DCC or not.

[panniertank]

I had recently bought a Gaugemaster Prodigy Advance 2 controller and a s/h loco fitted with dcc and the idea was to convert all my existing fleet of dc models to dcc - and here's where I start to get very disillusioned with dcc !

 

Firstly, I had no idea that each loco had to be programmed with tapping in various 'codes' for top speed voltage (?), acceleration (?) and other arcane stuff - I duly tapped in what I thought would seem like sensible values, but the end result is that the loco runs very erratically - and I have to fight to stop it when it eventually moves off in an anything like realistic speed ! There is NOTHING in the instruction manual about WHAT these speed/voltage values should be, and I cannot 'read' the chip in the loco (which type it is or anything as I bought the loco s/h on ebay) That aside: I bought a Hornby basic decoder to 'chip' one of my older dc locos, and THAT proved a waste of £15 literally, as I ended up chucking the damn thing against the wall when two wires broke off on the chip as I was installing it !

 

All in all, I think I have made a big (expensive) mistake in attempting to go dcc !

[Adrian Wintle]

You don't have to program anything more than the address of the loco. Decoders will have default values for all of their CVs. I would suggest resetting the decoder (if you know the type) or setting acceleration, deceleration, start voltage, etc to 0. This should give you a baseline, although it require more than speed step one to get it to move (in fact, it is likely to unless the decoder has back-EMF enabled). Once you are back in this state you can adjust the start voltage value to get the loco to just start to move on the first speed step (although you can happily run trains without worriying about anything except the address - and not even that if you only have one loco running).

 

There aren't any instructions for top speed voltage values etc. as the optimum values are dependent on the characteristics of the loco motor/driveline, the track voltage, how the specific decoder works, and how you (the user) like your locos to run.

 

DCC can be as simple or as complex as you want it to be.

 

Adrian

[ChrisB]

The basic Hornby decoder can, in my experience, cause eratic running in some locos. The basic Bachmann one is better. The basic Lenz, although a little dearer, is better still. There are plenty of others out there too.

 

I would confirm that, mostly, you should be able to install a decoder without altering any CVs apart from setting the address. Any further tweaking is mostly just a matter of personal preference. You will also find that some of the basic decoders from Hornby and Bachmann only have a limited number of CVs that can be adjusted anyway. The leaflet that comes with them tells you which ones can be adjusted.

 

What might be a good idea is to speak to someone who already has some experience of DCC and who can show you the ropes.

 

Stick with it. Once you get your head around it, you won't look back!

[Ravenser]

Firstly , you don't have to rearrange the CVs , and quite a few people don't. Setting the parameters you mention is by trial and error , and I think you should only touch them if you feel something is not perfect

 

Clearly , having entered values "blind" you now do need to do something to improve the running . There are two approaches:

 

1. Most decoders have a "reset to factory default" option . There will be a CV which does this , if you program the correct value into it. Check the paperwork with your decoder for this. The instructions for programming CVs are always with the decoder - not in the system manual. If you haven't got the instruction sheet for the decoder - and if the loco is second hand it sounds like you haven't- , you are in trouble here

 

2. Or you can try tweaking the CVs one by one until things improve

 

I am not an expert , and there are more knowledgeable folk around here, but some places to start:

 

a) Do you know what decoder is in the loco ? If you do, someone on here will probably have a copy of the relevant decoder datasheet

 

B) If you don't it's possible to identfy the decoder manufacturer from the number shown as the value in CV8

 

 

This may well be throwing you right in the deep end, but here is a weblink onto the part of the NMRA website which gives the DCC standards

 

http://www.nmra.org/standards/DCC/standards_rps/DCCStds.html

 

Of direct use to you are:

 

RP 9.2.2 - DCC Configuration Variables and

RP9.2.2 Appendix A - list of manufacturer codes for CV8

 

The list of CVs should at least give you a reasonable chance of finding what CV does what. - albeit using certain CVs for certain things is only optional

 

As a start point for emergency trouble shooting, what you describe sounds to me like acceleration and deceleration CVs are set way too high . The lag /response time is far too great . These should be CVs 3 and 4 , and as a starting point, take them down to zero , at which point the loco should respond immediately. Then increase the values in steps of one until you are happy with the degree of lag/inertia in response

 

Playing about with top speed voltage is only for things that insist on heading off at 125mph. The only loco I've done it to was a ringfield motor Hornby Lima diesel in order to tame the top speed. And you only play about with bottom speed voltage if the loco won't start until about speed step 20 - in which case you might want to make spewad step 1 a couple of volts instead of nothing

 

I'm not familiar with the Guagemaster /MRC system (I use NCE) but it sounds as if it gives you a set of "plain english " options , instead of simply expecting you to know what CV does what. That could be a lifesaver in unscrambling whatever you've done

 

I think a safe rule of thumb would be "Do not adjust a CV unless you have a clear reason for doing so"

 

Hope this helps

[AMJ]

I suggest putting the loco onto the sporgamming track and then as mentioned above do a decoder reset. Many this is sending 8 to CV 8 - see decoder manual. This will set it back to loco 03.

 

Try running it as loco 03 and it should be pretty good. Some sound decoders have optimised the various ACC/DEC etc to suit the model.

 

You will have frustrating days and good days we all did when we started out in DCC.

 

I have had wires off decoders, motors, pickups etc it's all part of the process of chipping locos. Just wait for your first blue smoke experience.

 

DON'T give up as the results at the end of the proverbial tunnel are worth it.

 

My rule was to chip the DCC ready stuff first (as it's easy) and you get many items running. Then go for the hard wire locos.

[Donw]

My first DCC was the lens compact didn't say to much about setting the CV's other than the address so I put decoders in a couple of locos and just ran them. I now have the LV101 and handsets LH100 and LH90 still don't find much need to change CV's as I am more than happy to drive locos so i just turn up the setting till it moves and adjust it by watching the loco. No problems.

Don

[Pete the Elaner]

The basic Hornby decoder can, in my experience, cause eratic running in some locos. The basic Bachmann one is better.

Irrelevant in the context of this thread & completely contradicts my experience with them. My R8249 chips all work exactly how they are supposed to. I have 2 Bachmann chips & they ignore CV3 so I have cascaded them to lighting-only decoders..

I won't be buying any more.

 

Back to topic: Why change the CVs for maximum speed etc? You really only need to do this for speed matching when pairing locos for creating consists. I would not bother with it otherwise.

[Steven B]

I'd agree with what the others have already said.

 

The only CV you have to change is the one that sets the address of the loco. I've never had anything not work because of what any of the other settings were set to.

 

If you do want to mess about with tuning the decoder, setting a top speed for example, then I'd suggest sitting down with someone with some experience. They'll be able to point you in the right direction.

 

You mention that you can't read back CV values on your Prodigy Advance 2. Is there another programming mode that will allow you to do this. The instructions on the Gaugemaster website suggest that it's capable of programming on the main line or using a programming track. Only the latter will allow CVs to be read back.

 

If there's nobody you know that can help then I'd seriously concider buying a SPROG and getting a copy of JMRI's DecoderPro running on your PC. Using the two together you can program a decoder in a fraction of the time that you'd manage if you were working out all the CV values by hand. It's got a nice graphical interface which adapts to the decoder you're programming and the settings are configured by clicking on option boxes, dragging sliders or typing in real numbers.

 

Wires tend not to fall off decoders. If yours has then it points to a poorly made decoder, or perhaps heavy handedness when it comes to doing the installation - either handling it too roughly or too much heat from a soldering iron.

 

Whilst you get your head round programming decoders stick with those models that are either DCC fitted or use 6, 8 or 21 pin decoder sockets.

 

Don't be in too much of a rush to jump in at the deep end until you understand the basics, but keep at it. It's worth perserveering with.

 

Happy modelling.

 

Steven B.

[Metalhip]

Programming decoders when you first start can seem very bewildering,but like most things,the more you do it the more familiar and easy it seems.

I always try to set the maximum speed to the scale speed the full size would do,then you can open the throttle right up and the loco won't exceed the maximum so there's no trying to judge what the right speed looks like.

 

To set the top speeds just adjust CV5 for maximum and CV6 to half that value or less,this will not work on the Bachmann six pin decoders because those CVs are not included,but it can be done by making a user defined speed table as per the supplied instructions,long winded but doable.I no longer buy the Bachmann decoders for this reason,and tend to buy the Digitrax six pin decoders instead,still less than £20.00 a pop.

 

Decoders that support main track programming can have the maximum speed adjusted on the fly by adjusting CV5 and mid speed on the throttle by adjusting CV6.

 

The struggle to stop the loco sounds like you've got momentum programmed in,set CV3 and CV4 to zero initially,this will get rid of any momentum setting.

 

Get a piece of track to use as a programming track and assuming the Prodigy can read the CVs which I think it can,you can adjust everything on the programming track and see what values you've actually got in the CVs..

 

Allan

[250BOB]

Its a little bit like the industrial revolution....many people are frghtened of DCC, or have too many old locos to begin again. Thats not a problem if you want to stay in that category.......but there is a whole new world out there with DCC, but it does take a little bit of getting use to, like anything new.

Ask all the questions you need on here, you get help all the way.......5 years ago I introduced myself as the DCC Knumbskull....not any more though......I'm 63 and love it to bits.

Bob

[johnd]

The flexibilty it offers of Loco control is like a whole new world and once experienced you will be unlikley to go back to DC control.

[roundhouse]

If you decide to go DCC dont try to do everything DCC can do all at once but start off learning the basics such as programming the loco address, start voltage, acceleration and braking.

When I first started DCC I used handheld contorllers on a dc layout, so I wired up the same type of plug as the handheld controller had but just the power to track from the DCC system (the 16v power to the handheld not being required) in the plug. This was then plugged in to the panel instead of the handheld controller and all section switches switche on.

 

Once I got the hang of these basics I then moved on to more advance DCC functions such as stationary decoders, wireless control and programmingllocos via a PC etc.

 

It can consume your time more so than the actual modelling if you so wish but DCC has many great benefits, even more so if what you are modelling has lights in the locos and coaches and you want to move onto Sound.

 

Ian

[34theletterbetweenB&D]

... I had no idea that each loco had to be programmed with tapping in various 'codes' for top speed voltage (?), acceleration (?) and other arcane stuff ...

...There aren't any instructions for top speed voltage values etc. as the optimum values are dependent on the characteristics of the loco motor/driveline, the track voltage, how the specific decoder works, and how you (the user) like your locos to run...

These are the very reasons some of us really value DCC. I spent a whole fortnight of operation sessions just getting to grips with literally everything my new system could do, in order to learn what was what and what I would actually use. Just as with any bit of new gear some orientation investment really pays off.

 

But I do wish my system let me do some sporgamming of spewad. But it is from Lenz and thus sehr ernst, none of this exotic stuff

[Suzie]

As others have said you should not need to adjust anything other than the address. Erratic running can require you to tune the decoder to match the motor, but the erratic running that you describe is down to a combination of a poor decoder and poor pickups on the loco. Fix either and you should be OK

 

Try a good quality decoder like a Zimo and fit it to your best loco and you should have a good experience without having to configure anything. With that you will see what you have to do to get the rest running as sweetly.

[GoingUnderground]

.......All in all, I think I have made a big (expensive) mistake in attempting to go dcc !

 

IMHO your mistake was to jump in without understanding DCC and how you use it.

 

But all is not lost. In addition to the advice given here, start reading up on DCC, Ian Morton's book on DCC is very good, and there are other books covering similar ground.

[shibushe]

It seems to me you have indeed jumped before you can walk. But as others have said do not give up, going from analogue to DCC is a big learning curve.

There can be a problem with cheap decoders as I have found in the past, best to spend a bit more. As for programming, well yes you can leave all of them at 0 except CV1 the loco Id, but to achieve the benefits of DCC and to get the best from it programming is a must. You do not have to get to involved with the more advanced CVs, you will run your railway just as good at the basics.

With decoders you get what you pay for, an example. I have hard wired a few tender drives, and soon found that a cheap decoder just will not drive a loco properly, I now use ZImo, in fact I have done one today, without any programming at 03 that loco like all the others will crawl at step 1. You say you have experiaced jerky running, this could be caused by not removing the suppression capacitor, usually fixes it.

Setting a top speed CV 5, is important to get realistic running, but to get the best you must use CV 6 also. Once you have a value of CV 5 find a percentage of that and set CV 6 to that value. Do make notes of how you proceed with setting Cvs so you know where you been. Or if your controller does it read back. If we know of your location there may offers to come and play a DCC set up, Glad to help if I can. Remember there is this forum for help no matter how daft the question. Regards.