Setting up locos when adding TTS Decoders

[WilliamDavid]

When adding an A3 decoder to a non sound A3 loco, Minoru for example, should one enter the Minoru and add the sound functions, or enter the Flying Scotsman TTS and change the title and picture? 

 

[St1ngr4y]

Hi William,

If you do it the latter way, RM will set up the sound functions for you, but you may need to add "on/off" to the descriptions of the latching functions. This has been discussed recently in this thread:-

 

https://www.hornby.com/uk-en/forum/railmaster-and-tts-decoders/?p=1

 

Ray

[WilliamDavid]

My point is there is a difference in scale speeds depending on how you do it?

Is the TTS decoder for each type neutral, as the standard decoder?

[St1ngr4y]

I asked that same question in the last paragraph of my first post on that thread, but no one has been able to answer it. Not even HRMS, who haven't even acknowledged receipt of the email I sent them.

 

Ray

[Britannia Builder]

I've investigated this a little further, using the example of my Peppercorn A1 'Bon Accord' which I fitted a TTS decoder to recently. I used the TTS Tornado template in RailMaster to set the loco up, which gives all the correct sound functions and is certainly the quicker way to do it.

 

The speed profile settings in Resource.mdb are quite different for the original non-TTS Bon Accord and the TTS Tornado, as shown below. The first figure is the 'Factor' and the others are the 'Speedcurve' values corresponding to 5, 10, 20, ... 80 mph. The Factor needs to be multiplied by the appropriate Speedcurve value to get the mapping from mph to speed steps (along with the speed and another constant). So for example at 10mph the multiplier is 0.8x2 = 1.6 for non-TTS and 0.692x1.881 = 1.30 for TTS. Hence the two approaches (adding sound functions to the original profile, or changing the name and picture on the TTS profile) will give quite different results -  the TTS will be slower at 10mph in this example.

 

0.8        2.300,2.000,1.850,1.519,1.313,1.174,1.075,1.050,1.020,

0.692    2.316,1.881,1.411,1.131,1.021,0.936,0.876,0.816,1.446,

 

Since the TTS profile has been set up by HMRS with the correct TTS decoder, one would expect this to give better results assuming the motors and gearing and wheel diameter and friction etc are the same in both models - I'm not sure whether this is the case here.

 

A further complication is that if you then change the motor algorithm by setting CV150 to 1, the speed changes quite a bit - generally faster in my case. HMRS will presumably have used the default CV150=0 when doing their speed profiling. I think it would be better if Hornby set the default CV150 to 1, since this seems to me to give better slow speed running in all 4 TTS models that I've tried.

 

Regards, John

 

 

[St1ngr4y]

Hi John,

Just nit-picking here - is that last figure for TTS (1.446) correct - should it not be less than 0.816 ?

 

Ray

[Britannia Builder]

Hi Ray

 

The speedfactor numbers do generally reduce from left to right but I don't think there's any reason why they have to. The higher factor at 80mph suggests that the decoder needs to be given a lot more speed steps to push the motor right up to the top speed. Interestingly my Duke of Gloucester TTS has a similar higher factor at 80mph, so perhaps it's a quirk of the TTS decoder?

 

Regards, John

[WilliamDavid]

Thank you, Britanniabuilder.

At last someone who was able to get what I was badly trying to explain.

I will give all of my fourteen TTS locos a try at CV150=1 to see what happens.