Re: Mar. fun run

["Ira Schneider" <ira_schneider@iname.com>]

Steve,

It is more complicated than that.

The TIU output still has to be connected to the Command Base so the MTH controller can send
the appropriate commands to TMCC engines.

I was wondering if we could connect the TIU output line to both the Command Base input line
and the Command Base output line, this echoing all TIU originated signals to both the
Command Base and the TPCs.  However, I don't like the idea of two RS-232 transmitters
connected in parallel to the TPC RS-232 receivers.  As you said, there might be data
collisions, but worse, it might overload the transmitters or receivers.

The ultimate solution may be something I have been thinking about.  I would like to design
a box that monitors the RS-232 traffic out of the Command Base looking specifically for
the HALT command.  When it detects the Halt command it would energize a relay (or set of
relays) that cuts power to all tracks, independent of the PowerMasters and TPCs.  That way, we
could have some tracks whose power bypasses the TIU altogether (like track 1 does now)
but that will still shut down when the Halt command is sent.  Also, we could have one or more
tracks controlled strictly by the TIU without going through a TPC.  Obviously, this design wouldn't work
correctly since we now know that the Command Base doesn't echo the Halt command sent
to it via the RS-232 port.  However, we could theoretically monitor both the RS-232 send and
receive lines for the Halt command, catching both the commands from the TIU and the commands
from the Command Base.

The major problem is that I have not figured out how to design this box at all.  I think about it
now and again.  Maybe someday I will get an inspiration and come up with a circuit that
should work.

In the mean time, what we have now works better than we had before.  The only exposure we
have now is that the E-Stop command from the MTH controller won't shut down power on track 1.
We can live with that for now.

By the way, I sent a message to Lionel tech support describing the problem and they were of
absolutely no help.  I haven't heard from MTH tech support yet.


Ira