CMRI clinic I am giving at the O Scale National Convention and the MER Regional Convention.

1. Bruce Chubb’s
Computer/Model Railroad
Interface (C/MRI)
101- The Basics
By Jay Beckham
http://jaysoscalelayout.blogspot.com/
james@thebeckhams.us
Visit the layout Sunday Afternoon
1

2. My presentation is based in part on Bruce
Chubb’s presentations used with his
permission. I am grateful that he not only
agreed to my use of his presentations but
furnished me the presentations 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.2

3. Basic Electronics
101
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.
3

4. 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
4

5. 5
A very extensive series
of articles about C/MRI
can be found in Railroad
Model Craftsman starting
with the December 2015
issue.
This series consists of
14 parts concluding with
the April 2017 issue.
Signaling in general and
C/MRI is covered in
great detail in this series.
Well worth the time it will
take to read all the parts.

6. Signaling Basics covered
in 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 available
directly from Kalmbach
and from NMRA’s Kalmbach
Memorial Library
6

7. 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
7

8. An updated V3.1 User’s Manual now available
However, if have V3.0 then do not need V3.1
8

9. 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
9

10. 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 pushbuttons
Can use USB port with USB to RS232 converter cable
10

11. 11

12. Simply connect
each signal,
switch motor,
detector, etc.
to the SMINI
12

13. 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
13

14. 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
14

15. Each input card provides 32 added inputs
15

16. Handling C/MRI inputs is straightforward
 Input open circuited is hardware logic 1 (+5Vdc)
 Input grounded is a hardware logic 0 (0 volts)
16

17. Example C/MRI input connections:
17

18. Each output card provides 32 added outputs
18

19. 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)
19

20. Drive almost any devices directly
from C/MRI output line
Within .3A , 40volt limit
20

21. Each output can drive multiple devices
21

22. 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
22

23. All C/MRI programs follow the
same logic flow diagram
23

24. During this presentation we will cover:
•
• Block occupancy detection
•
24

25. For best possible performance:
use the DCCOD for DCC railroads
use the OD for DC railroads
25

26. 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
26

27. Everything is out in the open with the C/MRI
Including full schematics, parts lists and assembly instructions
as well as extensive application information
27

28. A Mother Board (ODMB) is available to
further simplify wiring and system debugging
28

29. 29

30. During this presentation we will cover:
•
• Signaling and turnout control
•
30

31. 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
31

32. 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)
32

33. 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
33

34. 34

35. 35

36. Light Emitting Diodes (LEDs) are basic elements
to designing most signal systems
36

37. Preferred (most common) method of wiring color light signals
 Uses outputs configured for standard current sinking
 Applies when signals are wired with common anode
37

38. Driving a searchlight signal using a
3-lead bi-color LED
38

39. 39

40. 40

41. Two color signaling a small railroad
41

42. 42

43. 43

44. 44

45. 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
45

46. Connecting switch motors directly to C/MRI outputs
Requires 2 outputs per switch motor
46

47. Alternatively, only a single output is required
when incorporating an SMC12 card
Also, interface cards are available for
connecting to twin-coil switch machines 47

48. 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
48

49. 49

50. 50

51. During this presentation we will cover:
• Centralized Traffic Control Systems
51

52. 52

53. 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

54. A small size CTC
machine covering
the east end of
UP’s Albina Yard
in Portland OR on
the SVOS

55. 55

56. 56

57. Wiring switch and signal levers and
code button is easy with the C/MRI
57

58. Wiring the switch and signal indication
lamps is just as easy
58

59. 59

60. 60

61. 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
61

62. Monitoring operational status is readily
available by studying the graphics display
62

63. Modern dispatching with C/MRI
63

64. During this presentation we will cover:
•
• Additional applications
•
64

65. 65
Automated room and scenic lighting control tied
to fast clock simulating 24-hour day-night
operation easily accomplished using the C/MRI

66. 66
Night operation can be dramatic and including
sunrise and sunset effects can be spectacular

68. New Prototypical Grade Crossing Control (PGCC)
68
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

69. 69
Automate scenic lift-up to totally
eliminate duckunders

70. Two new
Railroader’s Applications Handbooks
are availiable
Together these totally replace single Volume V2.2
70

71. 71

72. 72

73. During this presentation we will cover:
• System assembly and simplified wiring
73

74. You can easily take
advantage of the
C/MRI
Several options available:
 bare board from JLC Enterprises
 complete kits fully assembled
and tested from Don Wood.
74

75. 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
75

76. 76

77. 77

78. 78

79. 79

80. 80

81. 81

82. 82
My CTC board. It is based on US&S type
board. Each panel is 30 inches wide so the
CTC is 120 inches wide. My board also
includes a screen display. The screen also
provides a number of trouble shooting routines.

83. 83
To add in wiring and reduce the number of printed
circuit boards required, I have developed two small
boards that are helpful. These boards are available
from me. They are bare boards but I provide a list of
parts and where they can be obtained. Currently the
cost is $2 for either board plus postage.
The boards use the standard network CAT5/6 cable (8
wires) to help with wiring. It has an RJ45 connecter for
that cable 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 Molex option and
the screw terminal option.

84. 84
The second board I call my Signal Control Circuit or SCC for
short. It also has the CAT5/6 connector at the right and 15 screw
terminals across the bottom. Also 2 screw terminals for 5+ Volts
and Common connections. It 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.
Currently these boards are also $2 each plus shipping.

85. In summary – You have seen that a
computer will add a new dimension
and even more enjoyment to your
model railroading hobby
85

86. •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!
86

87. 87
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 6.0 code, running several thousand feet of
wire, and building almost 100 temporary signals that
we are using till I have time to build detailed
PB&JRY 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.
A question and answer session will conclude my
presentation.

88. THANK YOU
For Attending
C/MRI 101- The Basics
By Jay Beckham
http://jaysoscalelayout.blogspot.com/
james@thebeckhams.us
Visit our layout:
Sunday Noon to 6:00
88