive's momentum using a DCC throttle, you are actually changing the values in CV3 and CV4 in the decoder. However, some manufacturers of DCC decoders have implemented momentum in a way that does not conform to the NMRA specs.

There is a whole lot more information here:
https://sites.google.com/site/markgurries/home/technical-discussions/momentum-compatibility

- Jeff
 
I personally like having realistic acceleration and deceleration in my locos, particularly with switchers. But when it comes to op sessions, I set both to "neutral" (0 or 128, I can't remember?). I've noticed that any of my guest operators who don't use the same brand of throttles that I use (NCE), get totally confused when their assigned loco doesn't stop on a dime, and start frantically pushing random buttons to try to make it stop! I always have to reload the decoder settings from its DecoderPro file to fix it.
 
IronBeltKen said:
I personally like having realistic acceleration and deceleration in my locos, particularly with switchers. But when it comes to op sessions, I set both to "neutral" (0 or 128, I can't remember?). I've noticed that any of my guest operators who don't use the same brand of throttles that I use (NCE), get totally confused when their assigned loco doesn't stop on a dime, and start frantically pushing random buttons to try to make it stop! I always have to reload the decoder settings from its DecoderPro file to fix it.
Click to expand...
Seeing you're using NCE, like me, do you use NCE's quick 0-9 settings or program to specific values in CV3/4. I have been using the quick button at 3. Any idea what the various steps would relate to as values? I also tune all locos to use 128 steps via the cab as well. Have noticed that some decoders don't always choose that automatically.
 
Toot -

The momentum values your NCE throttle places in CV3 and CV4 are explained in the NCE manual. For my Power Cab version 1.65 manual, this is explained on page 34. In brief it says:

Technical stuff - what happens when you set momentum
The digit entered is multiplied by 8 (factory default) and sent to CV3. The value
sent to CV4 is ½ the value sent to CV3. You can change these multipliers.

There is a lot more, but that's the basic info.

- Jeff
 
jdetray said:
Toot -

The momentum values your NCE throttle places in CV3 and CV4 are explained in the NCE manual. For my Power Cab version 1.65 manual, this is explained on page 34. In brief it says:

Technical stuff - what happens when you set momentum
The digit entered is multiplied by 8 (factory default) and sent to CV3. The value
sent to CV4 is ½ the value sent to CV3. You can change these multipliers.

There is a lot more, but that's the basic info.

- Jeff
Click to expand...
Thanks, I hadn't spotted that.
 
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