That's BEMF in action. Better 'cheap' decoders like the NCE ones, you can fiddle with the motor drive settings and CV2 and get them to creep pretty good on step 1, assuming the loco has a decent motor and drivetrain. I used to use D13SRJ's in just about everythign, and with tunign they would creep nearly as well as locos with more expensive BEMF decoders (in 10 packs, the D13SRJs are liek $12 each - advantageous if you need to convert several dozen locos). I'm using TCS deocders now, and every one of those just creeps right out of the box, they have very nice BEMF. But they aren;t $12, either.
Oh, and if you haven't noticed it yet, the display ont eh DT402 is a percentage, not speed step, so it goes from 0-100. Assumign everything is set for 128 speed steps, there will be a few clicks where the number ont he display doesn't change. In 28 or 14 speed step mode, the number will change by several per click. However, one click from 0 is always step 1.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I just got my DT402D duplex radio throttle and NOW I understand the speed step issue. It has definate clicks and visual displays of each speed step. Having only used a Zephyr prior to this there was no way I could have known what or where speed step 1 was. Also, I now can see where the differences are in cheaper decoders as they don't 'creep' like the better ones do and I couldn't get them ( the better ones) to creep as slowly as they do now with the DT402. Another mystery in DCC resolved! Thanks again for all the info on this thread.
-Bob
Life is what happens while you are making other plans!
It all depends on the decoder and the loco. Without some dort of BEMF, you'll have to tweak a few thigns to get the optimal slow speed, and some of the realyl cheap included decoders (ie Bachmann) might not even HAVE those settings. A GOOD non-BE<MF decoder like NCE has those settings. And a good BEMF decoder - I use all TCS in my locos- rarely requires ANY adjustment to make it creep at speed step 1. The most common adjustment is CV2 - the start voltage. This is where it comes in handy knowing if you are at speed step 1. You set the loco at speed step 1 (sometimes 2 - to cover variations if you use the loco on other layouts and because of the inaccuracy of potentiometer controls) and then use Ops Mode to gradually adjust the value in CV2 untilt he loco crreps at the slowest sustainable speed. That way you can have all your locos begin to creep as you crack the throttle, not have some that creep right away and some that need 25% or even more just to start creeping.
The thing with DCC is, when in 128 speed step mode, there's always 128 steps (couple less, actually) so when you adjust CV2 for starting and set a reduced top speed using CV5, it still divides the remainign range into 128 steps - each step is just that much finer.
Sometimes an engine needs a certain amount of power to start moving, and that might be more than the amount of power delivered at speed step one. Of course you can increase the amt of speed step one (CV2) to compensate for that.
The decoders that come with some engines (like non-sound Bachmann) are not very high quality, and usually replacing them with a TCS, Digitrax, NCE etc. decoder allows better operation.
I may not be understanding something you're saying, but in addition to what is speed step 1, it seems like there may be an issue with how your decoder is set up or it's quality?? If you've set up the decoder for 128 speed steps it should start moving with very little movement. I say this because I bought a DCC equipped loco recently and was amazed at how badly it operated. If that had been my only experience with DCC, I would have questioned the sanity of DCC supporters. Anyway, I replaced the decoder and it became a crawler.
I also have a DT402D and find it's pretty good. It uses batteries a lot quicker than the DT400Rs, so we've gone to Powerex quick rechargeables.
Richard
I believe at least some DCC systems allow you to actually see which speed step you're on. Like you I use a Zephyr and UT-4, neither of which have that option.
Thanks guys, that is what I wanted to know. Also, Randy, I just ordered a UR92 duplex loconet unit for my layout and when I have enough $$ saved I will be getting the DT402 wireless throttle. As you mentioned that you don't use the Zephyr as a throttle any longer, I feel I will be in the same situation. I also have a UT4 that I prefer to use over the Zephyr. I have the PR3 as well and use Decoder Pro to program my engines but have never tried it as a throttle; will have to look into that.
Thanks again for your quick response. Love this forum!
It's hard (nearly impossible) get get an exact speed step 1 on any system that uses a potentiometer throttle (Zephyr, UT4, other brands that use pots). Thottles liek the DT402 that use encoders, adn other systems with encoders, can actually adjust speed 1 step at a time. The only practical way to get a true speed step 1 on a Zephyr would be via a computer interface and a throttle in JMRI. The JMRI throttles will also advance one speed step at a time, so you can set a loco to speed step 1 and then adjust CV2 using Ops Mode until it begins to creep.
I had my Zephyr for about a year until I bought a DT400 - after that I hardly ever touched the Zephyr console. On my current layout the Zephyr is stillt he command station, but it's mounted under the layotu and not even easily accessible (to use the controls). I have a DT100, DT400m and DT402 to run my trains, and I have a standalone PR3 controlled with JMRI to do programming.
The only alternative is to sort of eyeball it. Nudge the throttle off the stop position and treat that as the slowest speed point. It may be anywhere from speed step 1 to step 5, but the potentiometer isn;t high enough resolution for it to be more repeatable than that anyway. With a computer connection and JMRI or a DTxxx throttle you can use the slot followign feature to actually see what speed step you're on when nudging the potentiometer, in case you are curious. There a bit of dead space and then the speed step starts going up, about 2 degrees of movement per speed step in 128 step mode - the range of motion of the potentiometer is 250-270 degress, divided by 128 speed steps (close enough anyway).
They are one and the same. Speed step 1 is 1 on your display. The hand held throttles also display speed from 00 to 99. They click too, but that can actually be turned off if desired.
One thing you may notice is a jump every third number. That's because the command station allows for the 128 speed steps that most decoders have built in. It squeezes in an extra step every third number.
I know this is going to sound 'sillly' to some but being rather new (less than 1 year) to DCC and using a Digitrax Zephyr, exactly what is speed step 1? I have seen it mentioned in many posts but my control knob moves until about the 1.5-2 position (it only goes to 6 so that would be about 25% of the speed range!) before any loco starts to move. Since it ususally is in reference to the lowest point of power going to the loco, I wondered if the '1' on my speed dial is the same as 'step 1' as mentioned earlier? I thought that these references were to the digital 'clicks' on other hand held throttles? Could someone please explain this to me? Thanks for all the help I have recieved from you guys in making the 'adjustment' into the DCC world so painless (relatively!!).
- Bob