Keyboard Shortcuts
Likes
Search
Locked Speed matching tips
I’ve been chasing my tail on speed matching an NCE D13SRF Rev D decoder with a WOW Diesel 101 SS3. Both are in Athearn Tunnel Motors. It seems the WOW decoder has so much momentum in it (that is proving to be hard to control) and NCE seems super basic (and probably really old) and has very few features comparatively.
How would you guys go about speed matching them because what I’m doing ain’t working.... Thanks Paul |
Paul
toggle quoted message
Show quoted text
The previous messages are correct. The reason for the difference - the default for cv3 is 32 and the default for CV4 is 96 - you are meant to use the brake to stop the loco. As said the NCE is primitive non sound decoder. Gerry On 1/12/2019 2:16 pm, Ken Cameron wrote:
Yes, speed match first. Then keep in mind that, regardless of the standard, --
Gerry Hopkins MMR #177 FNMRA Great Northern Downunder NMRA Australasian Region Contest & AP Chairman Web Administrator |
Yes, the whole issue of manual brake is another issue that some decoders can
do it and some can't. It is just another issue of which decoders can be matched to other decoders. Locos with matching speeds with matching momentum is another example of some will match and others will not match. But last thing to keep in mind, the physical locos may have issues that make matching difficult. Some models may never really match each other. -Ken Cameron, Member JMRI Dev Team www.jmri.org www.fingerlakeslivesteamers.org www.cnymod.org www.syracusemodelrr.org |
Note too that the old NCE decoder (almost certainly) has no BEMF, and a such will be much more sluggish at slow speed than the WOW, however hard you try to get it to match. ?Best thing would be to replace it with a modern decoder with tunable BEMF. A non-sound TCS decoder might be a good choice as it probably has the same motor drive algorithms as the WOW. |
As a follow up to Mick's comment, standardizing on one brand/model of decoder
toggle quoted message
Show quoted text
would also go a long way to keeping your hair where you would normally expect to find it. John ---------- Original Message ---------- |
You guys are a fantastic resource! Thanks to all. I guess by your answers this is a common challenge. And as desirable as it seems to upgrade the fleet's decoders to the very same exact model, the reality is that in a few years they will be "old" compared to the offerings available. So to upgrade, and try to stay at the leading edge of technology, seems like a very expensive proposition. I hadn't considered setting all momentum to zero and shall try that but this too has its limitations as the newer more robust features in the TCS decoder probably won't be able to be used to their fullest extent (BEMF). So, it doesn't appear there is a clear path for perfection except to further tap into my children's inheritance and keep the decoder fleet current and/or consistent from loco to loco.
I really appreciate everyone taking time to share your collective wisdom!!! Thanks Paul |
Paul,
toggle quoted message
Show quoted text
Just like any consumer product, if you try to stay on the leading edge of technology, you'll end up in the poor house. Do your due diligence, buy what is best for you and how you plan to use it, no tech lasts for ever let alone more than five years because the software/firmware keeps developing and breaking new ground, hardware is always a year or two behind. Technology is like owning a boat where a boat is a hole in the water to toss your money into and tech is a box to do the same. Remember, it is your railroad. John. ---------- Original Message ---------- |
I wouldn't bother standardizing on one brand or model of decoder. It's more trouble than it's worth. You will need decoders with similar features if you want to consist locos for features such as braking.
-- Peter Ulvestad JMRI Users Group Moderator - ( ) Tam Valley Group Moderator - ( ) Sprog-DCC Group Moderator - ( ) Edmonton Model Railroad Association - |
Paul,
We were saying that while working on speed matching, FIRST you do it without momentum enabled. Then after you get them running the same at slow, medium, and fast speeds do you work to get a compatible momentum setting. Again, just like matching the basic speeds, matching momentum is easier the more similar the decoders are. Last you get the issue of if they respond to a brake key the same or not. All depends on how far you want to go. -Ken Cameron, Member JMRI Dev Team www.jmri.org www.fingerlakeslivesteamers.org www.cnymod.org www.syracusemodelrr.org |
I would add the prototype also knows to not mix certain locomotives. So your
roster may end up with the same issue of some can be put in a consist together and some only with other locos. Speed matching at best gets you groups of locos that play nicely. Kind of like people at train clubs. Some work better together than other groups. -Ken Cameron, Member JMRI Dev Team www.jmri.org www.fingerlakeslivesteamers.org www.cnymod.org www.syracusemodelrr.org |
I agree, I use several makes and types of decoder, I have old decoders that have been out dated before I've managed to fit them, so long as they can do what I want I'll still fit them. Definitely set momentum to zero while matching otherwise you have to wait for the speed to settle, BEMF will still work the same, yes it effects sounds but not speed response.
I do mine on a rolling road, which means I can set them to set speeds and do it in a consistent way loco to loco, I haven't found a loco / decoder combination that doesn't work yet and I started this a long time ago. Mike Ruby |
I remember years ago (about 60 years!), I got to ride in the cab of a FP7 or 9 with an Alco (RS-10 probably) behind it for a passenger train power. Every start, got a 'bump' from the Alco unit to the emd unit. The engineer who took me along with him told me the Alco didn't start as smooth as the EMD units. Also for what it's worth. I use the Bachrus speedometer, and have found the Soundtraxx (TSU-1)? units best match TCS decoders (steam versions) unison?the Exponential 2 speed?curve in the speed tables. Jim Little, MMR |
I've heard the same and you can see it sometimes on videos that prototype locos start slightly differently even the same type. So long as your locos don't fight each other with slipping wheels it is ok. Mine even though well matched, will push or pull each other as they start moving, but they don't spin wheels unless the train is too heavy or grade too steep, much as the prototype.
Mike Ruby |
AS described in Wikipedia:? "Hysteresis?is the dependence of the state of a system on its history.?Hysteresis can be a dynamic??between an input and an output that disappears if the input is varied more slowly; this is known as?rate-dependent?hysteresis.?Systems with hysteresis are?, and can be mathematically challenging to model."
An example of hysteresis in an electronic system, such as a DCC decoder, would be that the rate of change of velocity of a decoder-equipped locomotive as you move the throttle at a constant rate between minimum speed step and maximum speed step would be different when going from min to max, as compared to going from max to min. So, to simulate physical momemtum in model railroad locomotives (which don't have very much mass compared to their real-world counterparts, and thus, not very much physical momentum), the decoder manufacturers employ "electronic hysteresis" in their model locomotives to simulate the "physical hysteresis" (a.k.a. "momentum") that is found in their Big Brothers in the real world. And again [from Wikipedia]:? "Often, some amount of hysteresis is intentionally added to an electronic circuit to prevent unwanted rapid switching. This and similar techniques are used to compensate for??in switches, or??in an electrical signal." |
...........and who said model railroading ain't fun? LOL
Doug Wagner
Bakersfield, California
AS described in Wikipedia:? "Hysteresis?is the dependence of the state of a system on its history.?Hysteresis can be a dynamic??between an input and an output that disappears if the input is varied more slowly; this is known as?rate-dependent?hysteresis.?Systems with hysteresis are?, and can be mathematically challenging to model."
An example of hysteresis in an electronic system, such as a DCC decoder, would be that the rate of change of velocity of a decoder-equipped locomotive as you move the throttle at a constant rate between minimum speed step and maximum speed step would be different when going from min to max, as compared to going from max to min. So, to simulate physical momemtum in model railroad locomotives (which don't have very much mass compared to their real-world counterparts, and thus, not very much physical momentum), the decoder manufacturers employ "electronic hysteresis" in their model locomotives to simulate the "physical hysteresis" (a.k.a. "momentum") that is found in their Big Brothers in the real world. And again [from Wikipedia]:? "Often, some amount of hysteresis is intentionally added to an electronic circuit to prevent unwanted rapid switching. This and similar techniques are used to compensate for??in switches, or??in an electrical signal." |
forfoum@videotron.ca
" Hysteresis "? This is one big mystery as there is mention on TCS web site of Hysteresis, but browsing the manuals explain nothing but " Hysteresis - change to notch " and is in sound related CV's of WOW There is a typo in the WOW manual.. They have it as "hysterasis"? reason why could not find it. This hysteresis is the amount of change from BEMF before it moves to next (+/-) notch.? Default is 80 (0-255). For use in "Prototype Throttle Mode" only.Marc. |