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How to shunt in excact distance?


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Posted

I want to shunt in exact distance. When I run a loc from 0 to 1 sec, I mark the distance. I repeat this from 0 to 2 sec, from 0 to 3 sec etc. The delay functions on the decoder are set to zero. The results are very unexpected. There seemed to be no logical relation between time and distance. The only way to set a program is by trial and error. When possible I want to use this sort of exact distance operating for an Inglenook Sidings Railpuzzel. What do I wrong?

Posted

I don't think you are doing anything wrong. It is the way RM works - time not distance until we get the loco detection system.. Their answer is to bash the buffers to provide the program with a known starting point, which takes away the variable you are seeing when you try to stop in the same place each time.

 

The Hornby decoder that supports asymmetric DCC and programmable actions (Sapphire) also works on time not distance.

 

the equivalent Lenz decoders (silver & gold) work on ADCC by distance, so may be better for what you want, although I don't know of a way to incorporate this into an RM program.

 

ADCC works by way of a 5-diode module biasing the DCC signal to either slow or stop a loco in an isolated section. This can be set for both directions or only one way. To restart you de-isolate the section.

 

you can read about it on Lenz website under ADCC. The basic BM1 equivalent module is easy to make.

Posted

You will never get it right. I have tried to write programs to get engines to enter my turntable, rotate and head off to do stuff then return but since the engine never stops in exactly the same place, the only way was to fit balsa wood stops on the oppposite sides of the TT to make the engine stop exactly. And this only worked with engines with no front coupler!

The RM programming works well but there are just too many variables with the engine such as age, cleanliness of tracks and wheels, supply voltage and basically the mood that the engine is in. It might work 9 times in a row but the 10th time, the engine will stop short and snag on the TT tracks. Same with just getting it to stop at a station. Works ok then it will overrun or stop short. If the program repeats, the error just gets larger and larger.

Posted

You will never get it right. I have tried to write programs to get engines to enter my turntable, rotate and head off to do stuff then return but since the engine never stops in exactly the same place, the only way was to fit balsa wood stops on the oppposite sides of the TT to make the engine stop exactly. And this only worked with engines with no front coupler!

The RM programming works well but there are just too many variables with the engine such as age, cleanliness of tracks and wheels, supply voltage and basically the mood that the engine is in. It might work 9 times in a row but the 10th time, the engine will stop short and snag on the TT tracks. Same with just getting it to stop at a station. Works ok then it will overrun or stop short. If the program repeats, the error just gets larger and larger.

Do you use the loco's acceleration/deceleration CV's or do you use the accelerate and decelerate program commands?

Ray

Posted

Just shunt ,cruise and stop commands. It appears the stop command is the culprit. Sometimes it works when it is supposed to and other times, the engine just keeps going for a bit longer. 

Posted

How does that make a difference? I am personally using the CVs for a more natural start and stop (I made CV3=25 and CV4=10 while both come from the factury with a value of 2). So I am wondering now what is better? To use the CVs or to use railmaster. And what is the difference between ticking the box or not? Interesting subject, not only for shunting but for stopping anyway.

Posted

If you use the decelerate command in a Railmaster program, it will send a speed command to the loco every second (the default interval but variable), so if one of these commands is missed for any reason, it doesn't make too much difference. With a stop command, sometimes it is missed by the loco or obeyed a second or two too late, which makes a significant difference to where the loco stops. Why not give the accelerate/decelerate commands a try. You can achieve superb realistic control with a little tweaking of the commands here and there.

Ray

Posted

How does that make a difference?

 

The loco either stops according to the CV decell value setting or it stops dead.

Posted

Well, I changed the decoder to a Lenz one. At the end I succeed in calibrating the shunting behaviour. With a shunting speed of 5 Km/hr, the loc is moving exact 5cm in 10 sec. (10cm in 20 sec etc).

Now I have to calibrate the Kadee couplers.

Is it possible to program "forward 10" km/hr. or "reverse 20" km/hr.?

Grzz, Hans

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