.: Block Detection Module FBM-2

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FBM-2 Description


The FBM-2 is a block occupancy detector designed to connect to the Free-mo occupancy bus providing train detection for a section of track on a Free-mo module. RJ45 jacks make connections to other occupancy bus modules very simple.

Although designed for Free-mo modules, the FBM-2 can be used on any model railroad layout where block detection is required.

Train detection is accomplished by routing the DCC track feeders through an air core transformer located on the FBM-2 board. When current flows through the track feeder wire, the module detects that current and delivers a stop signal to the occupancy bus which then sets the signals on a cascade module down the line.

The FBM-2 is microprocessor controlled ensuring proper output signals to the occupancy bus so that signals do not flicker when a section of track is occupied by a loco with dirty wheel sets.

An on board "Occupancy Status" led illuminates when current is detected.

The FBM-2 has been designed for universal operation. The occupancy bus is compatible to work with any Free-mo module that follows the Northern California Free-mo wiring standards for the occupancy bus.

The FBM-2 board consumes very little current and the board can be connected to any 12 volt supply.

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FBM-2 Features


* Microprocessor controlled for smooth signal operation.

* Low power consumption. Operates on 12 volts, AC or DC.

* On board isolated block detection.

* Block occupied status LED.

* Follows the Northern California Free-mo wiring standards.

* RJ45 jacks provide easy occupancy bus connections.

* Easy to install.

* Terminal strip for easy power connections.

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FBM-2 Notes



Connections to the FBM-2 board are very simple. There are only two screws to connect power to this board.

Once the board is mounted under your module and the wires are attached to the terminals, you are pretty much done. The only connections left to be made are by plugging in the category 5 crossover cables (used for the occupancy bus) from the adjacent modules.

The track feeder wire loops from the DCC bus, through the air core transformer and then to the tracks.

Terminal Connections

12v Max - Power input.

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FBM-2 Power


Power Sources

The FBM-2 can be powered from several sources. The maximum current draw for the unit is about 15mA.

-- A separate AC adapter that can supply 12 volts AC or DC.

-- Connecting the board to the accessory bus.

-- 12 volt power supply or battery.

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FBM-2 Diagrams


Board Layout

Click on the photo below to enlarge.

Board Connections

The FBM-2 can be connected to other signal boards that are compliant to the Free-mo wiring standards for signalling.

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