More than 4 functions in Atlas GP40-2?

[ryan_wilkerson]

So I'm looking at photos of DRGW 3118. At some point, it had cab lights, nose lights, ditch lights, classification lights AND a beacon...and that's just the front! So if I wanted to control all those separately plus rear lights, I think I would need a decoder with 6 functions, right? I'm a fan of TCS decoders and want to go with them (good performance and GREAT warranty experience). Most of the drop-in decoders have 4 functions so I think I will need a hardwire solution. I see a MC6 that looks to handle what I'm wanting to do here. Anyone have experience with one of these? If there is a better solution, I'd like to hear that too. Here is the photo of DRGW 3118 for reference:
http://www.drgw.net/gallery/v/DRGWDieselContainer/GP40-2s/DRGW3118/drgw_3118_jefferson_ia_unknown_000.jpg.html
http://www.drgw.net/gallery/DRGW3118

Thanks!
-Ryan

[jdcolombo]

I don't see an MC6 on TCS's web site, and the MC series is sized more for HO scale than N scale.

I'd get a separate 4-function function-only decoder like the TCS 1004 and use that along with a hard-wired motor decoder.   After programming them the way you want, you can "hard consist" them by setting them to the same address (e.g., 3118, or whatever you want to use) and control both together from a single address.

John C.

[peteski]

I agree with John.  But if you were to go with Digitrax, their 163 series of decoders has 6 functions available (but not documented very well).

[jagged ben]

I don't see an MC6 on TCS's web site, and the MC series is sized more for HO scale than N scale.

I'd get a separate 4-function function-only decoder like the TCS 1004 and use that along with a hard-wired motor decoder.   After programming them the way you want, you can "hard consist" them by setting them to the same address (e.g., 3118, or whatever you want to use) and control both together from a single address.

John C.

Two decoders in one loco?  How would you program them separately once their installed?

[peteski]

Although probably not 100% Kosher, I often see multiple locos being programmed simultaneously on single piece of programming track.  This is doable especially if the decoders are from the same manufacturer. But for tasks like function remapping, things would get more complicated.  One way would be it pre-program each decoder before installation, the other would be to install a small switch cutting off the power to each decoder.

[jdcolombo]

The way I do this for two decoders is to use separate DCC addresses for the function-only decoder and the motor decoder, and consist them.  You can then program them via ops mode programming (programming on the main) by selecting the individual address.

If you "hard" consist them by using the same DCC address, then ops mode programming will change the CV's in both decoders.   So what I usually do is assign different DCC addresses initially, and then when I'm sure that everything is programmed the way I want in both decoders (using ops mode programming), I change the address of the function-only decoder to the same address as the engine decoder.

And what if something goes wrong and you need to program them separately again?  I take the shell off, desolder the red or black wire from one of the decoders (making it inoperative), put the engine on a programming track, and change the address of the live decoder.  Then I resolder the wire, and now I can use ops mode programming to make changes in the individual decoders.  Note that some motor decoders have a "lock" function that allows you to lock the programming.  With these, you can program the motor decoder and lock it; then ops mode programming commands will only affect the other decoder.  This would allow you to change CV29 in the unlocked decoder to go from a 4-digit address to a 2-digit; then you could unlock the other decoder, program them both from ops mode; relock one; change CV29 on the other back to the 4 digit address, and you're done.

Here would be a hypothetical summary of the steps.

1.  Install motor decoder; select default 03 address and then assign 4-digit address (3118) via ops mode programming; then change CV29 to 4-digit addressing.  This decoder can now be programmed via ops mode programming at address 3118.
2.  Install function decoder; select default 03 address and then assign 4-digit address of 3119; then change CV29 to 4-digit addressing.  This decoder now can be programmed using ops mode at address 3119.
3.  Program each of the decoders to do whatever you want.
4.  Lock decoder 3118.
5.  Change 4-digit address on 3119 to 3118.

Now suppose you want to program them separately at a later date.  Here's what you would do.

Select 3118 for ops mode programming.   Change CV29 to enable 2-digit addressing.  The locked decoder won't change.  It will remain in 4-digit mode.  The unlocked decoder will change back to two-digit mode at the default 03 address.   Now you can program them separately, using 03 as the address for one, and 3118 as the address for the other (you will have to unlock the 3118 decoder to program it).   When done, relock 3118; change CV29 in the unlocked decoder back to 4-digit addressing, and your done.

Yes, it's more complicated than a single decoder.  As Peteski notes, the Digitrax DN163A0 has six functions (the two lights are on-board, and there are four pads for the other four functions).  I'm not a big fan of Digitrax's motor control, but this might be an easier way to do what the OP wants, provided he's OK with soldering wires to the pads and then figuring out Digitrax's programming for the other four functions.

John C.

[Ken Rice]

Another trick for dealing with two decoders in one loco that never requires a desoldering job.
Program them for different short addresses, but the same long address.  Normally use the long address.  If you need to tweak them individually, use programming on the main to change CV29 to short address, then you can program each on the main individually, and when you're done program them back to long address mode.

[peteski]

Another trick for dealing with two decoders in one loco that never requires a desoldering job.
Program them for different short addresses, but the same long address.  Normally use the long address.  If you need to tweak them individually, use programming on the main to change CV29 to short address, then you can program each on the main individually, and when you're done program them back to long address mode.

I like that!

The only problem arises if a loco in question has  a "real" address in the range of 1-127 and Digitrax command station.  While in most DCC systems those can coexist as both long and short, Digitrax forces them to be short addresses, and only addresses them as such.  At least that is what we determined few years ago when troubleshooting this type of a problem on friend's layout.

[jdcolombo]

Another trick for dealing with two decoders in one loco that never requires a desoldering job.
Program them for different short addresses, but the same long address.  Normally use the long address.  If you need to tweak them individually, use programming on the main to change CV29 to short address, then you can program each on the main individually, and when you're done program them back to long address mode.

That's a great tip!  I can't believe I didn't think of that over the past 15 years I've been using DCC

John C.

[jagged ben]

Another trick for dealing with two decoders in one loco that never requires a desoldering job.
Program them for different short addresses, but the same long address.  Normally use the long address.  If you need to tweak them individually, use programming on the main to change CV29 to short address, then you can program each on the main individually, and when you're done program them back to long address mode.

Makes me glad I asked the question.   Not planning to ever have to do this, but in case I do this is easy to remember.

[ryan_wilkerson]

Wow, just got back to check on this thread. Excellent trick installing two decoders.

It looks like the MC6 #1019 has BEMF and is larger than some of the hard wired decoders. Here is a spec I found:
http://www.tcsdcc.com/Customer_Content/Literature/Decoders/HO_Scale/MC-Series/MC6BEMFWeb.pdf

Comparing the FL4 size (1004) to the MC6:
MC6: Dimensions .729” x .417” x .189” or 18.5 mm x 10.6 x 4.8 mm
FL4:  Dimensions .555" x .359" x .115" or 14.1mm x 9.12mm x 2.92mm

I'm wondering if it would be easier to fit the MC6 or a pair of decoders (like a Z2 for motor control plus an FL4)? I haven't done many hardwire installations.
I don't have a GP40-2 handy to measure. I'm thinking the decoder WIDTH is the primary concern then the LENGTH. A single MC6 in the fuel tank area sounds easier than two separate decoders but maybe that's my inexperience speaking.

[RBrodzinsky]

There is another way to handle multiple decoders, at least for multiple TCS ones at the same address: use the Decoder Lock CVs (CV 15 and 16). You set each of the individual decoders to unique numbers 1 through 6 in CV16 (this is when each one has a different address). Then, once you've put all the decoders to the same address, you can "unlock" each decoder for programming with CV15.  0 = all unlocked; 1-6 = only that decoder unlocked; 7 = all decoders locked.

[ryan_wilkerson]

Thanks Rick,
I hadn't heard of that option before, good to know. I am assuming that feature is intended for other uses? Or is it for just this situation?
-Ryan

There is another way to handle multiple decoders, at least for multiple TCS ones at the same address: use the Decoder Lock CVs (CV 15 and 16). You set each of the individual decoders to unique numbers 1 through 6 in CV16 (this is when each one has a different address). Then, once you've put all the decoders to the same address, you can "unlock" each decoder for programming with CV15.  0 = all unlocked; 1-6 = only that decoder unlocked; 7 = all decoders locked.

[tehachapifan]

Getting wires and resistors for LED's adequately tucked so the shell will seat all the way seems to be my biggest challenge over not having enough outputs on the decoder. Then again, I've started with switchers as my first installs.

[RBrodzinsky]

Thanks Rick,
I hadn't heard of that option before, good to know. I am assuming that feature is intended for other uses? Or is it for just this situation?
-Ryan

They write it up for these specific instances; the examples show "motor decoder", "sound decoder", "lighting", etc.  This would be good for installing functional decoders to control car lighting, etc., too.  Was proposed in the NMRA DCC 2003 standards. The Paragon (BLI) decoders and SoundTraxx decoders implement these CVs, too.  And, I just found this on the Digitrax site (although not documented in their mobile decoder manual) http://www.digitrax.com/tsd/KB519/decoder-lock-cv15-cv16/.   Lenz looks they started implementing this around 2006, didn't check anyone else.