Zimo MS 500 chuff rate problem.

[rsh7684]

Evening all. I wonder if any of you good fellows can shed any light on a problem I have. The problem is this:- Zimo MS500 fitted into a Planet Industrials Victory, CV 267 set to value 255 gives a 'chuff rate' of seven per wheel revolution. I have tried altering CV 354 to 0 and 1, done a hard reset etc and all to no avail. This same rate occurs on two different sound projects- namely Paul Chetter's Peckett and Locoman 8f. Any insight will be greatly appreciated. 

[Nigelcliffe]

Check CV268 is zero,  if it is not-zero, the decoder is looking for a real chuff-rate switch on an axle.  

 

[whiteswan]

I reported this some while ago on another forum, here's copy of my reply

 

"

Finally the piece de resistance, I've sorted the chuff rate problem.

 

As well as CV158 bit 4 it seems in the MS series there is an additional CV setting for chuff rate in CV393 bit 6=1.  The CV393 bit 6 set to 64 gives a 4 times reduction in the chuff rate taking it back to normal figures.

 

It is on page 37 of the MS manual, it is greyed out but is active.

Edited November 8, 2022 by whiteswan

[Ruston]

23 hours ago, whiteswan said:

I reported this some while ago on another forum, here's copy of my reply

 

"

Finally the piece de resistance, I've sorted the chuff rate problem.

 

As well as CV158 bit 4 it seems in the MS series there is an additional CV setting for chuff rate in CV393 bit 6=1.  The CV393 bit 6 set to 64 gives a 4 times reduction in the chuff rate taking it back to normal figures.

 

It is on page 37 of the MS manual, it is greyed out but is active.

Which manual? Not this one, I take it? Page 37 here is all about effects for function outputs, smoke generators etc. http://www.zimo.at/web2010/documents/MS-Sound-Decoders_EN.pdf

 

How does one go about setting "bits" anyway? All I can do on my DCC handset is to alter CV values. There's nothing on it that mentions bits. I don't even understand what a bit is at all.

[Porcy Mane]

1 hour ago, Ruston said:

Which manual? Not this one, I take it?

 

Wots this? you've taken to reading the manual. Try pages 39 and 55 for CV#393 bit6.

[pauliebanger]

Dave,

 

Maybe this will help.

 

Some CVs just set the parameters for one thing only. This means that the full range 0 - 255 can be used to adjust this one thing. eg CV3 - inertia (or acceleration as it sometimes called). CV3 = 0 gives no inertia, CV3 = 128 gives high inertia (loco accererates slowly like a heavy train) CV3 = 255 maximum inertia. Other value in between produce greater or lesser inertia.

 

Some other CVs are used to set parameters for multiple features. The most well known of these is CV29. Using just one CV for multiple items means that the whole range is not available for any of them, in fact it is usually a specific value which sets the parameter one way when included and another when not included in the total value written to that CV.

 

To you and I these are are set decimal values for each feature e.g. 1, 4,16 and so on. These values represent each of the 8 bits available in each CV.

 

As follows for ZIMO (some others use slightly different terms for the same thing, range Bit 1-Bit 8 instead, but lowest Bit always has an 'On' value of 1)

Bit 0  Off = 0, On =1

Bit 1  Off = 0, On = 2

Bit 2  Off = 0, On = 4
Bit 3  Off = 0, On = 8
Bit 4  Off = 0, On = 16
Bit 5  Off = 0, On = 32
Bit 6  Off = 0, On = 64
Bit 7  Off = 0, On = 128

 

One decdes which Bit or multiple Bits are required (eg. by referencing the decoder manual), then one takes the 'On' value of each of the Bits required and adds these values up to a total. That total is then the correct value for that CV enabling all the features you require it to.

 

In this case we know that CV393 Bit 6 needs to be 'On' for the '4 x chuff rate' feature to be enabled. (there are other features controlled by other Bits in this CV, but none of them are needed, so we can concentrate on Bit  6 alone)

 

From the list above, you can see that for Bit 6 to be 'On' the you will need to but the decimal value 64 into CV 393.

 

You don't need to know the Binary Maths behind this to enable CV393 Bit 6, you just programme CV393 = 64 as you would with any other change using your DCC controller, following the table above.

 

Best regards,

 

Paul
 

Edited November 10, 2022 by pauliebanger

[rsh7684]

Thanks chaps. CV 393 set to 64 has sorted it and the Loco now sounds as it should, very much appreciated. 

[Ruston]

13 hours ago, pauliebanger said:

Dave,

 

Maybe this will help.

 

Some CVs just set the parameters for one thing only. This means that the full range 0 - 255 can be used to adjust this one thing. eg CV3 - inertia (or acceleration as it sometimes called). CV3 = 0 gives no inertia, CV3 = 128 gives high inertia (loco accererates slowly like a heavy train) CV3 = 255 maximum inertia.

 

Some CVs are used to set parameters for multiple features. The most well of these is CV29. Using just one CV for multiple items means that the whole range is not available for any of them, in fact it is usually a specific value which sets the parameter one way when included and another when not included in the total value written to that CV.

 

To you and I these are are set decimal values for each feature e.g. 1, 4,16 and so on. These values represent each of the 8 bits available in each CV.

 

As follows for ZIMO (some others use slightly different terms for the same thing, range Bit 1-Bit 8 instead, but lowest Bit always has an 'On' value of 1)

Bit 0  Off = 0, On =1

Bit 1  Off = 0, On = 2

Bit 2  Off = 0, On = 4
Bit 3  Off = 0, On = 8
Bit 4  Off = 0, On = 16
Bit 5  Off = 0, On = 32
Bit 6  Off = 0, On = 64
Bit 7  Off = 0, On = 128

 

One decdes which Bit or multiple Bits are required (eg. by referencing the decoder manual), then one takes the 'On' value of each of the Bits required and adds these values up to a total. That total is then the correct value for that CV enabling all the features you require it to.

 

In this case we know that CV393 Bit 6 needs to be 'On' for the '4 x chuff rate' feature to be enabled. (there are other features controlled by other Bits in this CV, but none of them are needed, so we can concentrate on Bit  6 alone)

 

From the list above, you can see that for Bit 6 to be 'On' the you will need to but the decimal value 64 into CV 393.

 

You don't need to know the Binary Maths behind this to enable CV393 Bit 6, you just programme CV393 = 64 as you would with any other change using your DCC controller.

 

Best regards,

 

Paul
 

Thanks, Paul. I won't pretend that I understand all of that but, basically, unless bit 6 of CV393 is switched on, which requires 393's value to be set at 64, then altering CV267 will have no effect, yes?

 

I have been talking to @rsh7684 about all of this and the MS500 that he fitted to the Victory came out of one of his Hattons Barclays. When fitted to the Barclay he had set CV267 to 93 and the chuff rate was almost perfect. He hadn't touched CV393 at all. I have never encountered CV393 before and nor has he. We both have lots of small industrial loco models and have always simply changed CV267 to get the desired result. This problem only occurred when the decoder was put into the Victory.

Is this because the gearing and wheel diameter on the Victory are so different to that of Hornby Pecketts, Hattons Barclays and other small engines where we normally use 60:1 High Level gearboxes in kit-builds? Will any project that is designed for a high-geared, small-wheeled engine need CV393 to be set to 64 before it can be used in an engine with larger wheels and lower gearing? I believe the Victory's gearing is 40:1 but have no idea what the Hornby Peckett, or Hattons Barclay are.

[pauliebanger]

Dave,

 

Your first point, well more or less in it's outcome.

 

Strictly CV267 (and CV354, for compensation at very low speeds) ) is still the cuff rate setting CV, and will still have some impact. However, because MS 'counts' differently from MX, there may not be a high enough value to bring the resulting chuffs into a usable rate for s particular model.

 

I'll add more detail later when I have time but the MS decoder software is not that which is loaded to MX decoders (it's far more powerful).

 

Whilst not strictly accurate, you can consider that currently, MS decoders are running MX projects in an 'emulation mode'. Whilst most MX features have been retained in more or less the same form when running on MS decoders/software there are some fundamental differences in some areas. The way chuff rate is calculated is one of these areas, recently revealed. CV393 has been used for other features for some time, but the Bit 6 assigned feature (4x multiplyer) has been added to remedy the issue.

 

I believe that when truly 'native' MS projects are possible, there will be no need for setting Bit 6 in CV393. But that's for the future......

 

Best regards,

 

Paul

Edited November 10, 2022 by pauliebanger

[Izzy]

Oh, that’s a shame Bit 6 CV393 isn’t on MX decoders. Following this thread I’d begun to hope it was the answer to my issues of an MX645 loaded with a J72 file that even with a 60-1 box ( reduced from 80-1) was still too high to get the chuff rate down enough, it’s set at 147 - CV 267- by default for some reason. I’ve been told a re-blow with another project is the only answer. For a minute I thought it wasn’t. Oh well.

 

Bob

[whiteswan]

19 hours ago, Porcy Mane said:

 

Wots this? you've taken to reading the manual. Try pages 39 and 55 for CV#393 bit6.

Yes, I'm one of the few but it pays dividends sometime. ;-)

[peterfgf]

As said in marine engineering when something has gone wrong: "RTF" or Read the F****** (Friendly) Manual.

Peterfgf

[pauliebanger]

3 hours ago, Izzy said:

Oh, that’s a shame Bit 6 CV393 isn’t on MX decoders. Following this thread I’d begun to hope it was the answer to my issues of an MX645 loaded with a J72 file that even with a 60-1 box ( reduced from 80-1) was still too high to get the chuff rate down enough, it’s set at 147 - CV 267- by default for some reason. I’ve been told a re-blow with another project is the only answer. For a minute I thought it wasn’t. Oh well.

 

Bob

 

Bob,

 

Hold on, we've only just put this Bit 6 feature into MS software. It's not even covered in the English language instructions yet. Lol.

 

Your issue with the J72 project is probably 'induced' by the sound project loaded. For me, the clue is in the project default, CV267 = 147.

 

The ZIMO default for CV267 is 70. This is just a starting point but is usually in the right ball park for 00 gauge models with 4 exhaust beats (2 or4 cylinders) or 6 beats (for 3 cylinder engines). The user should then adjust this value in relation to the actual model to which the decoder is fitted. That much is widely known.

 

However, if the loco is driven at a constant speed (typical 'set a speed step and let the model run' - often witnessed at exhibitions) the same 4 chuffs endlessly repeating begins to sound just that - artificially repetetive. In real life, there is an environment, wind, embankments, cuttings and so on which tend to distort the sound heard so although the sounds at the chimney may indeed remain the same, buy the time they reach an observer's ears, there is a variety of subtle and not so subtle random changes over time.

 

That's why I would recommend when driving at constant speed, operators should vary the chuffs by increasing or decreasing speed by 1 step  (of 128) which does not noticably alter road speed, but will change the sounds between Full Gear, Cut-Off, and Coasting. Additionally, the heavy/light mode key can be toggled to further vary the engine sounds played. Similar effects are available by using Speed Lock.

 

One trick I've used in my steam projects for many years is to double the number of chuffs in each set from 4 to 8 for 2 and 4 cylinder locos. Whilst this then produces 8 different chuffs per revolution it's only valid for Lord Nelson Class locos and any which have reduction gearing.

 

So. in order to reduce chuff rate to 4 per revolution, CV267 must be set at twice the value which would be needed if using only sets of 4 chuffs. This results in the first revolution playing the first 4 of the 8 provided and the second the next 4. Using 8 different chuff recordings helps to reduce the monotony in what is heard.

 

If you couple this trick with my recomendations for throttle and mode variations, long runs of identical 4 chuff repetitions can be avoided, providing a better overall simulation of how real steams loco exhausts sound.

 

CV267 = 147 looks to me like this technique has been deployed in this project.

 

Here's the problem with my 'trick'. If the wheel/gearing relationship is widely different in a particular model from the 00 norms, it may not be possible to set Cv267 at a high enough value to reduce the chuff rate sufficiently. This can be true of kit/scratchbuilt models or those of a different gauge (0 gauge, say).

 

You don't say what values you have tried or the model/gauge in which the decoder is deployed but if CV267 = 255 still results in a too high chuff rate, then the only remedy is to reblow the decoder with a sound project having only 4 chuffs per set to bring the value in CV267 within adjustable range. 

 

However, if you are happy with all the other aspects of the sound project, there's no need to move to a different project. Your supplier will need to make only one simple amendment to the base project to use 4 instead of 8 chuffs before reloading the same project and your chuff rate should be within the adjustable range of CV267. Unfortunately, this is one of the few parameters which are fixed during creation.

 

Best regards,

 

Paul

 

 

[whiteswan]

1 hour ago, pauliebanger said:

 

Bob,

 

Hold on, we've only just put this Bit 6 feature into MS software. It's not even covered in the English language instructions yet. Lol.

 

Your issue with the J72 project is probably 'induced' by the sound project loaded. For me, the clue is in the project default, CV267 = 147.

 

The ZIMO default for CV267 is 70. This is just a starting point but is usually in the right ball park for 00 gauge models with 4 exhaust beats (2 or4 cylinders) or 6 beats (for 3 cylinder engines). The user should then adjust this value in relation to the actual model to which the decoder is fitted. That much is widely known.

 

However, if the loco is driven at a constant speed (typical 'set a speed step and let the model run' - often witnessed at exhibitions) the same 4 chuffs endlessly repeating begins to sound just that - artificially repetetive. In real life, there is an environment, wind, embankments, cuttings and so on which tend to distort the sound heard so although the sounds at the chimney may indeed remain the same, buy the time they reach an observer's ears, there is a variety of subtle and not so subtle random changes over time.

 

That's why I would recommend when driving at constant speed, operators should vary the chuffs by increasing or decreasing speed by 1 step  (of 128) which does not noticably alter road speed, but will change the sounds between Full Gear, Cut-Off, and Coasting. Additionally, the heavy/light mode key can be toggled to further vary the engine sounds played. Similar effects are available by using Speed Lock.

One trick I've used in my steam projects for many years is to double the number of chuffs in each set from 4 to 8 for 2 and 4

 

Best regards,

 

Paul

 

 

Paul, it was in a MS manual I downloaded last February after receiving a 56xx sound project from John at Youchoos to go into a N gauge Revolution 56xx loco

that had the fast chuff problem.

 

By reading that version of the manual that's how I discovered the CV393 as the answer after John couldn't help.  If I remember correctly in the version of the manual I downloaded back in February the CV393 was shown clearly on one page of the manual but greyed out in the second entry so I just experimented with and it brought the chuff rate back within bounds.  I did notify John of the result at the time. 

 

Thanks for the expanded explanation of how it all ties together.

 

Caz

Edited November 10, 2022 by whiteswan