DCC Fitted Analogue Compatible

[carlwebus]

Hi All.

 

I know  there's always much debate  about whether DCC fitted locos can/  should be run on  analogue but the general opinion is that its best not to run a DCC  fitted loco on analogue. Even those who say you can  do  so add provisos about the type of controller, Relco, pulse etc.

 

But, having noticed  that DCC fitted locos often cost less (on eBay etc)  than  straightforward analogue, I have   begun  to notice locos advertised as "DCC fitted, analogue compatible".

 

Hattons have advised me that "in some cases,  some models are  completely fine to  run on both as long as it says DCC  fitted analogue compatible, it should run perfectly on both".

 

Is that correct, and if  so how does it work?

 

I run DC using an old controller built for me by a long-gone  friend.  It is NOT feedback but  does  do inertia.

[Magstheviking]

I think it's really a mixed bag in my experience. Most DCC fitted locos, with Hornby and ESU decoders are generally fine on analogue. Bachmann decoders, especially the older ones can be a bit less consistent and have witnessed some not working at all, to juddery running at lower speeds. 

I do believe however, that some decoders have a propensity to burn out if left on analogue too long, but haven't ever seen this personally. 

If you do find a dcc  fitted model which you want to run on dc however it might just be best to buy the blanking plates for the socket, if its a dcc ready model. These can be picked up for a few quid for a pack of 4 or so. 

Hope this helps!

Edited January 13, 2022 by Magstheviking
minor spelling mistake

[RJS1977]

Two of my club colleagues regularly bring their DCC locos along to our club analogue running nights (the controllers are handmade but AFAIK have no inertia or other 'special features'). We haven't experienced any major issues - the only problem(s) we have had have been with locos which have had inertia set up on the chip - which results in a very slow acceleration curve on analogue - and one loco which for some reason runs 'forwards' on DCC but 'backwards' on analogue!

[meil]

Can it be done - yes providing the appropriate CV is set. Would I do it - no.

[WIMorrison]

This works without issue and doesn't damage the decoder, or anything else (think about it, when on DCC the decoder is permanently on  ). Nor does feeding DC only cause the decoder any issues either - the decoder already creates the DC for the motor to turn!

 

The issues you *may* have is that  some decoders do not provide any of the acceleration or lighting when running on DC, many reasonable decoders do and this can generally be turned off/on by the appropriate CV.

 

The other thing that you may notice is that some decoders do not start the loco moving until a threshold of 2 to 3v is reached, but thereafter they are completely controllable in exactly the same manner as any DC loco.

[Ron Ron Ron]

2 hours ago, carlwebus said:

….I know  there's always much debate  about whether DCC fitted locos can/  should be run on  analogue but the general opinion is that its best not to run a DCC  fitted loco on analogue. Even those who say you can  do  so add provisos about the type of controller, Relco, pulse etc…….

I don’t think there’s much debate at all.

There are very clear warnings never to put decoder fitted locos on tracks where Relco type devices are fitted and advice that feedback type DC controllers can cause problems.

Otherwise, it’s perfectly safe to put decoder fitted locos on DC controlled analogue layouts.

Just ensure the decoder hasn’t had DC running disabled in the CV settings.

 

 

 

 

.

Edited January 13, 2022 by Ron Ron Ron

[WIMorrison]

@Ron Ron Ron sorry forgot about the Relco because I haven’t seen one for years

 

feedback controllers don’t seem to cause issues - at least not that I have seen.

[Legend]

I had Relcos installed until just before Christmas when I took them out ahead of delivery of Bachman’s Precedent and Caley which I think have coreless motors . So far so good .

 

im interested in this thread because I saw over in the Accurascale manor thread that their DCC sound versions would work on DC . I believe sound works at a low setting but you have to apply more power for the loco to move off.  Not really thinking about Manor but it did get me thinking that if it worked on that it would probably be the same on their Deltic . I’m not usually a sound guy  but a Deltic would be quite distinctive . Might well take the plunge if I was certain it would work .

 

I believe Bachman sound locos do work on DC but Hornby ones don’t . I’ve also seen occasions where DCC locos just don’t work on analogue . Presumably they don’t have the relevant CV (whatever that is) set to allow analogue running as the default when it leaves factory .

[Ron Ron Ron]

1 hour ago, Magstheviking said:

........I do believe however, that some decoders have a propensity to burn out if left on analogue too long, but haven't ever seen this personally........

 

With due respect, I think you may be confusing this with putting analogue (non-fitted) locos on DCC powered track.

Something that will lead to a motor burning out. Definitely not recommended.

 

Decoders should be fine on DC powered track and won't burn out, except where Relco type devices are fitted (very bad), or certain types of feedback (or was it PWM?) controller is used.

 

There was an issue with some coreless motors when fitted with DCC decoders, burning out being run on DCC powered track, but I understand this might not be such an issue these days.

This one isn't in my area of experience or knowledge, so someone else might be able to elaborate on this particular problem.

 

 

.

Edited January 13, 2022 by Ron Ron Ron

[Pete the Elaner]

9 minutes ago, Legend said:

 

I believe Bachman sound locos do work on DC but Hornby ones don’t . I’ve also seen occasions where DCC locos just don’t work on analogue . Presumably they don’t have the relevant CV (whatever that is) set to allow analogue running as the default when it leaves factory .

 

CV is a Configuration Variable. As its name suggests, it can be turned on or off.

All decoders should work on DC. Some of the older ones don't.

As has been mentioned, decoders need a couple of extra volts before they will respond. This can be annoying, but is actually quite useful to get across a poor joint between wheel & track which causes a DC loco to stall when it should crawl.

 

If decoders work on DC, why would you turn this off? To be snobby about not allowing your locos to run on DC??

Well maybe some do but there is a good reason: Some (not all) do unwanted things with DC enabled. When reading CVs from the programming track, power is restored in very short bursts to the main layout in between each CV read in. Some (but not all) of my locos which have DC enabled shuffle along the track slightly.

I have also seen a fitted loco bought from a show which responded the opposite way to the DC setting. When DC was enabled, it did not work on DC. With it disabled, it worked fine.

 

The problem is that you need a DC system to switch DC running on & off. If a DC users buys a fitted loco, it may already be switched off. The only options are to get a friend/shop to switch it on, or remove the decoder.

[Pete the Elaner]

1 hour ago, RJS1977 said:

Two of my club colleagues regularly bring their DCC locos along to our club analogue running nights (the controllers are handmade but AFAIK have no inertia or other 'special features'). We haven't experienced any major issues - the only problem(s) we have had have been with locos which have had inertia set up on the chip - which results in a very slow acceleration curve on analogue - and one loco which for some reason runs 'forwards' on DCC but 'backwards' on analogue!

 

Forwards on DCC but backwards on analogue:

DCC takes an alternating signal & deals with it so if wired correctly, the decoder knows which way is forward.
With DC, positive is the right hand running rail, so when running forward, the right hand side should be fed from the red wire, assuming of course the motor is not wired backwards too.

When fitting a decoder to a correctly wired loco (& I have seen some done wrong), feed the red pickup to the red wire on the decoder & the orange wire goes to this connection on the motor. Likewise the black pickup wire goes to the black decoder wire & the grey decoder connection goes to where black was connected to the motor.

Most wrong combinations will cause either DCC or DC to be reversed, or maybe both.

DCC can be corrected by changing a setting. Putting DC right is a solder job.

[Magstheviking]

7 hours ago, Ron Ron Ron said:

With due respect, I think you may be confusing this with putting analogue (non-fitted) locos on DCC powered track.

Something that will lead to a motor burning out. Definitely not recommended.

 

There was an issue with some coreless motors when fitted with DCC decoders, burning out being run on DCC powered track, but I understand this might not be such an issue these days.

This one isn't in my area of experience or knowledge, so someone else might be able to elaborate on this particular problem.

 

Ah yes, apologies, it was a club member who warned me about coreless motors and I misremembered. 

Thanks

[WIMorrison]

I run coreless motors on DCC and I use DC to clean the wheels of those locos, I think I have 5 that I have converted to coreless - absolutely no issue with DCC once you have changed the CVs to match the motor type.

[Pete the Elaner]

10 hours ago, WIMorrison said:

I run coreless motors on DCC and I use DC to clean the wheels of those locos, I think I have 5 that I have converted to coreless - absolutely no issue with DCC once you have changed the CVs to match the motor type.

 

Slightly off topic (but we will get back), but this highlights a real advantage of DCC:

 

Suppose you have 2 favourite older locos: 1 runs nicely with feedback but rather poorly without it.

The other is of a type which has a habit of overheating when you run it under feedback. Which DC controller would you use or would you use cab control & switch between controllers? You could very easily use the wrong controller in error.

With DCC, the decoder controls the motor & since each loco has a decoder, it is able to provide the appropriate control to the motor. This can be adjusted by the operator, but you need a DCC system to make the adjustment.

 

But we were talking about DC:

A feedback controller can damage a DCC decoder.

But the decoder controls the motor itself, not the layout controller. This can use a smooth DC signal from the layout controller to provide feedback control of the motor.

That's quite neat.

[TWG]

18 hours ago, WIMorrison said:

I run coreless motors on DCC and I use DC to clean the wheels of those locos, I think I have 5 that I have converted to coreless - absolutely no issue with DCC once you have changed the CVs to match the motor type.

Difficulties with coreless motors are, in DCC terms, ancient history.  It is a question of the decoder output PWM frequency.  Early decoders used low frequencies, about 150Hz.  When it was discovered that this was bad for coreless motors, a higher frequency alternative was offered of about 16kHz (the first decoder to provide this was, if I remember correctly, the Lenz LE80).  This was found to be suitable for all motors, so it became standard.  CT Elektronik decoders still offer the original choice, but the alternative on many current decoders is between 16kHz and a still higher frequency (32 or 36kHz).

[WIMorrison]

With Zimo you can swap from 20kHz to 40kHz by changing CV112. Strangely, some motors run better on 40KHz than 20kHz and I tune them by using PON switching between the two frequencies to get the smoothest running.