Newbie DCC user, loco seems too fast a speed step 1.

[G-BOAF]

Completely newbie DCC user here. Just playing with my first controller and chipped loco (no idea why it has taken me so long to convert!) and I'm having problems with really low speed control.

 

Prodigy Advance 2, Lenz 6 pin silver, Bachmann SR USA Class

All works lovely, BUT speed step 1 seems too fast.

I've adjusted the start voltage to Zero (I assume this means that speed step 1 is zero volts, but clearly not...?!), but this has not made any difference.

I've also set the mid speed to 24 out of 255 to give the loco fine control at the low end of the speed range (default was 48).

I've changed to 128 speed steps as well but no difference.

 

I appreciate that DCC is discretised, but would expect a really slow imperceptible crawl at speed step 1, even if at the expense of fine adjustments at higher speeds.

 

Can anyone help me???!

[Izzy]

Like many decoder makes Lenz do not have wonderful motor control at the bottom end of the range. And little or no real adjustments either. Few do. To get what you are seeking using Zimo decoders is the answer. No others, save CT, can match their motor control, or the wide range of cv adjustments they have. Just the basic £20 budget ones will do the job, the motor control is standard across the range irrespective of price. I don’t bother with anything else since it’s false economy. 

[SamThomas]

I would try lowering CV5 to something like 25 & CV6 to around 12 & see what difference that makes.

 

What settings have you for CV's 3 & 4.

 

 

[SamThomas]

4 minutes ago, Izzy said:

Like many decoder makes Lenz do not have wonderful motor control at the bottom end of the range. And little or no real adjustments either. Few do. To get what you are seeking using Zimo decoders is the answer. No others, save CT, can match their motor control, or the wide range of cv adjustments they have. Just the basic £20 budget ones will do the job, the motor control is standard across the range irrespective of price. I don’t bother with anything else since it’s false economy. 

A pretty unhelpful post.

 

At least we could try & help the OP & then if he cannot get the performance he is happy with then suggest a different decoder.

 

FWIW the few Zimo decoders I have are nowhere near as easy to set up as Lenz or ESU.

[Izzy]

9 hours ago, SamThomas said:

A pretty unhelpful post.

 

At least we could try & help the OP & then if he cannot get the performance he is happy with then suggest a different decoder.

 

FWIW the few Zimo decoders I have are nowhere near as easy to set up as Lenz or ESU.

I was being helpful, based on my experience of using such decoders. You may try all the cv tricks and changes you can - and believe me I have - but it will make absolutely no difference at all. Decoders with motor control firmware that can’t persuade a motor to turn over pole-to-pole won’t somehow change. Playing around with speed curves, acceleration rates etc certainly won’t. 
 

So, to help the OP avoid all the grief and frustration many of us have battled with over the years/decades I offered the simplest long term and most economical solution. He can take it or leave it as he sees fit, as can you.

[SamThomas]

I still find your post unhelpful in effectively telling the OP he needs to replace a decoder he has already bought.

 

People have different levels of sucess with different methods & equipment.

 

We both seem to have had opposite success rates with Lenz & Zimo.

 

I would be the first to agree that once you have tried with what you have then it's time to look around.

 

I can get a Lenz Silver or Gold to turn "pole to pole" (why you would want to do that in practical terms is beyound me) so "Playing around with speed curves, acceleration rates etc" (your quote) may, as I've already said give the OP the prformance he wants & is happy with.

 

I note that you have ignored my comment about setting up Zimo decoders compared to Lenz.

[WIMorrison]

Zimo decoders work 'out of the box', unlike Lenz which need a lot of tweaking to work as well as a Zimo decoder.

[Oldddudders]

Set CV3 to something like 30 or 40, and work from there. I'm also not clear why you have set mid-speed to be only 24. To my mind that means all your lower speed steps are compressed, although in 20 years I'm not sure I've ever tinkered with that CV. Surely setting it to well over 100 would give more room for adjustment as you drive? Few locos really need their top-end due to the limited space most of us have, whereas subtlety at lower speeds is very handy. 

[Harlequin]

14 hours ago, G-BOAF said:

Completely newbie DCC user here. Just playing with my first controller and chipped loco (no idea why it has taken me so long to convert!) and I'm having problems with really low speed control.

 

Prodigy Advance 2, Lenz 6 pin silver, Bachmann SR USA Class

All works lovely, BUT speed step 1 seems too fast.

I've adjusted the start voltage to Zero (I assume this means that speed step 1 is zero volts, but clearly not...?!), but this has not made any difference.

I've also set the mid speed to 24 out of 255 to give the loco fine control at the low end of the speed range (default was 48).

I've changed to 128 speed steps as well but no difference.

 

I appreciate that DCC is discretised, but would expect a really slow imperceptible crawl at speed step 1, even if at the expense of fine adjustments at higher speeds.

 

Can anyone help me???!

 

This may be a daft question but...

 

Since you say that none of your CV changes have made any difference, are you sure they are actually being written to the decoder? Have you read a value, changed it and read it back again and seen it actually change to the new value?

 

 

Edited October 5, 2021 by Harlequin

[SamThomas]

2 hours ago, WIMorrison said:

Zimo decoders work 'out of the box', unlike Lenz which need a lot of tweaking to work as well as a Zimo decoder.

Not my experience of them, but at least you admit that Lenz are as (or can be) good as Zimo.

 

It takes usually takes me less than 10 minutes to set up a Lenz & that includes acceleration/decelleration/top & mid speed/starting/light intensity for automatic running.

[G-BOAF]

I will check the CV read back when I next have my test track out; this is fair advice. I believe I will have to wire my end to end as a programming track to actually read the CVs.

 

I would have thought if I set the start voltage to zero, speed step 1 would have been zero volts (or zero out of 255 increments?), and yielded no response from the loco. Even if low speed control is not great, I would have expected if I set the decoder start voltage to below Vmin for the loco on DC (which is about 3-4 volts), it should NOT be moving at a.. So it is weird that the loco is even moving.

 

I bought the Lenz silver as I believed it was one of the better decoders out there. Its not cheap either... I guess I could try a Zimo...

I'm beginning to remember why I put off going DCC - expensive chips and a fair amount of trial and error. Maybe I will just stick to using only sound fitted models with DCC...

 

[Izzy]

1 minute ago, G-BOAF said:

I will check the CV read back when I next have my test track out; this is fair advice. I believe I will have to wire my end to end as a programming track to actually read the CVs.

Please don’t do what numbskull me did when I first got my Prodigy system and try wiring the main output and the program output to the same piece of track. They are both live all of the time, so it all just went belly up - the main blowing the program output - and had to go back to Gaugemaster for repair ……..

 

I also started off with Lenz decoders like you, the best etc. and nearly ditched it all being utterly dismayed with the poor control compared to what I was used to with DC. Luckily in the nick of time I found CT & Zimo along with Sprog and JMRI/decoder pro. It has been a long journey, now in the distant past.

[G-BOAF]

7 minutes ago, Izzy said:

Please don’t do what numbskull me did when I first got my Prodigy system and try wiring the main output and the program output to the same piece of track. They are both live all of the time, so it all just went belly up - the main blowing the program output - and had to go back to Gaugemaster for repair ……..

 

I also started off with Lenz decoders like you, the best etc. and nearly ditched it all being utterly dismayed with the poor control compared to what I was used to with DC. Luckily in the nick of time I found CT & Zimo along with Sprog and JMRI/decoder pro. It has been a long journey, now in the distant past.

I will not wire them at the same time to the same piece of track!

[jpendle]

Hi,

 

This won't solve your decoder issue but speed step 1 doesn't equate to zero volts that would be speed step 0.

 

Regards,

 

John P

[G-BOAF]

5 hours ago, Oldddudders said:

Set CV3 to something like 30 or 40, and work from there. I'm also not clear why you have set mid-speed to be only 24. To my mind that means all your lower speed steps are compressed, although in 20 years I'm not sure I've ever tinkered with that CV. Surely setting it to well over 100 would give more room for adjustment as you drive? Few locos really need their top-end due to the limited space most of us have, whereas subtlety at lower speeds is very handy. 

This is my confusion. - I set it to mid speed as 24 with the thinking this would put the VAST majority of speed steps towards the 'below mid' side of the curve, meaning speed step 1 (I hoped) would be slower. Have I in fact gone the wrong way? Default for the chip was I think 48.

 

21 minutes ago, jpendle said:

Hi,

 

This won't solve your decoder issue but speed step 1 doesn't equate to zero volts that would be speed step 0.

 

Regards,

 

John P

 

Oh, I thought the 'starting voltage' was speed step 1. I set the SV to 0 (assuming it wrote properly to the decoder), with the thinking step 1 would be zero and I could then work up from there. This doesn't appear to have happened.

Not had a chance to do a CV read back yet...

 

 

This is ALL new to me, which is weird as I count myself as a relatively experienced RTR modeller (both plonking, modifying (with occasional painting) and running), but DCC is a complete learning curve.

Edited October 5, 2021 by G-BOAF

[Nigelcliffe]

1 hour ago, G-BOAF said:

This is my confusion. - I set it to mid speed as 24 with the thinking this would put the VAST majority of speed steps towards the 'below mid' side of the curve, meaning speed step 1 (I hoped) would be slower. Have I in fact gone the wrong way? Default for the chip was I think 48.

 

You're reading things correctly.  Slower "mid speed" will mean that between "stop" and "halfway" on the throttle will only change the actual loco from "stop" to "slow mid speed", so there is more speed control at slower speeds.   

 

 

1 hour ago, G-BOAF said:

Oh, I thought the 'starting voltage' was speed step 1. I set the SV to 0 (assuming it wrote properly to the decoder), with the thinking step 1 would be zero and I could then work up from there. This doesn't appear to have happened.

Not had a chance to do a CV read back yet...

 

Zero might mean something else.  Depends on the decoder.  It doesn't mean "0volts" on the first setting on the throttle (and treating CV2, 5, 6 as "volts" is misleading anyway, as its a PWM on/off ratio).  

 

 

Some decoders (Zimo, CT, possibly others) offer ways to set the effective speed range before one starts tweaking the speed curve with either CV2/5/6, or the 28-point curve.  http://www.2mm.org.uk/articles/Zimo-decoders.htm    (I need to update the image in the article to reflect the update I made to the JMRI pane for Zimo decoders...).  

 

 

 

- Nigel

 

 

 

[HLT 0109]

I can't be sure this is relevant to OP's particular decoder but I have three locos with Lwnz decoders - 2 Junior 00 gauge items and one N gauge - all steamers.  The manual for my Lenz Silver states that the first step in setting motor control is to select the type of motor from a list of five in CV 50 - see section 6 on page 16.  This may be worth a try if available on the decoder in question.

 

Harold.

[Izzy]

22 hours ago, SamThomas said:

I can get a Lenz Silver or Gold to turn "pole to pole" (why you would want to do that in practical terms is beyound me) so "Playing around with speed curves, acceleration rates etc" (your quote) may, as I've already said give the OP the prformance he wants & is happy with.

 

In a word, inertia from rest. To help give the impression of a mass gaining increased velocity from a standing start. Not starting with a jolt at a fast walking pace as many decoders are only capable of delivering - whether using 28/128 steps (it's immaterial to the initial start voltage level)  and which the OP is trying to overcome with the Lenz silver he has, the inability of the decoder PWM firmware algorthms to deliver small/fine enough pulses for more efficient motors.  I haven't been able to achieve it with any of the Lenz I've had, goodness knows I've tried,  but it's just out-of-the-box performance with Zimo/CT on default settings.

 

As you seem to be indicating you have no problem with Lenz I can't quite understand why you are not advising which cv's/motor parameters to adjust to get this level of performance, eliminating the jolt from start/minimal fast walking pace. I for one would be most grateful to you. I'm always keen to learn.

 

[SamThomas]

1 hour ago, Izzy said:

 

As you seem to be indicating you have no problem with Lenz I can't quite understand why you are not advising which cv's/motor parameters to adjust to get this level of performance, eliminating the jolt from start/minimal fast walking pace. I for one would be most grateful to you. I'm always keen to learn.

 

Generally, I set the CV's in this order after the address (initial settings in brackets) ;

CV5 (100)

CV4 (50)

CV3 (50)

CV6 (50% of CV5)

CV2 (0)

Usually, I fine tune each CV before moving onto the next.

Works for me. However, my fleet is 100% European Mainland Models so, thinking about it, it may make some difference but lets not go there.

 

FWIW the two locomotives I have that have Zimo Decoders fitted are both Roco, both very light 4 wheel locomotives - a Glaskasten & a Koff. I purchased Zimo for the two reasons - the Lenz equivelent was out of stock at the time & I wanted to give Zimo a try.

 

That's all I have to say on the subject really.

 

Feel free to have the last word.

 

[Izzy]

6 minutes ago, SamThomas said:

Generally, I set the CV's in this order after the address (initial settings in brackets) ;

CV5 (100)

CV4 (50)

CV3 (50)

CV6 (50% of CV5)

CV2 (0)

Usually, I fine tune each CV before moving onto the next.

Works for me. However, my fleet is 100% European Mainland Models so, thinking about it, it may make some difference but lets not go there.

 

FWIW the two locomotives I have that have Zimo Decoders fitted are both Roco, both very light 4 wheel locomotives - a Glaskasten & a Koff. I purchased Zimo for the two reasons - the Lenz equivelent was out of stock at the time & I wanted to give Zimo a try.

 

That's all I have to say on the subject really.

 

Feel free to have the last word.

 

Thank you. If you criticise posts then don’t be surprised if people respond likewise.

[Sir TophamHatt]

On 06/10/2021 at 10:36, SamThomas said:

However, my fleet is 100% European Mainland Models so, thinking about it, it may make some difference but lets not go there.

 

Maybe we should...

 

I can't say I really notice much difference between Lenz or Zimo here in Sodor but older loco motors simply aren't the best with DCC, no matter how much effort you make.

For some people, they will have trouble with Lenz...  stick in a Zimo and away they go.  But there's simply too many variables with motors, how serviced the loco is and all sorts that can get in the way of valuable data on "which chip is best".

 

The main differences for me is whether the physical size of the chip fits in the space I have - with some locos it's literally come down to that, or whatever I have left in the box.