DCC-multi units vs. consisting?

[johncolley]

My question is this: I have a multi-unit diesel that is always run as 1 locomotive. Can I give all the units the same address even though I program the tail unit as reverse? Or do I have to give each a different number then consist the lot?

[ClinchValleySD40]

When you program the decoders, you can use the same address for all and you can specify forward/reverse any way you want to run them. However, I'd reconsider. Consisting is one of the real beauties of DCC, swap engines around however you like.

[dano99a]

I vote for consisting verses addressing them as one loco, I think you'd enjoy it more as a consist.

With DCC you can really see, and enjoy, how and why some consists get put together and broken apart.

my 2 cents

[:)]

[johncolley]

Thanks for the input. The reason I want to keep them as a loco is that it is a 4 unit diesel ABBA that I might in the future want to consist with a helper set mid train. It is always run as a loco with 3 powered units and one "B" being full of sound. The 3 powered units all have digitrax DH163D decoders. The tail "A" is run reversed. As I say I might want to combine that lashup with another 3 or 4 units in the future. If they were geeps or SD's I would do them in consists as you fellows said.

[cacole]

If all of the locomotives have headlights and/or rear lights, they will all be on if you set them up with the same address instead of as a consist. On the other hand, many decoders do not properly support consist lighting, so even if you do run them as a consist, the lights may not work properly. For an A-B-B-A set, where the B units have no headlights, you can easily get by with running them all on the same address. The rear A unit's headlight should not come on unless you are running in reverse if you have their decoders programmed for directional lighting.

[jfugate]

Although if you consist them instead of setting them all to the same address, you can independently tune the speed curves for perfect synchronized performance. Otherwise any CV change you make to one will go to all. I'd still opt for the consisting approach.

If you do consisting in the decoders, just add 128 to the consist number you put in CV19 and the loco will run in reverse. I use the last two digits on the lead loco as the consist number. So if your lead loco is 659, then put 59 in CV19 of all the units to consist them together as consist 59. Since the last loco is facing backwards, put 59+128 or 187 in CV19 and it will run as 59 reversed, which is what you want.

This way you can also address each unit independently for specific programming as needed. This will be especially true for the sound decoder (I'm assuming you are using a SoundTraxx decoder), since it's CVs will be slightly different from all the others.

[michealfarley]

There is another option.......

If you are able to measure the stall current of each locmotive, and only if the combined stall current for all locomotives is less than the maximum current listed on the decoder........

Then just use one decoder. Run little "MU" wires between your locomotives to connect the power pickup from all locomotives, and wire the motors in parallel up to the decoder. As long as you wire the rear locomotive's motor in reverse to the others, this will work. No speed curves to match, only one set of headlight and sound functions to worry about. I've tested this and it has worked, but I want to split up my F-units.

[johncolley]

Thanks, Joe F. for the tip. I was just going to use CV29 with a value of 34 for two units and 35 for the tail A unit. Won't that have the same effect? John

[jfugate]

QUOTE: Originally posted by johncolley

Thanks, Joe F. for the tip. I was just going to use CV29 with a value of 34 for two units and 35 for the tail A unit. Won't that have the same effect? John

Yes, John, that will also make the unit run backwards, although adding 1 to CV29 is considered primarily a fix for installing a decoder plug backwards (which makes the unit run backwards if you ever do that).

Adding 128 to the number in CV19 works easy enough as well, and it puts all the consisting "data" in one place, which is handy. If you use decoder-based consisting, that is.

[Anonymous]

Another thing you may be overlooking. You have total flexibility with each loco having its own decoder with its on address. When you form the consist your loco are faced on the track the way they are going to run, but all moving in the same direction. If the loco facing backwards is running in reverse when consisted it will run the same direction as the ones facing forwards. You can control functions of consisted locos still by calling up their address. When you want to run helpers on Digitrax the top loco of a consist can be the top loco of another consist (nested consisting) and the helper consist can be MU'ed to it.