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MU attempt issue

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  • Member since
    November 2015
  • 723 posts
MU attempt issue
Posted by UNCLEBUTCH on Saturday, April 6, 2019 11:19 AM

I have a Digitrax DCS51, two Atlas units I tryed to MU. One with sound, one w/o.

When I call up unit A, to move forward,it will move to my right.

When I call unit unit B to move forward it also moves to my right.

I attemp to mu acording to the book,have control of both,thru top unit number.

 But they move ''away'' from each other[.Not coulped at this point].

Book don't tell me anything, the guy I got hold of at LHS had no clue.

What am I doing wrong?  Thanks

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, April 6, 2019 12:09 PM

 How are you trying to MU them, with the Digitrax way or are you trying to fiddle with CV19? If they are both moving the same way immediately before pressing the button to add the second unit to the consist, it should work and keep going the same way, when using Digitrax consisting, since all it does is send the same commands to each loco in the consist. So if the direction lever in forward is to your right for both units, that shouldn;t change. Even if one has had CV29 changed to alter the direction of travel. But CV19 consisting works differently, it ignores the CV29 direction of travel setting and the direction for CV19 consisting is determined by the value used in CV19. Normal values are 1-127, but if you add 128 to the value, that loco will run the opposite way.

                                            --Randy

 

 


Modeling the Reading Railroad in the 1950's

 

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

  • Member since
    November 2015
  • 723 posts
Posted by UNCLEBUTCH on Saturday, April 6, 2019 1:58 PM

rrinker
How are you trying to MU them, with the Digitrax way or are you trying to fiddle with CV19? If they are both moving the same way immediately before pressing the button to add the second unit to the consist, it should work and keep going the same way, when using Digitrax consisting, since all it does is send the same commands to each loco in the consist. So if the direction lever in forward is to your right for both units, that shouldn;t change. Even if one has had CV29 changed to alter the direction of travel. But CV19 consisting works differently, it ignores the CV29 direction of travel setting and the direction for CV19 consisting is determined by the value used in CV19. Normal values are 1-127, but if you add 128 to the value, that loco will run the opposite way. --Randy

 No Sir, didn't mess with CVs, not that bold yet.

I followed the Digitrax book.

I had the LHS install one decoder, the other came DCC equiped,off the shelf.

Is it possible that one has a different CV value on CV19 ?

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Saturday, April 6, 2019 4:24 PM

 No, if CV19 were set to anything but 0, the locos wouldn't work properly when run independently. 

 This is a little easier to do with the DT40x throttles because you cna control both locos at the same time, but the way to be sure you are getting this correct is to have them both on the track. Select the lead loco, verify that it runs forward as expected. Do NOT have the locos coupled together. Select the trailing loco - whichever direction you need to have the sitch in to make them couple up is the direction is has to be in when adding it to the consist.

 You aren't leaving out a step in your desciption, are you? You didn;t pick up the second loco and turn it around before trying to MU it? Because if you did, you would want to select REVERSE for that loco before adding it to the consist. Direction in DCC has nothing to do with which way the loco faces on the track, ideally forward always means move towards the front of the loco. With a cab unit like an F7, that's pretty obvious (on the A unit, anyway), or a steam loco. With hoob units like GPs and SDs, it's not as obvious because some railroads ran them with the short hood in front and some with the long hood in front, and some had dual controls so either end could be 'front' as far as the engineer was concerned. However, if it is a detailed model, it ought to have a snall F decal on the frame near one end or the other - that was the designated "front" of the loco

 Anyway, with DCC - this is what matters. You might have a simple loop of track with a DC power pack. Putting the direction switch in "forward" might make locos run clockwise, and "reverse" counterclockwise. If you take the loco and turn it around to the froont faces counterclockwise, with the direction switch on the power pack in "forward", the loco will run in reverse, going around the loop in a clockwise direction. With DCC - it doesn;t matter which way the loco faces, forward means towards the front, there is no change of polarity on the rail like there is on DC, and the way a loco is put on the rails has no effect on which way it will move. If your loco moves to your right in forward, if you pick it up and turn it around, still in forward, it will now move to your left.

                                      --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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