Brake on DC
- Thread starter mbendebba
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shropshire lad
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Re:Break on DC
Hi Mohammed
Basically when the loco decoder, with brake on DC set up, detects a DC supply it will stop. You can switch a shortish isolated section in front of a signal for example so the train will automatically stop when it is set to danger. Quite useful to avoid over running sidings out of your normal sight too. No use if you want to run a chipped loco on analogue tho because it won't run.
Hi Mohammed
Basically when the loco decoder, with brake on DC set up, detects a DC supply it will stop. You can switch a shortish isolated section in front of a signal for example so the train will automatically stop when it is set to danger. Quite useful to avoid over running sidings out of your normal sight too. No use if you want to run a chipped loco on analogue tho because it won't run.
Neil Robinson
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Re:Break on DC
At the risk of thread hijack, I'm aware that some decoders, when used on an analogue system, will slow, pause and then accelerate in the reverse direction to before when the track supply is instantaneously reversed. The length of the pause and the rates of acceleration and deceleration are individually programmable.
I naively assume that all decoders with the brake on dc facility will do this.
I'd appreciate clarification of the above.
At the risk of thread hijack, I'm aware that some decoders, when used on an analogue system, will slow, pause and then accelerate in the reverse direction to before when the track supply is instantaneously reversed. The length of the pause and the rates of acceleration and deceleration are individually programmable.
I naively assume that all decoders with the brake on dc facility will do this.
I'd appreciate clarification of the above.
shropshire lad
Registered
Re:Break on DC
The DCC bus is AC, if you interupt one side of the supply the loco will just stop. If you have an isolated section of track and switch that to DC a brake on DC loco will use the Dc supply to slow down and stop,run the sound etc until it detects that the DCC bus has been reinstated at which time it will move on again governed by it's programmed delay if any.
Neil
Totally unscientific but I've just run an anologue loco 'forwards' then reversed the polarity (by turning the loco round) and it ran 'backwards' with the same command. Seems the faux dc from the system is directional?
The DCC bus is AC, if you interupt one side of the supply the loco will just stop. If you have an isolated section of track and switch that to DC a brake on DC loco will use the Dc supply to slow down and stop,run the sound etc until it detects that the DCC bus has been reinstated at which time it will move on again governed by it's programmed delay if any.
Neil
Totally unscientific but I've just run an anologue loco 'forwards' then reversed the polarity (by turning the loco round) and it ran 'backwards' with the same command. Seems the faux dc from the system is directional?
ntpntpntp
Registered
Re:Break on DC
Pretty sure that's a specific Massoth/LGB "feature" to allow automation of a back-and-forth shuttle service without the need for external electronics, although I think some other decoders will try and "soften" the effect of quickly changing the DC polarity under analogue, which in some ways has the same effect as the feature you're describing. Very much depends on the decoder though.
Generally the "Brake-on-DC" function is as Colin described, ie. use it to slow a loco to a gentle stop in front of a red signal, and accelerate away again when DCC is re-instated to the rails. I've seen it used to great effect on an N gauge modular system, you just have to spend some time programing all locos to have reasonably similar deceleration characteristics so that they stop in the same distance. You can leave the acceleration rate different to suit the type of loco and train it's hauling.
Colin, yes indeed the "faux dc" on a DCC system is directional, otherwise you'd not be able to drive your analogue loco back and forth at will!
There are some decoders out there that are not great at running correctly under DC, which is why a lot of people turn off the "run on analogue" function in the decoder to avoid runaways if they're strictly a DCC only operator. I've got an older NCE decoder that sometimes seems unable to make it's mind up which way to run under DC, so that loco doesn't get taken to friend's lines! It runs perfectly on DCC.
Neil Robinson said:
Pretty sure that's a specific Massoth/LGB "feature" to allow automation of a back-and-forth shuttle service without the need for external electronics, although I think some other decoders will try and "soften" the effect of quickly changing the DC polarity under analogue, which in some ways has the same effect as the feature you're describing. Very much depends on the decoder though.
Generally the "Brake-on-DC" function is as Colin described, ie. use it to slow a loco to a gentle stop in front of a red signal, and accelerate away again when DCC is re-instated to the rails. I've seen it used to great effect on an N gauge modular system, you just have to spend some time programing all locos to have reasonably similar deceleration characteristics so that they stop in the same distance. You can leave the acceleration rate different to suit the type of loco and train it's hauling.
Colin, yes indeed the "faux dc" on a DCC system is directional, otherwise you'd not be able to drive your analogue loco back and forth at will!
There are some decoders out there that are not great at running correctly under DC, which is why a lot of people turn off the "run on analogue" function in the decoder to avoid runaways if they're strictly a DCC only operator. I've got an older NCE decoder that sometimes seems unable to make it's mind up which way to run under DC, so that loco doesn't get taken to friend's lines! It runs perfectly on DCC.