MegaPoints Controllers

DCC ABC — Automatic Braking Control

How the MegaPoints ABC Module, Servo 4R and DCC Block Detector work together for prototypical signalling

NORMAL TRACK DETECTION SECTION BRAKING SECTION NORMAL GAP GAP GAP Isolation gaps on one rail only (insulated rail joiners) Direction of travel S SIGNAL (at danger) Servo wire UNDER-BASEBOARD EQUIPMENT MEGAPOINTS CONTROLLERS ABC Module DCC Automatic Brake Controller SW TRK To braking section rail MEGAPOINTS CONTROLLERS Servo 4R BRAKING LOGIC CONTROLLER SRV1 SW IN RELAY Reads detector → activates ABC brake MEGAPOINTS CONTROLLERS Block Detector Current-sensing block occupancy DCC OUT From detection section rail Occupied signal Relay activates ABC Servo to signal KEY: Normal rail Detection section Braking section Insulated gap Wiring Servo connection Signal Flow Summary Block Detector senses train in block → Servo 4R controls brake + signal → ABC Module brakes via asymmetry → Signal + Decoder train stops at signal Block clears → detector releases → Servo 4R deactivates ABC → signal clears

MegaPoints Servo 4R

The braking logic controller. Reads the Block Detector's occupancy signal on its switch input. When a train is detected, it activates the ABC Module via its relay output and moves the semaphore signal to danger via servo.

MegaPoints ABC Module

Generates asymmetric DCC for the braking section. Controlled by the Servo 4R's relay — when the relay closes, the ABC Module feeds asymmetric DCC to the braking rail, causing ABC-equipped decoders to brake smoothly.

MegaPoints Block Detector

DCC current-sensing occupancy detector connected to the detection section. Its output feeds into the Servo 4R's switch input, telling the controller whether the block ahead is occupied or clear.

Semaphore Signal

Driven by the Servo 4R's servo output at the detection/braking boundary. Arm horizontal = danger (ABC active, train braking). Arm lowered = clear (ABC off, train proceeds).

1
Block Detector
senses train ahead
→
2
Servo 4R reads
occupancy input
→
3
Servo 4R sets signal
to danger & activates ABC
→
4
Train decoder detects
asymmetry & brakes
→
5
Block clears, Servo 4R
releases ABC & signal

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Servo 4R ABC Module Block Detector Visit Shop

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