Questions about Digitrax UP5 Loconet Universal Panel......

Model Railroader Electronics and DCC
1

Hi!

As I noted in previous postings, I’ve got the Digitrax system all hooked up (DCS100, 2nd booster, two PSX-4 circuit breaker sets) on my under construction HO layout. Everything now works just fine.

I had the DT-400 throttle plugged directly into the DCS100 all this time as I didn’t want to wire in the UP5 panels until I was satisfied with the main system components. And now, I’m ready to place two of them on the layout.

My first impression was that the UP5 is simply a “cable connector” which would allow me to run a cable from the DCS100 to the first UP5, and then another cable to the second UP5. I guess that is correct, and the primary purpose of the panel.

Ha, as the panel circuitry is pretty complex and has some resistors, it obviously has additional uses. Yes, I did read the instructions, but I don’t believe I fully understand the additional purpose(s).

Your expertise on this would be greatly appreciated - as always!

Thank you,

Mobilman44

2

The additional circuitry on the UP5 allows you to supply power to it using a separate power supply or by using the rail A and Rail B connections. If you do not use one of these methods for power, then the throttle will draw power from the railsync lines of Loconet. This is not a problem with just a few throttles, but if you have several, railsync will not be able to power them.

Additionally, if you have Rail A and Rail B hooked up to your track, the status LED will light when that section of track has power.

3

What Robert said, plus I will also add that if it’s a long run from the DCS to the most distant UP-5 there might be enough voltage drop in the phone wire that is Loconet that it could have issues even with just 1 or 2 throttles. I will also add that you should NOT follow the instructions that say to power multiple UP-5’s from one power supply, just run a wire between the hole on the back of each one marked for that purpose. That leaves the ground side of the circuit within the relatively thin Loconet phone wire. You definitely can power more than one UP-5 with a single power supply (like a PS14), however the RIGHT way to do it is to splice in extra barrel connectors and plug into each UP-5 that way. A “UP-5 power bus” if you will - #18 wire or so connected to the power supply and a short pigtail with a barrel connector spliced in at each UP-5 location. How many you can chain depends on how many throttles would be expected to be in use. One PS14 can run about 3 DT400’s, so you probably don’t want to power 6 panels unless you won’t have more than 2 or 3 throttle plugged in. You can also use a more powerful power supply (more amps) but you should fuse each drop to a reasonable level (maybe 1/2 amp) to protect the UP5 and throttles.

–Randy

4

Hi!

My initial plan was to run a cable from the DCS100 to the first UP5 (about 3 feet distance) and daisy chain a second cable from it to the second UP5 (an additional 8 feet away).

Your suggestion (as I understand) is that I run a cable from the DCS100 to one UP5, and a second cable from the DP150 booster to the other UP5. Note that the DCS100 and the DP150 each has their own 5 amp power supply. In short, is this what you recommend?

Thanks,

Mobilman44

5

Mobilman44

Just run the Loconet cable from the first UP5 to the next UP5.

I have over 20 on my home layout and only have 2 powered with the little Wall-Wart power supplies. The rest run off the DCS200 Command Station.

Some people love to worry about what MIGHT happen.

I have had over 30 operators running on my layout at times (now most are running Radio Throttles - so they aren’t using the UP5 panels all of the time)! And in the 10 years I have been having Operations have never run into a problem with too many Throttles plugged into the UP5s and having drawn down the Loconet - with just the Throttles.

NOW - I did have one UP5 go junk and caused a lot of run aways but this was an isolated case!

BOB H - Clarion, PA

6

Just daisy chain them. But if you DCS and DB are in the middle of the layout aned you want to have 2 UP’s on one side and 2 ont he other, then obviously don’t run a long loconet cable back around fromt he far one to connect the two ont he other side - connect one pair to the DCS and the other pair to the free port on the DB. It’s basically just common sense - for the same reason you centrally locate the boosters, minimize the Loconet cabling and connect to the next nearest device rather than snake long cables all over the place.

If you only ever plug in a couple of throttles, no extra power should be needed. Plug in 5-10 DT400/402’s without batteries and it won’t. All those parts on the UP-5 are so you can have 4 different power sources and none will interfere with each other: battery in the throttle, Loconet pwoer using the Railsync lines, track power hooked to the terminals on the UP-5, and an external power source plugged in to the jack on the UP5. Any combination or all of these can be used, and the throttle will run off whichever is supplying the highest voltage with no danger of bad things happening like track power feeding back into the Loconet.

–Randy

7

Thank you!

Once again you all have come to the rescue and helped me better understand the wonderful world of DCC.

ENJOY,

Mobilman44

8

Just daisy chain them. They will be fine. I have 4 of them on a 16 x 16 around the room layout, unpowered, and run 3 throttles without the batteries in them and they work fine.

9

Just don’t daisy chain a booster off the side connector on a UP5 because the side connector doesn’t have the railsync pins, which are needed to keep the boosters in sync.

http://tsd.digitrax.com/index.php?a=541

Ask me how I figured this out [:)] .

10

Also make sure you put them together the right way. There was just a post ont he Digitrax Yahoo group where someone attached the faceplate to the back side and wondered why they didn’t work. The side witht he coaxial connector for the aux power is the BACK, the faceplat needs to be screwed on the other side - the side with the LED between the jacks.

–Randy

11

+1. Our club layout was wired like that. We had problems. I then redid the wiring.

One Loconet coming out of the DCS100 to a LNRP. From the protected side of the LNRP a cable runs to one DB150, then a cable runs from the other side of the DB150 to the other DB150 across the way. All the UP5s are hooked together, daisy chained. A “plug-in bus”, if you will. I found a two-way splitter with RJ12 ports-jacks to get the cables to branch off as needed. We do have a UR91 in the plug-in bus, works fine. We used the hole on the UP5 board to add power.

After rerouting the Loconet cables the system has been much less prone to corruption and failure.

12

Phantom thread alert!

We are having problems with a long (14) chain of UP5 panels at th club. I know the terminal screw connectors will light up the track status light, but do they also provide power for the loconet circuitry? In other words, will hooking up the terminal strips negate the need to get a PS14 power supply and run wiring to the contact points between the rear loconet jacks?

13

From the dark, distant past…

I just finished a round of UP5, UR-91 and UR-92 issues that had been vexing me for the past few weeks.

For my original Digitrax radio setup I ran two UR-91 recievers and about 6 UP-5 panels for convenient plug-in for address changes.

I did wire my track status LEDs to the appropriate rails and that is all they are, just LEDs wired to the rails. AFAIK they have NO relation to loconet or throttle functions.

I DID wire the little PC pad so I could daisy chain all the UR-91s and UP-5s together so I could take advantage of Digitrax “stay alive” battery feature that they mention.

In an earlier thread of mine, I mentioned that my UR-92 leaks!

Well, it was… somehow the 12v power feeding the UR-91s (and later UR-92s, I’ll get to that) so when the power was OFF to the DCS200 and boosters the green LEDs on the boosters was still glowing. [%-)]

THEN, I unpluged the Digitrax supplied wall-wart from the household 115v plug and with the DCS200 ON the LED on the wall-wart was glowing bright green even with the wall-wart unplugged from the wall.

SO, something strange was going on indeed!

Then, one day with the UR-92 still unplugged from the DC power supplyl, I turned on the DCS200 to run some trains and I happened to unplug my throttle from the UR-92 and I happened to look at the voltage status when it flashes on the display. It read something like 4.9 volts. So upon further digging, the only thing I came up with was that there must have been a fault in my loconet wiring.

By chance I found one of my RJ12 plugs had corroded slightly on only 2 of the 6 contacts but this seems to have been enough to cause all of this crazyness. All I can figure is that a little water dripped on the plug while doing some scenery.

Get your Loconet tester out and check all your Loconet connectors.

Everything on the layout ran fine even with this fault

14

Yes, they will provide power. No it does not negate the need to have a RELIABLE source of power.

There are 3 power inputs to the UP5: The track screws on the back, the coax plug on the side, and the railsync lines in the Loconet cable. There are all connected via diodes so the one with the highest voltage ‘wins’ - the diodes prevent reverse feedback into a lower voltage source from one with a higher voltage.

If you have block detection, the track status LEDs and drawing power via the track screws will trigger the occupancy detector. Another reason for not using the track power as the primary input is that in the event of a short, the track power will be down.

The BEST way to power UP5s is to run a power bus, tap off of it with feeders that have coax power connectors on the ends, and plug them into the socket on the UP5. The method of daisy chaining power to multiple UP5s shown in the manual has a serious drawback - there’s only one wire for the daisy chain, which is the plus side. The ground still uses the thin Loconet telephone wire. Running two wires to each UP5 and using the power plug on the side makes for a reliable power source, and it’s still easy to pull out and repalce a UP5 just by unplugging everything. No wire to cut, no screws to mess with.

–Randy

15

Thanks Ed and Randy. First off, I will definitely clean all the loconet contacts front and back. The panels were taken from the old layout we tore down in January 2013. They were securely stored, but cleaning contacts never hurts. The separate bus for the panel power sounds like the most cost effective method of powering the panels. I’m sure I can get the proper connectors dirt cheap. Probably won’t get back to work on it until the first of the year, but I will remember to post an update.

Jason