Hi Guys! I Know there is someone out there with much more knowledge that me on this DCC stuff. Building my new layout included designing it around DCC. To that end, I have invested in a Digitrax Empire builder set up. What I have run in to are decoder programming issues. It appears to me that although there are NMRA "standards" they do not unilaterally apply to programming mobile decoders. My problems are: MRC sound decoders can only be programmed in OPS mode on the main which is bad enough and raises other potentially hair pulling issues. More problematic is that the CVs cannot be read by the Digitrax system. Apparently this is common with MRC dedcoders. To that end, how does one know where they are going when one does not know where one is? How can you try to speed match in a consist when you do not know your existing values? I have tried using a Digitrax PR-3 with the JMRI system to no avail, Are all decoders mute in readback or is this limited to MRC? Are there other sound decoders that will provide readback values to a Digitrax system? I am hoping someone has a better way to DCC than this since analogue is starting to look good again. Thanks, Mike
Most (all?) MRC decoders I have encountered do not program easily and do not support much CV readback. If you are programming in OPS you can't read back anyway. With my Digitrax system if I want to get any readback I pretty much just use PAGED mode on a programming track. The other thing is that if you are used to the myriad of options for motor control, lighting, etc., with Digitrax or TCS decoders you'll not get the same sort of options from MRC decoders, unless these newer ones support more of these items. Soundtraxx decoders, in my experience, do support readback through Paged mode or using a Sprog II with JMRI. They'd probably do so through a PR-3, too, though I don't know for sure as I haven't tried that. Soundtraxx decoders tend to be easier to program and they have better motor control than MRC ones. You pay for it through a higher price, however. I can't remember. Is the Empire Builder the one that comes with a DB 150?
Mike your Empire Builder does not read back CV period. It is built that way and many don't think read back is such a great option. Older MRC decoders did not have a read back feature, newer one do. From your post I see you have access to a PR3 and Decoder Pro. The PR3 in standalone programmer mode will read any decoders that support CV read back, no need for a programming track booster. Jack W.
sound decoders need more power to write and read cv. you need a booster for your programming track. as far as i know pr-3 can be used as a booster. read the manuals.
The PR3 can run the programming track and give you CV feedback if the decoder is feedback enabled. Many of the early MRC decoders did not support feedback. It also can program sound decoders as it sits with no extra boosters or other electronics. You can setup a very good programming environment just using the computer with JMRI, the PR3 and a section of track. Nothing else is needed. The PR3 also lets you test the sound functions on the programming track. I have tried this configuration using the PR3 and a section of Kato UniTrak on my desk and it works very well. If you have a laptop, this becomes a portable use anywhere programming setup. No command station is needed.
Thank you all for your feedback. I have found additional things that may be of value to some and have had some limited success in programming and reading the CV values in these MRC sound decoders with the DigiTrax system. I called MRC and verified that all their decoders produced in the last three years indeed support read back. My Digitrax system contains a DB200 booster and is supplied by a 20 amp power supply. The throttle is their new 402D radio & duplex model. What I have determined is as follows: 1. The Digitrax programming track output is indeed too low to trigger the sound decoders. Putting a meter set to AC Volts (I know it is not a true measure) across the rails yields a relative 6 Volts when a packet is sent. 2. Adding a 1K resistor across the rails as suggested by DigiTrax is still not a sufficient load to bring up additional needed current to trigger the decoder. 3. Adding a JAX booster helped when it came to writing to the CVs but did nothing for the read back function. 4. OPS mode programming on the main line is sporadic at best; I was able to program 3 out of 4 MRC sound decoders O,K, however, I am not certain what the 4th one heard because it went unresponsive after an attempt at ops mode programming and had to be reset to default a number of times befvore it came back to life. It seems some of the packets get garbled in the transmission or receipt phase. 5. Setting the booster to HO gauge seems to have worked much better. The higher programming voltage now at a relative 10 Volts allows some but not all the decoders to read back their CV values. (This supports the low power output on the programming track issues). 6. The one decoder that needed "CPR" now thinks it is stuck in analog mode and runs full blast responding to DCC voltage on the rails. I am trying to reset this one now. 7. Although I have both the PR-3 as well as the R-R CirKits Loco Buffer, wew are wrestling with the setup of the PR-3 and the JMRI software. It seems the JMRI does not want to talk to the PR-3 as of yet. This DCC stuff is too much like work. I believe that in order to achieve any sort of reliability and enjoyment from these I may have to bite the bullet and find reasonably priced sound decoders to replace the MRC units. I hope these findings can be of help to others. Mike
Mike something puzzle me. What is your command station? Is it an Empire Builder DB150 or a Chief either DCS100 or DCS200? If it is an Empire Builder DB150, this system has no read back capability on a programming track. No matter how hard you try. If it is a DCS100 or DCS200 then this system can read back CV on a programming track. Your DB200 is nothing else then a dummy booster and can't read back CV The PR3 play nicely with JMRI, on what type of computer operating system are you trying to install it?
Yes what is the problem with the PR3? I had the Locobuffer USB and then O got the PR3 for throttle firmware upgrades. I was able to get it up and running in just a few minutes with JMRI.
Hi Jack, I believe I mis-posted something here. I have the Super Chief with a DCS200 booster, not a DB200 as stated. Sorry for the confusion. As to the JMRI issue, we are installing it on an XP Pro platform. It appears that JMRI is reporting the PR-3 on comm port 3 while the device manager is reporting the device as comm port 4. I have an audio engineer friend who installed the same thing on his computer without issues. We believe the issue to be somewhere in the set up and minor. He is bringing his system, decodered engines and test track to my place for comparison. Mike
Thanks for the reply, I am not thoroughly familiar with the interface of these units since I had a club friend do the install. We are going to try to debug the issue next week and I will report back with more detailed information or remaining issues. Mike
It is most likely conflicting with the LocoBuffer, and that should be a pretty easy configuration change. You can change the port settings in the JMRI Preferences tabbed window frames to match what the device manager is seeing.
Mike, I have successfully installed 6 PR3 on these platforms, Win XP Pro, Win Vista and Win 7. Just make sure of 2 things. 1- Install the driver provided by Digitrax. do not let Windows install its own driver. 2- As David said, match the port in JMRI Preferences window to what the Microsoft Windows Device Manager reports. The PR3/JMRI combo is a tool I will not go without when programming sound decoders.
FYI... I use the Programming Track Booster by SoundTraxx PTB-100 with my Digitrax Super Chief to program all my decoders; I leave it installed and program both sound and non sound decoders with Decoder Pro. The combination of the 2 has served me well and I have had no issues. MRC has issues which is why I only have 2 , 1 of 2 Challengers that I haven't converted to Soundtrax and a SD70MAC that "works" with the MRC decoder. Readbacks can be interesting.... Be really careful about switching your voltage from N to HO as the extra voltage can be unkind....over the long haul Brian
