Not into DCC yet, will very very soon and wondering being Im going to order decoders If ( I hope I have this right ) the EMF type are like, lets say cruise control as the engine will maintain a constant speed up and down grade.
do all units in a consist have to have the same type of decoder
Have a lot of grade to pull, is this type of decoder worth the bang for the buck
As always, a big thanx in advance…John.
When consisting locos, it’s best to have a decoder that can reduce or turn off the level of feedback. Why? Because no two engines run EXACTLY alike, so there will always be some “pushing and shoving” going on between the consisted locos. The one being pushed (or pulled, works both ways) will see that it is trying to be moved faster than the set speed, and will reduce power to compensate. The one doing the pushing or pulling will see that it is running slower than set and increase power to compensate. It just escalates from there.
Diffeent decoders handle this in different ways. Some have BAck-EMF that automatically trails off at higher speeds. Some have settings galore - Digitrax decoders have 3 CV’s that control Back-EMF, and each CV has 2 parts - one is for the loco running alone, the other is for when it is in consist (decoder assisted consisting, using CV19).
Personally, I am not a big fan of the ‘cruise control’ aspect of Back-EMF decoders. It’s not realistic. But for improving low speed starting, it’s great.
–Randy
People always look at back-emf as “cruise control” but that’s ignoring its main advantage. If you want absolutely fluid smooth low speed operation in steam engines, use back-emf. It helps to smooth out minor binds in the valve gear etc. So forget the grade stuff, the real show is at slow speeds.
Dave H.
I agree with Randy on back EMF decoders. You can set the loco with heavy back EMF and then forget working the throttle. The train will run uphill, down hill, around curves all at a constant smooth speed.
Great stunt. But it ain’t railroading.
I like to use light back EMF on locos to smooth out performance somewhat at slow speeds and through turnouts, etc. But watch out using any significant back EMF on locos in lashups.
If any of the locos in the back EMF lashup lugs, the others will try to push harder to compensate, then the lugger will try to compensate the sudden pull to keep the speed constant, and slow down more … the locos will jerk back and forth ever more violently each overcompensating for the other’s attempts to pu***hen pull in an attempt to keep everything at a constant speed.
Back EMF if used in moderation is handy, but it’s not a cure-all, and in lashups it can be just plain awful.
Sounds like the back EMF would be great for swich engines. Being all my engines are DCC ready what type of decoders would I order using Athern, Gennisis, P2K, stewert and Atlas. Perhaps a plain jane, being that none have sound.
O well I think me going DCC was in vain anyhow. According to the info from CVP it was 585 bucks to be in controll of one loco or consist, is a bit pricey. They stated there 4 to 8 weeks out, decided to wait a bit, now glad I did not order decoders today.
Thank you anyhow Randy, … your a true Jewell on this forum,… but for me Im just going to get better DC power packs, as mine are were obsoleat decades ago.LOL.
I have been using back EMF in my locos and have had none of the problems with consists that some people talk about, though I have noticed that back EMF is very sensitive to the CV settings. I’m using mostly Digitrax DH163 series decoders. I really like it for the smooth low speed control.
Da:
The loco fighting phenomen occurs when the locos are somewhat mismatched and you set the back EMF to stronger settings.
As long as your consists are well matched and your back EMF settings less pronounced, things should run fine.
If you want to try an experiment, try setting the speed curve in one of your back EMF units to be out of sync with the rest of the pack and see what happens. Or ramp up the back EMF to a high setting and if there is any mismatch at all in the consist, that’ll find it!
BEMF is very handy for locos that previously didn’t run too well at low speed - It’s especially good for 3-pole motors. It’s well worth paying the extra for it - I have tried the cheap Bachmann decoders and found them to be terrible, the Lenz ones with BEMF and silent drive are a lot better - you even get a nice diesel “growl” from the motor with some locos!
John;
Why have you settled on CVP? There seems to be a mis-match between what is being offered to you and your needs/wants at this time. For example, you could get into a Digitrax Zephyr or Atlas system (made by Lenz) for under $200, which would allow you to control several locomotives at once. Then you could add more throttles, boosters, radio, etc later.
Nigel:
You will, however, have to replace several parts of the Zephyr system in order to end up with a Chief system. Doing it incrementally as you describe will make the Chief cost you about double what it would be if you just bought it straight away.
I don’t know who John talked to at CVP, but their starter system lists for less than $250, so he must have got someone eager to sell him more stuff than just a basic starter system.
If you go way beyond a basic starter set up, you’ll pay a lot more for Digitrax, too.
Not at all. Just add a DCS100 and you have a Chief. NOTHING ever gets wasted in a Digitrax system, except maybe those old throttles that came with the Challenger system, which weren’t Loconet. But even that old DB100A could be used as an extra booster in a modern Digitrax system.
Sure, if you end up needing a Chief and just buy the set, you’ll have spent the $160 or so the Zephyr costs in excess of what it would have cost to just get the Chief in the first place. But that gains you a nice yard throttle AND an extra 2.5 amps of booster power. And if you never need to run more than 10 locos, you might never need the DCS100, so instead you can get a Super Empire Builder set and gain the 5 amp booster.
The only redundant thing seems to be the LT1 Loconet Testers they put in every set. They seem to multiply like rabbits and discarded X2f couplers.
–Randy
Randy:
Nice to have it spelled out from someone who knows the Digitrax system better than I do.
Whenever I have downloaded and read through the Digitrax manuals, the key sequences to do things in their system has always seemed less-than-obvious to me. In the other systems, you didn’t seem to have all the extra keystrokes to do even basic things like consisting.
Has the DT400 throttle improved things? Although you can economize by creating just a few generic keys like Digitrax has done with their other throttles, the “tv remote on steroids” look to the NCE controller at least meant if you needed to create a consist, there are a set of keys that say consist (setup, clear, add, delete) right on the controller and it’s pretty obvious what to press without having to keep the manual handy.
When I look at an older Digitrax throttle, I haven’t got the foggiest where to start to make a consist, for example. This was a big reason why I never elected to go with Digitrax – to this software engineer, the user interface (UI) always seemed harder to use than it should have been.
I’m hoping the DT400 has solved a lot of that … it’s seemed like a good system except for the somewhat clunky UI.
Randy since I posred last, chatted with Tony’s train exchange and you were on target with your explanation.
Joe. The main reason I posted the topic is that Im trying to look and cost out everything needed. I elected to go with radio as I like to run a prototype maintaince schedule of locomotives and need to add/remove units on the main to pull the hill. I want to do this without running a long control buss over the doors of my four swing ups, as one engine facility is on the other side of the room… Personaly feel radio only, is not the way to go as far as trouble shooting is concerned, but would like the freedom of it
Granted the starter set is $230 with 3 amps, with two fixed cabs. I need four amps max operating and selecting five amps Im not on the upper end. My electrical is wireing houses, shop machenery and from what little I know, Amps is the name of the game and the wire insulation is not there just to hold the smoke in LOL
Where I got off track is that a E mail from CVP stated with the five amp starter radio system, power supply for booster, is 581 less shipping. They also stated I would be in direct controll of one loco or consist at a time, actually NCE, Digitrax and Easy DCC is really all in the same ball park when everything gets added up. all of which are great systems.
This morning I was lucky to actually talk to someone at CVP, as they are hard to get, tried all last week, the system has two fixed cabs plus the radio, my two main yards are over each other, this could work out nicely. They also stated I dont need a decoder tester, perhaps needed with some other systems.
So now I m back taking another look at it, I will look at everything needed for each system, I dont like surprises on down the line, on a fixed income and trying to be a bit cautious about future expense or items purchased bought and not used.
I sincerely appriecate each and everyones input and sorry about my flustration the other day, but was mastakinly thinking, over 700 bucks to run on
John:
Great insight into your thinking!
As to amps in your system, I recommend not trying to do everything with a single booster. Prefer more boosters at lower amps per booster. That gives you more flexibility with your total system and limits the damage you will do things if you get a really bad short.
You can also start smaller that way. Start with one 3 amp booster and add another 3 amp booster later, giving you 6 amps total for your layout capacity (or more boosters, if you need still more).
Also, 3 amps at 12v is not the same as 3 amps at 120v from your house circuits. Amps and voltage have a mathematical relationship (ohms law) and if you lower the volts you get more amps capacity. That means 3 amps at 120v is over 20 amps capacity at 12v – plenty for running even larger layouts.
Joe.
Perhaps Im wrong but was thinking of using a four circuit breaker with one five amp booster. I have in essence a double loop on the bottom with a large yard, could use three breakers there, and the other for the helix and the upper around the room loop and small yard. Was thinking using that this type of breaker would be a snap to wire and provide better protection, not shutting down half the layout.
Thanks Joe, for the food for thought…have a good day…John
What is a ‘really bad short’, Joe? I thought that the circuit protector in the SEB controller (or is it in the booster?) would compensate for shorts (like a screwdriver inadvertently left with the shaft touching both rails while they are energized).
A really bad short in DCC isn’t really the kind like a screwdriver laid across the tracks - it’s more like the kind where there is some resistence but not low enough to draw more than the booster’s capacity. With those 8 and 10 amp boosters out there - 10 amps at 14 volts is 140 watts. Those kinds of power levels can melt things, but until they exceed the booster’s current capacity, no breaker will trip. 10 amps worth of locos, or 10 amps worth of power flowing into a semi-short, it all the same thing.
This is the reason for power districts. If you size them correctly, that stretch of track may only be capable physically of holding 2 or 3 locomtives at a time. Thus you can use an electronic circut breaker set to a fairly low current limit - it’s plenty of power to run the maximum locos, but far lower than the booster’s capacity.
–Randy
Yes, the DT400 does away with allt he various shifted keys of the DT100 and DT300. It’s a double-edged sword. Half the people look at the simpler controllers with fewer buttons and figure that must be easier to use, as compared to the oodles of buttons on the DT400. The other half realize ther are X number of functions you need to perform, and fewer buttons just means harder to remember sequences are needed to access them.
Consisting is pretty easy with the DT400. Since there are two actual throttles in the DT400, you dial up your lead loco on one side, dial in the first loco to add on the other side, hit Consist, + and it’s added. Consist - removes the loco that was d
dehusman wrote:
and jfugate wrote:
Of course, one could fix the binding problem or the bad trackwork in the first place. [:)]
The problem I have with BEMF is that it’s not realistic, both as “cruise control” and as a switcher. Sure, it smooths out problem locos and bad track. However, having a switcher with BEMF couple on to a string of cars and start to pu***hem without any speed change at all is bogus. Think of it this way. A diesel loco weighs in at about 125 tons more or less, and a string of cars (say 10) would weigh in empty at about 250 tons (25 tons each). It would be not unlike a kicker in football hitting an offensive lineman and pushing him down the field without effort. IOW, it’s not gonna happen.
If anything, I want “reverse BEMF” or “-BEMF” that multiplies the resistance felt to the motor to acurately replicate the effort it takes for a switcher to move a string of cars that weigh twice as much as the loco does.
jfugate
Um, not really. The only knock on Digitrax price-wise is the cost of their boosters, and this is because each booster is also a command station. Otherwise, the price for Digitrax products is right in line with everyone else for the most part (sometimes cheaper, sometimes more expensive, but not by very much either way for simular products).
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QUOTE: Whenever I have downloaded and read through the Digitrax manuals, the key sequences to do things in their system has always seemed less-than-obvious to me. In the other systems, you didn’t seem to have all
Do the BEMF decoders run plain DC? I like to have the ability to run on layouts that do not have DCC.