First TT120 layout

[96RAF]

1 hour ago, Paul-355679 said:

Are these HM7000 Bluetooth control compatible?

The device is to automatically control DCC track potential phasing. It has no bluetooth functionality. See the manual - 

It is a simple 2-wire input from the track and a 2-wire output to the loop. It is for DCC and if you are powering your TT:120 layout direct from a PSU not a DCC controller, then this is the wrong solution for a reverse loop.

 

 

 

[Fishmanoz]

RLMs work themselves, switching phase when out of phase is sensed.

The question for HM7000 is whether they will operate on polarity with a DC supply (if you are powering HM7000 with DC rather than DCC), something that’s uncommon but said to work with the foreshadowed Hornby RLM.

[Mac202]

1 hour ago, 96RAF said:

The device is to automatically control DCC track potential phasing. It has no bluetooth functionality. See the manual - 

It is a simple 2-wire input from the track and a 2-wire output to the loop. It is for DCC and if you are powering your TT:120 layout direct from a PSU not a DCC controller, then this is the wrong solution for a reverse loop.

 

 

 

So if I was powering my track from an Elite I could still control the locos using MH7000 ?

[Rallymatt]

A RLM runs autonomously so there is no need for a BT element. The ‘reverse loop’ is isolated from the main track power feed. It gets its feed from the RLM. Power to the RLM is from the main track power/Power Bus. When the live wheels of the loco first bridge the isolated section the RLM will detect if the polarity in the isolated section matches from where the loco has come from and if not switch it in fractions of a second. On leaving the isolated section it does the same thing but now matches the polarity of the isolated section to where the logo is going to.
This is why it is important that the isolated section will accommodate the entire length of the train. If the trailing end is drawing no power, ie no lighting or sound decoder and the wheel sets are fully isolated you can get away with it being longer but you must check carefully and this is why the general advice is ‘full train length must be within the isolated section’ or you will have short circuits. 
How fast the polarity correction works depends on the RLM. Over years I have had a few and some really are quite awful. Bachmann one is slow and dimwitted and best avoided. Ones from people like Lenz , Tam Valley Depot etc are solid state rather than relay controlled and are lightning fast. One consideration that is more important now as increased functions are common, is the current rating of the RLM. Many are 1a which seems enough until you consider double heading (2 locos, 2 lots of current draw) or much more common, multiple decoders, eg HST, motor and sound decoder up front and sound decoder in the dummy power car. Things like the FLiRT in OO will have 3 decoders. Coaches with lighting that have decoder control (Arnold double decker coaches etc). 1amp is no longer enough, you can experience drop out or reduced power through the isolated section. I replaced the Lenz RLM on High Fell with a Tam Valley ‘Frog Juicer’ to combat this. It can be a frog polarity device or a RLM and you can set the current to different levels. 
Once you have set up you RLM it will just do its thing and you don’t need to worry about anything. 
 

Edited Sunday at 10:31 by Rallymatt

[Paul-355679]

2 hours ago, 96RAF said:

The device is to automatically control DCC track potential phasing. It has no bluetooth functionality. See the manual - 

It is a simple 2-wire input from the track and a 2-wire output to the loop. It is for DCC and if you are powering your TT:120 layout direct from a PSU not a DCC controller, then this is the wrong solution for a reverse loop.

 

 

 

As the  Bluetooth HM7000 just connects with the loco decoders for traction presumably just additional power supply to the loop with this auto reverser will work?

[Rallymatt]

HM 7000 decoders are DCC, so they will work on any traditional NMRA standard DCC system. They also have an added feature of BT communication meaning the track can be alternatively powered by a DC supply as the BT part sends the control data over the air rather than down the rails in a DCC power supply (AC) 

DCC RLMs currently available will NOT work with DC track power. The forthcoming HM 7000 RLM will work with both DC and DCC track power. 

 

[Paul-355679]

7 minutes ago, Rallymatt said:

A RLM runs autonomously so there is no need for a BT element. The ‘reverse loop’ is isolated from the main track power feed. It gets its feed from the RLM. Power to the RLM is from the main track power/Power Bus. When the live wheels of the loco first bridge the isolated section the RLM will detect if the polarity in the isolated section matches from where the loco has come from and if not switch it in fractions of a second. On leaving the isolated section it does the same thing but now matches the polarity of the isolated section to where the logo is going to.
This is why it is important that the isolated section will accommodate the entire length of the train. If the trailing end is drawing no power, ie no lighting or sound decoder and the wheel sets are fully isolated you can get away with it being longer but you must check carefully and this is why the general advice is ‘full train length must be within the isolated section’ or you will have short circuits. 
How fast the polarity correction works depends on the RLM. Over years I have had a few and some really are quite awful. Bachmann one is slow and dimwitted and best avoided. Ones from people like Lenz , Tam Valley Depot etc are solid state rather than relay controlled and are lighting fast. One consideration that is more important now as increased functions are common, is the current rating of the RLM. Many are 1a which seems enough until you consider double heading (2 locos, 2 lots of current draw) or much more common, multiple decoders, eg HST, motor and sound decoder up front and sound decoder in the dummy power car. Things like the FLiRT in OO will have 3 decoders. Coaches with lighting that have decoder control (Arnold double decker coaches etc). 1amp is no longer enough, you can experience drop out or reduced power through the isolated section. I replaced the Lenz RLM on High Fell with a Tam Valley ‘Frog Juicer’ to combat this. It can be a frog polarity device or a RLM and you can set the current to different levels. 
Once you have set up you RLM it will just do its thing and you don’t need to worry about anything. 
 

Presumably I don’t have to wait for the Hornby tt120 RLM then which is not available atm - at about £32

[Rallymatt]

Provided you have a traditional DCC power feed, no. If you are using DC track power then it’s make your own or wait for the Hornby unit. 

[Paul-355679]

1 minute ago, Rallymatt said:

Provided you have a traditional DCC power feed, no. If you are using DC track power then it’s make your own or wait for the Hornby unit. 

Hi

I’m a bit of a novice re track power. I just have the mainline powered by the Hornby “train set” power rail and as I have two of these (from two sets) I was going to use the other one to power the reverse loop?

[Rallymatt]

This will not work. The PSU (power supply unit) in the sets is DC. Only use one PSU. 
Now you understand the PSU you have is DC, re read the advice previously given and hopefully you will better understand what you can and can’t mix. 
I would strongly recommend reading the guides on track power  in the HM 7000/DCC section. It’s not difficult but it is important to understand so you have a reliable layout. 

Edited Sunday at 10:50 by Rallymatt

[96RAF]

10 hours ago, Mac202 said:

So if I was powering my track from an Elite I could still control the locos using MH7000 ?

Yes.
Note that HM7K is the decoder series and HM | DCC is the app control.

[ukpetey]

I’m sorry to have to press this point further, but talk of DC, AC, DCC reminds me of a rock band, but doesn’t help me understand what I’ll need to get this to work with my layout. I’m thinking I will have to wait for the Hornby solution but I’m not anywhere near 100% about that! 

I use the Hornby DCC app as controller, and my track is powered via the power kit included with the DCC Easterner Train set, as pictured below. 

Would one of you knowledgeable types please advise me 

[Rallymatt]

The PSU included in the trainsets is DC. No control data is sent down the rails. It is sent over the air via a BT signal. Only the HM DCC app and HM 7000 decoders will work together in this set up. 
Traditional DCC uses a form of AC track power to transmit the control data down the rails to the decoder. An HM 7000 decoder can also work with this system, any NMRA compliant controller, like Select, Elite, Dynamis, Powercab etc is suitable. 
HM DCC is the free app that can be used to control locos, the type of power sent down the rails doesn’t matter, it can be DC or DCC (AC) and you can switch between App and DCC control at the tap of an icon on the App. 
The type of power being used is important to know as accessories and devices specifically designed for a DCC power feed will not work with a DC power feed and vice versa. 

Just to add, our model locos are described as DC, the motor is a 12v DC motor. Irrespective of what type of current is sent down the rails of the track, the decoder will ensure the motor only sees DC current regardless of what system you adopt. 

Edited Sunday at 12:34 by Rallymatt
Extra info

[LTSR_NSE]

There are existing RLMs that work on both DCC & DC.  One is mentioned by @Brew Man on other threads discussing RLMs.

”The REV2 Auto-reverser from Block Signalling works on DC and DCC

https://blocksignalling.co.uk/DC-Products/REV2”

[Paul-355679]

46 minutes ago, ukpetey said:

I’m sorry to have to press this point further, but talk of DC, AC, DCC reminds me of a rock band, but doesn’t help me understand what I’ll need to get this to work with my layout. I’m thinking I will have to wait for the Hornby solution but I’m not anywhere near 100% about that! 

I use the Hornby DCC app as controller, and my track is powered via the power kit included with the DCC Easterner Train set, as pictured below. 

Would one of you knowledgeable types please advise me 

Agree. This is the only power feed I have too.Hornby doesn’t supply a conventional controller any more  with dcc train sets - presumably because they think most will use HM7000 Bluetooth control of a loco.

[dBerriff]

They don’t have one to supply at anything like a sensible cost. A technically updated Select does not exist. 

Edited Sunday at 13:16 by dBerriff

[Rallymatt]

The ‘Digital’ sets are sold complete to run via the HM DCC App with a DC PSU, it’s not a ‘DCC’ set. Hornby don’t do a Select/Elite set. Note Select is now discontinued. 
Sets are always entry level to get people going, particularly with power and control systems. 
@LTSR_NSE, apologies for not mentioning that one, I don’t think the same unit will run DC or DCC, it has to be specific. I tried 2 for DCC and I know of one layout that tried the DC version and results were not good. I’m not sure if things have been updated since. 

[LTSR_NSE]

@Rallymatt if you look at the instructions:

https://blocksignalling.co.uk/pdfs/113GF3K.pdf

It is the same module for both - but wiring is different.  On DCC the polarity of loop is swapped/reversed - whereas on DC the polarity of entry/exit ‘main’ track is swapped/reversed.

[96RAF]

Just to clarify the HM7K system. All the 7K series bluetooth decoder needs to work from the app is power, which can be DC or DCC. It simply has to be kept alive. Your train-set power supply and adapter harness is doing that - providing DC to the rails.

The app as explained provides control commands over the air. DCC control as also explained is a special format signal via the rails.

[Fishmanoz]

Clarification of a few items in this topic, and some comment on the Autoreverser linked to by LT a couple of posts above:

• RLMs do not change the polarity (or the phase) of RLs, the change the isolated section within the RL
• For DC, the polarity needs to be changed (swap the positive and negative rails)
• For DCC, which is correctly speaking a bipolar square wave, not AC (sinusoidal wave), it is the phase which needs to be changed (by 180 degrees) to match, not polarity
• The Autoreverser is not a conventional RLM, it is a more specialized product.  It powers both the main track and the isolated section.  It also switches the points on a teardrop RL.  And it senses when to do so with IR sensors in the track to detect the train entering and leaving the RL, not when the loco wheels bridge the isolating fishplates at each end of the isolated section.  Given it switches using relays, the advance warnings from the IR sensors mean the relatively slow relay switching (versus faster solid state switching) is not an issue.  At least that’s my interpretation of the quite good info in the link.

[Rallymatt]

Great clarification Fishy👍, sometimes trying to simplify the concept can in itself complicate things 🤣 and best we don’t mention Märklin HO stuff that genuinely is AC…. 😳

[ukpetey]

Thanks for all the responses. I’m still unsure if it’ll work for me or not! I’ll get my coat! 

[StuLarge]

I can honestly say I understand more and have a lot to learn after reading this thread. Suffice to say I now understand my current set up to be DC 7k Bluetooth (DCBT to invent another acronym)... Not DCC!

[Fishmanoz]

Just a couple of first principles to remember here:

• HM7000 decoders can be operated as DCC decoders, just like any other DCC decoder, or they can be operated by the HM | DCC app over the air (OTA) via Bluetooth (BT)
• To power an HM7000 decoder in a loco on a track, you can use either a (recommended) DC PSU or a conventional DCC controller, either of which delivers full power to the track at all times.
• Even if you intend to always operate your HM7000 decoders via a DCC controller, it is almost essential that you first set them up using the HM | DCC app to ensure you have the correct sound profile installed at its latest version, and to install upgrades from time to time
• Non-HM7000 decoders can be operated via the app using the Hornby dongle connected to a compatible (read mostly Hornby) DCC controller (Elite or Select)
• HM7000 decoders have ABC braking functionality
• If your layout includes an RL, you will need an RLM to control an isolated section established in the RL to avoid short circuits.  Which RLM you use will depend in part on whether you are powering your layout with a DC PSU or a DCC controller

[Fishmanoz]

Petey, back on page 1 you inquired about ABC braking and I thought that was answered?

If you still have unanswered questions about operating your layout with HM7000-equipped locos, might I suggest you raise new topics to seek the answers.