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Locked train setSpeedSetting tracking

 

Hi, i am looking for a way to tell when a train has actually stopped through issuing throttle.setSpeedSetting(0) or has reached the actual setting issued through issuing the command?throttle.setSpeedSetting(0.4) for example. Is this possible?

Thanks Jim
[email protected]
 

I don't know if I am doing this right as I have not replied to this Forum before, so I may be stepping on some ones toes here, forgive me please.

In regards to the the people who are interested in understanding the term "hysterisis" and to keep it simple, just think "friction". Just about anything that moves (in any form) on this earth, has friction built in. As a visual example: take a compression spring (an automotive, internal combustion engine valve spring comes to mind) and measure the linier deflection verses load (within the elastic limits of the spring of course) and plot the curve on graph paper. The load in compressing the spring will be different than when the load is reduced when relieving the load of the spring, at the same delection readings. the difference between the two readings is the friction of the device or system. The dynamometer scale also will contribute to the friction, therefore one must consider the system when hunting for friction losses, or hysterisis of the device or system.. Yes, there is more to it than that but for a simple visual I hope this could help.

Bob
 

Unless you use Digitrax Transponding or Railcom, you can’t do this. ?Decoders don’t report back what’s going on, and indeed the command station doesn’t even know that the loco that you’re running even exists. ?it just sends out the commands. ?if the decoder has plenty of momentum set up, it can be many seconds or even minutes between sending out a speed zero command and the loco actually stopping.

Mick



________________________________
Mick Moignard
m: +44 7774 652504
Skype: mickmoignard

, so please excuse the typos.
 

OK thanks for the replie.

Jim.?
 

On Wed, Dec 11, 2019 at 12:13 AM, <rtarbox@...> wrote:


I don't know if I am doing this right as I have not replied to this Forum
before, so I may be stepping on some ones toes here, forgive me please.

In regards to the the people who are interested in understanding the term
"hysterisis" and to keep it simple, just think "friction". Just about anything
that moves (in any form) on this earth, has friction built in. As a visual
example: take a compression spring (an automotive, internal combustion engine
valve spring comes to mind) and measure the linier deflection verses load
(within the elastic limits of the spring of course) and plot the curve on
graph paper. The load in compressing the spring will be different than when
the load is reduced when relieving the load of the spring, at the same
delection readings. the difference between the two readings is the friction of
the device or system. The dynamometer scale also will contribute to the
friction, therefore one must consider the system when hunting for friction
losses, or hysterisis of the device or system.. Yes, there is more to it than
that but for a simple visual I hope this could help.

Bob
Bob,

You responded to a topic that has absolutely nothing to do with your response and the your response along with the others you were referring to are off topic for this group.
--
Peter Ulvestad

JMRI Users Group Moderator - ( )
Tam Valley Group Moderator - ( )
Sprog-DCC Group Moderator - ( )
Edmonton Model Railroad Association -

 

Hi James

The answer to your question is sort of.
I assume you are running a script to do this, if so then the time taken is dependant on momentum CVs.
These are defined in the NMRA DCC specs. Depending on the number of speed steps the decoder is set to and the CV value the equation tells you the time between speed steps.
You have to know the present speed setting and the new commanded speed setting to be able to do the calculation.
you can also use this to find the distance travelled.
Stiction/friction also play a part so not perfectly accurate.
Some decoders have a constant braking distance ability.

Hope this helps

Alan
 

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What Alan suggests assumes the decoder maker follows the NMRA numbers for momentum, and have speed steps which are linear and predictable, and measurable (ie. at throttle setting X, the loco will travel at Y-inches-per-second).

I’ve met several decoders where the speed steps are not linear.?

I know a number of decoder makers who don’t appear to follow those NMRA numbers for momentum, or have optional momentum settings which will take things way outside any sane calculation of values.? ?

?

?

-????????? Nigel

?

From: [email protected] [mailto:[email protected]] On Behalf Of alan.cook23
Sent: 15 December 2019 18:39
To: [email protected]
Subject: Re: [jmriusers] train setSpeedSetting tracking

?

Hi James

The answer to your question is sort of.
I assume you are running a script to do this, if so then the time taken is dependant on momentum CVs.
These are defined in the NMRA DCC specs. Depending on the number of speed steps the decoder is set to and the CV value the equation tells you the time between speed steps.
You have to know the present speed setting and the new commanded speed setting to be able to do the calculation.
you can also use this to find the distance travelled.
Stiction/friction also play a part so not perfectly accurate.
Some decoders have a constant braking distance ability.

Hope this helps

Alan

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