21 Aspect Signal?

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21 Aspect Signal?

Post by apemberton » 13.07.2019, 21:52

Dear Rocrailers,

I am having serious difficulties understanding Rocrail’s signal operations.

I am using Qdecoder signal decoders configured for Soviet / Russian colour light signals. I can control these manually with my Rocmaus/DR5000 though it is complicated and easy to get sequences wrong.

At present, I am not using RR automatic action nor blocks. That is for future settings when I solve my signal and block sensor hardware.

I show images from the Qdecoder setup for an example I am testing at present. See Below

Whilst I have set up 3 aspect ‘Mehrabschnitt’ (intermediate automatic block - I think) and 3 aspect ‘Hauptsignal’ with subsidiary speed bar(s) using RR Linear settings combined with RR actions and command outputs. This is because the Qdecoder has to use two DCC addresses to select any aspect other than red. A red command overrides any other command.

For example ‘Mehrabscnitt’ signal:-

Code: Select all

Aspect 0 – Red             – Halt                  – Pada Address 101 – Gate Red

Aspect 1 – Yellow          – Stop at next signal   – Pada Address 102 – Gate Red
                                                     Pada Address 101 – Gate Green

Aspect 2 – Green           – Proceed at full Speed - Pada Address 102 – Gate Green
                                                     Pada Address 101 – Gate Green

Aspect 3 – Flashing Yellow – Proceed at 60Km/H     - Pada Address 103 – Gate Red
                                                     Pada Address 101 – Gate Green

Aspect 4 – Flashing Green  – Proceed at 80Km/H     - Pada Address 103 – Gate Green
                                                     Pada Address 101 – Gate Green

Aspect 5 – Flashing Green  – Proceed at 120Km/H    - Pada Address 104 – Gate Red
                                                     Pada Address 101 – Gate Green
The the XML snippets from my plan are attached below.

Very Messy but it works – but a bit slow. An external script ought to be better but I cannot get one right.

However, I now have a six lamp, 21 aspect(?) signal as is commonly found on Russian railways used as a ‘Mehrabscnitt’ signal with diverging route, speed control plus white calling on / line shunt aspects. The basic configuration has 4 lamps but the number of aspects is multplied by the auxilliary (Zusatzsignal) yellow and added to by the white ‘callling-on’ signal. These are shown in the image above.

At present I am stuck with finding a way to make it work. I have tried most Control modes. Linear falls short as signal sequences are not linear. Patterns does not seem to have enough combinations even with added actions. Aspect numbers might be a possibility but I cannot understand how it works and in any case, the wiki https://wiki.rocrail.net/doku.php?id=signal-props-en does not properly describe the two sets of number/value and how to use them.

I am beginning to think I might have to build a Rocnet node with a spare Arduino and custom program the DCC command output to match the Qdecoder requirements.

I am trying to be constructive and use Rocrail for direct control rather than hand off to another platform.

Thoughts please. Thanks.
Mehrabschnitt Example.xml
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Re: 21 Aspect Signal?

Post by peter&basti » 13.07.2019, 23:00

Hi Tony,

i don't know the Qdecoder in practice, only the exorbitant price is aware for me.

If you think about Rocnetnode, you may get a proper solution without any signal decoder.

1. Take a look RaspberryPi as Rocnetnode, add a PI01 Hat for the I2C bus and a PI06 for a stable power supply.
2. Then have a look on the PI08 PWM Board, which controls the signal LED directy, controlled in Rocrail by patterns.

My opinion: the built-in logic in Qdecoder and similar stuff generates unnecessary complexity (a mess as you wrote). To control a complex signal directly out of Rocrail by patterns is more easy to understand and to control.

By the way, i am not sure that all possible combinations of a 6-bulb signal are relevant for a route ... :wink:

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Location: West Hertfordshire, UK

Re: 21 Aspect Signal?

Post by apemberton » 14.07.2019, 10:24

By the way, i am not sure that all possible combinations of a 6-bulb signal are relevant for a route ... :wink:
Hi P&B,

I'll have to ask the Soviet MPT or the DDR signal authority about those pesky EZMG signals and if they needed them! :)

Having invested in seven or eight Qdecoder units specifically for signalling, I don't really want to consign them to the spares bin. I have also several simple ZA1-16N decoders which are being used for Blue/White shunt signals (and the appropriate SVG symbols).

I have a test setup on my desk at the moment as per the unit displayed

I have, in the past, made RPi I2C to 1-Wire adaptors (before they became commercially available) for my house temperature sensors but I am not aware of the provenance or cost of the boards you mention. I'm not sure if that would be more cost effective anyway with the number of signals involved. (Russians -and East Europeans - seem to be fond of signals on any and every track or siding - just see cabview youtube videos!)

The Qdecoders do work well with my homebrew signal posts under manual control. Commercial signals for Russia are not available in N-scale so far as I know. I have tried getting some from the Czech Republic (by Rotter) but so far have failed. They are available in 1:120 and 1:87 from Russia but that doesn't help.

Still the challenges help keep the grey matter active even if technology can be frustrating at times. It never seems to do what I want it to do! :?

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Re: 21 Aspect Signal?

Post by apemberton » 16.07.2019, 23:51

I have made a bit of progress using actions and Outputs(2) with small ext.xml scripts to manipulate the 21 aspect signal using the action test button.
However, when I use the signal control in linear mode, the additional direct signal output interferes with my action controls and lights the wrong LEDs.

Signal tables are necessary to display my custom SVG's.

Therefore I have two questions.
1. Can signal outputs be turned off and just allow action/output to be triggered with an aspect change? (I don't think this is possible.)
2. Is it practical to send a signal command to a dummy address and then just rely on action/control to set the correct signal?

I'd really welcome some advice. :?

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Re: 21 Aspect Signal?

Post by rjversluis » 17.07.2019, 06:24


Signals commands should be set in Routes in case the number of aspects is greater than 4.

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