*Problem Solved* Issues with TMCC connected to DCS

Nick,

attempted assign my TMCC Phantom to 91 with DCS, but couldn't go above 90

That's because 91-99 are reserved for TMCC lashups, corresponding to TMCC TR numbers 1-9.

Then I started the Phantom up and ran it but the Diesel Revs didn't change from idle with DCS. They did with my cab 1 still hooked up with DCS.

How were you attempting to increase the diesel revs?

 

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Barry, the Diesel revs, using the cab 1, were automatic. With DCS, they don't change from idle. Thanks for the help,

NICKSTRAINS.

 

P.S. Thanks for clarifying the address question but should I change it to a "better" number?

Try switching your speed steps in the DCS remote from 32 to 100 steps. This is what I had to do when running a tmcc engine with DCS. If that doesn't work, don't be alarmed. Seems to be common complaint when running a tmcc with DCS.

Nick,

should I change it to a "better" number?

It really makes no difference.

Hi Nick,

 

I gotta tell ya, I purchased one of the MTH TMCC/DCS cables and I was going to connect my LIONEL Base 1-L to the DCS so I could run my LionMaster Conrail SD80MAC equipped with the LEGACY Control System through the TIU using the DCS Remote exclusively.  Well, I chose to connect the Base 1-L directly to my terminal block, (using 18 gauge wire from the "U" post on the Base 1-L to the negative side of the terminal block) and control the Legacy engine with the Cab 1-L instead of using the DCS Remote.  I have been able to run both the Lionel Legacy and MTH Proto2 and Proto3 Engines simultaneously using the Cab 1-L for the Legacy engine and the DCS Remote for the MTH engines .  They work GREAT together without any conflicts so far.  I am using the "Star" wiring technique as described in Barry's book.  If you don't already have the book, get it.  It's worth its weight in gold.  Just my 2 cents, your mileage may vary.

 

Chief Bob (Retired)

Good Morning, Well, I changed the speed steps as recommended by Riverrailfan and that solved the matter. It now "revs up" and "down" like with the cab 1. Thanks guys for your help,

NICKSTRAINS

I believe the explanation was posted for this issue some time back. This is what I remember from that conversation.

 

The DCS system in 32 step mode only sends absolute mode speed commands, in 100 step mode it sends relative mode speed commands.  The CAB1 uses only relative mode speed commands.  The CAB2 in 32 step (TMCC) mode sends a combination of relative and absolute mode speed commands.  The diesel rev issue is solved by receiving relative speed increase commands, which is why the Lionel controllers don't exhibit that issue in any of their modes.

 

It made sense to me, and that's how it appears to function when I have tested it.

John,

The DCS system in 32 step mode only sends absolute mode speed commands, in 100 step mode it sends relative mode speed commands.

Not exactly.

 

The DCS Remote is capable of sending speed steps in either absolute or relative modes for either speed step range. This behavior is set by using the REL soft key on the DFCS Remote's TMCC engine screen.

 

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Barry, I believe the issue is that if you select absolute, it only send absolute steps.  However, the TMCC mode in the Legacy sends a mixture, which is why you never see the ramp-up RPM issue using Legacy in any of the TMCC compatible modes.

 

I didn't realize that you could have 32 step mode and relative commands, thanks for that little tidbit.

 

I don't see how it send absolute mode commands in 100 step mode, as the TMCC specification only has 32 speed step capability in the command set.  The Speed command data field only has five bits for the speed, that gives you the 32 steps.

 

Given the way that relative commands work for TMCC, I don't see any functional difference between 32 and 100 step mode using relative steps.  At least with the CAB1 or CAB2, relative steps just keep coming as long as you twist the dial.

 

There is also an advantage to using the mixture of relative and absolute speed mode commands, Odyssey I locomotives tend to run better using the CAB2 TMCC mode than using the CAB1 or the CAB2's CAB1 emulation.  However, using absolute speed steps from the DCS remote doesn't handle the diesel RPM correctly, so you can't glean that benefit.