[Digitrax] Address Purging Made Simpler

Ross Kudlick posted this message from Don Crano to the Digitrax forum and the author believes it has very good information on the workings of the Digitrax address slots (along with a little history lesson).

Note:  This message was posted on the Digitrax Group by the late Don Crano on Sep 23, 2004.  I’ve posted here (as a document) to facilitate reference during discussions related to “Slot=Max” and purging. 

Don was perhaps the most knowledgeable person about Digitrax systems except AJ of Digitrax.  In the early days, AJ developed personal relationships with many of the early adopters, making himself available for ‘tech support’ as needed.  Don was one of those people – and with AJ’s blessing passed on much of his knowledge on the Digitrax list.  (Don founded the list, and put it into full operation in Aug 1998 – Ross has been on the list since Oct 1998). Ross got to know Don as a ‘telephone buddy’ getting help for his club’s Digitrax system.  He, along with John Philips (then the Digitrax tech support guy) gave me help for any issue Ross had. “Those were the days, my friend.”  🙂

Don ‘passed’ away far too young.  We lost a true friend (and giant) in the Digitrax world.

-Ross Kudlick

[Digitrax] Purging Made Simpler

Don Crano

Sep 23 12:29 AM

Glenn,

Not sure if this is going to make it simpler, or not. The details are typically not required for the normal user, it is just the system works most of which is behind the scenes, but does work as described.

As they say the devil is in the details so here they are:

First a little on slot status, just because the status changes, or is purged from the system to be used by data from another decoder address, does not mean all the data is removed from the slot, only the status flag is changed, the data that is there stays there to either be re-used by another LocoNet device 'COMMON', or be purged so another set of data can over write the existing data 'IDLE'. Or in other words you will not see the slot data go "Bing!".   But you should be able to see the 'Status Flag' change, as well as actual data be over written when required.

Next each slot does have its purge timer, but the timer is not always active or counting down, this will only happen when certain criteria is set up. Here is how it all works:

While a LocoNet device [Throttle] is maintaining a SLOT in the refresh stack it will be required to check the SLOT status matches its internal state before re-using any SLOT. If a device disconnects from LocoNet and so does not access or reference a slot within the system PURGE time, the Master [Command Station] will force the un-accessed SLOT to "COMMON" status so other system devices can use the SLOT.

The typical purge time of a Master is about 200/600 seconds. A good "ping" or Slot update activity is about every 100 seconds, i.e. if a user makes no change to a throttle/slot within 100 seconds, the throttle/device should automatically send another speed update at the current speed to reset the Purge timeout for that Slot. Note with a LocoNet wireless throttle, IR/Radio  you can see the ping or update being sent while the throttle is in PS mode, it will wake up send then go back to PS approx. every 60 seconds or so. This keeps the system from releasing that address back to the system and making it available to be selected by another throttle. There have been more than a few who have asked or wondered why the wireless throttles will wake up periodically then go back to PS mode, now they know.<g>

Again, before an address will be purged, i.e. slot flagged for use with other data from another decoder address, the following criteria must be met. The decoders speed data must be at '00' or the Master [Command Station] OPSW must be set to force '00' speed at purge, typically OPSW# 15 set from default 't' to 'c'. Also OPSW# 13 can change the purge time from 600 seconds to 200 seconds. Good for faster more rapid purges, but bad for tethered walk around, as now when an operator unplugs a non-wireless throttle from the LocoNet they only have 200 seconds to plug in somewhere else. OPSW# 14 can stop purging all together, not really a good idea unless one like to see a status of 'FF' Slot=Max.

Next any slot with an UP-CONSIST flag, this means this slot and decoder address is part of a consist, will never be purged. We would not want to be running a multi-unit train down a helix and have a loco purged right in the middle of it all.<sigh>

A good routine for any Digitrax layout, especially for club layouts where LocoNet devices and decoders come and go:

Before removing a throttle from the layout:

1. Un-Link any consists, that will remove the UP=CONSIST flag
2. Make sure all addresses associated with the throttle are at speed '00' and/or have the Master set to '00' speed at purge
3. Release or Dispatch any addresses associated with the throttle

Following the above will go a long way to keep the 'FF' or Slot=Max status from showing up.

The term UniVersal™ is a Digitrax registered trade mark. It is used to name or describe their command station assisted consisting. Digitrax actually uses what is called Unified Consisting, i.e. the system allows three modes of consisting, Advanced, Basic, and UniVersal™, and may be mixed, matched and even nested inside other consists, and it is Unified because it can all be done automatically without any real user intervention as they set up the consist.

The terms 'c' and 't' have nothing to do with switches such as light, OPSW's, etc. They are used to define turnout states, as example 'c' or closed is used to define a turn out set to normal route, this does not mean straight, only the normal route. As 't' or thrown is used to define the divergent route of the turnout. I know this get confusing when used with such as setting OPSW, as you indicated in your post about a light switch, etc. But once you note that to set a command stations OPSW's, you first set it to OP mode, then set the throttle to SWITCH mode, typical of setting a turnout position. Now you can see why 'c' and 't' are used, the throttle does not care if it is setting a turnout for 'c' normal route 't' for divergent route, or setting a command station or other LocoNet devices' OPSW.

Hope this helps!

Remember Always Have Fun and Enjoy!

Don Crano Akron, Oh NMRA #096211

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National Train Show 2022 Report

Model Railroader has posted a video report of this year's National Train Show with commentators Eric White and Cody Grivno.

Of interest to the author was the mention of Atlas Model Railroad Company having a MP-36 prototype model based on True Line Trains MP-36. This would be a welcome addition to Atlas' fleet since more model railroaders have been running commuter trains lately. Whether they bought the tooling from True Line or copied it was not apparent since True Line in no longer a viable company.

One other item of interest was the mention of Scale Trains working closely with Fox Valley Models on projects. So closely, in fact, that doing a little more research the author found that Scale Trains has acquired the Fox Valley HO Line. Also the original owner of Fox Valley models is working for Scale Trains.

The 15 minute video is available here.

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Automatic Bell On ESU Decoders - Updated 2022-10-16

As most model railroaders know when a locomotive’s bell starts to ring it is a warning “Look out, I’m moving”! The de facto standard to turn on the bell is function 1 (F1) and when pressed it starts to ring immediately and to turn the ringing off press F1 again or else it would ring continuously (blah!!). What if we changed things a little to have an automatic bell, i.e. press a function key and from then on when the engine is given a drive command the bell will start ringing and also stop ringing when a certain speed (call it S1) is reached. Also, we would like the bell to start ringing again when slowing and its speed drops below S1 and continuing until either it’s accelerated again beyond S1 or stopped in which case it stops ringing. This would be prototypical and similar to the engineer handling the bell without us having to worry about it.

As Ted Wentz showed on the LokSound groups.io forum this is not difficult to do if you have some experience with modifying ESU sound schedules. That would include doing some of the modification tutorials I’ve given in previous posts such as this one. I've taken Ted's demonstration and modified it to prevent the throttle from prematurely turning off the bell while the engine is still moving.

Before we begin, ESU has added the Auto Bell On/Off Template Pack to many of their sound files for modern engines on Function 2 to ring the bell when the horn sounds. You can read about controlling this in any sound file’s accompanying bulletin that has this functionality. The problem this creates is it will interfere with the auto bell feature we’re going to create on engine moving and engine stopping if the engine gives the standard two horn blasts to indicate forward movement. This tutorial assumes that the ESU auto bell feature is turned off.

We’ll use the ESU sound file S0539-LS5H0DCC-Diesel-EMD-12-645E3-T-V4-R4.esux located here. Let’s get started and you’ll see how easy it is.

First, in the Sound pane Overview sheet you’ll see that slot 2 is empty. Create an empty sound slot sound file by double clicking on it and naming it Auto Movement Bell. Add a container and connect it to mute using 2 transitions as shown in fig 1. Call the container Bronze Bell. We’ll come back to this shortly.

Figure 1 After creating the Bronze Bell sound slot

Double click on the container then drag and drop one of the bell loop files from the sound collection in the lower right corner to the created state. We’ll just pick the first one. Add 2 basic transitions as shown in fig 2.

Figure 2 Inside the Bronze Bell container

That’s all there is to the state so we’re done with it. Now, back to the container and its transitions which are the heart of the sound file.

Add 3 grouped conditions:

•     function = true
•    Whatever function you assign to this sound file must be “on”

•     speed > 0
•     don’t start the bell until the engine starts moving

•     speed < SoundCV16
•     use speed to determine when to turn off the bell

This is shown in fig 3.

Figure 3 The grouped conditions

Wait!? What’s this SoundCV16 thing? First off, if we put a hard coded value such as 40 here then if we ever want to change it we would have to go back into the sound file, change the value and then write the entire sound file to the decoder again (another half hour!!). By changing it to a SoundCV we can change the SoundCV value on the Sound Slot Settings sheet of the decoder pane and then just write the decoder values (about 20 seconds). See fig 4.

Figure 4 SoundCV16

There is almost always a free SoundCV available but I say almost because I have seen sound files where there were none.

<Update>There is another variable that can be used in place of SoundCVs. At the bottom of the Sound Slot Settings pane is the Sound Configuration variable shown in fig 5. 

Figure 5 Sound configuration variable

This is different for each sound slot and relates to the "select" variable in the conditions drop down of the sound slot schedule shown in fig 6.

Figure 6 The "Select" variable

This will do the same thing as the above mentioned SoundCV. The difference between the two is the Sound Selection variable is particular to a sound slot (local variable and all sound slots have one) while a SoundCV applies across ALL sound slots (global variable and can be called from any sound slot). Your call on which one to use.

The last step is to assign the new sound slot sound file to a function key on the Function Mapping sheet of the Decoder pane and make certain to also assign the “Drive” condition to the slot shown in fig 7. You could also set the checkbox “Play only if the drive sound is enabled” on the sound slot settings sheet.

Figure 7 The Drive condition assigned to F1

Utilizing the Simulator you can test this to make sure the bell sound you chose is what you want. Notice there are several different bell loop sound files included, some good, some not so good, so pick the one that works for you. Also note that you can use any function number you want to. It doesn’t have to be function 1 as shown in figure 5.

Next up will be automatic horn forward and reverse start and stop signals

Enjoy!

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SoundTraxx Announces New Blunami Decoder with Phone App

 August 2, 2022

SoundTraxx in partnership with BlueRail Trains has announced their new product, the Blunami decoder. You can now control your Blunami decoder equipped trains from your smart phone via Blue Tooth technology. The author believes this is a great way for the beginner to enter the hobby of model railroading. 

For all the information you'll need along with a YouTube video demonstration go here.

SoundTraxx's presentation is available for a limited time here.

SoundTraxx will have much more information available very soon, probably today.

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