Signal Systems in Model Railroading HANDOUTS/C467_Albers AC... · Placard Team Digital DBD2™...
Transcript of Signal Systems in Model Railroading HANDOUTS/C467_Albers AC... · Placard Team Digital DBD2™...
AC-DC-DCC
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AC-DC-DCC
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NOTE
This Clinic Is Highly Animated With Picture Overlays And Graphics.
PDF and Other Versions May Look Contaminated.
AC-DC-DCC
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AC-DC-DCC
ByDr. Gerry Albers
NMRA Life MemberCincinnati Div. 7, MCR
With Examples from the Author’s
Deepwater District, Virginian Railway
Photo credits: Gerry Albers, Clinician
AC-DC-DCC
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Deepwater District - Virginian Railway
Deepwater DistrictNew River Division
Virginian Railway
1600 Sq. Ft.
11 Hidden Staging Yards
49 Staging Tracks
AC-DC-DCC
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Introduction (Stuff I Wish Someone Had Told Me)
AC-DC-DCC
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• DC (Batteries)• DC From AC
– Half Wave, Full Wave– Unfiltered, Filtered
• DCC (A Square Form of AC)• DCC Layout Wiring
– Device Hierarchy, System Architectures– Detector Wiring, Characteristics– Switch Wiring– Multiple DCC “Track” Buses
• Neat (Cool/Tidy) Wiring Practices– Color Codes, Wires Sizes– IDC Connectors– Strap Gun Usage– Miscellaneous Stuff
• DCC Cab Buses – The Differences– Master/Slave vs. Peer-to-Peer
Preparing For Signals
Overview
“Take Aways”: Practical Information and Useful Tips
Vendor Independent
AC-DC-DCC
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DC From Batteries – Purest Form
• “Bagdad Battery” probably the first.Used for electroplating gold ontosilver objects (~ 200 BC – 200 AD).
• “Voltaic pile” invented by the Italian physicist Alessandro Volta in 1800.
• “Battery” coined by Benjamin Franklinfor an arrangement of multiple Leydenjars.
• Railroads used batteries for telegraphand signals.
• Modern hybrid locomotives employlarge arrays of batteries
• Model Railroad Uses– E.G., Wireless Throttles
Bagdad Battery
NASA Publication
Symbol
Nickel Metal
Hydride (NiMH)
Rechargeable
AC-DC-DCC
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Oscilloscope Trace
AC Basics
• 22.3 Volts Peak
• 44.6 Volts Peak-to-Peak
• 15.8 Volts AC RMS*
• 0 V DC
• 16.6 milliseconds per cycle
• 60 Hertz (cycles per second)(1/.0166 = 60)• *RMS: “Route Mean Square” (Square root of the
mean of the sum of the squares)
• Also known as “Effective Voltage”
• RMS = 0.707 * Peak (for sinusoidal waveforms only)
DMM(Meter)
120 VAC
60 Hertz
14 VAC
@1.14A1000 Ohms
GND
IN
MeasuringDevice*
* Digital Multi-Meter (DMM) or Oscilloscope
15.8V
1000= I = .016 A
V
R
For a Transformer:
The rated voltage is only
valid at the rated current.
Clock Timing
15.8VDC 15.8 VAC RMS
AC-DC-DCC
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Oscilloscope Trace
Half Wave DC
• 21.6 Volts Peak (22.3V - 0.7V)
• 8.3 Volts AC RMS
• 6.7 Volts DCDMM (Meter)
120 VAC14 VAC
@1.14A1000 Ohms
GND
IN
0.7V
A Diode (Half Wave Rectifier):
• Increases the DC component
• Decreases AC component
+
+AnodeCathode
Diode
Light Emitting
Diodes (LED)
Produce Light
AC-DC-DCC
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Oscilloscope Trace
Full Wave DC
• 20.9 Volts Peak (22.3V – 1.4V)
• 6.8 Volts AC RMS
• 13.0 Volts DCDMM (Meter)
AC
+14 VAC
@1.14A
1000Ohms
GND
IN
AC
A Full Wave Rectifier:
• Increases the DC component
• Decreases the AC component
Bridge Rectifier
AC-DC-DCC
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Oscilloscope Trace
Full Wave, Filtered DC
• 20.9 Volts Peak (22.3V – 1.4V)
• 2.6 Volts AC RMS
• 17.2 Volts DCDMM (Meter)
AC
+14 VAC
@1.14A
1000Ohms
GND
IN
AC
10 µf
A Filter Capacitor:
• Increases the DC component
• Decreases AC component
AC-DC-DCC
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AC vs. DCC
AC provides:
• Power
• Accurate Timing (60 Hertz)
DCC provides:
• Power (Square AC)
• Information (1’s & 0’s)
Oscilloscope Trace Oscilloscope Trace
1/60 Sec.
“1” “0”
~14V
(14 VAC)
AC DCC
NMRA RP9.2
Use “AC” Setting on DMM
AC-DC-DCC
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Power Hierarchy – Home Wiring Analogy
TransformerCircuit
Breaker/Disconnect
120/240V
200A
~7,500V
CB Panel
120/240V Ground FaultOutlet(GFCI)120V
20A
Similar To DCC Booster
Similar ToPower District
Circuit Breakers
Circuit Breaker-
Disconnect
AC-DC-DCC
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P1DP1CP1BP1A
DCC Device Hierarchy
DCCBooster
& CB
DCCBooster
& CB
Control Bus (or LocoNet)
DCC
Circuit
Breaker(S)
DCC
Circuit
Breaker(S)
DCC
Circuit
Breaker(S)
DCC
Circuit
Breaker(S)
Track Bus (DCC)
PowerSupply
PowerSupply
PowerSupply
Cab Bus(or LocoNet)
DCCCommand
Station
Throttles
(Cabs)T T T
Ground!
(Consult Manual)
5 Amp
8 Amp
Power Supply > Booster
Gap Both Rails
Only OneAs Many As Needed
Power
District
Definition
P1 P2
Switch Both Rails
Keep Same Polarity
Booster Near Track
Fan (12VDC) Fan (12VDC)
Fan (12VDC)
Magna Force
MF615
MCM
Electronics
AC-DC-DCC
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DCC Track Wiring
DCC Rail A (12 ga. stranded)
DCC Rail B (12 ga. stranded)
Simple (Undetected) DCC Wiring
Track Feeders, 20 ga. solid
3M Scotchlok 567
(All 12/20 ga.)
(Double 20 ga.)
• Wire color avoids NEC standards (12 and 14 gauge)
• 12 ga. stranded for “Track” (DCC Power) Bus (not “Block” Bus – more later)– DO NOT TWIST. Maintain ~1 inch separation
• 20 ga. solid for Track Feeder
• One pair of feeders for every section of track– DO NOT TRUST RAIL JOINERS (OR SWITCH POINTS) FOR ELECTRICAL CONTACT
– Nickel-silver rail is a poor conductor – compared to copper.
• All connections made with IDC’s (Insulation Displacement Connectors)– NO SOLDERING UNDER THE LAYOUT !!!!!
– Use appropriate IDC for wire sizes
AC-DC-DCC
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Detector Characteristics:
• Types– Current Detector (requires conduction thru motor, light, resistor, etc)
– Position Detector (light beam, magnetic, contact, weight)
• Uses– Automatic Signal Systems
– Centralized Train Control (CTC)
– Grade Crossing Protection
– Automatic Turnout Actuation
Determine the occupancy of a block or specific location.
Current Detector
14 AWG
Block Wire
Cardstock
Placard
Team Digital
DBD2™
(DBD22™)
Power
ToSignal Logic(Computer)
From Track Bus To Block BusTo Block Bus
• Design Criteria– Sensitivity
» Detect decoder only» Adjustable
– False Positive Indication» 1 second turn-on delay
– False Dropout» 3 to 5 second dropout
– Isolated from DCC Track Bus– Distributed – not centralized
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DCC Detector Wiring
• Detected rail (Rail A or Rail B) has its own “Block Bus” (14 ga. stranded)
• Gap only detected rail– Opposite rail becomes common rail
• All connections made with IDC’s (Insulation Displacement Connectors)– NO SOLDERING UNDER THE LAYOUT !!!!!
– Use appropriate IDC for wire sizes
• Detector must be on Block Feeder– NOT ON BLOCK BUS
DCC Rail A (12 ga. stranded)
DCC Rail B (12 ga. stranded)
Block 1 (14 ga. stranded) Block 2 (14 ga. stranded) Block 3 (14 ga. stranded)
Block 1 Current Detector Block 2 Current Detector Block 3 Current Detector
DCC Wiring With Current Detection
Block Feeders, 14 ga stranded
3M Scotchlok 567
(All 14/14 ga.
& 14/20 ga.)
3M Scotchlok 562
(All 12/12ga. & 12/14 ga.)
Block 1 Block 2 Block 3
AC-DC-DCC
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DCC Switch (Turnout) Wiring
DCC Rail A
DCC Rail B
Block X
Block X Current Detector
Block Feeder
Tillig Turnout
• Power frog and switch points (or use DCC-Friendly Switches)
– DO NOT TRUST SWITCH POINTS FOR ELECTRICAL CONTACT
• Switch is part of Block X
Switch Point Power - Contacts on Tortoise)(Not needed with DCC-friendly Switches)
Tortoise
®
DCC Friendly
AC-DC-DCC
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DCC Rail B
DCC
Ckt. Breaker
DCC Rail A
DCC Accessory Bus
DCC Layout Wiring – Multiple DCC Buses
Accessory
Decoder
DCC Rail B
DCC Rail A
DCC
Ckt. Breaker
17 ma.20 ma.
Tortoise 100 x .020 = 2.0 A
Signals 100 x .010 = 1.0 A
3.0 A
DCC
Booster
A Separate DCC Accessory Bus Provides:• Accessory Power independent of Track Power.• Sufficient accessory power for many devices.
XTortoise
®
Stalled
Motor
Locomotive and
Accessory Decoder
are dead!
Locomotive is dead.
Decoder is powered.
Accessories will draw ~5 times
more current than trains.
AC-DC-DCC
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Camera
Monitor
LightingAccessory
Decoder
DCC Layout Wiring – Multiple Buses (Continued)
DCC Rail B
DCC
Booster
DCC Rail A
DCC Accessory Bus
Accessory
Decoder
Computer
Power Supply
+12 VDC
GND
DCC Rail B
DCC Rail A
DCC
Ckt. Breaker
Tortoise
®
AC-DC-DCC
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DCC Layout Wiring – 12V DC Bus Applications
Camera & Monitor Lighting
AC-DC-DCC
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Miscellaneous Stuff
PowerFast
Strap Gun
12-14NM
IDC Connector
Detector
AC-DC-DCC
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Miscellaneous Stuff – Documentation !!!!!
AC-DC-DCC
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Bus (Network) Architectures - General
Bus Network (RS485)
- Multiple devices (32 to 256)
- Expanded distances (~4000 ft)
- Must be linear (cannot be “treed”)
- Usually Master/Slave, Polled
- C/MRI®, NCE (&other) Command Buses
Point to Point (RS232)
- 2 devices (e.g., teletypes)
- Limited distance, ~10 ft. Hub
Star (Ethernet, USB)
- Fast (~100MB/S)
- Most popular local area type
- Requires Hub
Ring Network
- Continues to work
if ring is broken
- Usually large
numbers of users
Tree Network
(LocoNet®)
- Connections
and routing not
constrained
- Slower
transmission
speeds
- Peer-to-Peer,
Event-Driven
P P P
P P
P
P
S S M S
AC-DC-DCC
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DCC Architectures (Digitrax vs. Others)
NMRA
RP9.2
No NMRA
Standard
Vendor
Dependent
CS
A
B
Cab Bus (RS485)
A L L
B
Control Bus (DCC Commands)
Track Bus (DCC Commands)
Optional
Most DCC Systems
TT
– Cab Bus is RS485 (IEEE Standard)
– Command Station is “Master”
– Master must “poll” each device to transfer data
– Cycle repeated continuously (constant activity on Cab Bus)
B
T
T CS/B
Command Bus* (LocoNet)
Digitrax DCC System
A A L L
Track Bus
Optional
T
*Combines Cab and Control Buses
– Peer-to-Peer relationship
– Distributed Intelligence – all devices equal
– Event Driven (only changes transmitted)
– LocoNet allows device-to-device communication
Note: This diagram does not address transponding.
B = BoosterCS= Command StationI/O= Input/Output DevicePC= Personal ComputerT = Throttle A = Accessory (Switch)L = Locomotive
May Be
Combined
Combined
AC-DC-DCC
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Suppliers
• Logic/Electronics
–See Handout
• Signals/Electronics
–See Handout
• Signal Operating Software
–See Handout
Acknowledgements
• Digitrax and LocoNet are registered trademarks of
Digitrax Corporation
• NCE is a registered trademark of North Coast
Engineering Corporation
AC-DC-DCC
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The Deepwater District Construction Crew
It’s not the destination that’s important,
it’s the journey (with friends).
AC-DC-DCC
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STOP!(Then Proceed)
Thank you for your interest and attention!
Standby For:
Signals
By
Spreadsheet
AC-DC-DCC
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