‘DC’ ‘DCC’ ‘BluetoothDCC’

[Foden 4400]

DC = Direct Current

DCC = Digital Command & Control

Does Hornby have an acronym for :-

‘Bluetooth Control’

Besides calling it ‘HM7000’ ?

[96RAF]

BLE - Bluetooth low energy.

Bluetooth is not DCC.

DCC is an NMRA formatted command signal through the rails to the decoder by way of a modified AC type square waveform.

BLE requires the decoder to be kept live by way of a threshold voltage (DCC or DC) on the rails, but the command signals are sent over the air (OTA) in their own code.

The 7000 series decoders can operate in either mode but not simultaneously in both modes at once.

[Foden 4400]

BLE - Bluetooth low energy.

 

 

Thanks 96RAF - it deserves its own acronym

 

 

It’s a Hornby ‘Game-changer’

No ‘Programming Tracks’ or ‘Busbars & Droppers’ required when you run

BLE

[Fishmanoz]

You still need power to the track so a bus and droppers is still the best way to achieve that.

If you rely only on a single connection and DCC point clips, you still have the current limitations caused by fishplate connections becoming loose or corroded meaning higher resistances that will limit current to some areas of your track. Similar limitations apply to point clips asked to carry higher current.

You can certainly start out single connection and see how you go. It may work forever but then again it may not. It would be prudent to allow for retrofitting a bus.

I am starting anew with TT:120 and will have only HM7000 loco decoders on my layout but anticipate having non-BT point decoders. I will start with a bus.

[Foden 4400]

You still need power to the track so a bus and droppers is still the best way to achieve that.

If you rely only on a single connection and DCC point clips, you still have the current limitations caused by fishplate connections becoming loose or corroded meaning higher resistances that will limit current to some areas of your track. Similar limitations apply to point clips asked to carry higher current.

You can certainly start out single connection and see how you go. It may work forever but then again it may not. It would be prudent to allow for retrofitting a bus.

I am starting anew with TT:120 and will have only HM7000 loco decoders on my layout but anticipate having non-BT point decoders. I will start with a bus.

 

 

Going to see how I go on - I only have a single oval & 7 point station yard feed by 2 feeds from a HM600O plus an addition feed for a kick back siding, points controlled HM6010, I have used PECO track so I don’t know if points clips will work with them ?

 

 

I wonder if BLE will lead to battery powered locos? - no track power needed ….

[Brew Man]

Yes, point clips work fine with Peco points, provided they are insulfrog type, but as Fishy says, it would still be advisable to wire in a bus with droppers.

[96RAF]

As long as you provide enough voltage to keep the decoder alive you can power it anyway you like. It could be dead rail with on-board battery power. Same thing goes if you wanted to power a trackside accessory under bluetooth control from the app like a fairground ride, windmill, water pump, etc.

[Rallymatt]

Battery powered locos are in development with a few manufacturers I understand. If they ever become viable or even worthwhile is another thing!

I would certainly agree with Brew Man and Fishy to improve reliability with a bus and dropper set up. There are plenty on DC that do this too and by the same token DCC will ‘work’ without clips etc but not as intended

[Foden 4400]

Battery powered locos are in development with a few manufacturers I understand. If they ever become viable or even worthwhile is another thing!

I would certainly agree with Brew Man and Fishy to improve reliability with a bus and dropper set up. There are plenty on DC that do this too and by the same token DCC will ‘work’ without clips etc but not as intended

 

 

Thanks for the information all very useful.

I wrongly thought that DDC required numerous track feeds to ensure a good command signal through the rails to the decoder by way of a modified AC type square waveform, I did not know it was done to eliminate the voltage or current drop through fish plates etc. to enable the loco motor to turn properly.

 

 

I was hoping that BLE and a ‘stay alive’ with a couple of track feeds through my HM6000 would be fine.

 

 

[96RAF]

You are correct in thinking that multiple feeds such as a power bus and dropper arrangement are preferred for DCC (Digital Command Control) through the rails.

BLE however sends the commands over the air (or you can drive it by DCC if you have a controller). As I said in radio mode the decoder simply has to be powered up by any means. In order to work.

Your HM6000 module can provide this power but only at 12V and the associated P9100 PSU will only drive a couple of trains. If you want reliable sound then you have to fiddle with the 6000 PWM frequency settings or simply take it out of the loop and use the PSU direct to the rails at 15v.

[Foden 4400]

You are correct in thinking that multiple feeds such as a power bus and dropper arrangement are preferred for DCC (Digital Command Control) through the rails.

BLE however sends the commands over the air (or you can drive it by DCC if you have a controller). As I said in radio mode the decoder simply has to be powered up by any means. In order to work.

Your HM6000 module can provide this power but only at 12V and the associated P9100 PSU will only drive a couple of trains. If you want reliable sound then you have to fiddle with the 6000 PWM frequency settings or simply take it out of the loop and use the PSU direct to the rails at 15v.

 

 

I am getting just over 14v across the rails while a loco is running at full speed with a reasonable long train behind it. I would rather leave my HM6000 powered up as this will link in with the Bluetooth Mesh System, this will help stabilise the link between my Bluetooth iPad & the BLE decoders on the locos. I have thought about getting a 15V 4 amp PSU from Hornby and using this to power the track directly and leaving my existing P9100 PSU Powering the HM6000 to help the mesh.

 

 

This is all new to me but I am enjoying gathering all this information prior to getting HM7000 app & decoders

I failed with Zero1 many years ago, it turned me away from the hobby - I am determined to get my HM7000 perfect.

[Fishmanoz]

I may be wrong but I suspect you still have a little to learn about track power and DCC and I’ll try to explain simply.

With conventional DCC, the controller puts full power to the track all the time - bipolar signal at full volts and current (a bit like AC v DC but the signal is a square wave, not sinusoidal and much, much higher frequency than AC in your house)

To control the locos, DCC signals are included in that bipolar signal, done by making those square pulses longer or shorter to represent 0s and 1s in a digital signal. The important thing is the DCC power and DCC signals to the locos are all in the one, they are not separate.

Then when making sure you don’t degrade that DCC, the best practice (but not the only practice) is to use a bus and droppers. With this system, you have 2 objectives:

• getting full power everywhere by not having any high resistance paths (via joiners and point clips)
• getting a clean, undistorted DCC signal to the locos wherever they are on the layout

With HM7000, the power system is a little simpler. Yes, you have to get power to all parts of the layout but the DCC signal goes to HM7000 decoders in the locos via the App and BLE, not via the track. Consequently, you can be a little less rigorous about power distribution as you are not worrying about the DCC signal.

One final point - in locos with all types of decoders, the motors are not connected directly to the track, they are powered via the decoder output. Only the decoders are connected to track power via the loco pickups.

[Foden 4400]

I may be wrong but I suspect you still have a little to learn about track power and DCC and I’ll try to explain simply.

With conventional DCC, the controller puts full power to the track all the time - bipolar signal at full volts and current (a bit like AC v DC but the signal is a square wave, not sinusoidal and much, much higher frequency than AC in your house)

To control the locos, DCC signals are included in that bipolar signal, done by making those square pulses longer or shorter to represent 0s and 1s in a digital signal. The important thing is the DCC power and DCC signals to the locos are all in the one, they are not separate.

Then when making sure you don’t degrade that DCC, the best practice (but not the only practice) is to use a bus and droppers. With this system, you have 2 objectives:

• getting full power everywhere by not having any high resistance paths (via joiners and point clips)
• getting a clean, undistorted DCC signal to the locos wherever they are on the layout

With HM7000, the power system is a little simpler. Yes, you have to get power to all parts of the layout but the DCC signal goes to HM7000 decoders in the locos via the App and BLE, not via the track. Consequently, you can be a little less rigorous about power distribution as you are not worrying about the DCC signal.

One final point - in locos with all types of decoders, the motorS are not connected directly to the track, they are powered via the decoder output. Only the decoders are connected to track power via the loco pickups.

 

 

Thanks for the info.

 

 

I do know the difference between the difference between DC DCC HM6000 & HM7000 control & how a Loco is controlled by each system. I have had the first 2 previously am currently running HM6000 and have HM7000 decoders on order and I have even had a 5th Zero 1 which you may not of heard of but it was very early form of DDC run at 18 volts DC. There was no plugs or sockets with Zero1 you had to solder the decoders wires to wheel pick ups & motor feeds, have done this quite a few times.

My layout is on a 3 1/2 by 5 feet. The single oval which works fine with with one feed using HM6000 and I know it will work just as fine with HM7000 (with full power to the track & loco motor control via decoder and Bluetooth single)

 

 

I know to get the best out of HM7000 I will have to make my sidings permanently live.

 

 

What I don’t know is why a Bluetooth decoder with sound behaves differently with the different PWM & which PWM gives the best sound quality?

 

 

I know why a motor operates differently with the same voltage but at different PWM’s

HM6000 enables you to set the PWM at various levels between 61.27Hz & 7811.92Hz

 

 

If you connect the PSU directly to the track you won’t be able to alter the PWM does this matter in respect to sound quality?

 

 

Thanks

[Fishmanoz]

PWMed signals interfere with HM7000 sound, hence the reason for connecting PSUs directly to the track so there is no PWM.

PWM adjustment on an HM6000 has been mentioned many times in this forum and, if I remember correctly, setting it to 100Hz minimises the problem.

[96RAF]

If you put a DCC fitted loco on your HM8K track and run it around, then alter the PWM frequency you will be able to see and hear the difference in control. Add sound into the mix and it all starts to go a bit awry. Experience has shown that low frequency is bad for the sound decoder quality but higher frequencies are tolerated better, hence why HM6000 is one of the few DC controllers suitable for use with the HM7K system.

[Foden 4400]

If you put a DCC fitted loco on your HM8K track and run it around, then alter the PWM frequency you will be able to see and hear the difference in control. Add sound into the mix and it all starts to go a bit awry. Experience has shown that low frequency is bad for the sound decoder quality but higher frequencies are tolerated better, hence why HM6000 is one of the few DC controllers suitable for use with the HM7K system.

 

 

Thanks RAF96 I have noticed that the PWM settings were modified on my HM6K on a software update. As you have HM7K you will know with authority that higher frequency are tolerated better. Hopefully I will find out for myself this month.

[96RAF]

I haven’t used HM6000 to power a recent HM7K decoder track but I did play with the PWM frequencies using a very early days Alpha decoder specimen which was a real knife and fork device. Big Green thing at right hand end of the loco. Same effect though, it stuttered and control was poor at one end and much better at the other end and that was apart from the motor noise variation when you tweak the frequency around.