Model Railway Forum

HI all

Looking to attempt to change my CV settings on some locos, I have some retro fitted and the time it takes to accelerate and decelerate is taking for ever and it is meaning its not actually moving, any help much appreciated, looking to use do this via either a hornby elink or a NCE powercab

Hi,
On the Programming track set the locos CV 3 to a value of 1 and do the same with CV 4 setting it to 1. These will put the Acceleration and Deceleration rates to almost nothing and the loco should move off immediately.
If you loco needs further fine tuning of the motor controls come back and we can advise you accordingly
Would be helpful to know what make of decoder is fitted too.

Thanks Brian will give that a go tonight, will see if I can get the make as have it on test bed so hopefully it is visible

Read CV8 and the number there should give the decoder manufacturer ID. Then use the table on the NMRA web site to locate the manufacturer. https://www.nmra.org/sites/default/file ... _2_2_5.pdf Assuming the manufacturer has registered their product!

cv3 and cv4 are part of the NMRA standard so the manufacturer shouldn't make any difference. Following the advice given by @brian will work for any decoder and will immediately reduce the auto acceleration and deceleration times to almost nothing giving you more precise control on your throttle. Maybe then play around with increasing the values a little until you get it running the way you'd like. I generally start with cv3=5 and cv4=2 which works for me.

Thanks Gents

All sorted on this one now going to go through them all to check what they are set at

So if I want to stop a loco which immediately changed direct when I switch from forward to reverse, is it simply modify Cv3 & Cv4?

station master wrote: ↑Tue Dec 13, 2022 10:11 am <Snip>
So if I want to stop a loco which immediately changed direct when I switch from forward to reverse, is it simply modify Cv3 & Cv4?

Hi
CV3 and CV4 set the amount of Acceleration and Declaration rates of the loco. CV3 setting the Acceleration rate (time) while CV4 does the Deceleration rate (time). So a loco on its own may have its CV3 and CV4 set to a value of say 3 or 5, while a heavy freight loco pulling a represented heavy load may have CV3 and CV4 values set higher to a value number of say between 30 to 50 (or even higher) to represent the loco pulling that long and heavy load to reach its set speed and the time it takes the loco to slow to a stop from whatever speed it was set at.
Switching the controller from forward to reverse will slow the loco to a stop then power it back up in reverse to whatever is set on the controller. The rate of slowing and acceleration is set by the values in CV3 and CV4. Of course if CV3 & 4 are set to a higher number then the loco will take a longer time to slow to a stop then take time to accelerate in reverse to whatever is set on the controller.

Surely switching from forward to reverse without stopping first is extremely bad practice

Walkingthedog wrote: ↑Tue Dec 13, 2022 4:49 pm Surely switching from forward to reverse without stopping first is extremely bad practice

On DC certainly. AFAIK DCC stops the loco before applying the reverse motor power.

Thanks Brian another scrap of information added to my vast knowledge of DCC.