To DCC or not?

[Butler Henderson]

8 minutes ago, Junctionmad said:

Seriously mate , it’s a connector with wires , it’s not magic , meter out every wire in the socket , then meter out the blanking  plug 

 

the fault will be a Homer Simpson moment 

Helps to have a multimeter that squeals when it has nil resistance across it, that's how I found the fault on my Std 4 Mogul tapping the contacts on the 8 pin socket.

[Junctionmad]

23 hours ago, Ravenser said:

 

 

I have some experience of using a MERG accessory decoder. It was cheap (about £2.50 per output) and I built it myself , a source of pride...

 

But the thing was horribly vulnerable to any short. Eventually I got tired of rebooting the entire layout every time we had a short, ripped it out and replaced with a DS64 decoder, which was 6x the price , entirely reliable and zero hassle. It was worth paying an extra £50 to be rid of the inconvenience.

 

Now I failed to implement best practice - the point decoders are on the same single circuit as the track bus , whereas really they should have been completely separate , with the point data feeds from a separate DCC bus protected by a circuit breaker

 

There are some advantages to the MERG units. They are cheap, they draw the oomph from a separate 16V AC supply (only the data signal is off the DCC bus) ans so don't overload the DCC system, they can be readily configured during building to support LED lights (output by output .. not a whole block) . But reliability was an issue

As a MERG member and designer of  CBUS modules etc. , I must in all fairness defend the society 

 

MERG has years of projects of various stages of technical sophistication. It’s biggest project is the CBUS layout control bus , where a plethora of input , output , signal , point and occupancy solutions are available , many the result of private work by members for their own layout. 

 

The system works , today , largely on 12vDC supplies. 

 

MERG also has its own CBUS compatible DCC system , involving a command station , booster and a handset , also modules are a available to interconnect smartphones , computers , raspberry Pis etc. Jmri is fully compatible with CBUS and work continues in enhancing the JMRI CBUS interaction . In addition , members have contributed a huge variety of software for layout automation. Virtual mimic panels etc.  the aforementioned accessory decoder is one of these ( albeit DCC decoder modules in MERG are somewhat of an afterthought ) 

 

taken as a whole , it’s easily and by far the biggest single range of layout technology from any one source on the planet. each day members enhance the offerings. The dramatic growth of the society over the last few years and the extraodinary growth in kit sales is testimount to that. 

 

HOWEVER , it’s not and.was never designed to be an “ out of the box”  solution , to get the measure of it , requires a reasonable understanding of electronics ( at a typical hobbyist level ) ability to decipher schematics and undetstand the limitations of a given implementation 

 

the worst experiences are from members , who simply view it as a cheap source of layout electronics “ , invest no time in understanding the modules and their needs and find the whole process frustrating. MERG is a sub hobby , and these issues are like an RTR person approaching etch brass for the first time. 

 

For those that do want to invest some time in understanding the various MERG solutions , the result is very rewarding , woth the ability to implement state of the art solutions at very low cost. 

 

Our club O gauge layout is completely controlled , other then traction , by the MERG CBUS system and demonstrates faultless operation with minimal wiring. It now has over 50 cbus modules and close to 400 IO endpoints and we are far from finished ! 

Edited February 24, 2019 by Junctionmad

[Junctionmad]

Quote

 

By the way I don't understand the concept of a "DCC ready point motor". As far as I'm concerned a Tortoise is a Tortoise is a Tortoise and the price is the same - I don't use overpriced special Wabbits - I plug 2 wires into the appropriate sockets on the decoder.

 

Maybe , cause tortoise haven’t moved with the times 

 

cobalts are available with integrated DCC accesory decoders , hence the point motor can be connected to the DCC track for power and immediately operated from the DCC control unit. , cuts down on external accesory decoders , track supply components and all interconnection wiring , some people clearly like the concept. 

 

Hence the moniker “ DCC ready “ 

 

There is also a continental track company , which integrates a DCC controlled point motor into the point. For example 

 

what’s so difficult to understand here 

Edited February 24, 2019 by Junctionmad

[Andymsa]

9 minutes ago, Junctionmad said:

 

Maybe , cause tortoise haven’t moved with the times 

 

Maybe you just can't improve a good product for the sake of it. 

[WIMorrison]

A point motor becomes DCC ready when the current drawn is reduced to a level the can be provided by a DCC Accessory Decoder, hence Peco releasing the PL10e for use (long time ago, and still not my choice though :))

[wasdavetheroad]

1 hour ago, Junctionmad said:

BPRC , which is an aside to this topic , is a niche product at present . It’s not possible at present to get realistic Li-ion batteries into small OO tank engines I converted a smokey joe! and the like , never mind the radio system , it’s hard even fitting DCC chip what's a realistic Li-ion battery?

 

the second thing is that BPRC brings very little that   DCC cannot already do, and currently BPRC is a good bit more expensive then DCC no track wiring needed, avoids the weak point of DCC and DC, the wheel track interface

 

the third thing and most important is the is no standard for BPRC with several manufacturers promoting incompatible systems, until a standards body of one form or another gets involved , BPRC will remain a niche product , suitable for a very small number of specialized applications ( larger scale garden railways and the like ) there is a ready made standard, Bluetooth

 

the  fourth is no BPRC company has shown scaled up control solutions , say for 200 locos or more , large scale accessory control etc BlueRail Trains, 100's of locos possible

 

all this technology is essentially to get around powering the rails , yet for most reasonably built layouts operating on nickel silver track indoors , pickup isn’t really an issue. it seems to be an issue with lots of posts on here, no track wires is so much easier

 

BPRC is not a viable alternative to DCC or even DC at present , what does viable mean?  and you are joking about DC the technology shows promise , but many technology solutions fall by the wayside over time and I suspect without significant progress in battery tech how big a battery do you want? hybrid battery/track power has already been released BPRC will remain a niche player 

 

[wasdavetheroad]

1 hour ago, Junctionmad said:

This is what annoys me about the DC versus DCC debate , this is a false truth being promoted as truth and it’s a big lie . ( see current political debates for similar stuff ) 

 

DCC allows you to move locos around your layout with the freedom of the protypes , locos can be stopped and parked anywhere , movements can take place with other locos on the same track section BPRC does that 

 

for example station pilot operations , attaching and detaching double headers and bankers , attaching or removing  stock at the end of trains , stabling locos close together , like the real thing BPRC does that

 

yes , a complex sectioned DC layout CAN APPROACH , certain aspects of that prototype like freedom of movement , but only in a certain geographical area of the trackwork, where the isolation breaks and section feed breaks have to be carefully positioned to enable the move. If loco or train sits outside that section or straddles two sections , tough , you can’t perform the move in DC you can perform those moves in BPRC

 

however ,in DC ,  where any sort of reasonably complex trackwork is involved , to achieve certain levels of loco movement can result in miles of wiring , interlocked sections and what not.  You only have to look at how DC cab control gets real complex real fast to see the issues , DCC has no additional complexity no matter how many locos you wish to control and where no need for any track wires for loco control in BPRC

 

instrinsically ,  dcc drives the loco from its cab , DC CAN NEVER do this , it’s just not technically possible BPRC does it

 

hence , while DC operation on a circle of track on your sitting room floor , may be similar to the same thing with DCC l it’s simply a false premise to put forward as a general comment. 

 

Dave 

 

[wasdavetheroad]

1 hour ago, Junctionmad said:

 

Firstly I’ve yet to see 100 radio controls cars being controlled by a radio system , yet I can see it being done by DCC 

 

secondly , however you dice the technology , at present, it’s simply not possible  to find a battery small enough , at a reasonable price, and powerful enough to fit into a small outline OO engine. , battery tech is limited by physics and moves much slower then electronic tech. It could be years away if ever. Powerful enough for what?

 

Secondly, radio tech to control a model railway is a far greater challenge then a few RC cars , you have to have a fully addressable radio system , capable of supporting a very wide address range , then you need standards to ensure cross compatibility , then you need allocation spectrums to ensure  that dense installations ( say at an exhibition) can all work reliably. ( for comparison see WiFi Alliance documentation and standards ) BPRC systems which use the 2.4Ghz band either use Bluetooth technology or spread spectrum technology such as DSM2 or DSMX which make them extremely reliable in dense environments. as I understand it any reliability problems at large exhibitions is that the whole 2.4Ghz band is saturated, in which case your smart devices will be having problems as well

 

This leaves the issue of how to implement points and signals and power accessories , a solution BPRC has failed to address at present , because the majority of wiring in a DCC layout isn’t track wiring at all. I have a BPRC transmitter that can control 60 points using servos 

 

the main manufactures won’t “ go in that direction” , because the technology is immature, l the demand is niche and uncertain , the battery size issue remains a formidable technical hurdle and the issue of point, signal and accessory control remains undecided , it’s nothing to do with selling you expensive control systems , because let me assure you , a comphrensive multi channel BPRC solution will be significantly dearer then current DCC. BlueRails first board cost £80 and they only made a small number of those.. Imageine the price in a large scale production run. It had 2 way coms, light, sound etc etc. The App to control it all was free

 

when NMRA look at standardizing BPRC, maybe then it might be worth looking at , I won’t hold my breath however 

 

[Junctionmad]

1 hour ago, wasdavetheroad said:

 

 

While this is off topic I’ll try and deal with the issues mentioned 

 

I should mention I’m a electronics engineer with 30 years in embedded systems , including WiFi , Bluetooth and canbus , I also develop apple software in macOS and iOS 

 

bluetooth is a communications standard , it is not a standard , like DCC designed for controlling model railway Locos or accessories , it was primarily developed as a single point to single point communications system. Yes there are extensions and non standard workarounds 

 

Bluetooth can’t be and isn’t a model railway standard because the interface to the loco is not defined in that standard, for example there is no standard command in Bluetooth to send a loco traveling forward at a particular speed. There is one in DCC which is why you can mix manufactures products. 

 

hence individual manufacturers of BPRC , have to implement there own schemes to control a loco and as yet there is no standard way to do this. Hence BPRC “ decoders” cannot interoperate “ 

 

Bluetooth, is not an ideal communications mechanism either , there are actually far better solutions out there , like versions of LoRa , any 2.4Ghz system is now prone to interference , due to the proliferation of devices clogging that spectrum and the complete abandonment of the authorities to regulate it.  Given Bluetooth  might have to operate over quite a distance , garden railways and the like, it’s actually a poor choice for a standard approach to BPRC and I doubt bodies like the NMRA would consider it.  Power consumption for Bluetooth is high , even with BLE too 

 

I have considerable expertise with li-ion  batteries in portable equipment and my lab is litered with examples of all versions of Li chemistry.  I stand by my statement as a OO modeler that it’s not possible with Li tech to fit a decent battery ( 3-4hours running ) into a small British outline engine , along with the requisite radio decoder and battery charging circuit . It’s also extremely tricky to cool that battery in such a space when subjected to high rates of charge, such rates typify model/hobby  recharging time. It’s no use of it takes an overnight to get the loco going again 

 

lastly , as you point out , BPRC does indeed do al, the things DCC does” , because it’s clearly a cab control system , but that’s the issue, because that’s all BPRC does .  to be adopted widely , BPRC, like DCC did over DC , must bring significant advantages over DCC , today it does not 

 

the most touted advantage mentioned , in fact the only real advantage at all, is the removal of the need for continuous track power , and in certain circumstances like larger scales and outdoor track , indeed this is a compelling advantage 

 

however for most reasonably well built layouts with modern locos with all wheel pickup, the advantage is far less compelling for the cost of BPRC . my experience is wheel pickup simply isn’t a major issue 

 

the other thing that BPRC fails to address are issues like ( point and signal  motor power/ operation  , things like track occupancy and computer automation ) , requiring significant amounts of technology and wiring not associated with traction control , DCC has solutions for this , as the track power can be used for far more then traction power and control , BPRC has none of these solutions as ( current ) physics doesn’t allow us to “ beam” power over the air to any great extent. 

 

So, on any basis of technical evaluation BPRC may have some promise , but currently with achievable cost size concerns , it is not standardized , and is suitable for a limited number of specialized solutions.

 

 It certainly at this stage  could  not be considered as any sort of challenger to DCC for control of model railway layouts

Edited February 24, 2019 by Junctionmad

[Chris M]

1 hour ago, Junctionmad said:

 

While this is off topic I’ll try and deal with the issues mentioned 

 

I should mention I’m a electronics engineer with 30 years in embedded systems , including WiFi , Bluetooth and canbus , I also develop apple software in macOS and iOS 

 

bluetooth is a communications standard , it is not a standard , like DCC designed for controlling model railway Locos or accessories , it was primarily developed as a single point to single point communications system. Yes there are extensions and non standard workarounds 

 

Bluetooth can’t be and isn’t a model railway standard because the interface to the loco is not defined in that standard, for example there is no standard command in Bluetooth to send a loco traveling forward at a particular speed. There is one in DCC which is why you can mix manufactures products. 

 

hence individual manufacturers of BPRC , have to implement there own schemes to control a loco and as yet there is no standard way to do this. Hence BPRC “ decoders” cannot interoperate “ 

 

Bluetooth, is not an ideal communications mechanism either , there are actually far better solutions out there , like versions of LoRa , any 2.4Ghz system is now prone to interference , due to the proliferation of devices clogging that spectrum and the complete abandonment of the authorities to regulate it.  Given Bluetooth  might have to operate over quite a distance , garden railways and the like, it’s actually a poor choice for a standard approach to BPRC and I doubt bodies like the NMRA would consider it.  Power consumption for Bluetooth is high , even with BLE too 

 

I have considerable expertise with li-ion  batteries in portable equipment and my lab is litered with examples of all versions of Li chemistry.  I stand by my statement as a OO modeler that it’s not possible with Li tech to fit a decent battery ( 3-4hours running ) into a small British outline engine , along with the requisite radio decoder and battery charging circuit . It’s also extremely tricky to cool that battery in such a space when subjected to high rates of charge, such rates typify model/hobby  recharging time. It’s no use of it takes an overnight to get the loco going again 

 

lastly , as you point out , BPRC does indeed do al, the things DCC does” , because it’s clearly a cab control system , but that’s the issue, because that’s all BPRC does .  to be adopted widely , BPRC, like DCC did over DC , must bring significant advantages over DCC , today it does not 

 

the most touted advantage mentioned , in fact the only real advantage at all, is the removal of the need for continuous track power , and in certain circumstances like larger scales and outdoor track , indeed this is a compelling advantage 

 

however for most reasonably well built layouts with modern locos with all wheel pickup, the advantage is far less compelling for the cost of BPRC . my experience is wheel pickup simply isn’t a major issue 

 

the other thing that BPRC fails to address are issues like ( point and signal  motor power/ operation  , things like track occupancy and computer automation ) , requiring significant amounts of technology and wiring not associated with traction control , DCC has solutions for this , as the track power can be used for far more then traction power and control , BPRC has none of these solutions as ( current ) physics doesn’t allow us to “ beam” power over the air to any great extent. 

 

So, on any basis of technical evaluation BPRC may have some promise , but currently with achievable cost size concerns , it is not standardized , and is suitable for a limited number of specialized solutions.

 

 It certainly at this stage  could  not be considered as any sort of challenger to DCC for control of model railway layouts

Why does it have to be seen a challenger? There are many ways of controlling trains and we are all entitled to use what works for us without being told we we are not using the correct method or that our layout is no more than "a circle of track on the carpet". Our choice should be respected by others. I choose dc because it suits my needs best. I came to this conclusion after investigation and carrying out a business analysis of what I needed and what each method of control provides. The person who helps run my layouts at exhibitions and has two dcc layouts at home has said that he thinks dc is the best for my layouts; from his use of dcc he believes that my layouts would be harder to operate at exhibitions if they were dcc. I think dcc is best for what he wants at home and so we are both happy that we have made different but correct choices. 

I  converted one 00 loco to BPRC just out of interest and am very pleased with it. I might convert another loco sometime in the future or I might not as I don't really run 00 gauge. It certainly is viable in certain circumstances and has advantages that could be important to some people. There could be an interesting future though. We know the automotive industry is investing billions in improving battery technology and word is that they are nearly there. Somewhere around 2021/3 we should have a reasonably priced electric car which can run 400 miles and then fully recharge in about ten minutes. Some years after this you can be sure the technology will have worked its way into all batteries which may or may not make BPRC more mainstream. It sounds like the OP should go for dcc primarily because his layout builder is most familiar with dcc and may struggle with anything else but he should be aware that there are other choices which may suit his needs.

[Chris M]

4 hours ago, Junctionmad said:

As a MERG member and designer of  CBUS modules etc. , I must in all fairness defend the society 

 

MERG has years of projects of various stages of technical sophistication. It’s biggest project is the CBUS layout control bus , where a plethora of input , output , signal , point and occupancy solutions are available , many the result of private work by members for their own layout. 

 

The system works , today , largely on 12vDC supplies. 

 

MERG also has its own CBUS compatible DCC system , involving a command station , booster and a handset , also modules are a available to interconnect smartphones , computers , raspberry Pis etc. Jmri is fully compatible with CBUS and work continues in enhancing the JMRI CBUS interaction . In addition , members have contributed a huge variety of software for layout automation. Virtual mimic panels etc.  the aforementioned accessory decoder is one of these ( albeit DCC decoder modules in MERG are somewhat of an afterthought ) 

 

taken as a whole , it’s easily and by far the biggest single range of layout technology from any one source on the planet. each day members enhance the offerings. The dramatic growth of the society over the last few years and the extraodinary growth in kit sales is testimount to that. 

 

HOWEVER , it’s not and.was never designed to be an “ out of the box”  solution , to get the measure of it , requires a reasonable understanding of electronics ( at a typical hobbyist level ) ability to decipher schematics and undetstand the limitations of a given implementation 

 

the worst experiences are from members , who simply view it as a cheap source of layout electronics “ , invest no time in understanding the modules and their needs and find the whole process frustrating. MERG is a sub hobby , and these issues are like an RTR person approaching etch brass for the first time. 

 

For those that do want to invest some time in understanding the various MERG solutions , the result is very rewarding , woth the ability to implement state of the art solutions at very low cost. 

 

Our club O gauge layout is completely controlled , other then traction , by the MERG CBUS system and demonstrates faultless operation with minimal wiring. It now has over 50 cbus modules and close to 400 IO endpoints and we are far from finished ! 

 

One of our club layouts uses the MERG cbus. It is troublesome and the likelyhood is that it will be removed and replaced with something less flaky. I can see it has some fantastic features but older Farish locos cause the points to change as they go round. I'm told the MERG suggested solution is to fit a better capacitor into every loco. This won't happen as we are not prepared to tell club members they must modify their stock. In other words the suggestion is that your locos aren't good enough for our point control system. At the moment the problem is still being worked on but I'm sorry to say most of us are totally fed up with it. 

[Ravenser]

3 hours ago, Junctionmad said:

Seriously mate , it’s a connector with wires , it’s not magic , meter out every wire in the socket , then meter out the blanking  plug 

 

the fault will be a Homer Simpson moment 

 

We now have 3 people - me, Butler Henderson, and Neil - reporting the same fault with the same locomotive (Bachmann 4MT)

 

The fault is therefore not in me, nor in DCC (no other models affected) - it's in the 4MT

 

The whole frustrating 10 days effort amounts to a blog post, but comments at the time are here:

https://www.rmweb.co.uk/community/index.php?/topic/129660-dcc-concepts-zen-decoder-with-stay-alive/

 

This loco has now destroyed a Zen Nano Direct, a Gaugemaster Opti mini, and possibly a TCS Z2. That is £31-£55 of damage.

 

There is no question of pins going through the socket and contacting a metal chassis , because 1) I ripped out the socket before fitting the Z2 and 2)  The socket is closed at the bottom. I saw that when I cut it out.

 

And clearly it can't be a short within the socket as I ended up removing the socket with a pair of Xurons , hardwiring a TCS Z2 in place - and still the damn thing shorted

 

I set out to get multiple stopped locos into service.

 

Of 3 DCC installations , I got one up and running okay after 3 days' tweaking (remaining issues are doubtless related to pickup design, not DCC or the decoder), failed with shorting on the 29 after multiple attempts and checking, failed on the 4MT with shorting after multiple attempts and checking, failed to sort out the Turbostar with its massive current draw, managed to get the 158 back in traffic - and by that time I was so frustrated and disheartened by things not working despite repeated attempts and systematic checking I didn't even attempt the remaining items of stock, but packed everything away , and turned to finishing a plastic coach kit , to clear my head. You eventually get to a point where pressing on for the fourth time becomes counter=productive

 

I should add that I've done 8-9 hard-wired installs and never encountered anything remotely like these problems. I've done lots of plug-and-play locos - I never expected to fail in this way with a DCC Ready RTR loco

 

As far as multimeters go - I've no electrical background. I bought a digital meter , which does not have audible indication. The documentation with it essentially tells you how to fit the battery, in Chinglish. I bought a small paperback called "Getting the Most from Your Multimeter". It says "This book is primarily aimed at beginners" but it appears to consist mostly of descriptions of the circuits used in the multimeter, and I'm struggling to find details of how actually to use the thing. 

 

Quote

I should mention I’m a electronics engineer with 30 years in embedded systems , including WiFi , Bluetooth and canbus , I also develop apple software in macOS and iOS 

 

To you the way to use a multimeter may seem so obvious it doesn't need saying. Unfortunately for most of us - if nobody bothers to say it , we won't find out ..  "Just use a ruddy meter!" doesn't unfortunately cover it

 

(As a concrete example , only through recounting my woes with the Turbostar on here did someone point out that to test current draw (Amps) you connect the probes in series on one side of the motor, not in parallel across the motor terminals , which would be how to measure voltage.. That basic piece of info was not mentioned either in the "instructions" or in the book on testing with a multimeter. So how was I to find out , trying to test current flow for the first time, late at night , on my own?? I'm sure multimeter testing is not a black art . But it becomes one if you have to learn the basics by telepathy)

[Ravenser]

4 hours ago, Junctionmad said:

As a MERG member and designer of  CBUS modules etc. , I must in all fairness defend the society 

 

MERG has years of projects of various stages of technical sophistication. It’s biggest project is the CBUS layout control bus , where a plethora of input , output , signal , point and occupancy solutions are available , many the result of private work by members for their own layout. 

 

The system works , today , largely on 12vDC supplies. 

 

MERG also has its own CBUS compatible DCC system , involving a command station , booster and a handset , also modules are a available to interconnect smartphones , computers , raspberry Pis etc. Jmri is fully compatible with CBUS and work continues in enhancing the JMRI CBUS interaction . In addition , members have contributed a huge variety of software for layout automation. Virtual mimic panels etc.  the aforementioned accessory decoder is one of these ( albeit DCC decoder modules in MERG are somewhat of an afterthought ) 

 

taken as a whole , it’s easily and by far the biggest single range of layout technology from any one source on the planet. each day members enhance the offerings. The dramatic growth of the society over the last few years and the extraodinary growth in kit sales is testimount to that. 

 

HOWEVER , it’s not and.was never designed to be an “ out of the box”  solution , to get the measure of it , requires a reasonable understanding of electronics ( at a typical hobbyist level ) ability to decipher schematics and undetstand the limitations of a given implementation 

 

the worst experiences are from members , who simply view it as a cheap source of layout electronics “ , invest no time in understanding the modules and their needs and find the whole process frustrating. MERG is a sub hobby , and these issues are like an RTR person approaching etch brass for the first time. 

 

For those that do want to invest some time in understanding the various MERG solutions , the result is very rewarding , woth the ability to implement state of the art solutions at very low cost. 

 

Our club O gauge layout is completely controlled , other then traction , by the MERG CBUS system and demonstrates faultless operation with minimal wiring. It now has over 50 cbus modules and close to 400 IO endpoints and we are far from finished ! 

 

No criticism of MERG as a society was intended. I merely report my experiences with the kit - concept excellent, but let down by a vulnerability to shorts resulting in a need to "turn it off and turn it back on again" to get the decoder to respond . This may well have been linked to sub-optimal set up : ie no circuit-breaker protection, and a unit conceived in connection with CBUS system architecture rather than straight DCC setups

 

In view of other comments, I should perhaps stress the excellence of the supporting MERG documentation supplied with the kit .

 

I hadn't attempted any kind of electronic construction in over 30 years (and previous experience had been some very simple school projects, most of which didn't work) . Despite this, the supplied paperwork was sufficient to let me build the unit successfully. I only had to step outside the papers in the kit once, to find out which leg was positive and which negative on a capacitor. 

 

The unit not only worked, it gave 5-6 years service before I finally tired of "pulling the plug" at intervals . The fact that I - a raw novice - was able to build it successfully and without any great difficulties reflects very well on MERG's technical support

[WIMorrison]

@Ravenser this might help you

 

http://bfy.tw/Ae48

 

 

[Crosland]

7 hours ago, Butler Henderson said:

There is also  the issue that  typically a rc battery is around 5v output and hence a voltage booster is needed, 

 

Not really, you just use different motors.

[melmerby]

Faultily wired sockets/pickups et al in locos are not unknown and I have also blown a decoder in a faultily wired loco, in my case a Lenz. OK on DC. Phut with a decoder in. (didn't try another until sorted.)

From what I've seen and as mentioned earlier one side track and motor connections get swapped or shorted somewhere which makes no difference on DC but instantly kills the decoder.

I am fortunate to be able to use a multimeter etc. (I even used to calibrate ther damn things!) so tracing what wire goes where, to me is easy, others are obviously not so fortunate.

They probably have a talent that I would envy!

 

If you are going to buy a multimeter and use it seriously I would try to buy something better than the market stall £10 job.

[Crewlisle]

Summing up all the previous comments, you can make DCC as simple or complicated as you like.  I converted my 00 gauge layout 'Crewlisle' from DC to DCC in 2008 when it was 40 years  old using a Lenz LZV100 command/power station, two LH90 handsets & a LKl00 reversing module for my reversing loop.   I retained my 30 Peco solenoid motors (20 of which are of the old original cylindrical design) operated via a CDU & 'stud' operation on mini track diagram panels.  Besides the basic requirements for DCC operation, the only additional 'extras' I have fitted are two PSX-1 circuit breakers - one for the high level & one for the low level.  If a short occurs in one, the other half is still operational. 

All track is Peco Code 100 together with Electrofrog Points & the last of my Insulfrog points  I had converted to live frogs.    The only polarity switch on the layout is for the live diamond.  All points rely on blade contact as when I fitted most of them there was no such thing as 'frog polarity switching'.  Over the last 10 years the number of point shorts/stalling I can count on one hand both at home & at exhibitions.  My 50 locos still have their original capacitors connected & apart from the 10 sound decoder fitted locos, all decoders are a mixture of Bachmann, Hornby, Lenz or TCS.   I have only managed to 'fry' two decoders!

By today's standards, my set up is prehistoric!  If it ain't broke, don't fix it!

Edited February 24, 2019 by Crewlisle
Punctuation.

[shiny]

 

1 hour ago, Chris M said:

 

One of our club layouts uses the MERG cbus. It is troublesome and the likelyhood is that it will be removed and replaced with something less flaky. I can see it has some fantastic features but older Farish locos cause the points to change as they go round. I'm told the MERG suggested solution is to fit a better capacitor into every loco. This won't happen as we are not prepared to tell club members they must modify their stock. In other words the suggestion is that your locos aren't good enough for our point control system. At the moment the problem is still being worked on but I'm sorry to say most of us are totally fed up with it. 

 

It sounds like a difficult position to be in.

 

From the kind of trouble you are talking about, am I right in guessing that those points driven by servos? Some servos seem to be sensitive to interference, and a badly suppressed loco passing by will play havoc with the electronics inside it.

Do the points will still change or chatter as the loco passes if you disconnect the servo signal wire but leave the power connected?

I seem to recall a post somewhere that a user experiencing similar problems fixed it by putting a resistor between the signal wire and the servo ground connection, which was enough to stop the wire from acting as an aerial.

 

If the layout is DC only, would fitting suppressors to the track in each section help?

 

Electrical interference from locomotives can be caused by a number of issues including sticking / worn out brushes and weak springs or even dirt and carbon build up in the motor, especially considering the age of the locomotive - and the (usually) higher current demands of older mechanisms only exacerbates the problem. Suppression capacitors can and do fail with age as well. Likewise, dodgy pickups and dirty wheels is another cause. If the motor in the loco is arcing badly enough to consistently interfere with nearby electronics, it would appear that the suppressors are not doing the job they were intended for quite likely because they have failed. I would be concerned that it would eventually stuff up the electronics in the controllers.

 

From my own experience, changing failed suppressors, for me at least, isn't a modification but an essential maintenance task in exactly the same way that changing the brushes would be. Converting to DCC has largely removed the need for suppressors, but i am well aware that failure to maintain the motor will eventually kill any decoder fitted to it.

The advice from MERG regarding suppression would naturally be on the assumption that the loco had been checked and serviced to begin with, but if the requirements relating to member's stock are more relaxed, then I suppose it is not really practical to make sure this happens.

 

A few years ago a neighbour knocked on my door complaining about interference on his telly, and it turned out that one of my locos was the culprit. When I checked using the hifi tuner - the amount of interference it was putting out was shocking. I cleaned the motor, changed the brushes and tightened the fishplates - and the problem did go away. It was a simple roundy-roundy without droppers, which I am sure only made it worse. This happened a long time ago, but I am still mindful of it whenever I run a train. On the layout I'm building EMI suppression is a requirement, simply as good wiring practice - not an afterthought. On a personal level I don't wan't to be a bad neighbour - or be prevented from playing trains when Corrie is on.

 

A little locomotive with a suitable aerial, say a few metres or so of N/S track - can be a surprisingly effective wideband radio transmitter. Marconi's first Transatlantic radio transmission was made in 1901 using a spark generator along pretty much the same principles.

 

If the operation of certain locomotives on your railway is sufficient to affect nearby electronics, consider whether it could be creating a nuisance with your neighbours' electronics as well. I do remember a few of my neighbours being raided and having their (illegal) CB equipment seized back in the 80s because of the RFI they were putting out, although I'm fairly sure the law has changed since then. If you see one of these parked outside and a bloke with a clipboard asking if he can speak to Graham Farish  - you'll know why..

 

 

 

[wasdavetheroad]

4 hours ago, Crosland said:

 

Not really, you just use different motors.

The RC batteries I use can have fully charged voltages of 4.2, 8.4, 12.6, 10.8 using single cells wired in series. Nominal voltages are given as 3.7, 7.4, 11.1 etc.  The batteries all lose voltage as they discharge, a single cell starts at 4.2V and falls to 3V which is considered as discharged. Voltage regulators are very useful if you want or need a constant voltage and essential if you want to consist.. The RC style batteries as used for model trains are not stressed in use or recharge as they are when used for model planes or drones.

[wasdavetheroad]

I see the future for model railways control like this, a 'decoder' which;

uses DCC protocols for commanding the loco etc if that is what the market wants

is user switchable to receive its commands via the track or via radio

for power seamlessly auto switches between the track or onboard battery (consider it a stay alive)

will recharge the battery from the track if needed

 

With this there is no need for any rivalry about which system is best You can run pure DCC with track power or run pure BPRC with battery power or run hybrid DCC/BPRC with considerably simplified track wiring. Your choice

[melmerby]

2 hours ago, Crewlisle said:

All track is Peco Code 100 together with Electrofrog Points & the last of my Insulfrog points  I had converted to live frogs.    The only polarity switch on the layout is for the live diamond.  All points rely on blade contact as when I fitted most of them there was no such thing as 'frog polarity switching'.  Over the last 10 years the number of point shorts/stalling I can count on one hand both at home & at exhibitions.  My 50 locos still have their original capacitors connected & apart from the 10 sound decoder fitted locos, all decoders are a mixture of Bachmann, Hornby, Lenz or TCS.   I have only managed to 'fry' two decoders!
 

My second layout (permanent) consisted of Peco Code 100 track and Insulfrog points, relying on blade contact and fishplates, because that is what was normal then. (DC of course)

It was great to start with, everything was fine but after a couple of years running deteriorated badly.

The amount of stalling and poor running could be counted on 1 hand, as long as it had lots and lots of fingers! I ended up having to put loads of extra power feeds to combat the voltage drops.

Point blades needed regular cleaning so they would carry on making contact. Those little wipers Peco fitted to them didn't seem to work very well.

 

My current layout (DCC) has all code 75, with electrofrogs, frog switching, bonded blades, regular power feeds etc. and I dont get stalls Full stop.

 

My 60 locos still have the capacitors and I use all Lenz decoders.

The only decoder I fried was in the incorrectly wired loco.

Edited February 24, 2019 by melmerby

[shiny]

Ravenser,

 

This might be slightly more useful: https://learn.adafruit.com/multimeters/overview

 

 

[Junctionmad]

8 hours ago, Ravenser said:

 

We now have 3 people - me, Butler Henderson, and Neil - reporting the same fault with the same locomotive (Bachmann 4MT)

 

The fault is therefore not in me, nor in DCC (no other models affected) - it's in the 4MT

.......

 

Quote

Of 3 DCC installations , I got one up and running okay after 3 days' tweaking (remaining issues are doubtless related to pickup design, not DCC or the decoder), failed with shorting on the 29 after multiple attempts and checking, failed on the 4MT with shorting after multiple attempts and checking, failed to sort out the Turbostar with its massive current draw, managed to get the 158 back in traffic - and by that time I was so frustrated and disheartened by things not working despite repeated attempts and systematic checking I didn't even attempt the remaining items of stock, but packed everything away , and turned to finishing a plastic coach kit , to clear my head. You eventually get to a point where pressing on for the fourth time becomes counter=productive

 

I should add that I've done 8-9 hard-wired installs and never encountered anything remotely like these problems. I've done lots of plug-and-play locos - I never expected to fail in this way with a DCC Ready RTR loco

 

......

 

(As a concrete example , only through recounting my woes with the Turbostar on here did someone point out that to test current draw (Amps) you connect the probes in series on one side of the motor, not in parallel across the motor terminals , which would be how to measure voltage.. That basic piece of info was not mentioned either in the "instructions" or in the book on testing with a multimeter. So how was I to find out , trying to test current flow for the first time, late at night , on my own?? I'm sure multimeter testing is not a black art . But it becomes one if you have to learn the basics by telepathy)

With respect , electronics and electric current are not " voodoo" , you need to test the resistance of the socket and verify that what is wired is actually going to where it should AND only to where it should     DCC decoders need four wires, 2 from the track and 2 to the motor , everything else is an accessory 

 

If all else fails rip out the socket  located the track feed from the pickups , verifying it is all OK , find the motor wires  VERIFY that both of these are not connected to the track feed in any way   and wire in teh decoder. The thing will work 

 

What you are probably finding is that the is a connection between one of the track feeds and the motor.  This wont affect DC running but will cause a short on the decoder 

Edited February 25, 2019 by Junctionmad

[Junctionmad]

3 hours ago, wasdavetheroad said:

I see the future for model railways control like this, a 'decoder' which;

uses DCC protocols for commanding the loco etc if that is what the market wants

is user switchable to receive its commands via the track or via radio

for power seamlessly auto switches between the track or onboard battery (consider it a stay alive)

will recharge the battery from the track if needed

 

With this there is no need for any rivalry about which system is best You can run pure DCC with track power or run pure BPRC with battery power or run hybrid DCC/BPRC with considerably simplified track wiring. Your choice

possibly yes , integrating a radio system with DCC commands would at least allow some interoperability , the issue of course is that the method you send commands over the radio  has to be standardised and at present no one to my knowledge is interested in that ,

Edited February 25, 2019 by Junctionmad

[Junctionmad]

Quote

One of our club layouts uses the MERG cbus. It is troublesome and the likelyhood is that it will be removed and replaced with something less flaky. I can see it has some fantastic features but older Farish locos cause the points to change as they go round. I'm told the MERG suggested solution is to fit a better capacitor into every loco. This won't happen as we are not prepared to tell club members they must modify their stock. In other words the suggestion is that your locos aren't good enough for our point control system. At the moment the problem is still being worked on but I'm sorry to say most of us are totally fed up with it.

 

I would assume you are using servos to control points , Ive I had tuppence for every badly fitted servo install with poor wiring , too ling a servo lead and no understanding or care in relation to ground loops, servo power and load dumping Id be a rich man 

 

servos were never designed for the way the average user tries to use them in a model railway , they work very well, but you have to understand how they consume current, and how the high impedance drive input is very susceptible to interference 

 

Once you appreciate the technical issues , the problems go away 

 

The issue is that people see servos as cheap point  motors without any understanding of the technical issues involved when they are used in a model railway . The merg forum is full of advice and shows how NOT to use them , sadly many dont understand or only learn after they have made the mistakes