Consisting Locos

[Butler]

Am I using Bachmann Dynamis Ultima, But i am getting short of space on the Rosta. The info says this system has a 40 loco Rosta to include consists. I have heard on this site, that despite the claims of 40, it is in fact only 30 locos on early versions. I bought this new  in about 2015.

But my question is:

can i run 2 or more locos on the same address to save on Rosta numbers? I have done accidentally before and both locos seem to move. I am not needing to operate lights or other functions, as they are unlit EMU’s. If I could run 2 or 3 units on the same address it would free up a lot of space.

Any ideas or comments welcome.

B

[johnb]

I regularly run two OO Bachman 2EPB emus together without actually consisting, but both have the same DCC id. They are well matched without having to tweak CVs. One is actually reversed to the other, using just the usual CV29 twiddle which is well documented elsewhere.

I use an NCE Powercab which during the chip setup process actually asks if you want it normal or reversed and does the CV29 twiddling for you!

[Butler]

Thanks John,

yes I’ve found that if the chips aren’t well matched they struggle on a Consist. I’ve got  a 4 Cep, with a Hattons chip, + MLV with Bachmann, consisted. The 4 Cep doesn’t like it, either being pushed or pulled by the MLV. It would really help if I can run my emu’s as you say. Not that it will cure the mismatch problem, I will have to fit 2 chips the same, unless they can be tweaked?

Having grown up with BR Southern Emu’s I cant resist them, and now have many inc 4Cep, 2Bil, 2Hal, 2 Epb, 2Hap Nd Now I see there’s a 2Hil. Anyway I digress .

B

[johnb]

Chips can be tweaked, but in my case I used identical chips in identical EMUs (I think EU621s). To do that level of tweaking you would really need a SPROG which presents the speed table graphically and is easily adjusted.

First off if possible is to run them on DC and see how they are speed matched, if they are pretty much the same then if the same chip is used in both then it is much easier.

 

Like you I've got too many of the things, I did get a 2HIL, but have yet to lash out on a 2HAP! Having said that I have 2 4TCs!! I've an MLV and a 4 CEP but don't run them together, the layout is too short.

 

John

Edited March 3, 2021 by johnb

[Butler]

Hi

that kind of  technical is getting a bit beyond me, as they say  “ When you’re up to your neck in Alligators, it’s hard to remember the original aim was to drain the swamp”  You tend to spend more and more time dealing with tech issues than doing what you originally intended, to run a model railway.

i could talk about Emu’s forever, and I reckon pretty much any combo could have been seen on the SR, but I guess that should move to another forum.

i will try to run my emu’s on 1 address, that would really help me. Thanks

B

[Dungrange]

I don't see anything wrong with running two or more units using the same address on each decoder, provided you don't want to split and re-marshal the train.  I have a Realtrack Class 156 unit, which has two decoders (one in each car) and these are both set up with the same address.

 

As has been said, you can adjust the top speed and speed curve on most decoders to allow two units to run together.  The most basic adjustments would be CV2 (the starting voltage), CV5 (the maximum voltage) and CV6 (the mid voltage).  If you one unit is appreciably faster than the other, then reduce the values in CV5 and CV6.  However, if you are using the speed tables set up in CV67-94, then you're probably going to need something that will allow you to see the curve graphically.

[WIMorrison]

If you want to run two decoders using the same address then what you need to do is tube one decoder on address X to get the speeds correct. You then remove this unit from the track and tune the second half, also on address X, to match the speed characteristics of the first half. When they are both running the same then you place both on the layout and join them together.

 

You will need a bit of track with a known length which you time each half over individually to match the speeds and I would advise that you learn about programming on main to make the process easier. 

[Butler]

Ok I’m starting to get all this, and yes 1 loco does  move faster than the other, but I can’t seem to read the set value of CV 5 or 6, so I don’t know what to change! If I’m correct, the higher the cv value the lower the top and/or mid speed will be. My Dynamis doesn’t give me a cv value , on program track I put in ‘read value’ but it reads, then gives 0 each time!

what am I doing wrong?

thanks 

B

[WIMorrison]

I suggest that you start by looking at some of the many videos that there are on YouTube showing you how to use the Dynamis, they also show how to read and write CVs - much more illuminating than text in a forum.

[Nigelcliffe]

"0" may be the value set in the decoder.   Many decoder makers don't set any values in CV's, and just assume a default behaviour if they are set to zero.   

 

If other CVs in the decoder are reading correctly (CV8 will always be something other than zero), then its reasonable to assume a reported value of 0 is a correct read.    

 

CV5 = low number means slow loco. 

CV5 = high number means faster loco. 

 

CV6 needs to be a smaller number than CV5, suggest starting with about half the value.  

 

 

- Nigel

 

Edited March 5, 2021 by Nigelcliffe

[Mike Buckner]

I don't know if this would help:

 

You have two or more sidings on the layout, each can be isolated from the main layout.

You park locos/EMU's/consists in the sidings.

A loco with address (say) 10 is parked in siding A. Another loco with address 10 is parked in Siding B.

If only one siding is energised, then only one loco will move in response to the controller.

That way, you can have more than 40 DCC locos  on the layout, while each can be controlled individually, remaining within the capabilities of the Rosta.

[Butler]

Ok I see now, yes the defaults for many CV’s on the decoder are 0, so by changing the start volt CV2 a bit and the acceleration CV3 the 2 locos pull away roughly the same rate now. It’s hard to tell if they are fighting each other at higher speeds. That’s really helped thank you.

B

[WIMorrison]

Time both units flat out running over the same bit of track three or four times then take the average. 
 

one you have that play with CV5 to get both the units to the same time for the same length of track.

[Butler]

Ok, but 1 thing I don’t get, on these 2 locos, cv5 and 6 read 0, that’s the default, so how can I reduce below zero? I think the decoder cv Max reading is 255? The leaflet ( it’s a Hattons decoder) say the higher the number the slower the speed/:

CV Number Name Use Advice CV2 Start Voltage Set the voltage that it takes to move the locomotive If the locomotive does not move off on speed step 1, inclease CV2 until it does. CV3 Acceleration Inertia Set up the acceleration curve of the locomotive Increasing this value slows the acceleration of the locomotive. CV4 Deceleration Momentum Set up the deceleration curve of the locomotive Increasing this value slows the deceleration of the locomotive. CV5 Top Speed Set the top speed the loco- motive will achieve The higher the value, the lower the top speed. CV6 Mid Speed Sets the mid speed of the locomotive Recommended to be 1/4 to 1/3 of the value of CV5.

copied  from web site

this contradicts what others have written before.

confused B

[jpendle]

Hi,

 

The Hattons information is incorrect, it's probably just a typo. Increasing the value in CV5 increases the top speed. If CV5 is set to 0 then that is just a default setting meaning that CV5 is in fact = 255.

So to reduce the loco's top speed set CV5 to something lower than 255.

 

Regards,

 

John P