Zimo 645R Steam

[John K]

A question - probably for Paul I think.

I am struggling a bit with a Zimo 645R with 2-4 cylinder LMS steam sounds in a kit-built Coronation.

The the decoder only starts to chuff after the loco has got to about 5 scale mph. Which mean that it managed to lift a heavy train with no exhaust bark.

I have fiddled with the speed cvs to try to get it to start more in line with the sound but no joy yet.

Can I have some further pointers please.

Thanks

John

[Nigelcliffe]

1 - set up the chuff rates to match the driving wheel rotation.  This is two CV's on current Zimo's.

 

2 - setup any startup delay for blow down

 

Its either wading through the Zimo manuals for details (CV302 page 40 to get the motor tuned, then page 41 for chuff rates cv267 and cv354 to fine tune, finally any blow down delays (also page 41)), or use JMRI/DecoderPro.  For the latter, I can provide pointers.

 

They should chuff when pulling away on every cylinder pulse if set correctly, which is four chuffs per wheel revolution for a typical 2 cylinder loco.

 

 

- Nigel 

[tarifa]

The Coronation Class is a 4 cylinder loco so this number of cylinders requires the chuff rate to be set at 8 and therefore 8 chuffs per sound box.  You have not stated whether it is your sound project or shop bought.  If it is your own sound editing through ZSP is easy but decoder contained sounds cannot be edited or are you using the preloaded sounds supplied by Zimo.  In any case you will need to adjust CV's as Nigel has suggested. 

Mike

[pauliebanger]

A question - probably for Paul I think.

I am struggling a bit with a Zimo 645R with 2-4 cylinder LMS steam sounds in a kit-built Coronation.

The the decoder only starts to chuff after the loco has got to about 5 scale mph. Which mean that it managed to lift a heavy train with no exhaust bark.

I have fiddled with the speed cvs to try to get it to start more in line with the sound but no joy yet.

Can I have some further pointers please.

Thanks

John

 

John,

 

Happy New Year,

 

Yes, one for me I think! (Assuming this decoder/sound project is from Digitrains, I can't speak for any other supplier.)

 

This is a ZIMO speciality.

 

Sound set one (default) is for light loco. It is not intended to chuff at low speeds around the yard, so it is working correctly. At higher speeds

/acceleration, light exhaust beats will begin - and stop again when speed is returned to below the threshold.

 

When the loco is to pull a train, you will need to set your reverser and regulator accordingly, like a locoman would. Fortunately, this is simulated for you in a different sound set.

 

Before setting off, press F5 (latched) to go to the second sound set, 'heavy train'. Not only does this set chuff straight away, it plays more powerful chuffs with a long cut-off. After a few seconds accelerating, the sound should change to a more muted beat, simulating the driver selecting a  shorter cut-off.

 

For even shorter cut-off, switch off F5 when cruising.

 

For more power again, increased throttle will give heavier exhaust beats, and F5 will supply max power sounds. Toggle between the two sets as you wish, switching F5 on or off. You will be able to hear sounds from four different cut-off/regulator combinations, plus coast if you reduce dialed speed steps by one (or more).

 

This should add to your enjoyment as not only does it give variety in exhaust beat volume and timbre, but it allows more prototypical steam engine sounds than what you may get from other suppliers.

 

Don't tell anyone about this, though, as some people still claim that varied cut-off simulation can't be done.

 

When you've got the hang it, try this. Roll up to your train, light loco (F5 off), couple up, switch F5 on and pull away with the loco sounding like it's working hard as it 'feels' the weighty train 'on the hook'. 

 

Kind regards,

 

Paul

[pauliebanger]

The Coronation Class is a 4 cylinder loco so this number of cylinders requires the chuff rate to be set at 8 and therefore 8 chuffs per sound box.  You have not stated whether it is your sound project or shop bought.  If it is your own sound editing through ZSP is easy but decoder contained sounds cannot be edited or are you using the preloaded sounds supplied by Zimo.  In any case you will need to adjust CV's as Nigel has suggested. 

Mike

 

Mike,

 

This is not entirely correct.

 

It's true that 4 cylinder loco's have 8 power strokes, but since each time two strokes happen at the same time, the result in sound terms is that only 4 exhaust beats per revolution are heard.

 

Only one British 4 cylinder loco had 8 distinct beats, Southern Railways' Lord Nelson.

 

LMS Pacifics have 4 beats per revolution.

 

Kind regards,

 

Paul

[John K]

Hi Paul and thanks,

Yes it's your sound set...

...I do understand how it should work, but with F5 toggled to the heavy setting the chuff does not start immediately. The train is still well under way before it produces any significant hard work sounds.

Thanks to the others for their input.

Best,

John

[pauliebanger]

Hi Paul and thanks,

Yes it's your sound set...

...I do understand how it should work, but with F5 toggled to the heavy setting the chuff does not start immediately. The train is still well under way before it produces any significant hard work sounds.

Thanks to the others for their input.

Best,

John

John,

 

Thanks for the confirmation. Sorry, I get quite a few emails asking about this and that's usually the answer which works. (Do you get any sounds before the Chuffs begin?)

 

Ok, that's a different issue (from the one I wanted to eliminate), and the project is currently not operating correctly with your loco. Will you confirm that CV265 = 1, please?

 

What type of motor has been fitted to the model?

 

You will at some point, need to set the chuff rate CV267 at about speed step 10,( Isuggest starting around value 50), then CV354 for very slow speed steps, since the measured rate will vary with each motor and gearbox combination.

 

However, this should not prevent the chuffs playing immediately, the first blow should be as movement begins.

 

You will need a little inertia set in CV3 (and in CV4 for coasting and brake squeal to work correctly). Values around 25-30 should be about right. Are you using a PowerCab? If you adjust momentum on the handset (even inadvertantly), it writes new values to the decoder. Not always my favorite NCE feature with sound projects.

 

There is a start delay to allow for Cylinder Drain Cocks to be opened and closed prior to movement. This should either allow any blow down sounds to finish before movement begins, or modulate the exhaust beats with the cylinder clearing sounds if movementstarts before blow-down ceases. In either case, you should hear exhaust beats from the off. By all means adjust the delay (CV273) to your own preferences. The project value is 30.

 

I don't want to seem impertinent, but the way the loco is driven can have an impact too. I find that it works best to gradually build up the speed steps rather than setting to a high speed step and allowing the momentum/inertia to control rate of acceleration. (This ensures max power sounds during acceleration. These sounds are a timed event; each time a speed step increase is entered, the timer starts again. If you flick directly to say speed step 65, that will only count as one acceleration instruction, so acceleration sounds will play for only 1 x time specified.)

 

Cylinder clearing is not required so often with hot cylinders. To simulate this, there is a minimum time that the loco remains stationary before next movement triggers a blow down. This is adjustable with CV274. In the project it is set at 150 meaning if the loco is restarted within 15 seconds of stopping, there will be no blow-down. This should not cause the problem you are experiencing in and of itself, but may be a contributory factor.

 

If the above adjustments do not solve the problem, ensure that Cv 265 = 1 and the re-set using CV8 =0. If the reset doesn't cure the problem, we can at least be sure the CV values you have loaded are the one's I can see in the project software.

 

Let me know how you get on and we can take it from there.

 

Kind regards,

 

Paul

[Lady_Ava_Hay]

The Coronation Class is a 4 cylinder loco so this number of cylinders requires the chuff rate to be set at 8 and therefore 8 chuffs per sound box.  You have not stated whether it is your sound project or shop bought.  If it is your own sound editing through ZSP is easy but decoder contained sounds cannot be edited or are you using the preloaded sounds supplied by Zimo.  In any case you will need to adjust CV's as Nigel has suggested. 

Mike

 

I regret that this is completely incorrect. Only one loco requires 8 chuffs per revolution and that used to run on Southern Region.

 

All other 4 cylinder locos run at 4 chuffs per revolution as two cylinders exhaust at the same time, hence the severe and loud chuff that these Coronations give out plus the awesome tractive effort that they produce.

[tarifa]

I regret that this is completely incorrect. Only one loco requires 8 chuffs per revolution and that used to run on Southern Region.

 

All other 4 cylinder locos run at 4 chuffs per revolution as two cylinders exhaust at the same time, hence the severe and loud chuff that these Coronations give out plus the awesome tractive effort that they produce.

 

OK DC, sometimes I get things wrong.

 

Mike

[John K]

Hi Paul,

Thank you for your time and trouble.

Please feel free to appear be impertinent I have very thick skin, and you are the expert with this decoder.

 

With the loco idling I get the correct steam sounds.

The motor is a Buehler driving through an MSC gearbox.

Yes CV 265 = 1

Chuff rate is set for 4 per rev and optimised for both slow and faster running.

I am using a Lenz system with LH 100 controllers - all working fine with all 19 functions.

CV3=25 CV4=28 all ok.

The drain cock sounds occur as the loco starts and then the chuff comes in at about step 25/126. I have not yet tried adjusting CV273 - a job for tomorrow evening.

 

I have been experimenting with different styles of throttle opening but although this changes the way the cut off changes it doesn't get chuffs until the loco is under way.

I will recheck all that you have suggested and then have a play with CV273.

I will report back.

John

[pauliebanger]

Hi Paul,

Thank you for your time and trouble.

Please feel free to appear be impertinent I have very thick skin, and you are the expert with this decoder.

 

With the loco idling I get the correct steam sounds.

The motor is a Buehler driving through an MSC gearbox.

Yes CV 265 = 1

Chuff rate is set for 4 per rev and optimised for both slow and faster running.

I am using a Lenz system with LH 100 controllers - all working fine with all 19 functions.

CV3=25 CV4=28 all ok.

The drain cock sounds occur as the loco starts and then the chuff comes in at about step 25/126. I have not yet tried adjusting CV273 - a job for tomorrow evening.

 

I have been experimenting with different styles of throttle opening but although this changes the way the cut off changes it doesn't get chuffs until the loco is under way.

I will recheck all that you have suggested and then have a play with CV273.

I will report back.

John

 

John,

 

I think I see the problem, thanks for your description.

 

The drain cocks should open before the loco moves. This sound should more or less finish before any movement. (that's the role of CV273 - start delay). That's probably why the chuffs aren't starting early enough. I'm not a 'motor' expert, but if your combination is a exotic as it sounds to me (I'm easilly impressed) then maybe it's characteristics need to be catered for in the decoder set-up. More efficient, perhaps?

 

I'm happy for anyone with the relevant experience to step in here, but from the symptoms, it seems your loco is taking off too early in the sound scheme, so we either need to get the sounds starting earlier or delay the movement (or both).

 

Start Voltage, CV2 is set to 1 in the project, (range 0-255). You could try different values here. Sorry, I've no idea of the impact on your motor, but I would be interested to know the outcomes.

 

I believe there is a way to start 'driving' sounds before 'pre-start' sounds have finished (in addition to CV 273).But I need to look that one up.

 

What are your current values in CV 29 and CV 124? (speed table and shunt mode), and CV312 (manual blow down)

 

Taking a different tack, there is a special setting in CV273 which triggers the blow-down sounds, but not movement. It will only work in 128 speed steps. Enter CV273 = 1. Open throttle to speed step 1 only, wait for the blow-down to finish, then drive the loco away. This setting also translates to 'no start delay' so it should begin to chuff immediately.

 

Paul

[John K]

Thanks Paul,

John