I have the above DCC system and would like to have a track dedicated to programing, but I would like it to also be part of the layout. There has been so many questions concerning the powercab and a program track that it has become somewhat confusing. I think some are just making it more than what it is.
My question is, can I simply have a toggle routing power from the main SB3 bus and the other leg from the original Powercab panel to utilize as a fully functional program track? This way once the loco is on the layout I will not have to move it with 0-5-0 crane anymore. I know there is an auto switch but you cannot utilize it with the SB3 and a toggle is only a couple bucks anyway.
As long as your toggle completely isolates the transformer of the PCP panel for your programming track from the transfomer of the SB3 it should work. You’ll end up having two sets of track wires going to your programming track.
If I’m reading you right, what you’re suggesting could allow both boosters to be be connected to your programming track at the same time. With that setup, you could have the output of one booster feeding into the other.
Even if one isn’t powered up at the time, and/or is “only” providing current-limited programming power, that generally isn’t a good thing because they’re both designed to source current, not to sink or dissipate it.
My suggestion would be to use a double-pole, double-throw, center-off toggle.
The programming leads from the PowerCab/PCP would go to the contacts at one end of the toggle, the track power from the SB3 to the other end, and the center contacts would connect to the isolated programming track.
That way, it’s only possible to have one booster at a time connected to the programming track, and the center-off position prevents shorts while switching from one booster to the other.
Of course, you still have to be sure that a loco’s wheels don’t bridge the gap between the programming track and the “powered” track, but that’s true no matter how you wire it.
Thanks for the input, Steve. Yes, you understood me correctly. I was wondering whether a DPDT switch would be needed for that to work. Is this what you are describing?
Click diagram to enlarge
So, the center contacts of the DPDT switch going to the programming track would only be functional in the Left or Right positions. (Center position being OFF.) What you would be switching between is the SB3 (or Left position) and the Power Cab/PCP panel (or Right position). Yes?
Steve, is the diagram also correct that you would need to have the SB3 connected to the mainline so that you bring your locomotive onto the programming track before switching it to programming mode (Right position)? Hopefully I’m not too far off base…
Tom, this is exactly what I intend to do. Someone responded to me on a different forum suggesting that I use a relay instead, but htat is beyond my ability.
You now see what I mean by “it seems too easy”. There is still a degree of risk with this if the operator has the powercab on in the program track while pulling a unit onto the track from the main powered by the SB3.
I captured these diagrams from Joe Fugate’s Volume 3: Electrical and Control DVD that I bought earlier this month: (Click diagram to enlarge)
Run mode
Programming mode
In the DVD, Joe describes using a 4-pole DT toggle switch for programming his locomotives and has a dead section on either end of his programming track so that there aren’t any accidental shorts. (A stub end track would only need one dead section.) As seen in diagram 2, each section is 1.5X the length of his longest locomotive so that there is plenty of room to program.
As Joe describes it, since the dead sections are not powered during programming, this takes the “oops” factor out of accidentally frying a decoder by bridging the gap between the programming and mainline tracks. No locomotives can come into or out of the programming track without stopping.
Yup, a picture is worth a thousand words. You nailed my suggestion exactly with your diagram, although to avoid confusion I probably would have shown the leads from the SB3 to the DPDT coming off the SB3’s track leads.
And while that was the KISS version without the dead section(s), Joe’s diagrams show how to include those for even more safety. Basically, he adds another pair of poles with one side dead to power or “deaden” the safety sections.
Depending on your point of view, that might be more trouble or expense than it’s worth, but there’s no doubt it’s the safest method. John seems concerned with the possibility of bridging the gaps so I’d be willing to bet he goes with Joe’s version. [tup]
Yeah, but you didn’t have to go through the trouble of re-doing it! I was just voicing my opinion that to me anyway, showing it this way makes it a little more clear.
Nice job on the diagrams, BTW. If you don’t mind me asking, what did you create them with?
Hey, I don’t mind at all. I used MS Paintbrush and saved it as a .jpg file. If you run Windows, it’s in your Accessory file under START.
Truthfully, I only had to modify the original drawing slightly. I erased the two lines and redrew them coming off the track wires from the SB3. It took me maybe 5-10 minutes to modify and upload the file. I wanted an accurate diagram to keep for my records, too.
Steve, I knew you were only mentioning it for clarity sake. Since I’m still trying to learn and comprehend this stuff, I just wanted to make sure that I understood it right in my own mind. The revised diagram is clearer to me in that respect.
Thanks again for the help and the suggestions. [:)]
MS Paint??? And here I thought you were going to tell me about some slick, RR-oriented drawing program… [sigh]
I guess I’ll need to work on my Paint skills. I use it for my PanelPro backgrounds and icons, but I find it to be rather clunky. Most of the time I use a word processor or presentation software for block diagrams and such, but unfortunately they can’t be saved in an image format.
I’ve ordered from them several times and have always received good service. Shipping is a flat $7.00 so get your list together and see how much of what you need they have on hand.
Yep, sorry - MS Paintbrush. You’re right, Steve. Paintbrush is pretty clunky to use. I have used and prefer to use Word to make block diagrams and simplified drawings. But, as you already stated, you can’t save Word files in an image format - unless you have a scanner. (Which I don’t, at present.)
Paintbrush works okay on simple diagrams but I sure wouldn’t want to draw anything like Joe’s diagram with it. [xx(]
You’re guess is correct, “( )” means momentary. Two sources that I use for electronic components are Digikey(www.digikey.com) and Mouser(www.mouser.com).
Hey guys a bit of an update. I wired in the SB3 to the layout and installed the toggle for the program track. Works great. I had three of 10 locos that locked up on me, so its nice to finally have them back in the pool again.
Click diagram to enlarge
