Bruce Chubb’s Computer/Model Railroad
Interface (C/MRI)101- The Basics
By Jay Beckham
http://jaysoscalelayout.blogspot.com/
Visit the layout Saturday or Sunday1
My entire presentation is based on Bruce Chubb’s presentation used with his
permission. I am grateful that he not only agreed to my use of his presentation but
furnished me the presentation which I have modified and adapted.
First I would like to briefly present some electronic/electrical fundamentals that
confused me when I first got into building and using the C/MRI system.
Then I will cover the basic parts that makeup the signaling system and CTC.
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Basic Electronics101
In C/MRI grounding a circuit turns it on and no ground turns it off. This is just the opposite of what
we would normally think. This method is called Current-Sinking and it the default method used by
C/MRI devices. In house wiring we put the wall switch on the hot side of the circuit.
In C/MRI we would ground an LED to make it light or ground the terminal on the switch machine circuit
(SMC12) to make it throw the turnout to the diverging route. And the occupancy detector grounds the pin on an Input board to tell the computer that a electrical block is occupied.
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Example C/MRI application areas:• Optimized occupancy detection (OD and DCCOD)• Signaling systems (very simple, ABS, APB and CTC)• Interface with Command Control including DCC• Staging track control (manual to fully automated)• Grade crossing warning systems (PGCC)• Turnout control (including software diode matrix) • Junction and terminal interlocking• Fast time clocks and layout-room lighting• Driving real-time engine/dispatcher simulators•Automated operations• Reducing layout wiring
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Signaling Basics coveredin a 4-part series:
“Signaling Made Easier”
January through April 2004 Model Railroader Magazine
This series is an excellent source for getting started in Signaling and the C/MRI
Copies are availabledirectly from Kalmbachand from NMRA’s Kalmbach Memorial Library
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32 pages in the March 2007 issue of Scale Rails covering:
State-of-the-Art Electronics to Enhance Operations
Sunset Valley Oregon System
My Life with Bruce and the Sunset Valley by Janet Chubb
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An updated V3.1 User’s Manual now available
However, if have V3.0 then do not need V3.1
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During this presentation we will cover:
• Interfacing made easier
• Block occupancy detection
• Signaling and turnout control
• Centralized Traffic Control Systems
•System assembly and simplified wiring
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Interfacing your railroad to a computer is as easy as connecting a single “super mini-node” card (SMINI) to your computer’s serial port
48 outputs for driving signals, switch motors and panel LEDs 24 inputs for reading block occupancy detectors, switch position and pushbuttonsCan use USB port with USB to RS232 converter cable
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Simply connect each signal, switch motor,detector, etc.to the SMINI
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Distributed serial:
• Up to 128 nodes
• Devices connect to nearest node
• Use maxi-node for• concentrated I/O
• Everything connects w/single 4-wire cable
• 72 I/O per SMINI
• 2048 I/O capacity per MAXI-node
• 262,144 total I/O capacity
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Each card adds 32 inputs or outputs up maximum of 64 cards per node (2480 I/O lines)
Need more I/O, simply plug in another I/O card
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Each input card provides 32 added inputs
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Handling C/MRI inputs is straightforward
Input open circuited is hardware logic 1 (+5Vdc)
Input grounded is a hardware logic 0 (0 volts)
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Example C/MRI input connections:
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Each output card provides 32 added outputs
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Every C/MRI output can be considered to be a simple SPST toggle switch
Software simple turns the toggle switch on or off When the toggle is on it is grounded Each SMINI provides 48 output lines (switches) Each DOUT32 provides 32 output lines (switches)
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Drive almost any devices directlyfrom C/MRI output line
Within .3A , 40volt limit
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Each output can drive multiple devices
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Programming the C/MRI is straightforward: - like using the English language:
An extremely active User’s Group is available to help you in every step:
http://groups.yahoo.com/group/CMRI_Users
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All C/MRI programs follow the same logic flow diagram
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For best possible performance:use the DCCOD for DCC railroadsuse the OD for DC railroads
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Advantages provided by DCCOD are numerous:
Transformer isolated
High 150K ohm pot adjustable sensitivity
Turn-on turn-off delay
Monitor LED for setting sensitivity
Open collector output (.3A, 40Vdc)
Track current up to 20A
Small modular unit for easy plug-in and system debug
Priced very reasonable - $9 for medium size layout
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Everything is out in the open with the C/MRI
Including full schematics, parts lists and assembly instructions as well as extensive application information
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A Mother Board (ODMB) is available to further simplify wiring and system debugging
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Signaling can add so much interest, beauty and operational realism to a model railroad…
…and it is so easily and cost effectively accomplished using the C/MRI
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Five great reasons for using a computer to signal your railroad:
1. Simplicity
2. Flexibility
3. Prototypical fidelity
4. Easy expandability
5. Low cost
(See www.jlcenterprises.net or separate handout provided for details expanding upon each benefit)
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Using the C/MRI makes prototype signaling easy to accomplish:
• Straightforward application• Well proven technology• Available as boards only, complete kits or fully assembled and tested• Everything out in the open - full schematics, parts lists and abundant software• Total flexibility to accomplish every need • Very cost effective solutions
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Light Emitting Diodes (LEDs) are basic elementsto designing most signal systems
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Preferred (most common) method of wiring color light signals
Uses outputs configured for standard current sinking
Applies when signals are wired with common anode
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Driving a searchlight signal using a3-lead bi-color LED
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Two color signaling a small railroad
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Three color signals with 2-headed signals leading into passing sidings
In each example, C/MRI documentation leads you step-by-step through the complete interfacing project
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Connecting switch motors directly to C/MRI outputs
Requires 2 outputs per switch motor
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Alternatively, only a single output is required when incorporating an SMC12 card
Also, interface cards are available for connecting to twin-coil switch machines 46
Easiest to implement local panel for emulating the operation of a dual-
control power switch motor
Additional options provided in Handbook include adding padlock function and using separate toggles for the Selector Lever and Hand-Throw Levers
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CTC machines can be great additions to any size railroad
Dirk Start using a GRS style machine modeling the C&O operating on the former PM between
Holland and Grand Rapids Michigan
A small size CTC machine covering the east end of UP’s Albina Yard in Portland OR on the SVOS
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Wiring switch and signal levers and code button is easy with the C/MRI
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Wiring the switch and signal indication lamps is just as easy
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CSX Clinchfield Dispatching Center is quite applicable to a C/MRI based club size system
Some C/MRI users are already interfacing to five monitors within computerized dispatching centers
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Monitoring operational status is readily available by studying the graphics display
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Modern dispatching with C/MRI
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Automated room and scenic lighting control tied to fast clock simulating 24-hour day-night
operation easily accomplished using the C/MRI
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Night operation can be dramatic and including sunrise and sunset effects can be spectacular
New Prototypical Grade Crossing Control (PGCC)
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Drives gates, flashers (w/fade-in and fade-out), real grade bell digitally recorded sound and 4-prototypical bell control options
and all exactly like the prototype
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Automate scenic lift-up to totally eliminate duckunders
Two new Railroader’s Applications Handbooks
are availiable
Together these totally replace single Volume V2.269
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You can easily take advantage of the
C/MRI Several options available:
bare board from JLC Enterprises
… and from SLIQ Electronics: complete kits fully assembled and tested
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The C/MRI documentation is extremely thorough and follows a step by step everything explained process:
User’s Manual V3.1
Application Handbook Volume 1
Application Handbook Volume 2
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My original CTC board. By next year I will have rebuilt it to match the many changes that have been made to the railroad.
This is a photo of half of the CTC. Each panel is 30 inches wide so the finished CTC will have four 30 inch panels.
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To add in wiring and reduce the number of printed circuit boards required, I have developed two small boards that are helpful. From time to time I make the blank boards available to the C/MRI group.
The first board uses the standard network CAT5 cable (8 wires) to help with wiring. It has an RJ45 connecter for CAT5 on one end and either a Molex connector or a screw terminal block on the other end. The Molex fits all the standard C/MRI boards. The photo shows the Molex option.
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The second board I call my Signal Control Circuit or SCC for short. It also has the CAT5 connector at the right and 15 screw terminals across the bottom. Also 2 screw terminals for 5+ Volts and Common connections. I allows 4 pair of wires to control a total of 12 LEDs in signals. Previously you saw a diagram of a standard OS section which had one double head three color signals and two single head three color signals. That is a total of 12 LEDs to light. Rather than use 12 outputs from a SMINI board we only need 8 outputs thus saving on boards, wire, and effort. The 12 resistors can be matched to the particular LEDs you use.
In summary – You have seen that a computer will add a new dimension and even more enjoyment to your model railroading hobby
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•The C/MRI is easy to apply• It is an educational project• It is a fun project• Include the C/MRI on your railroad• I know that you will love it!
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I would like to thanks a number of people who have been helpful with my understanding of C/MRI, with the building of the 100+ printed circuit boards, wiring my CTC panel, creating over 5,000 lines of Visual Basic code, running several thousand feet of wire, and building almost 100 temporary signals that we are using till I have time to build detailed WM and PRR signals.
They are: Bill Carr, Gail Carr, Bruce Chubb, Jim Withrow, Don Wood, and the members of the C/MRI Users Yahoo Group.
THANK YOUFor Attending
C/MRI 101- The Basics
By Jay Beckham
http://jaysoscalelayout.blogspot.com/
Visit our layout:Saturday 1:15 to 6:00Sunday Noon to 6:00
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