Rail Control DCC Loop Controller (RCDCCL) is my design for an automated reverse loop controller. I have designed and installed two of these controllers on my HO railroad. THis makes it possible to run a loop-to-loop railroad automatically with DCC engine controll and occupancy detectors. I do not need to throw switches, since I use ROCO switches that "can be run into without throwing them". An alternative wold be to use more complex hardware based on short circuit loop controllers and controlling switches from my computer/DCC central. Features are :
1. Automatic running throught a loop.
2. Detects the train when engine enters block2 and reverses polarity of both block.
3. Output for block detection signals separately for each block inside loop
4. Controller can be powered by DCC track voltage or separate powersource 8 - 15 Volt AC or DC.
5. Train detection signals can be opto-insulated from track signal
Requirements/implications are:
1. only one way throught the loop.
2. Detection circuit reduces DCC voltage by 1.4 Volts inside Loop.
3. Requires two separate blocks inside the block (block 1 and then block 2
Component list:
D1 Diode 1N4001 1 ampere
D2 Diode 1N4148 or similar
D3 Diode bridge 1.5 ampere (ore larger depending on train powerconsumption in loop)
D4 Diode bridge 1.5 ampere (ore larger depending on train powerconsumption in loop)
T1 Transistor BC547 (or similar NPN small signal transistor)
IC1 4N25 OptoCoupler
IC2 4N25 OptoCoupler
IC3 7805 or 78L05 - 5 volt powersupply who accept inputvoltage
C1 Electrolytic capasitor 100uF, who accept input voltage
C2 Electrolytic capacitor 25uF, 16 Volt
R1,R2 Resistor 1Kohm 1/4 Watt
R3,R4 Resitior 10Kohm 1/4 Watt
RL1, Relay 5 Volt double Throw, (Meisel)
Building Instructions: Picture 1. Printboard seen from couper side:
Picture 2. Finished controller seen from component side:
White IC's are 4N25, pin 1 up to the left
IC3 is a 7805 (block standing)
blue capacitor is C1
black/gray capacitor is C2
Blue resistors are r1 and r2
black diode is d1 (installed with anode to the left)
glass diode is d2 (installed with anade to the left)
relay are the big block one to the right, Pin1 to the lower right corner)
1. Cut couper strips as indicated in picture by light brown lines:
2. Mount sockets (black boxes) and wires according to picture:
(Picture is wrong (for clarity !) - components should be mounted on other side)
3. Mount resistors (values according to picture 2) according to picture:
4. Mount diodes (brown) according to picture:
5. Mount transistor and IC 7805 (also brown) according to picture:
6. Mount capasitors (black circle, and black filled square) according to picture:
7. Mount relay and optoCouplers in sockets according to picture:
8. Install circuit into layout as in schema :
Installation instructions
The diagram shows the simplest installation where the board takes power from rails (dcc power signal). LED's for traindetection are not installed. The Picture shows the rail loop - trains must be run according to arrow. You must insulate tracks where indicated with a red mark (6 places). I use db9 plugs and they are shown from soldering side (I install female on layout and male on controllerboard). Controllerboard are show from component side - marks show strips on board.
fpedersn@online.no
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