Today I was finally able to test my LocoNet wiring. I thought I would test it with my DT400 and try to read a loco on the program track. I don't have any trackwork or bus lines run.
So basically it looks like this:
Zephyr-->LocoBuffer-->UP5-->UP5-->UP5
|
Program Track
The DT400 worked at the first UP5 jack, worked intermittently at the second jack, and didn't work at all at the third jack. So I figured I had something wonky with the cabling.
I tested the cabling with an LT1 cable tester and everything checked out.
I plugged in a new UT4 throttle and it worked at all 3 UP5s.
So, do I not worry about the DT400's reaction untill I have some track wired in? The funny thing is that in the first jack, the DT400 came on immediately that is, there was a propt ont the LED screen. In the second jack, it took maybe 5-10 seconds for the prompt to appear. In the third jack, the LED never came on.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
Chip,
Break down the LocoNet.
What kind of LocoBuffer do you have? Our club has a LocoBuffer II with a USB/Serial converter - it is attached as the last device on the Loconet.
I have a a LocoBuffer USB, also attached as the last device.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
SOunds liek there is just too much voltage drop int he Loconet bus. Do you have cut to size Loconet cables or just fixed lengths bundled up? The DT400 draws more power than a UT4, which is why one works and the other does not. The Locobuffer has pretty solid traces from one Loconet jack to the other, but you could take it out of the daisy chain and using anothe rLoconet cable, plug it in to the side jack on the first UP5. Or into the second Loconet jack on the back of the Zephyr.
WHen you first plug the DT400 in, the display shows the voltage it sees. Bet it's lower on the second UP5 than the second.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hey Jim,
It's been a while.
jrbernierIf all checks out, I would suspect a cabling problem.
My cable tester says it's fine.
jrbernierWhat kind of LocoBuffer do you have? Our club has a LocoBuffer II with a USB/Serial converter - it is attached as the last device on the Loconet.
An early one, I suspect. It is also serial with a Serial to USB cable. It seems to work fine. It read my troublesome Bachman dercoder.
The computer is right under the Zephyr so it is the first in the daisy chain.
rrinker Do you have cut to size Loconet cables or just fixed lengths bundled up?
I used two stock cables for the first two lengths--18 " to the LocoBuffer then 24" to the first UB5. Then I ran about 9 feet to the second UB5 and then another 42" to the third UB5.
rrinkerWHen you first plug the DT400 in, the display shows the voltage it sees. Bet it's lower on the second UP5 than the second.
You're right, The DT400 reads 6.6V in the first UB5 and 5.9 in the second UB5.
Question: Can I run the Locobuffer on a second leg? The second cable currently crosses over the Zephyr.
Also, I have enough cable that I can run back to the LocoBuffer from the 3rd UB5 as Jim implicated.
Both those voltages are too low, although the one is obviously just barely enough if the DT400 works.
The two jacks on the Zephyr are exactly the same, it doesn't matter where you plug it in. If it's cloer to the computer to run it off the second jack on the Zephyr, do that instead of running a long cable out to the last UP5 and then back.
The lines to the UP5s aren't really such a long run that it would require power to the UP5s, at least not for one throttle. But that's always an option. You would need a 14V DC power supply and a couple of 2.1mm coax plugs.
rrinker Both those voltages are too low, although the one is obviously just barely enough if the DT400 works.
I thought they might be. I'll disconnect the Locobuffer and retest.
Then I'll play with the lococation of the locobuffer.
Okay, I disconnected the LocoBuffer and retested. The first UB5 read 7.0 for a second then went to 6.6V. I disconnected the LocoBuffer and got the same reading. I then plugged my DT400 directly into the back of the Zephyr and the reading was 13.0V.
Thinking the problem might be in the first cable I made a new one. I disconnected all the cables except the new one. It read 7.7V then dropped to 7.0V. Thinking the first UB5 might be the problem a attached UB5 #2. Same reading.
Not sure what to do next. I have not connected any track wiring.
Hmm, that is rather excessive drop for just one Loconet cable and one throttle (and a pair of diodes - so the voltage at the first UP will be lower than directly to the back of the Zephyr - but not by almost half). All my stuff is packed away so i can't set up a similar configuration and see what my DT400 says, but I am pretty sure it was well over 8V at the first (and only) UP. The diodes do sometimes fail, but if it failed open you'd have no voltage (unless there was a battery in the throttle) and if it failed shorted there would be little noticeable unless you connected track power to the UP or applied power to the jack on the side.
I would not hook track power to the UP5 though. It may solve the immediate problem, but a short on the section of track feeding the UP5 will then suddenly drop the throttle voltage back to what you get off the Loconet cable and you may end up with no control as the throttle dies. Plus if you ever do detection, the LED and resistor across the track power connections will make the block appear always occupied.
rrinker would not hook track power to the UP5 though. It may solve the immediate problem, but a short on the section of track feeding the UP5 will then suddenly drop the throttle voltage back to what you get off the Loconet cable and you may end up with no control as the throttle dies.
I do have 12V AC as close as the track power is right now. I can use a wall wart to power my lights if I need to.
So using my heightened sense of deduction, there are are only two common elemets in this situation--the Zephyr and the DT400.
And to throw an egg sac in the works, yesterday I saw a spider run across the top of the LED and under the glass inside the Zephyr. I'm beginning to suspect that the little guy has hooked up a sound system and is partying with 300 of his closest friends and drawing amps in the process.
I sent an email to the Digitrax Users Group this morning. Maybe someone there has had this experience.
I found this on the Internet. I comes from Dick Bronson's RR-CirKits Notebook:
It seems I was mistaken about the power needed. I need DC not AC. I'm sure I can come up with a 12 Volt DC Wall Wart if I need to. If I understand this correctly, I need to hook the positive to 1 & 6 and the Negative to 2 & 5.
I found this on the Digitrax site:
The UP5 draws up to 30mA. It must be powered with a DC power supply. Do not rely on LocoNet to power the UP5. The PS14 is ideal for powering the UP5. If using a generic power supply, it must provide between 12-15vdc.
I never powered my UP5's. .
SpaceMouse I found this on the Internet. I comes from Dick Bronson's RR-CirKits Notebook: It seems I was mistaken about the power needed. I need DC not AC. I'm sure I can come up with a 12 Volt DC Wall Wart if I need to. If I understand this correctly, I need to hook the positive to 1 & 6 and the Negative to 2 & 5.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Yeah, I've pretty much decided to get 3 PS14 power supplies and hopefully be done with it. Of course, that means running 110V out into my peninsula.
That document about 30ma per UP5 is wrong. SOmeone typed UP5 when they meant UR90, UR91, or UR92 (the IR, simplex radio, and duplex radio panels, respectively). A UP5 consumes no power, there's no active circuitry on it (except the LED, which is across the track power screw terminals, not the railsync feed).
You don;t need 3x PS14's to feed 3 UP5's, one is plenty to power several throttles at the same time. You need a single PS14, and a couple of 2.1mm plugs. Make a power bus fed by the PS14, and tap off it at every UP5 with a feeder termianted with a 2.1mm plug. Polarity counts, I can look it up which way it goes.
SO no need to run 110VAC to your penninsula.
DigitalGriffin SpaceMouse I found this on the Internet. I comes from Dick Bronson's RR-CirKits Notebook: It seems I was mistaken about the power needed. I need DC not AC. I'm sure I can come up with a 12 Volt DC Wall Wart if I need to. If I understand this correctly, I need to hook the positive to 1 & 6 and the Negative to 2 & 5. Why on earth is his hooking a 12V supply to the railsync lines?!? That makes absolutely no sense. There's a possibility you could fry some accessories with that wiring! Railsync is there to repeat what is out on the tracks. It's basically a DCC signal. If you have something that reads the railsync signals, it will get the wrong information if wired up this way. That is bad mojo.
Why on earth is his hooking a 12V supply to the railsync lines?!? That makes absolutely no sense. There's a possibility you could fry some accessories with that wiring! Railsync is there to repeat what is out on the tracks. It's basically a DCC signal. If you have something that reads the railsync signals, it will get the wrong information if wired up this way. That is bad mojo.
Perfectly legitimate way to do what that is set up for. Only throttles go downstream fromt he side that has fixed power. The throttles do not need or use the signal on railsync, all they do is rectify it for power. The other Loconet branch with the intact Railsync is the one that feeds downstream boosters and devices that need the actual signal on the Railsync lines (not very many - BDL-168, especially if Transponding is used, is about the only one - or the new devices which all have transponding built in to teh detection unit).
He's not.
If you look closely at the diagram, the railsync is only between the points marked "Master" and "Slave".
The "LocoNet" part of the diagram is the only part fed by the separate 12VDC supply. And that's perfectly fine if all you're going to run off that part of the LocoNet is throttles (or other devices which don't need/use railsync.)
Edit: Oops, Randy and I were typing at the same time.
rrinker You don;t need 3x PS14's to feed 3 UP5's, one is plenty to power several throttles at the same time. You need a single PS14, and a couple of 2.1mm plugs. Make a power bus fed by the PS14, and tap off it at every UP5 with a feeder termianted with a 2.1mm plug. Polarity counts, I can look it up which way it goes. SO no need to run 110VAC to your penninsula. --Randy
I'm absolutely with Randy on this approach to providing power to UP5's. It's how I have mine set up and I don't have any issues with my DT400's even though I never put batteries in them.
But the voltage drop being discussed in this instance concerns me. I'm not convinced that simply adding external power should be the next step.
I added power because at the far end of my layout (about 40 feet of LocoNet away from the command station), the voltage would get a little lower than I liked when both of my unpowered DT400's were both plugged in there. But here we're talking about it dropping by nearly half after only a couple feet of cable and a UP5!
Since the UP5 and of course the LocoNet cable are basically pass-through devices, that indicates a problem to me.
Either both those UP5's are bad, the LocoNet cable is bad, or the command station is unable to hold up it's railsync under a load (although that's unlikely since the throttle sees sufficient voltage when plugged directly into it).
If it were me, I'd try one or both of two things:
First, I'd buy or borrow a known good UP5 and a known good LocoNet cable and re-do my testing with them only.
Second, after giving my "old" UP5's a *thorough* cleaning and inspection, I'd try them on another layout, or at a shop, with a known-working LocoNet.
COuld be the plugs on the ends of the Loconet cables or the contacts in the UP's are corroded a bit after being in storage. You can eliminate the cable by picking up a short 6 wire phone cable somewhere local, doesn't matter for this purpose if it's a phone cable and flipped. Some plastic-safe contact cleaner (or just some 90% isopropyl) wiped on both the plug contacts and the contacts in the UP5 jacks (just be careful not to snag the contacts on whatever you use to apply the alcohol) should work. Do botht he front and rear jacks ont he UP5, and the plugs on the cables and the throttle.
Stevertf it were me, I'd try one or both of two things: First, I'd buy or borrow a known good UP5 and a known good LocoNet cable and re-do my testing with them only. Second, after giving my "old" UP5's a *thorough* cleaning and inspection, I'd try them on another layout, or at a shop, with a known-working LocoNet.
All the cables I'm using are freshly made with new connectors. They test as good with an LT1.
Testing the UP5s is a little more problematic. The closest store I know is Lichfield Station about 2 hours one way from me. I know that's lame and I can order online, but let me try with your and Randy's suggestion of cleaning.
rrinkerYou can eliminate the cable by picking up a short 6 wire phone cable somewhere local, doesn't matter for this purpose if it's a phone cable and flipped. Some plastic-safe contact cleaner (or just some 90% isopropyl) wiped on both the plug contacts and the contacts in the UP5 jacks (just be careful not to snag the contacts on whatever you use to apply the alcohol) should work. Do both the front and rear jacks ont he UP5, and the plugs on the cables and the throttle.
As I mention, all my cables now are brand new (or rather newly made). I'll clean the contacts on everything else and report back.
I see you got the same stock response on the Digitrax group as well. Yes, if you run long distances (10's of feet) or plug in more than 1 or 2 throttles, you absolutely need power to the UP5. But that does not explain why you are dropping half the voltage at the FIRST panel which sounds like you have a fairly short cable to.
Those last results, were they with the Locobuffer in the second port oon the Zephyr or with the Locobuffer completely disconnected? If you haven't tested witht he Locobuffer completely disconnected, try that. It shouldn't load the Railsync at all as it is not powered from that but Murphy can be pretty sneaky.
You can test if it's the panel dropping the voltage. If your meter probes are pointy enough you should be able to get a reading off the outer two pins of the plug on the cable. If not, if you have an extra cable you don't mind sacrificing the end for, you cna cut off an end and spread out the wires. Of if you have a 6 pin coupler (to extend the cords), you can try just plugging the throttle into the end of the Loconet cable (so not into the panel) to see what the voltage is at the end of the cable where the only drop would be caused by distance.
rrinkerThose last results, were they with the Locobuffer in the second port oon the Zephyr or with the Locobuffer completely disconnected?
It was disconnected. That was with only one UP5 connected.
rrinker But that does not explain why you are dropping half the voltage at the FIRST panel which sounds like you have a fairly short cable to.
Yes, about 2 feet.
rrinker You can test if it's the panel dropping the voltage. If your meter probes are pointy enough you should be able to get a reading off the outer two pins of the plug on the cable.
I switched two of the UP5s and got the same reading. I have lots of jacks. I can make a test cable.
I just did some testing to use as a reference point. Equipment was a DCS100, an unpowered UP5, and an unpowered DT400.
First test was the DT400 plugged directly into the DCS100, nothing else connected. Voltage indicated on the DT400 was 12.3V.
Second test was the UP5 plugged directly into the DCS100 using an 18-inch LocoNet cable, nothing else connected to either the DCS100 or the UP5. When plugged into either of the front jacks of the UP5, voltage indicated on the DT400 was 11.5V. When plugged into the side jack or other rear jack of the UP5, voltage indicated on the DT400 was 12.3V.
Third test was exactly the same as the second, except an 8-foot LocoNet cable was used instead of the 18-inch cable. Voltages as indicated on the DT400 were exactly the same as the second test.
So I am getting NO voltage drop, except from the steering diodes when plugged into the front jacks on the UP5.
That would be about the expected reading. It may vary depending on the setting of the scale switch on your DCS100.
I am beginning to suspect bad diodes on Chip's UP's, but odd they would all go bad especially since they've been in storgae since his previous layout.
OK, REALLY dumb question (but you would be far from the first to do this) - you DO have the panels assembled the right way? If you look at it from the top (looking at the circuitry) with the front panel facing up - the side jack should be on the left and the connector for the power should be on the right.
rrinker That would be about the expected reading. It may vary depending on the setting of the scale switch on your DCS100.
Yeah, forgot to mention that my DCS100 is set to "HO"
rrinker I am beginning to suspect bad diodes on Chip's UP's, but odd they would all go bad especially since they've been in storgae since his previous layout.
That was my first thought, too. But like you said, all at once while in storage?
rrinker OK, REALLY dumb question (but you would be far from the first to do this) - you DO have the panels assembled the right way? If you look at it from the top (looking at the circuitry) with the front panel facing up - the side jack should be on the left and the connector for the power should be on the right. --Randy
Or more simply, the LED between the jacks should point towards the front panel.
rrinkerOK, REALLY dumb question (but you would be far from the first to do this) - you DO have the panels assembled the right way? If you look at it from the top (looking at the circuitry) with the front panel facing up - the side jack should be on the left and the connector for the power should be on the right.
StevertOr more simply, the LED between the jacks should point towards the front panel.
Uhhh....No
So, I reversed all the UP5s and everything is all hunky dory. All three are reading 12.1V on the DT400. That is, all three have that reading when they are daisy chained.
On the bright side, all my connections are spiffy clean and I have a new made for the occation, voltage tester cable.
I have to say, that although it seems like a dumb question, the reasoning was brilliant.
I appreciate all the effort you guys put in to help me.
The case is solv-ved.
I suppose I should still power them.
It only occurred to me because I thought hmm, maybe when you packed them away, you took them apart to pack better. The one I was using on my layout, I just tossed in a box witht he faceplate on, but I was pretty much last minute throwing things in boxes as the movers were hauling stuff out.
You really only need to power them if you have more than just that one DT400 and UT4 to plug in. Easy enough to test - plug the UT4 in the furthest one, and then plug the DT400 in next to it and check the voltage. If it's still 10 volts or better, you'll be fine.
rrinkerYou really only need to power them if you have more than just that one DT400 and UT4 to plug in.
Too late. I sent away before the issue was resolved.
Just don't wire them together like the Digitrax instruction say - it's not a great way. The whole point is to avoid the drop in the Loconet cable, right? And you know a circuit needs to be complete to work, you can't just run one wire and bam, it works. So if you follow those instructions and run a wire from the whole in the board of one UP5 to the next one, where do you think the other side of that circuit goes to form a coomplete circuit? Through the Loconet cable. Hence the suggestions to run a power bus and attach 2.1mm plugs to plug into the side of the UP5 where the first PS14 would plug in. Once PS14 can drive many throttles, so you really only need one for all 3 of your panels. One each is way overkill.
So you are far from alone, Chip. There was a post in the Digitrax group about a guy who was having a problem using his DB150 as an autoreverser. He has now solved his problem - his UP5's were put together backwards so the railsync signal was not coming through from the command station.