TMCC signals: Continuous or discrete?

Once.  When you release the whistle button it stops.  The bell is programmed as an on off function, even in conventional you turn it on with a DC offset, and turn it off with a second DC offset.  G

Any TMCC or Legacy command is sent in response to the button press.  I believe all the commands are sent more than once in succession to allow for a mis-read, but that all happens right at the button press time.

GGG:  How silly of me!  Of course I know the difference between WHISTLE and BELL button pushes.  Thx for catching this oversight.

gun....:  2 comments:

1. "I believe" is not exactly what I'm seeking.

2.  Can anyone quantify "more than once"?

Back to GGG:  I think that "once" is not correct for the WHISTLE button....Since you MUST hold it down, the transmission must be continuous....Agree?

The buttons are continuous, 100msec between commands.  Exception, throttle, perhaps some others but don't recall off the top of my head.  The commands are converted in the radio that is in the loco or accessory to one shot actions. 

For example the lights on/off with AUX2.  Aux2 is sent continuously, but the lights don't flip on, then off, then on, ect.

I defer to Jon, but I was reading your continuous differently than you meant.  Yes the command would be continuous as long as the button is pressed, but once released it stops.  In the case of the bell you press the button and the bell starts, when you release the bell the signal stops.  Same for AUX2, correct Jon?

What I'm saying is you get multiple copies of the command for each button press, even if it's a brief push.  When I look at the serial data to the sound card, even a brief push gives you multiple copies of the command.

This is just for reliability, as it all happens very quickly, the command doesn't repeat that many times, there is also a time window for the processing.

So, it's 10 reps/second while holding the buttons down.  The throttle must be different, since we can switch from 1 engine to another, the 1st 'remembers' the command....somehow.

For Legacy, I believe the number is five that the remote remembers for throttle positions, I seem to recall reading that somewhere.

The CAB1/command base doesn't remember anything, but remember it's only addressing in relative mode, so it just tells the locomotive to change speeds from it's current speed.

gun....:  WHAT "number is 5"? 5 reps/sec?  Also, I meant that the engine "remembers", in that it holds the last speed setting.  Not the Cab 1.  OK?

I mean that the Legacy remote holds the data for the last five engines addressed.  The CAB1 runs only in relative mode and so doesn't remember anything.

It "remembers" some things, like the last ENG or TR addressed....

OK, but very little.   It's not like Legacy where you can control maintain settings for multiple locomotives.

the old zw puts out continuous dc to whistle the old engines.  when you release the whistle button the whistle quits.  how it affects the whistle in a tmcc engine running in the conventional mode requires you to hold the whistle control on to blow the horn for duration.  once you release it the whistle stops.  if the tmcc mode requires constant horn dc offset to blow or not is the question I do not know.

In conventional mode TMCC/Legacy need a DC offset just like any other conventional locomotive for the whistle/horn.  The bell is an on/off toggle.

gun....  Thx for explaining.  You just taught me a feature of Legacy that I didn't know!

jon:  What's the significance of CAB1 remembering the last ENG?

If you click over to a switch to change it, the speed and direction buttons still control the engine.

gunn.... But isn't this true in the following, normal for me, case:  I can switch between 2 or 3 or 5 engines, each holding the last speed set?

The reason you can switch between engines with the CAB1 is that they're all being operated in relative mode, the CAB1 has no idea what speed they're going at.  The CAB1 just sends a "faster" or "slower" step for each "click" of the throttle wheel.  OTOH, if you switch to a 3rd or 4th running engine on the Legacy CAB2 in TMCC or Legacy mode, you'll get the throttle graph of the current speed setting.

gun.... Understood.  Thank you.