Specifications

RailCorp Engineering Manual — Signals — Equipment Manual

Cerberus Level Crossing Monitor Field Equipment Manual TMG E1261

Issued August 2012 UNCONTROLLED WHEN PRINTED Version 2.1

2.3.6 Replacement

Disconnect the wiring from terminals 1 to 4. Make sure these are identified and will not be

shorted out.

Unclip the current sensor from the Klippon rail. Confirm that their will be no trains

approaching and that it is safe to disconnect the wire through the current sensor if it is on

a lamp circuit. Disconnect the wire threaded through the current sensor measurement

aperture.

Thread the wire through the measurement aperture for the new current sensor. Ensure

that the wire is securely attached and that the lamp resistor has not been damaged or

interfered with.

Make sure the link on the replacement unit is set the same as the original current sensor.

Note: Ensure that the wire is threaded through the measurement aperture in the

same direction otherwise the sensor will not operate. It is sensitive to the

direction of the current.

2.4 VIO

2.4.1 Description

The VIO is a Vital Indication Optoisolator. It is a Klippon rail mounted device. The module

has an identification label of "S-2000 J 1.1 xxV VITAL INDICATION OPTOISOLATOR".

Refer to drawing M08-559 for details of its physical aspects. xxV is either 12V for

monitoring 12 volt circuits or 50V for monitoring 50 volt circuits. Refer to drawing M08-

558/2 Circuit details.

CAUTION

A 12V VIO must never be used on 50 volt Vital Signalling Circuits.

Although a 12V VIO will work on a 50V DC circuit a failure of the 12V unit could result in

excessive current being drawn from the 50V circuit it is connected to.

All VIOs are clearly labelled with their working voltages on the main label of the unit and

on the left edge of the unit when viewed from the side.

2.4.2 Function

The VIO is used to monitor the state of an intermediate point in a Vital Signalling circuit

when it is not practical to do so by other means.

The VIO provides an isolation of greater than 10 KV between the indication circuit and the

Vital Signalling circuit. It is also designed so that the current drawn is less than half that

required to hold a BRB 930 series Safety Relay energised.

2.4.3 Operation

Terminals 1 and 2 monitor the Vital Signalling circuit. Terminal 1 is connected to the more

positive voltage than terminal 2.

Terminals 3 and 4 provide the indication of the state of the Vital Signalling circuit.

Terminal 3 is connected to the more positive voltage than terminal 4.