Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 41 of 118
This document is uncontrolled when printed.
 Unplug the 2 and 8 way green connectors by pulling them directly
outward from the board.
 The Cables are removed by unscrewing the two thumb screw
fasteners on each D25 connector, then pull the D25 plug directly
outwards.
 The Optoisolator board is removed by twisting the board off the
Klippon rail. Twist by pulling the board on the 'thick' side of the
Klippon rail whilst holding the board on the 'thin' side of the Klippon
rail.
To install a board:
 Looking at the mounting feet on the base of the Opto board, one
side has a square hole running along the length of the board with a lip
that extends to be in line with the side of the board. This side goes
toward the 'thick' side of the Klippon rail. The other end has a clip
which extends diagonally out from the base of the board. The notch
at the end of this clip is inserted into the edge of the rail at 'thin' end
of the Klippon rail. Position this notch on the rail first then clip the
board into place by pushing the board at the thick side onto the rail.
Check that board is correctly in place by lightly tugging the board
(Do not twist the board).
 Plug-in the D25F connectors. The D25M plug on the Cables is
connected into its corresponding D25F connector ( 'O/P1' or 'O/P2').
Screw the thumbscrew fasteners in to place. Ensure that the screws
are not so tight as to distort the plastic hood of the D25M plug (finger
tight is sufficient).
 Plug-in the 2 and 8 way connectors into their respective sockets.
3.6 Output Optoisolator
3.6.1 Description
The 8 Way Output Optoisolator Board ('Output Opto') is used to control
the battery test and operate no fault and no warning relays if required.
They are called Optoisolator Boards since the main components on the
board which electrically isolates one side from the other are
Optoisolators. An optoisolator is a 'chip' that uses an internal LED
which emits light to switch a phototransistor on.
The main functions of the output optoisolator boards are:
(a)To isolate the main box from any possible power surges
encountered on the level crossing supply (1500V isolation).
(b)To convert the output voltage levels of the main box (0 VDC, +5
VDC) to DC voltage levels suitable for operating relays such as
QBCA1 and HH23-PW.