Digitrax DS74 Stationary Decoder on DCC w/o Loconet?

BigJake Oct 31, 2021

  1. BigJake

    BigJake TrainBoard Member

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    Good point... DS52 is $14/switch MSRP (Kato dbl xover = 1 switch).
     
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  2. CSX Robert

    CSX Robert TrainBoard Member

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    When a product is replaced it's not that unusual for people to be willing to spend more for the old version to get something they are familiar with and where they know what it can do. Additionally, there are differences that could make some people willing to spend more for the DS64 - a couple of examples: the DS64 has screw terminals for the inputs while the DS74 uses a ribbon cable and the DS74 has to use four consecutive addresses while on the DS64 the four addresses are programmed individually.

    Just to make sure there's no confusion, both the DS64 and DS74 can also throw a Kato double crossover from a single output.

    If you don't need any of the additional features of a DS64 or DS74, then the DS52 absolutely is a better deal. In my staging yard I'll be using the internal routes, but even on other turnouts the DS52 wouldn't work for me because it has no inputs for local control.

    I went ahead and ordered a DS74 since I'll need some eventually anyway, so I'll be able determine definitively whether or not they can be programmed without Loconet. It looks like it will ship today so I should have an answer sometime next week.
     
    Last edited: May 27, 2022
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  3. Mark Ricci

    Mark Ricci TrainBoard Member

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    Before discovering the DS52 and/or until sufficient DS74 non-loconet info is available was going to build one of these DCC decoders (Arduino based) since have Arduino + shield but the DS52 at street price $25 is very cost efficient, even less than Arduino parts. Yes, sometimes have to forego tech interest for fiscal responsibility. No local control out of the box but could be adapted.



    It was a rhetorical question and point. Think a DS64 or DS52 instruction sheet can be given out to "average" person and within 15 minutes, its working. Unsure if one can make the same claim with the DS74. I do like the DS74 options with connectors-ribbon and panel switch assembly. See that as a DS74 plus. The DS74's newer components and its smaller footprint, are advantages. 2 DS52s larger footprint = 1 DS74.

    No question here, it would have never been on the list in the first place if it could not throw the Kato Double Crossover. At least 1 Kato Double Crossover will always find a place on each of my layouts. :)

    Definitely with a larger or switch intensive layout having manual control would be my choice too. Having the switches are nice even though haven't used them once, also a reason to semi-scratch build structure (first one ever) to conceal switch assembly but as you know, without loconet or other bidirectional comm, no system feedback occurs with manual switch control so throttle does not indicate the manual switch changes. As DCC EX progresses with future bidirectional bus support, having a DS74, or other with signal feedback + external LED circuit indicating turnout position is on the next layout's reqs.

    Outstanding! Will be most interested in the approach, especially to what degree it follows in concept, the step by step programming as outlined in either the DS64 or DS52 instructions.
     
  4. Mark Ricci

    Mark Ricci TrainBoard Member

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    @CSX Robert , If time permits and your exploration involves any of the following..

    Some questions regarding the DS74 refer to a thread on a different forum. The person has 7 DS64s. Ordered 2 more but had to get 2 DS74s. The first one seemed to work after programming but unable to program 2nd one to other than 4 3 2 1. A following post that preceded yours’ commented that the DS74 needs to be “activated” before use. I contacted Digitrax last July and was informed that unlike the DS64, no default address exists on the DS74. Possibly this is what the poster was referring to?

    The thread creator described the sort of strange outcome resulting in both DS74s addresse(es) set but in reverse order 4 3 2 1. Was the 4 3 2 1 set by just turning it on because he indicated that based on DS74 LEDs, the programming appeared to fail. No other prior steps were documented.

    1-Out of the box. What happens if one connects the DS74 to track and turnout, goes to Engine Driver-Turnouts, enters 4 or 3 or 2 or 1?

    2-Is “activation”, for lack of a better word, simply turning it on or going thru the process of “first time” address programming or is there some other on-device activation” configuration steps required prior to programming address(es).

    3-What, if any, is the impact of a hardware reset on the device and/or address(es). If the activation process is anything other than reprogramming the address(s), is re-activation necessary before re-programming?

    A while back ago you had replied in helping me understand the relationship between routes and turnouts specifically making each turnout a separate route if a DS74 was to be used. However, would routes still need to be setup if the non-loconet on-device programming process does set the DS74 to 4 3 2 1 addresess(es) or whatever?


    Thank you for the help.
     
  5. CSX Robert

    CSX Robert TrainBoard Member

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    Some good news and some bad news (mostly good though, in my opinion). The DS74 worked out of the box, without Loconet, using addresses 1,2,3,and 4 and with no activation of any kind. It initially would not reliably throw the Atlas turnout I was testing with because the default is to not use capacitive discharge; however, I was able to enable it with the Opsw setting which made it throw the turnout reliably. I was also able to change the base address of the DS74. So, all of the basic functionality works without Loconet.

    I'm not sure what you mean by hardware reset, unless you mean power down and back up, because there is no hardware reset, at least not exposed to the user. If you are talking about powering down and back up, it had no effect on the addresses or configuration. The software reset (closing opsw 40) did reset all options to their defaults and reset the base address to 1.

    Where I ran into an issue was when trying to program routes - apparently you cannot program them without Loconet (I opened a ticket with Digitrax to confirm this but have not heard back yet). After several tries, I decided to look through the DS64 instructions and articles to see if there was anything to givbe me a clue as to why I couldn't get them to program and came across a Digitrax article about programming routes that stated "During this procedure the DS64 must be connected to an active Loconet with an active command station", so apparently the DS64 routes also could not be programmed without Loconet. You do not specifically need a DT602, but you do need a throttle or computer that can generate Loconet switch commands. The method I described earlier about using routes to give you a separate open and close input for each turnout works, and continues to work without Loconet, but again, you do have to have Loconet to program the routes in the first place.
     
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  6. Mark Ricci

    Mark Ricci TrainBoard Member

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    @CSX Robert .. Thank you for checking out the DS74. The activation term, as mentioned, was for lack of a better one from another posting.

    Contacted Digitrax in January regarding default base address and the response "The DS74 does not have a factory base address as the DS64 used. Instead, it uses a Base address and that determines the 4 output addresses. By default the output address are q, 2, 3 and 4"
    Very interesting that q = 1 by default based on your out of the box experience.

    Yes. Was referring to OPSW 40 in terms of hardware reset. Your reset test seems to conclude that q = 1 by default.

    Curious... regarding how you programmed... Per page 1 of the Digitrax DS74 Instruction sheet, shown below, Section 1.0 titled "DS74 Quick Start - Solenoid Installation" .. Did you just skip steps 1-3, No PS14, connect DS74 to track + turnout, turn power on and begin at step 4?

    1.0 DS74 Quick Start - Solenoid Installation
    The DS74 is simple to install and begin using on your LocoNet layout.
    1. Figure 1 shows the recommended factory default connections to operate
    the DS74 on a LocoNet layout and controlling four e.g. Atlas or Bachmann
    3-wire snap type 12V pulse-solenoid switch (SW) turnouts.
    2. Connect a PS14 DC or similar power supply to your DS74 via the DC cen- ter-positive 2mm power
    jack. Power on the DC supply. The green ID LED should light and will briefly wink OFF every 2 secs
    as a product 'heartbeat' showing unit is powered and operational.
    3. Plug in an active LocoNet to a DS74 RJ12 connector. The red OPS LED will light up showing
    connection. Any good LocoNet message seen will cause DS74 OPS LED to blink OFF briefly.
    4. Press and hold down the ID button for about 3 seconds until the RTS and
    OPS LEDs blink alternately, then release the ID button.
    5. From your system send a SW command to set the Base Board address as this switch#. The OPS
    and RTS LEDs will stop blinking showing the DS74 has set the unit's Base SW# to the switch number
    (SW#) you just sent.
    6. Operate turnouts with a switch# and direction Thrown (T)/Closed(C) at the
    Base SW#, or the next 3 SW#'s in use for this DS74.
    That’s all that’s required for installation of your DS74 on LocoNet!

    Thank you..
     
  7. CSX Robert

    CSX Robert TrainBoard Member

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    Yep.
     
  8. BigJake

    BigJake TrainBoard Member

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    Thanks for the info and confirmation! Now I just have to decide whether I want the smaller space requirements and included enclosure for DS74s, or cheaper cost of 2X DS52s.

    I was wondering about the capacitive discharge option; thanks for confirming it too. I have a couple of Unitrack double crossovers (each w/4 bidirectional coils in parallel), so I was expecting to need the CD option.

    Lack of routes on the DS74 is not an issue for me since I can set those up in JMRI if needed. JMRI is required for my Pi SPROG 3 DCC system anyway.
     

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