Decoder Manufacturers, Speed Tables And CV2, 5 and 6

The NMRA S9.2.2 specifies that all decoders must provide CV2 (Vstart). The provision of CV6 (Vmid) and CV5 (Vhigh) is optional. These three CVs are to be active only when Bit 4 of CV29 is 0. Speed tables are also optional and use CVs 66 (Forward Trim), 67-94 (the actual speed curve) and 95 (Reverse Trim). These thirty CVs are to be active only when Bit 4 of CV29 is 1. The disadvantage of this speed table specification is that any tweaking of starting or maximum speeds requires reshaping of the entire speed curve. Here we'll look at Soundtraxx, QSI, ESU LokSound and BLI decoders and how CVs 2, 5 and 6 effect user defined speed tables.

Soundtraxx

SoundTraxx Tsunami decoders differ from the standard. When the speed table is active (Bit 4 of CV29 is 1), the value in CV2 is not ignored but is effectively (in the decoder) added to CVs 67-94 in the speed table, pushing it upwards. The advantage of this variation from the NMRA standard is that you can tweak the starting speed without reshaping the whole curve, but the disadvantage is that you can effectively flatten the top end of the speed table it the maximum speed was already high.

QSI

QSI decoders differ from the standard. When the speed table is active (Bit 4 of CV29 is 1), the values in CVs 2 and 5 are not ignored. If either of CVs 2 or 5 are non-zero, these become the actual Vstart and/or Vhigh and the effective values in CVs 67-94 are compressed or expanded (scaled) in the decoder so the actual curve starts and/or ends on any non-zero value in Vstart and/or Vhigh. The advantage of this variation from the NMRA standard is that you can tweak both starting and maximum speeds without reshaping the whole curve, but the disadvantage is that if your speed table already covered a restricted range, the curve will be expanded, with possible integer multiplication errors producing glitches in the speed table.

ESU

ESU V4 and Select decoders differ from the standard (except in some early firmware versions). When the speed table is active (Bit 4 of CV29 is 1), the values in CVs 2 and 5 are not ignored, but ALWAYS specify the actual Vstart and Vhigh of the loco. In addition the value of CV67 is fixed (read only) at 1 and the value of CV94 is fixed (read only) at 255. You therefore need to fit your speed table curve shape between these fixed end points. The effective values in CVs 67-94 are compressed (in the decoder) so the actual curve always starts and ends on the values in Vstart and Vhigh. The advantage of this variation from the NMRA standard is that you can tweak both starting and maximum speeds without reshaping the whole curve and without the possible multiplicative errors in the QSI approach. The LokProgrammer and JMRI DecoderPro software both enforce the restrictions on CVs 67 and 94 so you know what your speed table will actually look like. Also, the minimum value for CV2 is 1, so you cannot set the loco to be stationary at step 1.

BLI Paragon 2 & 3

BLI Paragon decoders v3 & 4 follow the NMRA standard. If CV29 bit 4 is set to 1, CVs 2, 5 and 6 have absolutely no effect on the speed curve. However, CVs 66 & 95 (forward and reverse trim) do have an effect on both the 3-point speed curve and the speed table speed curve regardless of the value in CV29 bit 4. In other words they ignore that value.

Moral Of The Story

Know which decoder you are working with, and what effects CVs 2, 5 and 6 have on it when working with speed tables.

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JMRI v4.15.6 Now Works with ESU LokSound v5 Decoders

After MUCH work by Dave Heap of the JMRI developers group, DecoderPro of JMRI now works with LokSound's new v5 decoders. Before clicking your heels though, read the following

JMRI Users Group user Mick Moignard reported the following,

"Just for the record: I just read a Loksound 5 XL (South West Digital A4 steam), via a Digitrax DCS240 connected with a Locobuffer. Successful read in Direct Byte mode, 128 minutes.". Read my previous blog post about saving time here.

Dave Heap's reply:

Thanks for that report. My NCE Power Pro takes about 50 minutes.
FYI:

A V4 definition/roster entry has 1016 CVs and 4410 Variables**.
A V5 definition/roster entry has 2035 CVs and 9895 Variables**.
There are also some CVs/Variables in both I'm not yet reading ~60ish from the import log.
I dont think any other definition in JMRI is in this CVs/Variables league...

When we get into this territory, command station processing speed, the inherent bit rate limitations in the DCC waveform and the protocol packet counts start to become limiting factors.

** A variable is something you can read/set, a checkbox, a number, a text box (as in the Loco Name).

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A Great Easy Time Saver For JMRI And ESU LokSound Decoders

Those of us who know and use the Java Model Railroad Interface (JMRI) know that after you create a roster entry for a locomotive in JMRI you should immediately Read All Sheets of that entry to get all CV settings into JMRI. After that, you are free to change and tweak any of these settings. One serious issue with this read is with LokSound decoders. If you attempt this reading with a LokSound you will probably be close to finished reading War And Peace before it is complete (slight exaggeration).

Thanks to Dave Heap of the JMRI developers group for reminding this writer that if you are running a recent version of JMRI (as of this writing the version is 4.15.5) the procedure is nowhere near as bad as it used to be (time for an upgrade??). Take a look at the following and you will be able to save the cost of a copy of War And Peace.

1. Read the decoder data in your LokProgrammer (anyone with LokSound decoders had better have one of these!!)
2. Export CV List File is available in the Tools menu of LokProgrammer. Give the exported file a ".txt" extension
3. Open your roster entry in a recent version of JMRI
4. There is a File->Import->LokProgrammer CV List File Item of the opened decoder entry (in the File menu of course)
5. Use that to open the CV List File you exported from LokProgrammer
6. Watch the status bar at the bottom of your roster entry. When it changes from "Importing ..." to "OK" you are done and can Save the roster entry

You won't even have time to make a cup of coffee.

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Bachmann Develops Three New Train Models For Siemens Mobility

Philadelphia, PA. . .For immediate release April 24, 2019

Following the success of the HO scale Siemens ACS-64 model train, Bachmann Industries is excited to announce three brand-new HO products: the Charger SC-44 passenger locomotive, the S70 light rail vehicle, and a single-level mainline passenger car.

Bachmann has committed to producing full-featured models similar to the ACS-64 with DCC sound and lighting functions using Siemens Mobility’s original design documentation, and sound files for all three projects. Siemens’ Charger diesel-electric locomotive boasts high-speed, high -efficiency and clean energy performance, and their sleekly modern S70 has been adopted by many light rail systems across the United States. Their inter-city passenger car uses the latest engineering to offer passengers an extremely comfortable ride while providing state-of-the-art conveniences. Bachmann’s Charger models will be the first out of the gate, with a 2020 delivery date.

“Combining Siemens’ acclaimed designs and Bachmann’s modeling expertise, all three products will be sure to thrill any hobbyists who model in the modern era,” said Rich Janyszek, Bachmann’s Senior Vice-President of Sales and Marketing. Spearheading the effort are Dave Ward, Chief Advisor for Siemens Mobility, and Larry Harrington, Vice-President of Product Development for Bachmann Trains.

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Athearn Announces Genesis 2.0

Genesis 2.0 is the latest brand to join the Athearn Trains family. The first model in this new line is the HO scale Electro-Motive Division (EMD) SD90MAC-H. The model is based on the Phase II version of the 6,000 hp, six-axle road locomotive.

The Genesis 2.0 model, scheduled for release in March 2020, will feature all-new tooling, with what the firm calls “better than brass detail.” Other features on the SD90MAC-H include etched-metal see-through steps, illuminated number boxes, and ground effect lighting.

Athearn will offer the SD90MAC-H decorated for Canadian Pacific, EMD demonstrator, Fortescue Metals Group, and Union Pacific. Direct-current models will retail for $249.98. Versions with a dual-mode SoundTraxx Tsunami2 sound decoder with EMD 265H diesel engine sounds will be priced at $339.98.

For more information, visit Athearn's website.

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