DCC head-scratcher

[MVW]

This has happened several times now, and I'm at a loss. An internet search shows others have experienced the same issues, but I haven't seen a generally accepted cause or fix.

I have 5-6 pairs of locos set up as two-unit consists. Occasionally, for no apparent reason, a pair will suddenly decide to start responding to another pair's address. This has happened to with Atlas, BLI and Lifelike engines, so it's not manufacturer (or decoder) specific.

The fix is to remove each loco from the consist, then set up the consist again. Then everything works fine for some indeterminate time (weeks or months), and then all of a sudden (for example) consist A will suddenly start responding as if it's consist B. Consist A will still respond to the consist A address, but it will also mirror commands sent to consist B.

Suggestions?

Jim

[MK]

What command station?

[MVW]

I'm using an old Digitrax DCS 50.

Jim

[Maletrain]

Are you just using the throttle on the DCS50, or are you using additional throttles?  If so, what are they?

[peteski]

While I'm not very familiar with Digtrax consisting, do you know what type of consist you are using? Is it advance consist (Digitrax might use different name for it) where CV19 in the locos is the consist address, or a consist where the command station keeps track of the loco addresses?

[eja]

'Aint DCC fun.

I enjoy the basics, but the rest of it drives me insane......

[peteski]

'Aint DCC fun.

I enjoy the basics, but the rest of it drives me insane......

The brand of your DCC system makes a big difference in user-friendliness.  Some systems are easy and intuitive, others not so much . .  .

[MVW]

Are you just using the throttle on the DCS50, or are you using additional throttles?  If so, what are they?

I'm using both the command station throttle and a basic UT4 hand-held, plugged in at 4-5 other spots on the layout.

Jim

[MVW]

While I'm not very familiar with Digtrax consisting, do you know what type of consist you are using? Is it advance consist (Digitrax might use different name for it) where CV19 in the locos is the consist address, or a consist where the command station keeps track of the loco addresses?

My experience with DCC is pretty limited. But with Digitrax, you program in a "top" address -- which will be the address the consist responds to -- then add other locos (using their individual addresses) to the "top" address.

Seems to me I've heard the term "advanced consist" before, but it doesn't show up in the index of the command station manual.

Jim

[peteski]

My experience with DCC is pretty limited. But with Digitrax, you program in a "top" address -- which will be the address the consist responds to -- then add other locos (using their individual addresses) to the "top" address.

Seems to me I've heard the term "advanced consist" before, but it doesn't show up in the index of the command station manual.

Jim

Jim,
I believe (looking at https://www.digitrax.com/tsd/KB837/zephyr-xtra-and-zephyr-multiple-unit-locomotive-op/ ) that you use what Digitrax calls "universal consisting".  The consist makeup is kept and tracked inside your command station.  So if there are issues with the consists, the command station is at fault - not the decoders. I just pointed that out to narrow down troubleshooting.

[MK]

Correct Peteski!  Jim, have you tried resetting the command station?  I have the 0G DCS50 just like you and I can't say that I have encountered anything like that.

[peteski]

Correct Peteski!  Jim, have you tried resetting the command station?  I have the 0G DCS50 just like you and I can't say that I have encountered anything like that.

Does this command  station also use "slots" (like other Digitrax systems do) to keep track of addresses being used?  I guess even if it does, a reset would take care of clearing those out.  Also, what is the max number of consists DCS50 can control?

[MK]

Does this command  station also use "slots" (like other Digitrax systems do) to keep track of addresses being used?  I guess even if it does, a reset would take care of clearing those out.  Also, what is the max number of consists DCS50 can control?

Yes, it does use slots.  The DCS50, being Gen 0, only has 10 slots.  But when MUing/consisting, I don't know if that only takes up one slot or as many slots as the make up of the consist.  I briefly looked over the manual and it doesn't say how many slot(s) a consist would take.  It would be an easy experiment to find out given that it only has 10 slots and you don't really even have to have a real loco on the layout to test.

But like you said, resetting will clear all the slots.

[GaryHinshaw]

I've had numerous issues with Digitrax command stations dropping (universal) consists.  I switched to advanced consisting using the decoder's CV-19 and have never looked back.  Advanced consisting is less convenient if you frequently consist on the fly, but it is much more stable, in my experience.

[jagged ben]

Yes, it does use slots.  The DCS50, being Gen 0, only has 10 slots.  But when MUing/consisting, I don't know if that only takes up one slot or as many slots as the make up of the consist.  ...

Each loco uses a slot when it's in universal consist.  I believe if you use advanced consists you only need one slot for each consist.
That said, I'm doubtful you issue is due to slots or consist type.

You say that one consist responds to another consists address.  This sounds like a throttle address selection issue and not a command station or consist issue per se.  That is, I suspect you are somehow failing to change the throttle address selection.  Do you have this issue on both the DCS and UT-4 throttles?  The UT-4 throttle in particular is so nearly devoid of feedback that I could easily see one thinking that you've selected a different address but the throttle is still set to the previous one.  Changing the dials on that throttle does not select the address until you push 'Sel' and then there is no confirmation the address has updated.  In my experience Digitrax command stations also sometimes tend to kind of 'hang on' to a throttle's address even after you try changing it from the throttle.