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Stupid QSI BMEF question.

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  • Member since
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  • From: Reading, PA
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Posted by rrinker on Thursday, October 8, 2009 8:12 PM

 Talk to the volleyball. Without the QSI manual OR JMRI, there's no way you could possibly figure out those indexed CVs. You need to use the index values to read them as well as write, so even if you went through all CV values from 1 to 255 you wouldn;t get the indexed ones.

 And even if you have a full list that said 56.4 is the throttle control, without the QSI manual to show you just how you access an indexed CV, I doubt you could figure it out. You'd never just figure out from playing around that you need to put 4 in CV49 to access the index. And what about the double index CVs, like 55.3.1 - no way you would figureout that that meant set CV49 to 3, CV50 to 1, and then program CV 55 with the value.Armed with the QSI manual instead of just a list of CVs and you could program it no problem.

                                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by maxman on Thursday, October 8, 2009 9:42 AM

rrinker
Easy - JMRI. Instead of going through all the conniptions of programming CV49 and CV50 with the indexing values, you can go into JMRI and there's a dropdown

Well, yes, this is true.  I was thinking more along the lines of someone who bought a decoder and didn't have access to JMRI.  For instance, if you are washed up on a deserted island with only the decoder, a list of CVs, a command station, and a 12 volt (battery) power supply, is there any way you can figure out the proper sequence using the old logic method?  Or would it be more useful to just engage the volley ball in meaningful discussion until you get the raft built?

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Posted by rrinker on Thursday, October 8, 2009 6:57 AM

 Easy - JMRI. Instead of going through all the conniptions of programming CV49 and CV50 with the indexing values, you can go into JMRI and there's a dropdown that allows you to select Standard, RTC,  Load Compensated BEMF, or CSC modes. There is also a table of indexed CVs so if you are lookign in the QSI manual and it lists possible values for CV 56.4 you can just look up 56.4 int he table and enter the desired value. JMRI then handles all the settings required to actually program those CVs, you just need the basic number for the CV as listed in the QSI manual.

                                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by maxman on Wednesday, October 7, 2009 11:45 AM

tstage
Whenever you see a decimal(s) in a CV, it generally means that CV49 (primary index) and sometimes CV50 (secondary index) needs to be changed FIRST before changing the CV itself.  I'm guessing that with CV56.4, you'll change CV49 to "4" then CV56 to whatever value it needs to be.

I don't know if the CV configuration process for all of the latest version QSI decoders is the same or not.  However, I have the QSI Revolution A instructions in front of me.

For the Throttle Mode (STC and RTC) CV, 56.4.0, it says that you first set CV 50 to 0, then you set CV 49 to 4, and then you set CV 52 to either 0 or 1.  A value of 0 gives you Standard Throttle Control, and a value of 1 gives you Regulated Throttle Control.

They then have a CV 56.5.0 which is called R.T.C. Minimum BEMF.  For this they want you to set CV 50 to 0, CV 49 to 5, and then CV 52 to some value between 0 and 31.  They define value 0 as equaling NO BEMF for RTC, and a value of 31 as equaling all BEMF for RTC.

Now, how one knows that CVs 50 and 49 must be changed when those numbers don't appear in the 56.5.0 CV number is beyond me. But I suppose someone can jump in and explain how we know this without instructions.  

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Posted by tstage on Wednesday, October 7, 2009 10:00 AM

Hey Ken,

Whenever you see a decimal(s) in a CV, it generally means that CV49 (primary index) and sometimes CV50 (secondary index) needs to be changed FIRST before changing the CV itself.  I'm guessing that with CV56.4, you'll change CV49 to "4" then CV56 to whatever value it needs to be.

Also, it's BEMF, which stands for Back Electromotive Force

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by rrinker on Wednesday, October 7, 2009 6:40 AM

 It's on the QSI Misc tab, right in the middle: Throttle Mode. It's also on the Indexed CV page if you scroll down, 56.4 is listed. If it's not showing up on yours then you aren't using a version 7 decoder definition - Version 6 QSI firmware did not have these options.

                                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by cudaken on Tuesday, October 6, 2009 11:07 PM

Randy I do not seem to have a CV56.4? I tried to do a copy and paste of the BMEF control panel and it would not let me. Do you use Decoder Pro Randy? In the BMEF section, it shows what the CV's do, but not there CV. Just the values you can set them to.

 Thanks for the effort.

               Ken 

I hate Rust

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Posted by rrinker on Tuesday, October 6, 2009 11:56 AM

 If two locos are connected and are fairly well speed matched, it usually is fine if ONE has BEMF so long as they both don't. The loco with the DH123 definitely doesn't - the DH123 series deocders don;t have BEMF. So it's just the QSI. CV 56.4 is the control. 0 = standard throttle control, 1 = RTC, 2 = BEMF.

 RTC in QSI won't work well with a non-QSI decoder - it attempts to maintain a set speed no matter what, it's a little different than standard BEMF in that if it starts pushing the other unit it won't back off, it will try to keep going the same speed. And when it's being dragged by the other unit, it will keep going at the same speed. OK for consisting multiple QSI locos, but not so much for QSI and another decoder.

                                           --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by wjstix on Tuesday, October 6, 2009 8:15 AM

If the engines only have trouble when they're running together, it probably is the BEMF fighting each other. It might be easier to turn the Back-EMF off on the Digitrax equipped one, I think it has one CV that controls the amount of BEMF compensation. I'm not sure right now which one. Maybe try turning that to zero and see what happens, then try increasing it a little at a time until it starts bucking again, then go back down a number or two.

Stix
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Stupid QSI BMEF question.
Posted by cudaken on Monday, October 5, 2009 6:57 PM

  Running a PK 2000 E-7 with QSI sound with a PK E-6 B with a Digitrax DH 123. E-7 has started bucking, think I might have turned the BMEF back on by mistake. I used Decoder Pro to read CV's and in the BMEF section I found around 8 different sub listings. Do I turn them all to OFF?

 Thanks for answering a stupid Cuda Ken question again.

I hate Rust

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