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Greg

Very easy if you are using Decoder Pro. On the program track - go to the pane with the loco number. Below the number you will see "Direction" = Normal, change this to Reverse and Save Changes.

This is all you need to do. Once you get used to it there are a few other things you can do, like set up an advanced consist with different number locos and setting a few things in CV21 + CV22.

Gerry

I want to setup a consist temporarily to run on a friends layout for two F7’s, using the same engine number for both locomotives.

Can I get the trailing unit to run “backwards” using CV settings (or DecoderPro?) so I don’t have the locos running as “elephants”, nose to tail?

I definitely don’t want to re-wire the decoder in the trailing loco to do so.

Both locos are equipped with WOW Diesel v4 - Mfr date 7/16/18.

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Thanks, in advance…

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Greg Komar

gkomar@...

“You can't buy happiness. But you can buy model trains, and that's pretty close!"

Virus-free.

-- 
Gerry Hopkins MMR #177 FNMRA
Great Northern Downunder

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Adding 1 to whatever value is in CV-29 for the unit you want to run backwards will reverse the direction, operation of lights, etc.

See for all of the possible values of CV-29.

Steve Long

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-- 

Gerry Hopkins MMR #177 FNMRA

Great Northern Downunder

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Hi Greg,

? While adding a value of 1 to whatever value is in CV29 will reverse the normal direction, you may find it has some unwanted features as well.? I suggest trying it out at home before hand.? You will likely experience horns and bells working in both units at the same time.? The headlights, too, will likely not be terribly realistic.? Try it out.

? Question: what make of DCC system does your host have??? The NCE system makes it easy to assemble an advanced consist.? Though for optimum effect (e.g. brakes, brake release, mute etc.) in all units in the consist you need to program at least CVs 21 and 22.

? Advanced consists can also be used by other systems but there is a little math involved (CVs 19, 21, 22, etc..).

? Ask if you need more information.

Best regards,
KJ

"Adding 1 to whatever value is in CV-29 for the unit you want to run backwards will reverse the direction, operation of lights, etc.

See for all of the possible values of CV-29.

Steve Long"



Hmm... probably will work... not not always..

But what if CV29 is 7 already?? (motor wired backwards, and bit 0 already set?)

then CV29 would be 8 by simply adding one... that would make a mess... you would be back at 14 speed steps...

This works:

Add 1 if CV29 is even
Subtract 1 if CV29 is odd

(or you could do it right)

Greg

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Greg, Since my post had generated 4 posts from you, I guess I need to reply to get this settled down.

Yes, if the motor is wired backwards and that has been compensated for by setting the first bit (usually called "bit zero") in CV-29 to make the motor run backwards to get the loco to run forwards, then just adding "1" to whatever is in CV-19 would work for reversing the loco direction, but would also make some other changes, depending on what other bits were already set and not set.

So, you are right that it is better to think of it as:

"Add 1 if CV29 is even
"Subtract 1 if CV29 is odd"

because that will only change the first ("zero") bit, either way.

I did put a link in my first post that allows folks to calculate the decimal CV value to enter from a throttle to get the binary value for any combination of functions that they desire to turn on.? Repeating that here: .

By using that calculator, you can see that the effect of just adding "1" to whatever value is in CV-29 when the first ("zero") bit (which is numerically "1") is already set to 1 will have various effects on other functions.

For instance, if CV-29 is set for backward motion, enable 28/128 speed steps, and use address above 128, the CV value will be 35.? Just adding "1" to "35" makes the CV value "36", which, in binary, is equivalent to turning off the zero bit and "1" bit and turning on the "2" bit, which would reverse the motor direction, turn off 28/128 speed steps, and enable DC analog operation.

I will let those interested to use the link to get a better understanding of how that works, rather than make this post any more complicated.

Anyway, good catch on making the advice more error proof.

Steve Long

uhh...

1. sorry, I was fumble fingers, I did not generate 4 posts (if you look online), but posted and edited 3 times... and the dumb forum software does not allow you to do a minor edit and NOT send to everyone... (but if you are a administrator, you can)

2. yes, wholeheartedly agree to do it the right way, a CV29 calculator is painless.... although nowadays, be sure to get one that also "sees" the railcom bit.

3. I only commented because I have been bitten in the butt many times when I assumed something (like the bit was not already set) and then go way down the road with a false assumption, so "bullet proof" is my modus operandi, and in this case I felt was needed because the direction bit is one of the ones I consider fundamental understanding DCC, you have GOT to understand CV29.

Best regards, Greg

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And, I see that I typoed, too.? I posted "CV-19" in one place where I really meant to type "CV-29" in my last post.

At least, that typo was not in the directions for what someone should actually do.

Steve Long

Greg K,

As mentioned by others, the way to reverse ALL directional functionality of a decoder/loco is to Set Bit 0 of CV 29 (add a value of 1 to the current, making the total an ODD number). Doing this will reverse the motor control and all directional lighting.

Is there a reason why you want to do it this way instead of using an ? Creating a consist with this method can open up more feature options which you otherwise may need to use special programming to circumvent. If your locomotives have a road number higher than 127, you can use the last two digits as the Consist Address and add 128 to the one to be reversed to reverse it.

I’ll not be setting up a “consist” for this, only two engines running on the same engine number.

By definition, this is precisely what CV 19 does - operates two or more locomotives by using the same DCC (short) address. When not set up using a command station's "voodoo magic" consist creators, the layer of obfuscation is removed.

You can save different consist configurations to each decoder in the User Presets if you want to change which engine is leading, or if you want to run them on their own without being in a consist. I always recommend backing up your known-good programming in a User Preset so that you have a "safe state" to return to if something gets messed up.
--
Dan

Engineering and Product Development
Train Control Systems

Just want to take a minute to say I love how Consitting works on a TCS throttles great work?