Model Railway Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
133 Posts
Discussion Starter · #1 ·
In a post about the Toy Fair Spongebob raises something that I had not thought about - if I have understood him correctly- but which is important. I find it so surprising that I can hardly believe it!

"The controllers do look good but i have to say i aren't a fan of the twiddly knob thing they use for a power regulator, my bachmann one is ok until you go back to a loco having adjusted the power to a different loco then as soon as you touch the dial the damn thing either slows to a crawl or shoots off like a startled hare." Spongebob

Spongebob suggests, I think, that with a Bachmann controller you can get the following problem. You drive say loco 1 and set the rotary controller to the high speed that you want the loco to go & then decide to leave it at that speed & to go & shunt say loco 2 whilst loco 1 is still going. Loco 2 as soon as you touch the rotary control is getting a message that the speed you set loco 1 is what you want it to do & lurches off at high speed in the siding. Having recovered control & changed underwear the last thing you do with loco 2 is stop it before you go back to loco 1. The rotary controller is now at stopped when you go back to loco 1. As soon as you touch the speed control loco 1 which has been running nicely is told that it should be stopped as this is where the rotary control is set & thus it comes to a juddering halt.

I have only tried button control with more than one loco & find all this surprising. I had imagined that rotary speed controllers were not simply volume controls but accepted where they were pointed as the current state when you change loco selected & you either moved up or down from there. This would mean that you could go from loco 1 running flat out to loco 2 moving very slowly & then back to loco 1 without lurches of speed.

Have I understood this correctly & is it a problem with all rotary speed controls?

Chris
 

·
Registered
Joined
·
205 Posts
That is a problem with most rotary speed controls, the exception being the Digitrax DTxxx series throttles which function as you mention in the last paragraph. There may be other's that work the same but I'm not aware of them.
 

·
Registered
Joined
·
5,592 Posts
With the digitrax DT series of handcontrollers you can either use the knob for speed control, or the +/- key. The speed of each loco is memorised so you simply don't have this problem. I'm sure this is also true about other good quality systems, again select your system on features not disasters.
 

·
Registered
Joined
·
121 Posts
I am operating the NCE Power Pro system. Occasionally I have the same problem of a reselected loco not resuming its last setting, this does not happen every time. I would need to run a carefully monitored test to establish if there is a set of circumstances which cause this to happen. I can not find any reference in the manual to whether it should remember individual settings or not.

Another occasional problem I have is that, without selection, one of my chipped locos takes off like a scolded cat and then stops. Interrogation of its CV1 setting using the programming track reveals that it has reset itself to 255 (it is normally 2) none of my other chipped locos do this.

Brian
 

·
Registered
Joined
·
205 Posts
Branchliner, how old is the decoder? There was a software problem in some old decoders which caused the problem you mention. If the decoder can't be returned under warranty, then reseting it to factory default twice (CV08=8), then programming it to exactly the same settings twice should solve the problem, at least for a while.
 

·
Registered
Joined
·
133 Posts
Discussion Starter · #6 ·
I am genuinely amazed that many conrtrollers work this way as it appears to nullify one of the major advantage claimed for DCC. If you cannot change locos without something unwanted happening then what is the point. I know this sounds daft but as Make Mine a Double says you should buy your system based on features but when unexpected features like this arise it does make you wonder what other "features" you have missed.

This is definitely something to look out for & it will now feature on my demo list.

As there have been posts here about people waiting for the Hornby system does anyone know if this will have this exciting feature?

Chris
 

·
Registered
Joined
·
28 Posts
Branchliner,
I am also using NCE Power Pro, all my trains at the moment are using TCS decoders.
I can set train 1 running and then select another Loco, when i select the second the speed readout is nought,set that one away and return to the first and it still gives the speed setting that i left it on,go back to loco 2 and that still runs as it did when left it to go to loco 1,so it must retain the settings.Don't know what the solution to your problem is as I haven't had the system long.
MickD
 

·
Registered
Joined
·
121 Posts
As I said before (I think), most of the time all running locos behave themselves. It is just occasionally that one decides to run at the same speed setting as the previous loco. A study is required taking notes as you go, better still set up a test plan in advance. If this is a fault in the NCE system the manufacturer will supply an updated Eprom to rectify it.


Brian
 

·
DT
Joined
·
4,794 Posts
The Hornby Digital system will use a rotary encoder. This is not a volume control with a fixed 'low' to the left and a fixed 'high' to the right. This is a never-ending dial that will pick up the speed of the selected loco as it is.

So if you select a loco that is at a halt, the dial speed will be zero; if you select a loco that is moving, the dial speed will be exactly at the speed of the loco. Turning the dial left slows the loco, just until you reach zero (turning it further to the left has no effect) and turning it right, speeds up the loco, just until the max speed is reached (turning it further to the right has no effect).

My Arnold systems use this - I suppose this is what Digitrax use and it is what all dial systems should use. I'm not sure about Bachmann as I have not had the opportunity to use that system.
 

·
Registered
Joined
·
1,918 Posts
QUOTE That is a problem with most rotary speed controls
Sorry I can't agree with this. Most rotary speed controllers actually work as Doug has described. They only serve to adjust speed and usually there is no setting that the nob itself marks. This being said I have seen exceptions such as the new Viesmann Control Station where the nobs rotated by themselves to the last set speed of the locomotive selected. So besides looking weird they worked perfectly.

Chris,

Any problem with rotary controllers are the EXCEPTION and not the norm. In rare cases an error may occur between certain controllers and certain decoders which usually can be rectified following manufacturers instructions.
 
1 - 12 of 12 Posts
Top