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QSI Decoder Questions

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QSI Decoder Questions
Posted by cudaken on Sunday, February 8, 2015 6:29 PM

 I am getting ready to speed match my PK2 E-7 with QSI sound to my PK2 E-6 using a Digitrax DH-163. While looking at the E-7 QSI decoder CV's using JMRI I saw a few CV's I don't know what they are for.

 V Start it looks like it is CV 2 and is set at 43 which is on the low end. Is this like Digitrax CV 2?

 Max Volts It is sat a 9 volts? But I can set it as 255, well I am sure that is not the Max Volts I think? 255 seems like CV 5 for Digitrax decoders. Hum, if Max Volts is like CV 5 no wonder the thing is slow! Laugh

 Any other tips you folks can think of? I know on paper the PK2 E-6 should be faster that the E-7 due to gear sizes.

 Any thoughts on how to set up the QSI BEMF?

 Thanks folks, Ken

 

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Posted by maxman on Sunday, February 8, 2015 6:46 PM

cudaken
V Start it looks like it is CV 2 and is set at 43 which is on the low end. Is this like Digitrax CV 2? Max Volts It is sat a 9 volts? But I can set it as 255, well I am sure that is not the Max Volts I think? 255 seems like CV 5 for Digitrax decoders. Hum, if Max Volts is like CV 5 no wonder the thing is slow!

Per the NMRA, http://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-9.2.2_decoder_cvs_2012.07.pdf, Vstart (CV2) is a madatory CV and should mean the same thing on any NMRA compliant decoder.

Vhigh, CV5, is an optional CV that may or may not be found on all decoders.  However, to the best of my knowledge CV5 means the same thing on any decoder where it is used.

If you have CV5 set at 9, this does not mean 9 volts.  The value is a proportion.  Folks can correct me if I'm wrong, but what the 9 means is that the value represents 9/256 of the available voltage,assuming that the voltage delivered by the decoder is linear across its range.

There should be some default CV settings included with the decoder, or somewhere in the QSI manuals.  I doubt very much that the default value in CV5 should be 9.

CV2 should be set so that the loco just starts to move at speed step 1.  The actual value depends on the motor drive. 

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Posted by Iansa on Sunday, February 8, 2015 7:14 PM

Don't worry about different gearing in different locos.

I think most decoders have CVs 2-5-6.

CV2=start speed  CV5=top speed CV6=mid speed.

As Maxman said, set CV2 so loco just starts to move at speed step one.

Then set CV5 so loco is at your required top speed at full throttle.

Then set CV6 = 1/2 to 2/3 of value in CV5.

Set a master loco to above method then match all locos to that loco again using CVs 2 5 & 6.

The other alternative is to do a full 28 step speed curve (which I do) but unless you have access to Decoderpro that can be a pain in the rear end.

Cheers

Ian

 

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Posted by Mark R. on Sunday, February 8, 2015 7:59 PM

Not all decoders support CVs 5 and 6 - especially the cheaper decoders.

To start speed matching, I always first turn off momentum - CV3 (acceleration) and CV4 (deceleration) - set them both to 0. Set CV2 first so the engine just begins to move on speed step 1. Set CV5 to where you want your maximum speed. Set CV6 (mid speed) to a value that is half way between the values in CV2 and CV5 - this will give you a straight line speed curve.

Once you have the two engines matched in their speed characteristics, you can then start adding your acceration and deceleration rates - they both won't necessarily be the same.

If you are using BEMF, do your setting with it turned on. If you turn it off after speed matching, you will have to re-tweek, especially CV2.

Mark.

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Posted by cudaken on Monday, February 9, 2015 8:24 PM

 Thank you folks. There are a few options I can use to set the speed curve, I will try them and see how it does. Top speed with no cars is around 71 MPH which is what I have read from other owners. I know, that is plenty fast, but what does bug me some what is the way the speed changes.

 My layout has a grade from the garage floor it is bulit on. Guess it is around 1 degree or so. So I will play with the BFME so and see what happens.

 Thanks again, Ken

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