Hi team,
I have a stationary decoder (say a digitrax DS64) and my goal is to connect it to my JMRI computer (through a PR3 which I already have). It will be connected to the Rail A and Rail B connections of the DCC COMMON bus.
Do I need to hook up to the Loconet via an RJ-12 cable or would JMRI be able to control with the track connections?
NP
Yes, you can do it that way. JMRI can control it via the track as if it were a throttle.
It is better to use a dedicated loconet connection: If you have a short caused by running against the points, the constant power cycling until the short clears will not let you throw the switch, unless you manually clear the offending item that is creating the short.
I would use a loconet connection. Over the years many have found DS64 operation to be better using loconet to handle the switch commands and either track power or (even better) auxiliary power to run those DS64's and switch machines. My DS64's are not connected to track at all but function perfectly. Even when track power is off.
Martin Myers
NO NO NO!
The track A and B connections on the PR3 CAN NOT be connected to the live DCC track on the layout. In order to control the layout with JMRI, the PR3 must be connected to your Loconet network, and set to MS100 mode (JMRI will do this for you, you can forget about the instructions in the PR3 manual about 'blinking' and 'winking' LEDs.) The track connections on the PR3 are exclusively to use it as a standalone programmer, connected to an ISOLATED piece of track. You need to have a power supply connected to the PR3 for this mode of operation (again, JRMI will set it for you). You can have it connected to a piece of track AND connected to Loconet at the same time, but you can only do one function at a time - either control the layout, or program on the program track.
DS64's can be connected to track power, or to Loconet. They seem to be most stable when powered with an auxiliary power source and controlled via Loconet (no track power connections). This keeps "noisy" power out of the unit and seems to help keep it from scrambling its brains - even if you don;t short out the track, the motors running and the noise generated by interruptions in power that you can;t even see cause electrical noise and some people have had problems with DS64's getting confused and needing to be reprogrammed.
A cheap solution, if you have several DS64's, is t use one of Tam Valley's boosters as a dedicated power source for the DS64's, this would be track power, but since it would not be powering any actual track, it wouldn't have the electrical noise.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Let me add a third vote for NOT powering your DS64's with track power, even from a dedicated booster or non-track power district.
Besides taking away booster capacity (wall-warts are cheaper than DCC boosters), DS64's using track power have been known to lose their programming from the electrical noise that a track short can generate.
There is also the previously-mentioned temporary loss of control since the short kills the input power to the device.
The ten DS64's on my layout are powered by a dedicated 12VDC regulated power supply, and receive all their commands via LocoNet. I personally wouldn't consider setting them up any other way.
I am convinced, then!
I was just looking for theoretical feasibility, which seems OK. I am planning a high amp capacity 12V and 3V bus around my entire layout for AUX power.
I was getting a wee bit concerned around RJ12 runs.
Hi guys
I know this post is a few months old but I though I'd add a couple of observations as its something I'm currently working with. Its my first poist here so if in the wrong place please excuse!
I would agree with powering DS64s externally. Be careful though with a high current 12V bus - if using such put a fast acting fuse in series at each tap for the individual DS64 (don't have my manual beside me so cant remember the rating I use)
I also connect them via Loconet. Recently I've had an interesting problem - currently using a Z21 CS from Roco/Fleischmann which "speaks" Loconet. It has an handy option whereby you canfigure a switch in software to save having to swap the wires on the DS64. However when powered by Loconet this leads to constant re-setting when the screen focus changes. This doesn't happen when the DS64 is powered by DCC (something I'm not keen on for the reasons mentioned above). Presumably this means the Z21 despite licensing the Loconet protocol from Digitrax is implementing it slightly differently.
The joys of the hobby (& once again please excuse if I'm in the wrong thread)
Fionnbarr
It's not recommended to power DS64's from track power because the various transients seem to cause them to periodically loose their minds. However, you can apply external power to teh rail a and b connectiosn from a seperate power supply.
WHatever they are doing to swap addresses witht he output, unless it is actually reprogramming the DS64, is not anything I am aware of as being a feature of the DS64. It sounds like what you can do with the Z21 is if say the third output of a given DS64 ahs address 20, and the fourth one is address 21, and it turns out you have the wires connected to the wrong switch machines, you can set the Z21 so that activating switch address 21 actually triggers the third output on the DS64, not the fourth. This to me would seem like something being done in the Z21 that is in no way programming the actual DS64 so if you close that screen I wouldn;t expect it to be saved.