I guess it all depends on who operates your layout and who does the programming. If it's just you - the chances of making a mistake and bridging the program track to the track power are very small. If someone else comes over and is like "Hey I cna program this" and it's completely familiar with your setup, they could amke that mistake. So NCE has not seen many instances of systems needing repair that they could trace to bridging the program track to main track with track power live - this could just mean that people who set up the simple DPDT switch method are careful when driving locos onto the program track. It COULD mean that in the case of the PowerPro's circuit design, it isn;t a problem to have this happen - but I wouldn;t want to deliberately test it, given that it's soemthign you shouldn;t do no matter what, even if no harm would come from it.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
For info, while getting forum input this weekend and obtaining parts for a 4PDT / isolation track upgrade, I had inquired on the program track protection issue with the NCE PowerPro of Tony's Trains and NCE. My inquiry follows:
"I have a 5A PowerPro system with my on-layout program track (selectable by a DPDT toggle) not having adjacent deadzones. While the PowerPro cuts off mainline power when the NCE is set to Use Program Track, if I am in Ops (not program) mode and incorrectly leave the DPDT in "program" position and then drive a loco into the program track, booster power can feed via the loco back into the NCE program system outputs. Will this situation damage the NCE such that I must put deadzones (with 4PDT toggle) adjacent to the program track? I want to be sure my setup is foolproof. Thanks."
Here is the reply from Larry at NCE:
"Paul, This set up will work fine. If the DPDT is left in Program Track and you're in Ops mode, it will be dead."
I understood this to mean that the NCE PowerPro Ops mode signal feeding back (via an incorrectly thrown 2PDT switch) via a loco and the program track, into the output of the NCE program section will not damage this. I wanted to be doubly sure I understood this and I talked with Larry this morning. He confirmed my understanding. Familiar with the issue, he also discussed it with Jim, the system designer, for good measure. He also noted that many, many of PowerPro users use the DPDT arrangement and suggested that if their guidance was wrong there would be many problems reported (with the PowerPro) and that does not happen.
I likened the issue to my stereo, when off, having a signal attached to it's output section. Whether damage to the internals would occur might depend on what was hooked up to it; e.g., a AA battery vs a 144KV signal. So they are saying that for the PowerPro, I'm ok with my current setup.
I just wanted to round out this topic for PowerPro owners.
I don't quite have the nerve to test this out as it would be rather inconvenient to send in the system for repair if the experts (there's always that possibility) are wrong. I'll have the parts for the conversion if I get more nervous than I am now. Or for the "next" layout...building it with a 4PDT arrangement would prep it for any DCC system chosen.
Paul
Modeling HO with a transition era UP bent
Randy, thanks, I'll leave out the LED. I appreciate the explanation about LEDs.
Well, yes, the LED would go out when you stiched to programming mode, but then neither could you drive a train into the dead section. Witht he switch flipped to program, the red LED would be on as long as track power was still on, saying stop, do not enter this section of track (or your loco will stop, since the switch would be in program position and the dead section not powered at all).
DCC swings positive and negative, referenced tot he system common. That's why a DC meter reads a nominal 0 volts when trying to meaure track voltage in DC mode. For an LED, this means half the time it will be on, polarity correct, and half the time it will be off. At normal DCC frequenceies, this basically appears as 'on' to the human eye because the off time is so brief. Another way to put an LED on DCC is to use a 2 wire bicolor LED< which inside is made oup of (usually) a red and a green LED, wired back to back, opposite polarities. So on DCC, half the time the green LED is on, and half the time the red LED is on, making it sort of orangish. They usually appear more red than orange because the red LED is more efficient than the green and for a given resistor, the red will be brighter.
It doesn;t matter much for NCE, because it can;t do this, but some other systems allow a loco without a decoder to run on address 00. This works by making either the positive half or negative half of the 0 bit in the LED data stream longer, effectively shifting the apparant DC voltage more one wy or the other - more positive time vs thge negative means it will appear more positive to a DC motor, or a DC meter. As such, the bicolor LED will also be either more red or more green.
Your wiring plan sounds good. With that much of the layout connected as the 'dead' section, there is absolutely no way you cna ever bridge track power to the program track terminals, unless you have some sort of wierd 50 car train that has jumper wires connecting the power pickups on every car.
While awaiting a 4PDT switch from Mouser, a question about the optional LED indicator shown in the WikiDCC 4PDT wiring diagram.
http://www.dccwiki.com/Programming_Track
I'd like to incorporate that option but am uncertain whether it would just add confusion given that the NCE ceases mainline booster output when the NCE is put into Program Track mode. For instance, if in normal mode I first threw the 4PDT to Program Track position, the LED would light, powered by the booster. Great. But when I then switch the NCE itself to Program Track mode, the booster mainline output shuts off, so the LED would go out. Yes?
Would the LED still be useful (or a nice feature) as it would be on when the booster output is on (and the NCE program output off) and the 4PDT is in the Program Track position, when I don't want to be running a loco into the isolation section. It would tell me I had not returned the 4PDT to operations position after programming. I guess I lean towards leaving it out as it may be just confusing. I really just want to know when the 4PDT is in the Program Track position. (Maybe I should just look at it). Is there a good way to do this with the NCE?
A related curiosity relates to my lack of understanding of DCC voltage, polarity, etc. For my DC Tortoises I had to ensure proper polarity for the LED. Does the DCC power LEDs in cycles, where 1/2 the time it's off and 1/2 the time on, but it happens so fast it looks "on"? Is there no polarity for LED powered by DCC?
I did some prep today for the 4PDT addition. I've decided to make the whole subdistrict (other than the program track) the protective deadzone by re-routing the subdistrict buss through the 4PDT to the existing branches. This is ala the last program track option in the wiringfordcc.com article. Adds about 6' of buss wiring but using 14AWG for the addition. Since I have a Big Boy of about 16-1/2" total wheelbase I really needed more than the existing 46" available for program track plus adjacent deadzones. A bit of extra wiring work but no required track or track connections changes.
Thanks for your patience and explanations. I'll get a switch on order (the article suggest a Mouser one) and take a close look at which way to handle the re-wiring (creating small adjacent dead zones or making the adjacent sub-district as a whole the dead zone. Glad you all clarified the issue that the Tony's guidance may have oversimplfied and the reliability of my original is not what I assumed.
I just took a look at the existing track and wiring. With a 46" existing program track (part of an engine yard entry, I could have roughly 15" sections for the program track and two adjacent deadzone sections. Doing it that classic way is probably easier than the "without deadzone" approach that would require re-wiring the subdistrict buss through the control panel 4PDT.
peahrens I think I may begin to understand the issue more. If I am in normal operations mode and have the DPDT (but not the DCC system) inadvertantly set for Program Track "input" (position) and run a mainline loco across the gap, then the mainline juice can feed back into the (inactive) program track output wiring. Can that fry things in the NCE DCC system program output?
I think I may begin to understand the issue more. If I am in normal operations mode and have the DPDT (but not the DCC system) inadvertantly set for Program Track "input" (position) and run a mainline loco across the gap, then the mainline juice can feed back into the (inactive) program track output wiring. Can that fry things in the NCE DCC system program output?
That is correct.
It isn't that both "sides" (main and programming track) of the command station are active at the same time - That's not possible with an NCE system.
The problem is that with the DPDT switch in the "programming" position, a loco bridging the gap will backfeed the booster's output into the programming track outputs. That can be a Very Bad Thing, but the 4PDT switch and deadzone help to prevent it from ever happening.
peahrens I want my system to be reasonably foolproof. I see in the following article that it is possible to install a "Layout Programming Track without Deadzone" (near the end of the article). The switch kills all power to the zone adjacent to the program track. I would have to install a 4-pole switch and re-route my mainline normal power buss for that subdistrict through the switch, if I understand it. http://www.wiringfordcc.com/track_2.htm This is way over my head, and I'm 6'4".
I want my system to be reasonably foolproof. I see in the following article that it is possible to install a "Layout Programming Track without Deadzone" (near the end of the article). The switch kills all power to the zone adjacent to the program track. I would have to install a 4-pole switch and re-route my mainline normal power buss for that subdistrict through the switch, if I understand it.
http://www.wiringfordcc.com/track_2.htm
This is way over my head, and I'm 6'4".
Yes, way down on that page shows exactly what I was suggesting. But you don't have to reroute the entire bus through the switch. Just cut another set of gaps so you have two adjacent sections that are isolated, and route a set of feeders from your bus through the switch as shown in that diagram.
For example, assuming a dead-end spur that's three feet long, and no loco wheelbase over a foot long:
Cut a set of gaps 6 inches past the turnout. That's the beginning of the dead zone.
Cut another set of gaps a foot past that. That's the end of the dead zone.
The remaining 18 inches is your programming track.
Yeah, putting track power into the program track outputs is probably not a good idea, and definitely can cause damage.
The diagram on the Wiring for DCC page is about as simple as it gets, all nicely color-coded with red and blue wires. There's nothing complex about that, it's just a switch with more contacts than usual. So it can turn on anf off more than just one thing at a time.
jrbernierMy unerstanding is that the PowerPro can run trains on the main track while you are programming on the program track.
No, with the PowerPro if you want to use the programming track operation on the rest of the railroad stops.
My understanding is that the PowerPro can run trains on the main track while you are programming on the program track. Accidentally running another loco over that gap may cause serious damage. This issue can happen with any system that has a dedicated program track and allows concurrent operation. Most folks seem to think having the 'program' track as part of their engine service 'cool' - Until this happens. Here is a link to the wiring:
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Theoretically you should be safe, the NCE system does indeed turn off the main track output when you engage programming on the program track. Never did get that, Digitrax you can run trains and program on the program track at the same time.
Just because no power is being applied to the track outputs though, does not mean that if power is jumpered back in from the program track outputs, there's no chance for harm. It would be rather slight, since the program track power output is low current and feeding back into components designed to handle 5+ amps shouldn't harm them. The usual danger is going the other way - feeding the full track power back into the program track outputs, which could still happen here if you had the DPDT switch set to program track, and drove a train in from the main and crossed the gaps.
I would go with the 4PDT method just to be safe. Or just be VERY cautious in the use of a drive on/drive off program track. If it's a seldom-used siding, and you use powered turnouts, an extra set of contacts on the switch could be used to lock out the switch motor when the toggle is in the program command, making it impossible for a train to run in off the main. Just the dead section is all it really takes though.
jrbernierBe very careful that you do not run an engine from the layout(Main Track) onto the Programming Track while that DPDT toggle is flipped to the Programming Track mode - This is sure fire way to destroy a decoder(or at least require a RESET).
I'd like to confirm my understanding of the potential damage to the DCC system (from running a Operations Mode loco onto the Programming track) regarding my NCE PowerPro system. I recall reading about the issue when deciding to use just a DPDT switch for the programming section. When selecting Program Track mode with the ProCab throttle the Program Output is activated (which the DPDT can route only to the isolated program section) and the rest of the layout (always hooked to the main tracks) stops any loco on those tracks. I assume the NCE system stops main track output whenever Program Track output is selected. (And would the same thing happen if using Decoder Pro to tell the NCE system to output Program ("Service") track mode?)
If I understand this right I can't, with my NCE, run a non-program track loco into the program track interface. Of course, a loco on the program track could "jump" with a CV change to the interface if near it. If the mailine is dead, no issue. Not sure what would happen if a loco was bridging Program Track to mainline isolation gaps when switching to or from Program Track mode, whether there is a time gap or simething to make the switching foolproof.
I'd appreciate your confirming my understanding for NCE, so I don't have to consider changing my arrangement. I can get out my DCC meter and test this, I guess (have never used it).
UPDATE: I got into my DCC file folder and Tony's Tech Notes "NCE DCC System Hints & Tips." Regarding program track it states: "Some DCC systems recommend that a dead section of track be placed between mainline poewer and program track to protect the Command Station from damage due to another loco accidentally placed over the gap. This is not necessary because the NCE system turns the mainline power off when you go to the program track mode and the program track input is electronically protected." (Might benefit from some wording enhancements but this plus I recall some verbal advice led me to my approach). Do let me know if I have a threat that remains, as Murphy lurks around my hobby activities).
jrbernier Be very careful that you do not run an engine from the layout(Main Track) onto the Programming Track while that DPDT toggle is flipped to the Programming Track mode - This is sure fire way to destroy a decoder(or at least require a RESET). Our LHS set up an isolated spur off of a turnout on their 'Test Track' and I wound up resetting decoders at lunch time for several weeks until they pulled the turnout - Lesson Learned!
Be very careful that you do not run an engine from the layout(Main Track) onto the Programming Track while that DPDT toggle is flipped to the Programming Track mode - This is sure fire way to destroy a decoder(or at least require a RESET). Our LHS set up an isolated spur off of a turnout on their 'Test Track' and I wound up resetting decoders at lunch time for several weeks until they pulled the turnout - Lesson Learned!
I'm surprised that they didn't blow the output stages of the programming circuitry, by backfeeding the booster's output into it. Having a loco straddle that boundry has been know to do that.
That's why a better solution is a 4PDT switch wired to give you a dead zone longer than your longest loco, between your main line and your programming section, when the switch is in the programming position.
Search the archives here, this was discussed at length several years ago and Tom Stage (I believe) posted a really nice diagram of how to implement it.
Paul,
Congratulations on getting it working! The NCE system has a dedicated 'programming track' output. I assume you have this wired to one side of that DPDT toggle. Just make sure that the DPDT switch is hooking the NCE 'Program Track' output to your isolated section of track. You should not even need the ProCab throttle plugged in.
JMRI/DecoderPro will direct the programming commands to either the 'Program Track' or the 'Main Track' depending on what you have selected on the Decoder Pro panel. You will note that after starting Decode Pro, you will have a panel with 'Service Mode' and 'Operations Mode'. Selecting 'Operations Mode' will send programming commands to the Main Track. You can basically program everything except the engine's DCC Address on the Main Track.
Service Mode send the programming commands to the Programming Track and allow one to change the address of the engine.
I decided it's time to get Decoder Pro capable. I pulled out a USB/serial adapter and 10' serial extension I ordered at least a year ago. At first I thought it would not work but when I figured out the right sequence of starting Decoder Pro, turnng on the NCE, then plugging in the USB PC connector it worked (showed me the COM port, etc so I could set the system preferences (NCE, serial connection, etc). Using Windows 8.1 and seemed to work ok with the adapter hardware, etc. I did have to install Java as the PC apparently had not formerly needed it.
BUT, I'm rather confused about using the programming track mode. I have an isolated section of track on the layout that has a DPDT (center off) for switching between NCE Operations (on the main) and Program track output from the NCE. The dumb question: do I have to use the NCE throttle to select Program Track mode? I'm assuming yes; i.e., that the Decoder Pro selection of Program Track programming is done in addition to having to use the throttle to select Program Track output (which stops mainline power). Conceivably, the Decoder Pro output when selecting Program Track programming could cause the NCE system to switch accordingly w/o touching the throttle. I might figure this out by trial and error but thought I'd ask. I did not find the answer in the NCE or Decoder Pro documentation so far.
I did take the precaution of taking all my locos but the programming track target off the main track, so I won't find a way to mess them all up at once. I may have added to my confusion by starting with loco #39, which gets into the short 39, 039, long 39 address thing. I read an old thread on that and think I can sort that out tomorrow.
Thanks for advice on the program track handling. I need to get on the Yahoo user group but first have to find my current Yahoo ID(!).