DCC addresses again!

[Mr. Moto]

Well, I'm finally getting around to painting and lettering my collection of Spectrum steam engines and it's time to give them their own addresses.  However, I'm running into that problem of them not wanting to change from 3.  I'm running on an NCE PowerCab system and I've tried programming on the main and in programming track mode and I get nothing.  I've searched the threads here and seen a couple suggestions at changing cv's 17 & 18, but which one is correct?  Is that really my problem? I have a 2-8-0 and SY Mikado and neither one will accept the numbers I need them to.  I have a 4-6-0 that accepted address 2 right away.  The other two need to be double digit numbers.

Any help is appreciated.

[pdlethbridge]

I also use the NCE power cab. I find that programing can be a challenge at times but if you want to start at a factory reset, you have 2 options. Programing CV8 to 8 or using the programing track mode use option 7, select yes and this will set it back to factory settings. If you have any digitrax decoders, select 1 in programming track mode, and let it name off the makers code, etc, then you'll see the short and long address come up. Next go to 2 and hit CV, select the following, cv3, acceleration, cv4 deceleration, cv5 top speed, and cv6 mid speed. If you are programming the bachmann decoders, they will rerspond to my first suggestion. PM me if you need further help.

[Jim Banner]

"Just enter the numbers in CV17 and CV18" is the simpleton's explanation of what is a fairly complicated mathematical problem.  Usually the command control system takes care of the math for you.  But if you want to do it the hard way, here is the explanation.

CV's 17 and 18 are where the extended (four digit) addresses are stored.  And one of the bits of CV29 informs the decoder whether you want to use the primary (two digit) address in CV1 or the extended address in CV17 and CV18.  But wait, it gets even more interesting.  The addresses in CV17 and CV18 are not the first two digits and the last two digits of the digital address but the first two hexadecimal digits and the last two hexadecimal digits of the hexadecimal address after you offset it by C000.

This gets really complicated if you have to convert from hexadecimal to decimal and back again with pencil and paper, but is much easier if you use the calculator that comes with Windows.  The steps are as follows:

1. Set the calculator for Scientific View.  Note that right under the calculator display, there are four radio buttons labeled Hex, Dec, Oct and Bin.  We will use the Hex (hexadecimal notation, 0 to F) and the Dec (decimal notation, 0 to 9) buttons to switch back and forth between the two numbering systems.

2. Make sure the Dec button is selected (has a dot in it.)

3. Enter the digital address you want to use.  For example, lets use 1234.  You can type it in or click on the calculator number buttons to put 1234 in the calculator display.

4. Click on the Hex button.  The display will change to 4D2, the hexadecimal value of decimal number 1234.

5. Add C000 to this in the usual way.  That is, click on +, then C, then 0 three times and finally click on =.  The display should now read C4D2.

6. Enter C4.  The display should read C4, the most significant hex digits of the address.

7. Click on the Dec button.  The display should read 196.  This is the value to enter into CV17.

8. Click on the Hex button.  Then enter D2, the least significant hex digits of the address.

9. Click on the Dec button.  The display should read 210.  This is the value to enter into CV18.

10. Read back the value of CV29.  Add 32 to that number if its value is less than 32.  Enter the new value into CV29.

You are now ready to run with an extended address, in this case, 1234.

Everybody should try this method at least once to understand what is happening and to get a feeling for what it was like in the days of wooden computers and iron men.

Jim

[pdlethbridge]

Thanks for the headache Jim

[mabloodhound]

Jim,
In steps 7 and 9 you entered both into CV17.   Is that correct? or should one be CV18?

[Jim Banner]

Thank you, Mabloodhound.  I have corrected my posting above.

Jim