The Dark side beckons - CBUS and JMRI

Many apologies for my lack of posting lately, but I do have an excuse, honest.

My local MERG group (Tayside Area Group) are running a course on GBUS and JMRI, and I've signed up for it.

And to make it easier participants are asked to have at least the following kits
Kit 80A CANUSB4
Kit 97 CANPAN
Kit 11 CANVOUT
Kit 497 CANTM7

The USB4 is needed to communicate between your PC and CBUS to configure the modules.

The CANPAN is an ideal module(s) for a control panel and will act as an input module via the TM7 push buttons and also to drive LEDs on the TM7 to indicate things like block occupancy or point position.

The CANVOUT has 8 inputs and 8 outputs as standard but when loaded with Ian Hogg's Universal Firmware, that we will do later in the course, and with a few extra components, it will be capable of also driving servos directly.

So I've been busy building up the kits and in addition Kit 13 CANVSERVO, and Kit 98A CANMIO

The kits have been built, and I decided to modify my Prototypeing board to take the units.
Two reasons, everything is in the one place for the course, and the units need configuring and is easier if done on the bench rather than on the underside of the layout.

I drilled 5mm dia holes and glued in the M3 brass inserts, then mounted the units

On the front right hand side is the USB4 interface, which will connect the unit

Then from left to right -

CANPAN with the TM7 mounted on top

CANVOUT

CANVSERVO & CANMIO

In addition I have some servo's and opto isolated relays to be controlled.

Finaly got them assmbled and wired today.

Software installed on the laptop and everything seems to be recognised, so hopefully I'm ready for the course.

Now I have done a little with CBUS before but to be honest, just got a couple of 1st gen units set up as a demo, but the newer devices have a few extra tricks up thier sleeves like mid point triggers - once I've learnt this I tell you more.

So the desk is ready

For those wondering what the rest of the board has,
on the left behind the CANPAN + TM7 is an Arduino Uno rev 3 and a Arduino Mega.

In the middle is a block of 3 5+5 x 80 breadboards allowing me to prototype circuits.

On the right behind the USB4 is a yellow 5+5 x 17 breadboard currently with an Arduino Nano fitted
Behind that is another breadboard 5+5 x 30 (white), used to work with multiple PICs or PICs with greater than 20 Pins.
Finally 2 PIC test boards designed by Fraser Smith which will accodate any pic upto 20pins
Along the back edge are two breadboard power strips one for 12V the other for 5V.

The whole lot is powered by a ATX Power supply breakout board



The version I bought uses a 13 - 24V DC supply - in my case an old IBM 16V laptop power supply.



Other versions will take a 20 / 24 pin ATX power connector from a PC power supply.
As can be seen it supplys 12V, 5V, 3.3V and an adjustable supply from 1.7V to 10.8V.
A nice touch (pun intended) is the 12V, 5V and 3.3V power use touch sensitive switches, just touch the acrylic case surface where the appropriate sensor is and it will toggle the power off / on.

So I'm ready - I hope

Paul

 

Who said any of this would make your loco's run better

Not wanting to start another religious war, well ..... maybe .......

I think the DC / DCC argument is generally misplaced.

The discussion should really be how am I going to control my locomotives, my layput and my accessories / ancillaries.

So lets look at each

Locomotive / Train control
DC or AC (One of our club members uses Marklin AC sysyem) I'll lump them all in the DC camp
Command control, including DCC, Zero 1, etc. where a chip is fitted to each locomotive and a Command unit sends out instructions. These I'll lump together as DCC
Dead Rail (no power to the tracks) - Radio or Wireless control, with a control unit and battery in each locomotive, Live steam, Clockwork and Battery operated

Layout operation - essentially how we operate our pointwork
Mechanical - wire in tube, cable, Finger of God etc etc
Electro-mechanical - Solenoid, Servo, Slow moving motor, Stall motors

Layout control
Depending on how you control your locomotives will influence these choices
Dead rail, only needs a method of setting the points, no power switching required
Live rail - DC or DCC, requires power switching of Point V's if the are live, DC requires isolated sections to allow more than 1 locomotive to be on the layout at a time, and even seperation of tracks to allow more than locomotive to be in motion at a time. For larger DCC systems they may need to split the layout into power districts with a booster for each district.

For this control we have traditionally used a single or multiple control panels. spread around the layout as required.
Each panel controlling thier area of control, much like the signal boxes of old. Having a mix of electrical and mechanical control system. Gormo's Great Chesterford Junction layout uses mechanical operation of his points via lever frames, rods, cranks and wires and the results are impressive. It's biggest downfall (just like the real thing) is distance from the panel / signal box, due to mechanical losses you are limited in how far you can hove the point / signal from the panel.
The majority use electro-mechanical systems, where the control panel has some form of electrical switch, which is wired to a device connected to the point to set the correct direction. These have the advantage of being able to control devices from a far greater distance, allowing all powerful master control panels to be made. Great for Johny no mates when he has to operate verything, but a real paint when he does get a few mates and they're all trying to operate on the one panel.
A couple of disadvantages ;
DC voltage drops off over distance, often visable on large ovals using traditional resistance controllers. Modern feedback controllers notice the slowing of the locomotive and will apply more power - hence the selling point of not letting the loco slow down going up hills or running away going down the hill. Also why 16V ac from older controller were used to throw points on solenoid motors.
Secondly the sheer number of wires required to control the layout, often involving long runs. It's tempting to use thin telecom wire as they are relativley cheap, but can make the DC drop off even worse. One of our fairly simple club layouts has 50 wires from the control panel to the middle board - picked with the highest number of point motor, then 25 connections to the board on the right, and 15 on the left.

Recently, Layout Control buses have become popular, and tend to be of two types.
Power Bus - heavy gauge wire to carry main current, and
Data Bus to carry the instructions.
DCC has an advantage here as it already carries the commands on it track bus, so in theory you'd only need to have two wires going around the layout, with both locomotive decoders and accessory decoders getting thier power and commands from the track bus. Down side of this is the track bus is a broadcast bus, just like the TV programs the commands are sent out and there is no feedback from the recipriant. Also the locomotives and accessories are using the power, and you may need to install additional boosters to cope, especially on entry systems that are limited to 1.5A.

My preferred method is a Track bus of 1.0mm mains cable for OO or smaller, or 2.5mm mains cable for O gauge. 1mm cable is designed to take upto 11A, 2.5mm upto 20A. My OO layouts are unlikely to have a booster greater than 5A connected, whereas the O gauge may get a 10A fitted.

Also fit an accessory bus of 1.0mm wire which will carry either 16V ac or 12V dc - if a long distance then I use 16V ac and step it down to 12V or 5V DC with a bridge rectifier and 7812 (12V) or 7805 (5V) voltage regulator.

In the past most mains controllers used a 240V to 16V transformer which then passed through a bridge rectifier to give 12V dc. A variable resistor would allow the output to the track to be controlled. Transformers are big, heavy, expensive and electrically very noisey. The PC requires nice smooth clean DC, and for portable devices these needed to be small and light weight (i'd like to discuss these last points with my laptop supplier). Hence the advent of the Swich Mode Power Supply. A good one is can still be expensive, but there are plenty of reasonably priced ones available, and a massive market in second hand / refurbished laptop PSU's. Not all is good news, we have lost the 16V ac output as the PSU's don't provide one.

I digress, back to the data bus a bi-directional bus allowing comms to and from the command station and devices (handsets, Input output units, etc, etc) this is normally either a 4, 6 or 8 wire connection using telecom or ethernet cables. As these only carry data they can be thin. Cat 5, 6 & 7 cable runs are 100M or 328ft. Actually the recommended distance is 90m allowing for 5m at each end for the connections from wall to device.
Most of the DCC systems use a Data bus of some form, NCE Cab Bus, Digitrax LocoNet, MERG CBus. These allow the handsets to talk to the command station so you can pass on your instructions to a locomotive, accessory decoder etc.


Now this brings me to the MERG CBus system. It's based on the industry standard CanBus system used by most car manufacturers, giving an well tested, almost bullet proof system designed for far electronically noiser environments than a model railway. The Cbus system doesn't require a central command station, but can respond to messages between each device. Initially the devices were one of two types Prosumer and Consumer. A prosumer (Input device) would create an event message when a change took place on one of its inputs. The Prosumer device is listening to the bus and is programmed to respond to an event occuring and change one or more outputs to reflect the change.
The newer CBus2 devices (Next Gen) have become both consumer and prosumer devices, for Example the CANVSERVO has 8 outputs for servo's, and 8 inputs which can be used for feedback.

This getting a bit long in the tooth ......

I'll be back later

Paul

 

See a religious war

When I get the juices flowing again, the point of this thread, is not for loco control, but layout and accessory control.

Just imagine the control panel for the layout empire of your dreams, and only 4 wires between it and the layout, or maybe multiple mimic panels across the layout all having real time indication and control over sections, again only 4 wires, or if you use a tablet or touch screen no wires at all.

Loco can be DC or DCC, I'm after the control panels

A bit of my background as the American would say for you to see where I'm coming from. When I came back to the hobby must be about 15 years ago, I had a few OO loco's but they were a bit old and I wouldn't get rid of them for sentimental reasons. A partially built fictitious P4 layout set in the Highlands, half a dozen HR wagons, a converted Lima class 20, and a partially converted Airfix 4F. For control I had a 35 year old H&M Duette controller, and a defective Gaugemaster panel mount controller.
I had made the decision to go DCC, and after a couple of calls with Bromsgrove Models and abit of research on tinternet, purchased an NCE PowerCab and a couple of TCS T1 decoders. I cannot recommend highly enough the NCE DCC system (don't worry about starting another religious war, NCE is just the best ).

Letter to Santa was sent and the chief elf got one reserved provided I behaved.
While at the Dundee show one of the traders had a Hornby sound fitted 08 Green Gronk, for a very reasonable price, and SWMBO agreed to let me buy it, I had to wait until Christmas to test, boy is the chief elf tough.

The P4 layout was in bits up in the loft (20 years can have that effect), and I could never get the points to work properly - H&M point motors tend to knock hell out of fine scale point rods, and was too big to use downstairs. The idea was born to make a small test OO layout, which would be DCC, and Victoria Road was born.

It wasn't long after that I met Toto and the other repribates that used to frequent on YMR and eventually formed Platform1mrc

Now one of the major limitations of the NCE PowerCab (and most entry level systems) is they are limited to between 1.0A to 2.0A output (PowerCab is 1.5A). For DC in OO thats not an issue as your controller is only powering one loco, however DCC has power to all locos all the time, so even the 0.1A ish standby current can add up quite quickly.
The quick answer for NCE is to add a SB5 Smart booster, this has the PowerCab command station with a 5A booster for not much more than a PowerCab. Unfortunately for me, I always wanted to have some for of automation, and even with the v1.65 firmware upgrade, it wouldn't support enough I/O or Minipanels for what I would need.
During my research, I found MERG, thier DCC accessory decoders, took thier instructions from the Track bus, but used a seperate supply to power the device, using minimal current from the Track bus. They still produce a few kits for standard DCC, Kit 52 DCC Accessory Decoder (Pulsed Output for solenoids), Kit 53 DCC Accessory Decoder (steady state outputs for slow motors eg Tortoises), Kit NB2 DCC Booster, Kit 57 DCC District cutouts (overload / short circuit protection), and some occupancy detectors.

As stated before, they have thier own CanBus based system called CBus now at version 2 - the earlier version 1 devices work with the version 2. I have a few of the older devices, and they will get used.

Time to raise my head above the parapet to see if a cease fire has broken out

Paul