Tweaking CV's

Post all your DCC only problems, solutions and discoverys here.
User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Tweaking CV's

Postby Essex2Visuvesi » Thu Aug 09, 2012 11:39 am

how many of you spend more time tweaking CVs on a decoder than actual running?
I get something running and then get to thinking "what if I change this a little?... that's a bit better... now what about this one" Next thing you know you have wasted half an hour fiddling and gained little or nothing
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

User avatar
SRman
Posts: 1006
Joined: Fri Oct 03, 2008 2:26 am

Re: Tweaking CV's

Postby SRman » Thu Aug 09, 2012 12:45 pm

That's where Decoder Pro (JMRI free software) comes in handy if you have a computer linked to your command station/programming track (and your system supports a computer link, of course).

1. You can read and write 'pages' of changes at a time.
2. Doing so takes mere seconds, as opposed to programming each CV through your controllers or command station.
3. You can save settings so you can restore the decoder to earlier settings if you deem it necessary.
4. You don't have to know what CVs do what as it is all set out for you on the screen - changing which function works on which number is as easy as ticking or unticking a checkbox.
5. If the decoder supports speed tables, you can drag the sliders to wherever you want them on the scale for each speed step, again without ever having to know which CV sets which speed step.
6. You can also create virtual throttles to control more locomotives on your layout for no extra cost.
7. It's free! (Yes I know I said it before but that's such an important point I thought i would repeat it!!!!) . :lol:

I have no connection whatsoever to JMRI or any computer manufacturers either, just a very satisfied user of the software. If you are able to connect a computer and use it, it is worth a try. Not knowing which brand of DCC you are using, I can't say for sure that you can do so.

In answer to your original poser, yes I do fiddle and tweak settings until I am happier with the running, or until I give up after not achieving any improvements. :roll:

User avatar
pete12345
Posts: 838
Joined: Fri Apr 14, 2006 7:53 pm
Location: Coventry

Re: Tweaking CV's

Postby pete12345 » Thu Aug 09, 2012 12:59 pm

I tend to set up the starting voltage and maximum speed in order to improve the control of the loco, but otherwise I don't feel it's necessary unless you're playing around with lighting effects etc.
Once an engine attached to a train, was afraid of a few drops of rain...

User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Re: Tweaking CV's

Postby Essex2Visuvesi » Thu Aug 09, 2012 4:33 pm

SRman wrote:That's where Decoder Pro (JMRI free software) comes in handy if you have a computer linked to your command station/programming track (and your system supports a computer link, of course).

1. You can read and write 'pages' of changes at a time.
2. Doing so takes mere seconds, as opposed to programming each CV through your controllers or command station.
3. You can save settings so you can restore the decoder to earlier settings if you deem it necessary.
4. You don't have to know what CVs do what as it is all set out for you on the screen - changing which function works on which number is as easy as ticking or unticking a checkbox.
5. If the decoder supports speed tables, you can drag the sliders to wherever you want them on the scale for each speed step, again without ever having to know which CV sets which speed step.
6. You can also create virtual throttles to control more locomotives on your layout for no extra cost.
7. It's free! (Yes I know I said it before but that's such an important point I thought i would repeat it!!!!) . :lol:

I have no connection whatsoever to JMRI or any computer manufacturers either, just a very satisfied user of the software. If you are able to connect a computer and use it, it is worth a try. Not knowing which brand of DCC you are using, I can't say for sure that you can do so.

In answer to your original poser, yes I do fiddle and tweak settings until I am happier with the running, or until I give up after not achieving any improvements. :roll:


I use JMRI myself... when I mentioned teaking CV's I meant in general... as in whatever way you find the best beat via the controller or via decoder pro
My system is unique... a mismatch of things lol
Fleischmann Twincenter as the main control system connected via com port to the PC. But I also have 2 Digitrax loconet throttles and a Fleischmann LOK boss (Even more basic than the Bacchy E-Z Command but it does have loconet)
I have a Veissmann commander as well but that's still in a box

All I need now is a permanent layout lol
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

User avatar
thebritfarmer
Posts: 1490
Joined: Tue Jun 14, 2011 11:46 pm
Location: Windsor, Ontario
Contact:

Re: Tweaking CV's

Postby thebritfarmer » Thu Aug 09, 2012 4:39 pm

So far I have been lucky and not had to tweak anything. Maybe I should be? and have just not noticed anything or have been lucky?

I am using the Bachmann decoders 8 & 21 pin I do have a Hornby decoder but not happy with that.
All Aboooooard !!

Brossard
Posts: 303
Joined: Thu Apr 26, 2012 1:37 am
Location: Brossard, QC

Re: Tweaking CV's

Postby Brossard » Thu Aug 09, 2012 5:22 pm

In my experience there isn't a lot of CV tweaking needed. I like to ensure that the loco just moves on speed step 1 by adjusting Vmin, as Pete has said. If this takes a lot of adjustment, Vmid and maybe Vmax may need adjusting as well. The other thing I might do is to adjust Back EMF to get the loco moving reliably at a crawl.

I am not a fan of Bachmann or Hornby chips. While they do work quite well, I don't like that there is so little CV support. For 21 pin I would opt for Lenz Silver. For others I have used NCE, Digitrax and most recently DCC Concepts. All these are good with lots of CVs to tweak. I like DCC Concepts because they come with flying leads to attach a "stay alive" if one is required. My sound decoders are all ESU Loksound - excellent.

John
John

User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Re: Tweaking CV's

Postby Essex2Visuvesi » Thu Aug 09, 2012 5:25 pm

The best decoders I have found for my needs ar the Digitrax DZ125, SDN144PS and the CT SL75 and 76
I am slowly amassing a selection of "blown" Decoders for carriage and other lighting projects
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

lennie
Posts: 154
Joined: Tue Jan 25, 2011 1:02 pm

Re: Tweaking CV's

Postby lennie » Thu Aug 09, 2012 5:59 pm

The whole idea of a loco fitted with a decoder to to be able to run a loco in a realistic manner. You could of course just set Cv1 and run the loco on the throttle. By taking a bit of time setting the CVs much more rewarding and you only have to do it once.
Personally I only use CVs 1 to 6. You have probably noticed in the instruction sheets there are many more Cvs all doing different things, with top end decoders the numbers are vast, I must admit they are beyond my capability.
Cv 6 The speed curve can look a bit confusing. The best way, and easier is. Once CV5 is to your liking then divide this by a percentage, say 80% then apply that figure to CV6 this will bend the curve, raise or lower the percentage to your liking. Its a known fact that Cv5 & 6 should be applied together to smooth out the curve.
If you have locos with lights, then its only one button press FO to turn them on/off.
If your decoders have BEMF better still. Good Luck.

User avatar
raistlin295
Posts: 686
Joined: Thu Dec 14, 2006 1:04 pm
Location: Wolverhampton

Re: Tweaking CV's

Postby raistlin295 » Thu Aug 09, 2012 6:16 pm

I have the LOK Programmer connected to my test track. Can the JMRI software work via that please?
Paul

Finsbury Road My Layout

User avatar
Essex2Visuvesi
Posts: 2357
Joined: Thu Aug 28, 2008 4:51 pm
Location: Finland, Finland, Finland!

Re: Tweaking CV's

Postby Essex2Visuvesi » Thu Aug 09, 2012 6:52 pm

raistlin295 wrote:I have the LOK Programmer connected to my test track. Can the JMRI software work via that please?


Fraid not... thats purely a esu sound decoder programmer.... I think you can do CVs via the ESU software with it tho
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

Proud member of the OAM
(Order of the Armchair Modeller

User avatar
raistlin295
Posts: 686
Joined: Thu Dec 14, 2006 1:04 pm
Location: Wolverhampton

Re: Tweaking CV's

Postby raistlin295 » Thu Aug 09, 2012 7:23 pm

Essex2Visuvesi wrote:
raistlin295 wrote:I have the LOK Programmer connected to my test track. Can the JMRI software work via that please?


Fraid not... thats purely a esu sound decoder programmer.... I think you can do CVs via the ESU software with it tho


OK, thanks for that :)
Paul

Finsbury Road My Layout

User avatar
SRman
Posts: 1006
Joined: Fri Oct 03, 2008 2:26 am

Re: Tweaking CV's

Postby SRman » Fri Aug 10, 2012 1:49 am

Mostly, I find that leaving things as they are works well, with the exception that I, personally, like a lot of inertia/momentum, which means tweaking CVs 3 & 4. Some of this stems from having quite a few sound-fitted locos and my desire to match the running characteristics for both sound- and non-sound-fitted items.

Just occasionally I come across something that doesn't want to 'play ball', such as one of my double-motored LT Underground units, and then I delve into Decoder Pro a lot more to find settings that work better without having to mess around with lots of different individual CVs.

Another example was one of my three M7 tanks: all three are fitted with TCS DP2X-UK decoders and two of them worked perfectly from the word 'go' so no adjustments were necessary (apart from my applying the usual CV 3 & 4 tweaks), but the third locomotive exhibited odd behaviour in one direction only, which was fixed by turning off the Back EMF settings and tweaking quite a few CVs to compensate, such as start voltage and top speed, inertia and momentum and a few others as well.

Bigmet
Posts: 6889
Joined: Tue Aug 14, 2007 2:19 pm

Re: Tweaking CV's

Postby Bigmet » Fri Aug 10, 2012 10:54 am

I have been quite amused at exhibitions to find DCC operated layouts with locos left on default values for CV's 3 and 4, and all the acceleration and slowing essentially on direct control. I do much the same as SRman describes and use big values to model something like a heavy unbraked freight realistically. With CV4 set to 150 you soon realise why these things went slowly in reality: run it up to maximum speed, then set to speed step zero, and it won't stop for over two minutes. And you get the most beautifully regulated gradual slowing.

User avatar
SRman
Posts: 1006
Joined: Fri Oct 03, 2008 2:26 am

Re: Tweaking CV's

Postby SRman » Fri Aug 10, 2012 12:54 pm

I usually use settings somewhere in the vicinity of 15 - 30 for CV3 and 12-15 for CV4, depending on the type and brand of decoder as well as the motor characteristics. Even those make for some interesting times when shunting! Your settings must really take some forward planning and driving skill, Bigmet. :) I have to agree that having these higher values really smooths out the acceleration and deceleration, though.

Brossard
Posts: 303
Joined: Thu Apr 26, 2012 1:37 am
Location: Brossard, QC

Re: Tweaking CV's

Postby Brossard » Fri Aug 10, 2012 3:19 pm

Yep, Bigmet, if you want to annoy me, leave momentum at 0. Locos leaping into action or stopping suddenly are very irritating. So many people don't get it.

John
John


Return to “DCC Forum”

Who is online

Users browsing this forum: No registered users and 5 guests