Some locos today can't get to their prototype speed, just too slow--particularly psgr diesels. So no adjustment can help. Also if decoders added by you, they will slow the loco down some with a voltage drop.
Richard
Hmm, just looked in the manual, no CV5 either. I thought that one was a required one, guess not. Leaving out CV6 is a pain, also leaving out CV5 in just plain bad. Yeah, not buying any more Tsunamis after the one I have. Already said that, but liek the new good things I keep hearing coming out of ESU enhancing my decision to standardize on Loksound decoders, well, this is more ammo for rejecting Tsunami. Not to menion I don;t see program problems with Loksound, without add-on program track boosters (though mine reads and writes fine on my Zephyr AND PR3).
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy,
I thought Tsunami decoders skip over both CVs 5 and 6. Their non-sound motion decoder supports them, but not the Tsunami.
CV6 mid speed is the one missing in some (of currently manufacturered decoders you can buy, as far as I am awawre of ONLY SOundtraxx Tsunami skips this). CV2 and CV5 for start and top speed are NMRA required CVs, CV6 is optional.
As has been stated some decoder manufacturers do not support CV5. There is a way around that minor problem; if you have CV's 25 and 29 set to accept 128 speed steps, you can adjust forward and reverse top speeds by adjusting CV's 66 (forward trim) and 95 (reverse trim) to an acceptable top speed. Check the manuals for each of the decoders that you have for the factory setting. If that seems too high, lower the value for a lower speed in both 66 and 95; raise the values if too slow.
Remember that locomotives are not running at top speed all the time. The exception to this is the UP turbines which had two speeds: on and off. When the turbine was started there was no change to turbine speed; locomotive speed was regulated by controlling the power sent to the traction motors, similar to a diesel.
Just thought I would chime in here about CV's. I have a Bachmann GE 44-tonner with a TCS Z2 decoder, have CV5 set NOT to max voltage but to 30 scale mph and 10 scale mph at half throttle. That was a guess of top speed from me but have found a 44-ton manual available online and will most likely reprogram the decoder to math top speed and readjust so rated continuous tractive effort speed will be about 1/4 throttle.
I don't run trains full out at all so I really don't bother with Vmax setting (CV5).
Just remember, they don't have to be in exact lockstep. Close is good enough.
Real example - for a while this week I was pulling my train on the club layout with just my Atlas Trainmaster, it has a factory QSI decoder. I cranked up the momentum so I could get the engine to load up when starting and coast down. After the first couple of days, certain sectiosn started having poor contact, so I stuck on my pauir of Proto 2000 GP7s which have TCS motor decoders. I didn;t turn off the momentum on the Trainmaster, so if I cranked the throttle wide open wuickly, the Geeps were dragging the Trainmaster until it got up to speed (well, pushing and pulling it, one Geep in frona dn one behind). If I throttled up slowly, absolutely no issue. I ran it like that for 3 hours straight, no problems. No overheating, etc.
have fun getting all THOSE TO MATCH, Ive been struggling for a week with the same brands ,QSI-Q1,TSUNAMI , TSUNAMI-NON SOUND,NCE & LOCKSOUND SELECT . can BE FRUSTRATING
just be PATIENT, write down every thing you do, decoder-pro makes it easier (more or less) still struggling with the locksound .
important : get some ink, leaf of paper ,and download and print ALL manuals for each brand decoder , good luck ....Jerry PS I have set my top speed or 99 on digitrax ,to 55 mph ,...
richhotrain Mark R. The default value for CV5 is 255, not 0. On an NCE decoder, the default value for CV5 is 0. Setting CV5 to 255 uses the maximum possible voltage to run the motor when full speed isrequested. You can set CV5 to a smaller value to reduce the top speed. If CV5 is set to 0, the decoder will use 255 for maximum speed. Rich
Mark R. The default value for CV5 is 255, not 0.
The default value for CV5 is 255, not 0.
On an NCE decoder, the default value for CV5 is 0.
Setting CV5 to 255 uses the maximum possible voltage to run the motor when full speed isrequested.
You can set CV5 to a smaller value to reduce the top speed.
If CV5 is set to 0, the decoder will use 255 for maximum speed.
Rich
Sorry about that - NCE is one decoder I've never used.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Alton Junction
Why do you want to run your loco at top speed?
I never ever run mine at top speed. The most I normally run is 20 speed steps for mainline trains. It just not very realistic to run them too fast. Not to mention, if you have a derail, you now got a major disaster with cars flying everywhere.
Michael
CEO- Mile-HI-RailroadPrototype: D&RGW Moffat Line 1989
Depends on the decoder. SOme are 255, some are 0. All means the same thing - no restriction on top speed, full voltage will be applied to the motor at the highest speed step.
Tomkat,
The CV's can be set for 14 or 28 speed steps. That said, most decoders made in the past 10 years automatically interpolate the 28 speed steps to 128.
CV5 is the Vmax - Most decoder default to a value of '0'. Changing that value will restrict the top speed. Remember, this is a 'decoder' function, not a function of you NCE system.
With all of the above said, some decoders do not support CV5 - You will have to review the detailed manual for each of your decoders. If you decoder does not support CV5, you can enable the speed table in the decoder and adjust it. If you do not have Decoder Pro from JMRI, I would highly suggest setting it up on you home computer - it is a lot easier to program CV's from Decoder Pro.
For example, I have 4 Kato SD40-2 locomotives, each with Digitrax SDH164 sound decoders installed. Their maximum speed out of the box is around 71-75 scale mph - Pretty close. I did not adjust CV5 on any of them. I did adjust CV2(Vstart) on each so they all would start moving on the first click of my throttle. IIRC, 1 has a value of 7, two have a value of 4, and one has a value of 3. When in consist, they start moving together. Since my SD40-2's are the slowest freight engines in my modern fleet, I have adjusted my Atlas GP38's to match their max speed(they ran about 82-85 scale mph out of the box). The nice thing about JMRI is that I can save each of the roster entries to the roster file. I have a record of what I have adjusted, and if I fry a decoder, I know where to start programming again.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
If CV5 has NEVER been set, then your loco will run as fast as it can at top speed. If some are slower than others, then you use CV5 to slow down the faster ones to match.
Hi all
just wondering , how do I get my locos to run at their top speeds at speed steps 28?
Do I adjust CV 5 to 255 if I use NCE .?
And is it the same for all decoders im thinking they are all different somehow
I have 2 x QSI , a Loksound, a nce , A tsunami if that helps
thanks for all suggestions. I am a bit lost as to what I do