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Hornby Class 60 decoder problem

The Bulldozer

By The Bulldozer
in Hornby DCC

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The Bulldozer Rookie

The Bulldozer

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Hi,
I'm having trouble fitting a TTS decoder to R3572 Class 60.

I've run the loco in with 40 minutes each way on a rolling road on dc power adn the loco is running smooth and is responsive.  I fitted the TTS decoder last night and test ran it.  The sound is working fine but the motor response is not good.  My NCE Power Cab has 128 step speed control but I find that nothing much happens up until I get to about 110  of those speed steps.  The top speed is very slow - I would approximate that it's doing approximately 30 miles per hour top speed.

I've seen other other posts on the forum (and in the decoder manual) regarding speed steps and Back EMF and have made sure that CV10  is set to 128.

I've also seen posts regarding CV150/151/152.  I've set CV150 to 0, CV151 to 255, CV152 to 1 but this has made no difference.  I also found a post saying try CV151 and 152 to 35 but this has made no difference.

I tried the decoder in R3487 Class 66 and it responds fine - immediate response and good top speed.

I have tried a different decoder (not sound) in the Class 60 and whilst it responds immediately at a low speed step, the top speed is not improved.   

Can anyone suggest something that might explain this adn help me fix it?

Simon

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Fishmanoz Grand Master

Fishmanoz

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Setting CV10 to 0 turns off back EMF load compensation entirely and should not be necessary.  The Hornby notes say in rare cases reducing it will give smoother low speed operation.  This seems weird as at low speed BEMF will still be working unless the CV is reduced to a very low value and this isn’t recommended.

 

There are certainly very many reports on here that changing motor algorithm improves jerky running.

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The Bulldozer Rookie

The Bulldozer

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Thanks for your replies - late last night, I tried CV150 last night with 153 and 154 set to 35.Repsonse was much improved at low speed stpe but the top speed was not affected.I'll do much more testing tomorrow including seeing what current the loco is drawing.

Any suggestions where I should start with the settings for CV153/4 ?

Otherwise, it's gonna be try it and see.

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96RAF Grand Master

96RAF

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This explains the basics behind PID tuning of motors. TTS allows part of this process to be carried out. Read this then reread the explanation in the TTS leaflet.

https://tonystrains.com/dcc-motor-control-with-back-emf-and-p-i-d/

A bit ‘techy’ but every little information helps us understand what we re fiddling with.

Rob

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jane1707819582 Rising Star

jane1707819582

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Thanks for your replies - late last night, I tried CV150 last night with 153 and 154 set to 35.Repsonse was much improved at low speed stpe but the top speed was not affected.I'll do much more testing tomorrow including seeing what current the loco is drawing.

Any suggestions where I should start with the settings for CV153/4 ?

Otherwise, it's gonna be try it and see.

alter  the values of cv 153/4 by values of 5 up or down until smooth running is achieved , my rule of thumb is  

 if the jerking is whilst accelerating alter 153 .

 if decelerating alter 154 .

of coarse there will be exceptions to the rule !!, 

please compare the service sheets of your class 60 with the class 40 tts , if similar i will set up my 40 and alter the c.v 's

and try to create a similar fault 

 

 

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The Bulldozer Rookie

The Bulldozer

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Thanks for everyone's replies -

Rob, The PID/Back EMF info was a very interesting read though not the final solution in this case.Fishmanoz, flipping between the 2 algorithms has smoothed out my lumpy low-speed performance but had no effect on the top speed.Jane2, the class 60 was drawing around about what I was expecting - a bit high perhaps - about 0.5 amps normal with a peak of 0.85.  As per above, the CV150 change hasn't had any effect on the top speed - only on the smoothness at low speeds.

However, I have made some progress - I found this post on a different forum http://www.rmweb.co.uk/community/index.php?/topic/52016-help-with-nce-powercab/

The symptoms were identical to mine so I decided to try the 60 using my e-link (which I am using for the accessory bus).  I found the class 60 runs fine on e-link so I know that the problem must be the low track voltage supplied by the Powercab.

My options now seem to be

1. to upgrade my Powercab with a better Power Supply - I have seen comments that Digitrains do one but that they are currently sold out,2. buy a booster which will cost me more than I paid for the Powercab, or3. perhaps investigate using a tablet as a throtle with e-link

Thanks again for your replies,

Simon

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  • 11 months later...
Sultan Collaborator

Sultan

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Having just fitted a Hornby TTS decoder to my R2488 '60026' I am also getting jerky running at speed steps below 10. Interestingly the running is perfectly smooth in both directions with the sound off.  I am running NCE Power Cab as my DCC controiller with addition Pro Cab hand set and Engineers throttle.  I do not get this behaviour with any other loco currently on my layout.

I have disabled DC operation and that has made no improvement.

Many decoder fitting guides advise removing any capacitors on PCBs of wired directly across the motor terminals.  I am not sure whether this would improve sound running as it does not affect non sound running.  To access the capacitor on my particular model will require removal of the PCB and all those lighting wires etc and rewiring to the motor as there is no slack on the capacitor connections.  Has anyone on this forum removed the capacitor?

I have read alot about this fault on this and other forums and it would appear that this is a programming/manufacturing fault and as such should be rectified by Hornby.  Has anyone approached Hornby directly and if so what was their reply?

I understand that TTS decoders are much cheaper than Loksound or ESU etc but they must be fit for purpose.

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