deceleration cv values - hornby 08 shunter

2432 Views 10 Replies 7 Participants Last post by Brian Considine, Nov 19, 2008

Brendan11

Discussion Starter · Nov 18, 2008

hiya group,

I've got a hornby 08 shunter (hornby decoder in it), i like the slow speed it runs at. However if i put it into reverse (without slowing it down) it stops dead and revereses. If poss I'd like it to gradually slow down and then reverse and not stopping dead. With other locos they slow down gradually before reversing.

I've not been brave enough to tinker with any cv values before but might give this a go. Any help advice suggestions would be great.

thx

bren

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zmil

· #2 · Nov 18, 2008

Hi Brendan

CV 3 adds time to acceleration CV4 adds time to deceleration
put a value of 5 in each to start with . and go for higher value if you want a more realistic momentum 10 or so

Regards Zmil

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valetman

· #3 · Nov 18, 2008

To add on to the first reply , the most important thing to remember is you can't mess things up, so experiment.

you can always set the cv3 and 4 values back to 0 to get what you have now, so don't be afraid to experiment.

Depending on what DCC system you have, if you can do programming on the main , its a bit more convenient in that you dont have to go back and forth to a programming track, but otherwise what I tend to do is start quite high and try lower values each time till I get the effect I'm after.

On a big US steamer this can be 35 or more, but its all down to personal taste and the motor and the decoder combination.

Try some numbers, as said, you can always reset the cv's to zero(or whatever the manual says is the default value on the decoder), so you can't really do any harm just changing those 2 cv's.

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Brendan11

Discussion Starter · #4 · Nov 18, 2008

thx zmil & noggin,

I tried a few cv values for accel and decel and it worked a treat. Shunter no longer stops dead but gently slows down before setting off in opposite direction - well chuffed.

I've got a few older locos which I rarely run out as there a bit too jerky at lower/slow speeds, any advice on helping these run better by tinkering with cv values?

thx again, made my day that working. I've got a dynamis and my learning curve in dcc is getting better. I entered values on the programming track rather than risk the scary main programming track. I car'nt read back the cv values (as i've not got the dynamis pro) but at least I can put them in.

thx again

bren

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Doug

· #5 · Nov 18, 2008

With my Lenz, switching direction of a loco (under power) stops it dead. Deceleration is not taken into account.

Deceleration is taken into account when the loco is rapidly slowed using the control knob or buttons.

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zmil

· #6 · Nov 19, 2008 (Edited by Moderator)

Hi Doug

I'm running the Lenz LZV100 (ver 3.5) at the moment and mine does go through the deceleration and then acceleration when direction is switched , using the LH90 , MultiMAUS or computer to control the loco

I had to pull the LH90 out and the manual to check though

Maybe you have an older version of software on your Lenz LZV100 , I'm considering sending the Lenz away for an update to 3.6 to get the extra functions and have the ability to have non latching functions

Regards Zmil

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Kelly88

· #7 · Nov 19, 2008

acualy i think if you read the manual it distinctly tells you not to change direction of the loco without coming to a stop first
as this could damage the controler and/or the decoder

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Brian Considine

· #8 · Nov 19, 2008

QUOTE (Mike88 @ 19 Nov 2008, 10:59) <{POST_SNAPBACK}>acualy i think if you read the manual it distinctly tells you not to change direction of the loco without coming to a stop first
as this could damage the controler and/or the decoder

Don't remember seeing that in the manual - I use a Lenz LH100 for the G/45mm in the garden & of course that's exactly what the kids do - so far (touch wood) nor harm has come to anything, although the decelleration/accelleration has been set to give very gradual speed changes so the locomotives are stopped before changing direction.

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zmil

· #9 · Nov 19, 2008

QUOTE (Mike88 @ 19 Nov 2008, 19:59) <{POST_SNAPBACK}>acualy i think if you read the manual it distinctly tells you not to change direction of the loco without coming to a stop first
as this could damage the controler and/or the decoder

Hi Mike

I think you must have an early version of the manual
The LH90 (ver 3.1) manual says -

"If you flick the direction-switch to the
centre position while the locomotive is
in operation, the locomotive will stop
with the amount of delay in braking
which is set in the locomotive decoder.
If you afterwards flick the switch in a
different direction, the locomotive will
speed up again, also with the amount
of delay that is set in the decoder."

It all depends on what version of software you are running

Regards Zmil

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34C

· #10 · Nov 19, 2008 (Edited by Moderator)

QUOTE (Brendan11 @ 18 Nov 2008, 18:39) <{POST_SNAPBACK}>..I've got a few older locos which I rarely run out as there a bit too jerky at lower/slow speeds, any advice on helping these run better by tinkering with cv values?..
You can use what you have learned on the 08 to adjust CV2 (start voltage) so that the loco motor only just turns on speed step 1, and then try values in CVs 3 and 4 to produce smoother acceleration and braking. Depending on the performance characteristic of the loco it may also be worth adjusting maximum and mid speed, CVs 5 and 6, to deliver the performance that best suits you. As posted earlier, all these CV values may be reset to factory defaults at any time, so don't be concerned about making performance worse, you can go 'back to square one' very easily.

There is however a significant caveat to this, and that relates to the performance of these older locos on DC, before decoders are fitted. DCC does not improve a graunchy old mechanism that cannot maintain a smooth crawl, or will only start if it gets enough current for a scale 30mph. A good decoder can compensate for, and thus mask, some of these deficiencies; but the running performance will not be as good as with the same decoder in a sweet running mechanism. I assume the Hornby 08 is the new scale model; if you have not done so, check it out on DC without a decoder fitted. It is a decent mechanism and powered by an ordinary DC resistance controller will move reliably at a slow walking pace, and will start and stop very smoothly and realistically. From that mechanical performance a DCC decoder can extract extremely realistic motion. You should not expect the equivalent performance from an older model with a worn open frame motor, and relatively low reduction ratio single stage gearing, that only starts on DC with a big jolt, and will not smoothly maintain a slow speed.

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Brian Considine

· #11 · Nov 19, 2008

Good points from 34c.

The thing to remember is that DCC cannot make a bad runner better (in some, if not most cases it will be worse!), but it will make a good runner better when correctly set up.

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