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Z21 and Signalist SC1


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I have four Absolute Aspects O gauge GPS units. Wonderful pieces of kit! They are connected to a Signalist SC1 decoder. My main controller is a ROCO Z21. Thanks to lots of help from Paul at Signalist they all work perfectly but ....
With help and by changing the value of CV37, when I power off and on, the SC1 resets all the GPS units to stop ie red and white light at the bottom, side by side.
However, if I leave one of the GPS units on go ie diagonal two white lights when I power on and off that GPS will come back on as stop ie red white light at the bottom but the display on my Z21 will show that signal as green on the display on the Z21 ie two white lights. It is easy to just cancel it by tapping the screen.
Paul at Signalist suggested putting a switch on the SC1 and I tried this. So, if I power of and switch the SC1 off before I power on and then switch the SC1 back on after the Z21 has powered up then any GPS units I have left on ie two white diagonal lights come back on in the state with a green light on the Z21 track and accessory screen.
While leaving GP signals in go mode ie two white diagonal lights is bad railway practice and I should cancel them after a loco has passed is there some way of changing a setting on my Z21 to recognise that a GPS has been changed by the programming of the SC1 and it, the Z21 should change the signal on its display from green to red without the need for me to install a simple on/off switch. Yes, I understand good railway practice should prevail but surely the technology should cope with what I am trying to do. I understand from Paul at Signalist that it is something to do with reset packages but exactly what they are I have no idea at all! 
Thanks in advance for simple explanations.

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The Z21 will react to DCC signals sent to it and remembers the state of any accessory at power-up. If you change the accessory outside the Z21 eco-system (phone app, Multimaus) then that device needs to tell the Z21 it has been changed otherwise the Z21 will simply power up in the last state that you set within the Z21 eco-system.

 

For example, if I change a signal using my automation program (iTrain), then the program tells the Z21 to change the signal and the Z21 issues a DCC command to the accessory decoder. I can switch everything off and when I power up all will be hunky dory.

 

If I was to switch off the Z21 and then change some signals and turnouts in my automation program, or manually, then the layout will be out of sync with the program when power on the Z21 and reconnect. This is the situation that you have I think.

 

In essence, the Z21 will remember its internal state and that is what it will switch on using. If you change the status of a signal with then you need to change it through the Z21 otherwise the Z21 will not know about the change. When switched on the Z21 does not issue any reset commands, it simply powers up in the last state.

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It appears that when the Z21 is powered on it is sending a decoder reset packet (hard reset in NMRA speak) and the decoder is responding to this and resetting to a known value as the NMRA spec requires when a decoder recieves this packet. Other command stations notably Lenz do this as well.

 

The issue here is that while the Z21 sends the reset packet to reset the decoders, it does not reset its own internal state to match. I don't unfortunately have a Z21 here to see how it displays signal states on the command station.

 

The simple workaround is to disconnect the track feed to the layout with a switch before power on and reconnect it after the command station has sent its reset packet, that way the decoder will retain its previous state when it was powered off and not be reset.

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When I switch on my Z21 nothing changes on the layout - nothing is reset, nothing has its position changes, no signal change - absolutely nothing happens - other than power becomes available to light the signals, loco lights etc.

 

If I connect the app then again nothing changes - until I change it. If I changed something on the app whilst the layout is disconnected then it remains different on the app and the layout until I switch the appropriate device to get it synchronised. If I have manually changed something on the layout whilst the Z21 was switched off then the same happens - the app and the Maus are out of sync with the layout.

 

In summary, the Z21 doesn't issue any reset 'packet' on my layout.

 

 

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My understanding from talking to Paul Harman at Signalist is that the Z21 is sending reset packages to the Signalist decoder via CV 37 on the SC1. CV 37 is telling all my signals to come back on in stop mode. The Z21 is then not changing the signal icon internally to show this.

 

Certainly turning off the SC1 as suggested while the Z21 powers  up  and then powering up the SC1 afterwards will leave all the signals on the layout and on the Z21 in the state I left them. An easy solution is to manually set the signals on the Z21 to red, stop mode, before I turn the layout off. This is what I believe would happen in real life? It is also quite easy to tap the signal icons on the screen on the Z21 and change them back to red.

 

I was just wondering if there was some tweak I could make to the Z21 so that it might actually recognise the packages it may or may not have sent and change the signals internally without having to install an on/off switch. I only have to tap the screen to do it but I thought the technology that I don't really understand might be clever enough to do it. Interestingly the two replies I have had seem to have differing views about what the Z21 is and is not doing doing with reset packages. All I know is what happens and the on/off switch method cures it. I was wondering if there was more of a "technology"  answer. Thanks. 

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I can’t see why the Z21 has a fault when it only affects your system - that would suggest that it it something to do with whatever it is that you are using and that they need to fix their issue. The Z21 has been on the market for many, many years and has regular firmware updates to cure any issues and something as fundamental as you are suggesting would have been resolved before now.

 

As I said earlier, the Z21 doesn’t reset anything on my layout when it is switched on - it does absolutely nothing, until you tell it to do something.

 

 

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  • 3 weeks later...
On 30/04/2022 at 12:05, WIMorrison said:

I can’t see why the Z21 has a fault when it only affects your system...

 

...As I said earlier, the Z21 doesn’t reset anything on my layout when it is switched on - it does absolutely nothing, until you tell it to do something.

 

The Z21 is sending a reset packet, you will probably notice that if you turn your Z21 off with trains running, when you turn it back on again the trains will stop because they respond to the reset packet.

 

It is quite a small issue, but if the Z21 sends a reset packet it should also reset its internal state to match. There are a lot of decoders that ignore the reset packet, and if you have some of these you will not see the effect.

 

The Signalist SC1 decoder allows you to set a default state so you know what state your signals will be when your system is reset. A simple power down will not reset the signals - they will come back on in the state they were left in so that a simple glitch will not upset anything.

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14 hours ago, Signalist said:

 

The Z21 is sending a reset packet, you will probably notice that if you turn your Z21 off with trains running, when you turn it back on again the trains will stop because they respond to the reset packet.

 

It is quite a small issue, but if the Z21 sends a reset packet it should also reset its internal state to match. There are a lot of decoders that ignore the reset packet, and if you have some of these you will not see the effect.

 

The Signalist SC1 decoder allows you to set a default state so you know what state your signals will be when your system is reset. A simple power down will not reset the signals - they will come back on in the state they were left in so that a simple glitch will not upset anything.

 

MY Z21 doesn't reset anything on startup and all signals, turnouts, and lighting remains in exactly the same state as when the Z21 was switched off.  The Z21 App also holds the state of all signals and accessories when the power is regained.

 

 

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2 hours ago, WIMorrison said:

 

MY Z21 doesn't reset anything on startup and all signals, turnouts, and lighting remains in exactly the same state as when the Z21 was switched off.  The Z21 App also holds the state of all signals and accessories when the power is regained.

 

 

If I set a train moving with the Maus, switch the Maus off, then switch the Z21 off, when I switch the Z21 back on nothing moves, if I then switch the Maus on, still nothing moves until I operate the throttle on the Maus. (this is outside of TrainController)

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Keith

 

i was only addressing accessories as that is where the discussion started, however when I switch on nothing moves as I have the Z21 set to Track Off when switched on.

 

I have confirmed that all signals and accessories remain in the same state as when they were switched off by literally pulling the plug on the Z21 and then replugging to restore power - even this drastic action does not reset an accessories on the layout or in the Z21 application on the iPhone.

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Hi,

 

I have a wild hypothesis. Could this behaviour be related to how the STOP button is configured. i.e. whether it turns off track power or sends an emergency stop?

 

Regards,

 

John P

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John

 

because I can 😂, I just tested your hypothesis and it makes no difference.


With the layout powered up if the plug is pulled when I switch it back on all accessories remain in exactly the same state as before the ply was pulled.

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Posted (edited)
23 minutes ago, WIMorrison said:

Keith

 

i was only addressing accessories as that is where the discussion started, however when I switch on nothing moves as I have the Z21 set to Track Off when switched on.

 

I have confirmed that all signals and accessories remain in the same state as when they were switched off by literally pulling the plug on the Z21 and then replugging to restore power - even this drastic action does not reset an accessories on the layout or in the Z21 application on the iPhone.

I can't do that as my (so far only) signal resets anyway if you remove the DCC signal.

 

Edit

I have some points using MP1 motors driven by an Arduino decoder and can confirm that powering the Z21 off/on does not change the state of the points.

Edited by melmerby
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