Easy as ABC...

[aleopardstail]

Had a go with ABC braking on one section..

tried three, four then five diodes, messed about with decoder settings, wired the diode block the other way

nada.

have some "fast" diodes on order and will have another go.

one of these things that in a video everyone makes look remarkably simple, yet I have not yet seen anyone show how to actually set the decoder up (in theory its easy, CV #27 bits one and two.. tried all four combinations, the only one that worked was "disable ABC"...

[Bigmet]

Despite a Lenz based DCC system, never used ABC. Seen it work though - by accident - the former layout of a friend had residual 'slow down one way only' diodes over rail breaks, and when I had my Lenz sytem wired to his layout, a couple of my locos with gold decoders, slowed right down at a couple of these locations... My steam locos typically have CV4 set to 100 or more, possibly that had to do with the unintended effect?

[centenary]

Had a go with ABC braking on one section..

tried three, four then five diodes, messed about with decoder settings, wired the diode block the other way

nada.

have some "fast" diodes on order and will have another go.

one of these things that in a video everyone makes look remarkably simple, yet I have not yet seen anyone show how to actually set the decoder up (in theory its easy, CV #27 bits one and two.. tried all four combinations, the only one that worked was "disable ABC"...

Presumably your DCC decoder supports ABC braking and your diodes were correctly wired with at least one the opposite way to the others with suitable track section having one rail cut to create the braking section?

DCC Concepts cover ABC braking and how to set it up in one of their documents on their range of decoders \ ABC braking modules.

[aleopardstail]

Had a go with ABC braking on one section..

tried three, four then five diodes, messed about with decoder settings, wired the diode block the other way

nada.

have some "fast" diodes on order and will have another go.

one of these things that in a video everyone makes look remarkably simple, yet I have not yet seen anyone show how to actually set the decoder up (in theory its easy, CV #27 bits one and two.. tried all four combinations, the only one that worked was "disable ABC"...

Presumably your DCC decoder supports ABC braking and your diodes were correctly wired with at least one the opposite way to the others with suitable track section having one rail cut to create the braking section?

DCC Concepts cover ABC braking and how to set it up in one of their documents on their range of decoders \ ABC braking modules.

Zimo MX600, supports it, tried it turned on for the left rail, the right rail, for both rails. checked the block occupancy thing to make sure the wires go to the right actually bit of track (been there, still have the scars). totally isolated section. three, then four then five diodes in one direction with another the other way - tried all of that both ways around.

I suspect the diodes are not suitable and not creating a signal the decoder can see. the circuit is the one from the MX600 decoder documentation, annoyingly with the diodes they specify - though they do not specify the reverse diode other than it being a Schottky (which the one I am using is)

according to the handbook CV #27 gets set to turn this on or off, with others to adjust how it works. zero impact, and its not the loco just taking too long to respond as I've parked it in the brake section and it drives off both ways just fine.

CV readback gives me the correct values

[aleopardstail]

Circuit (only change is I never got as far as fitting the switch)

this is the four diode version, tried with three and with five, pretty much has to be the diodes causing the issue

note also have tried with the diodes this way and the other way around

[centenary]

Circuit (only change is I never got as far as fitting the switch)

ABC.png

this is the four diode version, tried with three and with five, pretty much has to be the diodes causing the issue

note also have tried with the diodes this way and the other way around

DCC Concepts set up is only a cut in one rail in the braking section not two as your diagram shows?

Also, have you tried setting cv27 to 3 to activate ABC so it activates whether loco running forward or reverse? Is your loco running too fast for the length of braking section and passing over the track cut onto powered rail beyond?

[aleopardstail]

Circuit (only change is I never got as far as fitting the switch)

ABC.png

this is the four diode version, tried with three and with five, pretty much has to be the diodes causing the issue

note also have tried with the diodes this way and the other way around

DCC Concepts set up is only a cut in one rail in the braking section not two as your diagram shows?

TrackGaps.png

Also, have you tried setting cv27 to 3 to activate ABC so it activates whether loco running forward or reverse? Is your loco running too fast for the length of braking section and passing over the track cut onto powered rail beyond?

hi, have both rails cut as there is also block detection stuff working so its easier as a full isolated section. have tried CV 27 = 3, and also run through at a crawl, even stopped manually and restarted. the section is short but longer than the locomotive - its likely far too short to use this in a practical way but curious on why its not activating.

have found out a fair few bits on this that I have yet to see an online guide mention, e.g. the bit about "make the brake section longer than the train plus the stopping distance" doesn't seem to be in any of the guides, and to be honest unless you run all trains the same length sort of renders the whole thing pointless - there are a few ways around wheels bridging the gap though to mitigate that (also not in the guides). plus some seem to say the type of diode is critical, and others that it hardly matters.

noteable that DCC concepts diagram doesn't even mention the full train length & metal wheels bridging the gap for example

[centenary]

Circuit (only change is I never got as far as fitting the switch)

ABC.png

this is the four diode version, tried with three and with five, pretty much has to be the diodes causing the issue

note also have tried with the diodes this way and the other way around

DCC Concepts set up is only a cut in one rail in the braking section not two as your diagram shows?

TrackGaps.png

Also, have you tried setting cv27 to 3 to activate ABC so it activates whether loco running forward or reverse? Is your loco running too fast for the length of braking section and passing over the track cut onto powered rail beyond?

hi, have both rails cut as there is also block detection stuff working so its easier as a full isolated section. have tried CV 27 = 3, and also run through at a crawl, even stopped manually and restarted. the section is short but longer than the locomotive - its likely far too short to use this in a practical way but curious on why its not activating.

have found out a fair few bits on this that I have yet to see an online guide mention, e.g. the bit about "make the brake section longer than the train plus the stopping distance" doesn't seem to be in any of the guides, and to be honest unless you run all trains the same length sort of renders the whole thing pointless - there are a few ways around wheels bridging the gap though to mitigate that (also not in the guides). plus some seem to say the type of diode is critical, and others that it hardly matters.

noteable that DCC concepts diagram doesn't even mention the full train length & metal wheels bridging the gap for example

Regarding your last para, it's only the loco length plus stopping distances not the whole train that matters though. The only time the 'whole' train length would be a factor is if, say, running a top and tailed train or 2 HST power cars where each has a decoder. In that scenario, the rear most loco could be outside the ABC braking section and therefore not activating the brake function.

If the loco has a stay alive fitted, this could override the ABC and power the loco through a short braking section. I dont know if block detection could also affect the braking but think it unlikely?

[aleopardstail]

the train length bit thats unstated is stuff like stock with metal wheels bridging the section gap, or say coaches with lighting picking up on multiple axles bridging it etc. (both of which will eventually be an issue here - though testing with just the loco alone also fails currently so thats not the problem)

Stay Alive shouldn't have any effect as that is on the DC side of the decoder and won't feed back into the AC side, plus test loco here doesn't have one anyway

its all just minor details none of the "look what you can do with a few diodes!" videos or articles bother to cover.

will be sticking with it for a while

[bulleidboy]

I installed two DCC Concepts ABC units on my branch line (one at each end) and they work well, and were easy to install. My loco (Class 3 MT) has a Hm7000 sound decoder, so it is very easy to adjust CV's using my iPhone. A little playing around with braking distances and time stopped, but generally it works well. Ideally it would be best to install (cut slot in track) when building the layout, but I appreciate in most cases this will not be possible.

[aleopardstail]

I installed two DCC Concepts ABC units on my branch line (one at each end) and they work well, and were easy to install. My loco (Class 3 MT) has a Hm7000 sound decoder, so it is very easy to adjust CV's using my iPhone. A little playing around with braking distances and time stopped, but generally it works well. Ideally it would be best to install (cut slot in track) when building the layout, but I appreciate in most cases this will not be possible.

have, largely, given up on this, main problem is needing the full train to be in the braking zone (resistor wheelsets and/or vehicle lighting) so the train doesn't keep resetting it as it bridges the gap - had I known that in advance maybe could have used this, as it is the sections are not set up for it (also I have trains of different lengths so the start of the braking would be in different places)

I did consider making it the full length, then having like an IR point location sensor trip a relay to make the whole block "stop now".

still haven't gotten a single loco to actually stop, even mucking with different diodes, guessing I have something set up wrong as this seems very simple in principle

[bulleidboy]

On the branchline, the two coach train has lighting in the carriages, with power taken from pick-ups on the metal wheels. This does not appear to affect the ABC - as the line was already in place when the ABC was installed, the end of the track is one break and at the other end there is a lift-up section across a door, so again one break in the track was in place before the installation of the ABC. The slight downside is that the loco has to be brought to a halt in a shorter distance than I would like - it doesn't come to an abrupt halt, but has only about twelve inches from track break to buffer stop. I find it a useful addition, as you can leave this train running back and forth, hence movement on the layout, while running another loco elsewhere on the layout. With the Hornby HM7000 decoder you can set the stopping time on ABC from a matter of seconds to about four and half minutes.