Railcom and bus supressors/terminators

[Kaput]

I have a Z21 and before getting it I had the DCC concepts bus suppressors fitted to the ends of my main bus wire https://www.dccconcepts.com/product/new-bus-suppressors-terminators-2-pack/

 

I can't seem to get Railcom on the Z21 to work (the Z21 won't read any CV's at all on the main and even on program track mode it doesn't read properly) with the suppressors installed so I removed them.

However since removing them I've managed to end up with a total of 3 new models develop an issue with the motor randomly speeding up/slowing down (2 Accurascale 37s and now a KR GT3).

It could just be bad luck but I'm getting a little paranoid.

 

Questions:

Could the Z21 be buggering up motors without the suppressors fitted to the bus?

Can railcom be made to work with these suppressors fitted?

Do the suppressors even do anything useful?

 

 

I am thinking of rewiring the layout (its only a 6x4 board so nothing major) since a number of my droppers use little spring loaded connectors to extend the wires to reach the bus and I'm honestly wondering if the wiring just isn't good enough to handle the Z21's power output (old controller was a PowerCab so much lower power).

[WIMorrison]

Whilst the DCC Concepts suppressors are significantly overpriced for something that costs pennies they will not affect Railcom, and neither will the cheap, self installed items.

 

The Z21 Railcom works perfectly assuming that you have;

 

a) switched on Railcom in the Z21

b) decoders that support Railcom

c) you have set the decoder to respond to Railcom CV29 bit 3 needs to be set on (8), and also at least bit 0 in CV28 needs to be set to on (1), ideally you should set bit 1 on (2) making CV28=3 (in decimal).

 

The power makes no difference, but poor wiring will impact the performance of everything.

[RAF96]

B) is very important. If the decoder does not support Railcom you can whistle until you are blue in the face and still not read back from the main.

[Kaput]

Railcom works perfectly fine when the suppressors are removed from the bus. The only oddity there is it seems to have a limit of 2 or 3 locos with decoders on the track at once or it stops being able to read via Railcom. It also works fine when hooked up to my N gauge board which uses Kato Unitrack so doesn't technically have a bus, just a few daisy chained Kato 3 way adaptors.

 

90% of my decoders are Zimo or ESU so they support Railcom perfectly. Only a handful of locos (and Caroline) use anything else.

[WIMorrison]

I have 40 odd locos on my tracks and I built my own suppressors that cost me around 10p - incidentally installed on the advice of DCC Concepts because their Cobalt IP Digital motors kept losing their addresses, there was no difference after fitting them and I simply haven’t bothered to remove them - but I have changed a lot of the Cobalt IP Digital for more reliable motors ;)

 

Railcom works perfectly using a Z21 irrespective of how many locos are on the track at the time.

[jpendle]

9 minutes ago, Kaput said:

The only oddity there is it seems to have a limit of 2 or 3 locos with decoders on the track at once or it stops being able to read via Railcom.

Hi,

 

I have seen very similar issues when using the Z21 with multiple locos on the track, and I have been round the houses about this with Iain @WIMorrison  😀

 

I couldn't get Railcom to work with more than 4 or 5 locos on my layout. FWIW my layout is N gauge rather than OO.

I then started to automate the layout, so now I have 20 or 30 isolated sections each with their own Railcom feedback from a Roco 10808 occupancy detector unit.

 

Railcom now works exactly as it should on al the isolated sections but it still doesn't work on the bits of my storage yards that don't yet have feedback detectors added to them.

 

I'm hoping that as I add feedback to more and more of the layout I'll be able to work out why I had the initial problems.

 

One hypothesis is a rogue decoder, or maybe there really is a "Railcom" limit.

 

Regards,

 

John P

[DaveArkley]

10 minutes ago, jpendle said:

Railcom now works exactly as it should on al the isolated sections but it still doesn't work on the bits of my storage yards that don't yet have feedback detectors added to them.

If you have no detectors there how do you expect it to detect?

[WIMorrison]

43 minutes ago, Kaput said:

Railcom works perfectly fine when the suppressors are removed from the bus.

 

How do you know that Railcom doesn't work? How are you confirming that Railcom works?

[Kaput]

4 minutes ago, WIMorrison said:

 

How do you know that Railcom doesn't work? How are you confirming that Railcom works?

 

Use Z21 app.

CV Programming

Loco (POM)

Pick a Zimo decoder loco and let it read the driving data (address, accel/decel etc)

Or Manual > Program on Main > Enter address of loco > read a CV

 

Without the suppressors in place the above works perfectly fine (as long as not more than 2 or 3 locos on track and correct type of decoder) and the CV's are read as expected.

 

With the suppressors in place the above just results in the app reporting "no loco at this address" or similar.

 

 

Did a quick test with the track plugged into the program track output and with the suppressors in place even programming track reading doesn't work correctly, the values it gives for trying to read CV's are basically random. Try it with a completely separate programming track and it reads fine.

[WIMorrison]

It does sound like the DCC Concepts suppressors are causing an issue - perhaps a reason to avoid 😉

 

If you really want them then a 150Ω 5w resistor with a 0.1µF capacitor in series across the bus. That's what I use with no issues, but personally with a 6 x 4 layout I don't think that you need them anyway.

[RFS]

I too have a Z21 with about 80 locos on the track - 70 with Lenz decoders and 10 Zimo. Not had any problems reading or writing to any of them regardless of where they are on the track. I don't have Railcom-enabled detectors (I use Digikeijs DR4088RBs) and just use the built-in Global Railcom Detector. Reading and writing is done purely from the Z21 Maintenance tool on the PC as I don't use the wifi option. I have a Lenz LH101 throttle for manual use.

 

Do you have any devices that don't support Railcom connected to the bus? I use NCE Switch-8 accessory decoders for my Tortoise point motors and these do not work properly if Railcom is enabled. So all my accessories are on the Z21's internal booster with Railcom disabled, and a twin booster is used for the trains with Railcom enabled. 

 

EDIT: I have spent a few pennies on self-built suppressors as per Brian Lambert's web-site.  These don't seem to make any difference....

Edited October 2, 2023 by RFS

[Kaput]

Nothing else connected to bus. I only have 4 point motors on the entire board (Peco surface mounts) running off a separate DC supply with nothing fancy (no polarity switching etc).

[jpendle]

6 hours ago, DaveArkley said:

If you have no detectors there how do you expect it to detect?

Because the Z21 itself acts as a Railcom detector. With just one or two locos in the part of the storage yards that doesn’t have dedicated feedback I can still use Railcom to readback CVs using POM.

If I put 6 or 7 locos there then Railcom stops working, i.e. if I try to read from a loco it says no loco found at that address.

 

Regards,

 

 John P

[peterm1]

7 hours ago, WIMorrison said:

I have 40 odd locos on my tracks and I built my own suppressors that cost me around 10p - incidentally installed on the advice of DCC Concepts because their Cobalt IP Digital motors kept losing their addresses, there was no difference after fitting them and I simply haven’t bothered to remove them - but I have changed a lot of the Cobalt IP Digital for more reliable motors ;)

 

Railcom works perfectly using a Z21 irrespective of how many locos are on the track at the time.

I bought a batch of the first DCC Concepts motors and had nothing but trouble. In the end I ditched them and bought Tortoise. 20 plus years and with 30 odd motors, I've had one small problem which I fixed myself after contacting the manufacturer and bing told that I won't invalidate the warranty.

 

Sorry. Back on thread. :-)

[DaveArkley]

16 hours ago, jpendle said:

Because the Z21 itself acts as a Railcom detector. With just one or two locos in the part of the storage yards that doesn’t have dedicated feedback I can still use Railcom to readback CVs using POM.

If I put 6 or 7 locos there then Railcom stops working, i.e. if I try to read from a loco it says no loco found at that address.

 

Regards,

 

 John P

Ah, so effectively, all on one detector. Is it simply that the Railcom window isn't long enough to receive 6 or 7 feedback messages?

 

Cheers

Dave

[jpendle]

1 hour ago, DaveArkley said:

Ah, so effectively, all on one detector. Is it simply that the Railcom window isn't long enough to receive 6 or 7 feedback messages?

 

Cheers

Dave

That may well be the case.

 

Regards,

 

John P

[WIMorrison]

The Railcom Monitor on my Z21 doesnt seem to suffer from any liitations

 

 

haven't counted how many are on the screen, but definitely more than 4 😂

[DaveArkley]

11 minutes ago, WIMorrison said:

The Railcom Monitor on my Z21 doesnt seem to suffer from any liitations

 

 

haven't counted how many are on the screen, but definitely more than 4 😂

How many local detectors were involved there or is that all on the Z21 itself?

[WIMorrison]

That is from the Z21 - using the Z21 Maintenance tool

Edited October 3, 2023 by WIMorrison

[DaveArkley]

7 minutes ago, WIMorrison said:

That is from the Z21 - using the Z21 Maintenance tool

Understood, but is that Railcom detected by other modules (Digikeijs, Yamorc, Roco or similaf) an then transmitted over Loconet, R-bus etc. What I'm trying to understand is how many decoders per detector are being detected on average. 

[WIMorrison]

This screen came from the layout with nothing running, and LocoNet DISCONNECTED.

 

The only way for the Z21 to read the Railcom is via DCC as Roco do not recognise the ability of LocoNet to carry Railcom data, and as the only Global Detector I am using in the Z21 it has to be collected there. The DR5088RC that I have do not function without LocoNet connected and no feedback is returned to anywhere. Previously I use3d a totally separate Loconet that was connected to the PC via USB, ergo again no way that the Z21 could read any Railcom data other than through the DCC rails.

[DaveArkley]

20 minutes ago, WIMorrison said:

This screen came from the layout with nothing running, and LocoNet DISCONNECTED.

 

The only way for the Z21 to read the Railcom is via DCC as Roco do not recognise the ability of LocoNet to carry Railcom data, and as the only Global Detector I am using in the Z21 it has to be collected there. The DR5088RC that I have do not function without LocoNet connected and no feedback is returned to anywhere. Previously I use3d a totally separate Loconet that was connected to the PC via USB, ergo again no way that the Z21 could read any Railcom data other than through the DCC rails.

Thanks for clarifying

 

Cheers

Dave

[Kaput]

Done some random testing with my N gauge board (its a lot easier to get out) and so far I'm at 5 decoders on the track (3 Zimo, 1 ESU, 1 LaisDCC) and Railcom is working normally.