56.5 is the Pi paremeter in teh BEMF equation, basically the strength. Default it says depends on the loco.
Read page 307 here: http://qsisolutions.com/pdf/QuantumDCCRefManual_5_0_2.pdf
It tells you how to set it to get the loco to operate at minimum speed between speed step 1 and 8. Personally I would follow those directions except use maybe step 4 for the upper limit not 8. Most of my locos creep nicely on step 1, the BEMF ones without ever modifying CV2. Factory settings on the QSI seem good, my Atlas Trainmaster creeps nicely on step 1, so I haven't attempted to mess with those settings.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
So what does the minimum backemf setting on CV56.5 do for him?
Page 17 of that manual only lists valid values of 0 for standard and 1 for RTC. There is no other value listed for that CV.
The full v3.0 of the manual lists the values as 0 for standard throttle control, 1 for speed control, and 2 for RTC. Speed control is the cruise contorl mode with strong BEMF that will do whatever it takes to maintaint he same speed, up hill, down hill, loaded, light. The one most people point to when they say BEMF is not realistic. RTC is the more realistic mode that still uses BEMF to maintain approximately the same speed but the loco will slow down goign up hill and speed up goign down.
The upgrade chips woudl appear to NOT have Speed Control, just standard and RTC, based on the upgrade chip manual.
To add more confustion, the full Quantum Reference Manual, version 5.0.2, lists FOUR options. 0 is standard, same as before. 1 is RTC, 2 is Calibrated SPeed COntrol (same as "Speed control"), and 3 is BEMF COmpensated Speed Control - just a variation on speed control.
Note at the bottom of the page make it all make sense. The first one notes that early QSI decoders used 1 for Speed Control and 2 for RTC. This is now reversed. A second note at the bottom of the page says CSC and BEMFSC are not available in any Q1a or Q2 decoder. So - not the upgrade chip. 0 for none, and 1 for RTC, those are the options. Exactly as is also states in the Upgrade CHip manual linked above.
wobblinwheel Does this mean it has no BEMF, or is BEMF incorporated into REGULATED throttle mode? Also, I have FOUR other BLI locos all with upgrade chips (of varying ages, dating back to the first N&W A-class upgrade) and NONE of them respond to a setting of CV56.4=2! Everything I have read online from the QSI solutions website suggests the upgrade chips all have CV 56.4 settings of 0, 1, AND 2. But I ain't gettin' it!
Does this mean it has no BEMF, or is BEMF incorporated into REGULATED throttle mode? Also, I have FOUR other BLI locos all with upgrade chips (of varying ages, dating back to the first N&W A-class upgrade) and NONE of them respond to a setting of CV56.4=2! Everything I have read online from the QSI solutions website suggests the upgrade chips all have CV 56.4 settings of 0, 1, AND 2. But I ain't gettin' it!
I don't know shipe from shinola on this subject, but when I go to the QSISolutions website and look for the manual for upgrade chips, I see something called "Q1a/Q2 Diesel Manual v4.1 for upgrade chips". From there I get to here: http://www.qsisolutions.com/pdf/q1a_diesel_v41_man.pdf. Looking at the list of CVs on page 23 of 24, I see CV 56.4 is for RCT/SCT throttle mode select. Then I see that there is a CV 56.5 for minimum back emf.
Is it possible that you are trying to change the wrong CV?
Well, I found out on my brand new QSI Upgrade chip, It does not respond to CV 56.4=2. It only responds verbally to CV 56.4=0, or 1. Does this mean it has no BEMF, or is BEMF incorporated into REGULATED throttle mode? Also, I have FOUR other BLI locos all with upgrade chips (of varying ages, dating back to the first N&W A-class upgrade) and NONE of them respond to a setting of CV56.4=2! Everything I have read online from the QSI solutions website suggests the upgrade chips all have CV 56.4 settings of 0, 1, AND 2. But I ain't gettin' it!
Mike C.
Yes, you must have a firm grasp of which manual relates to which QSI version you have in hand. It does get confusing. If you can't seem to get to the nub of it after a bit more research, you could always call QSI and ask to speak to someone who knows what to do in your case. Sometimes that is the quickest way to pain relief in the hobby.
Crandell
Make sure that the reference manual you downloaded is for the chip version you have. Sometimes the web site can be a little behind the current version. It won't hurt to try all the CV 56.4 setting to see what it does to your performance.
Joe
Finally downloaded the "Complete QSI DCC Reference Manual" using the link supplied with the instruction sheet that came with my chip. It says CV56 is set to "1" (default) which is "speed control" (bemf). "0" is "standard", and "2" is "regulated". Even the sheet that came with the loco says the defalt on the chip is cv56=1 which is "regulated throttle control." (I know you must first set cv49 to 4). It seems the downloaded manual is contrary to everything else I've read. I guess now I'm officially confused...
Thank you SO much! This is exactly what I wanted to know.
Download the manual from QSI solutions for the version of chip you have. See my previous post.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
wobblinwheel My loco's speed changes significantly as load changes, even with new chip (in RTC mode). Acts as if BEMF is not even ON. How do I turn BEMF on and off?
My loco's speed changes significantly as load changes, even with new chip (in RTC mode). Acts as if BEMF is not even ON. How do I turn BEMF on and off?
Wobblin:
BEMF is part of CV 56.4. To change CV 56.4 you FIRST need to set CV 49 to 4 then set CV 56 to the value you want. CV 56 = 0 is regular throttle control, CV 56 = 1 is RTC and CV 56 = 2 is BEMF. I hope this helps.
You may need to read what version chip is already in your loco. All of mine came came with the version 7 chip that has RTC and BEMF. I like the RTC better then the BEMF for the reason that it is smoother transition between speeds and hills really slow it down. From what you describe is you have too much momentum in CV3.
Download the QSI manual for the version decoder you have. It helps tremendously.
http://www.qsisolutions.com/pdf/htrqsi_dcc.pdf
I've just installed the new chip, and can't say I see much difference. Obviously, the drivetrain on this loco has a lot of "snags" (always has, even after many attempts to work them out). The new instruction sheet says to turn-off "regulated throttle control" and switch to "standard throttle control" in order to fine tune the starting voltage. I notice the loco really binds up at slow speeds on standard. The RTC on the old chip seems to behave very much like the new chip. How do you know the "BEMF" feature on the new chip is ON, or is it part of the "RTC" on the NEW chip? Can just the BEMF be turned on and off? The new chip operates pretty smoothly, but an occasional snag at really slow speeds (step one). The only glitch is when running light (no load), the loco has a "camming" effect at certain speeds that is not noticable with a consist. Can the BEMF feature be fine tuned also? Thanks for any ideas.
wobblinwheel I'm not very DCC savvy, so I want to ask, which CV do you change (and what to you change it to) to go from 128 speed steps to 28? I just want to experiment with the differences in the two. from the manual, I gather it's CV29?
I'm not very DCC savvy, so I want to ask, which CV do you change (and what to you change it to) to go from 128 speed steps to 28? I just want to experiment with the differences in the two. from the manual, I gather it's CV29?
CV29 is a multi-function CV. One function is to adjust the speed setting to either 14 or 28/128. But CV29 is not used to adjust the speed setting between 28 and 128. That is typically done on the throttle. On my NCE Pro Cab, there is a single button to toggle back and forth from 28 to 128 and back again to 28.
Rich
Alton Junction
I've repeatedly "heard" that BEMF in consists is no good. I constantly run pairs of locos consisted together that both have BEMF decoders with no issues. Try it and make up your own mind. Note that running a pair of light locos is NOT going to behave the same way as if you had a train behind them, with the weight of a train, the load is more balanced out and each loco will properly pull its share without fighting. But even light, running at slow speeds, there is very little back and forth between say my pair of GP7's with TCS decoders (and BEMF enabled). With a train, absolutely nothing unless one hits a dirty spot of track and stalls. One unit could pull the train but one unit will not tug a dead one plus the train. Never have a problem at home, just the club layout.
If you're not liking the way the CVs work, particularly with QSI which are indexed CVs, you might consider using Decoder Pro a JMRI download. Loading that into your computer and using a Locobuffer USB(or similar interface) makes programming a lot easier as it puts things in common language and stores your last settings.
http://jmri.sourceforge.net/
Richard
Just ordered the QSI upgrade chip from Tony's. Tony did say the BEMF feature should help slow-speed performance a lot. One thing I did read online was that BEMF at higher speeds when double-heading, or using a pusher could cause two locos to "fight" each other. Ever heard of this? Can the BEMF be turned off at higher speeds, if necessary? Also, is BEMF part of "regulated throttle control" in the QSI chips?
You need the upgrade chip for that. They were shipped without due to a legal dispute, once that was settled QSI offered an upgrade chip for each of the earlier models that added back the missing features and updated sounds in some cases.
It has the original BLI chip. Only thing I have changed is the Accel. and Decel settings. Which CV turns on BEMF?
Starting voltage will help. Has this loco been upgraded with the upgrade chip, if it's an original BLI one? If so, look into turning on the BEMF. The upgrade chip is well worth it, some have improveed sounds and the better operation at slow speeds you get from the BEMF are well worth it.
Thanks to all who have replied! After playing with this thing, I believe I need to experiment with the starting voltage, not the speed steps. At speed steps 1 thru 19, the loco creeps along, but somewhat jerky while pulling a load. If I increase throttle to about 22 from the beginning, it starts out slow and smooth. Thinking about adjusting start voltage to see what happens. Make sense?
What DCC system do you have? If it's Digitrax and you have a 400 series throttle you can call up the engine on your throttle and then select EDIT. Use the hit knob to scroll through the entries and stop at 28 speed steps. Hit enter and you will be in 28 speed steps.
You don;t need to change a CV, the decoder settings for responding to 128 speed steps is the same as the setting needed to respond to 28 speed steps. You need to tell your system to deliver 28 steps instead of 128 - but why in the world would you want to reduce the resolution of the control?
I have a PCM Pennsy I1sa 2-10-0 with QSI sound. I.m not very DCC savvy, so I want to ask, which CV do you change (and what to you change it to) to go from 128 speed steps to 28? I just want to experiment with the differences in the two. from the manual, I gather it's CV29? But I don't understand anything after that! I know, I'm stoopid.....