Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 12 of 118
This document is uncontrolled when printed.
 More lamps are operating than expected (possible short circuit).
A status indication of FAULT & BATTERY is indicated if the level
crossing has:
 the battery voltage is below the alarm point configured in the
expression file as measured by the level crossing monitor for more
than 3 seconds.
 the Store 74 Low battery alarm card has tripped for more than 3
seconds.
 The remote testing of the level crossing battery has not produced
the test current specified in the expression file.
It is possible to have multiple status indications which would indicate
that more than one fault or warning has occurred. For example a failure
of a flasher unit will give FAULT & LAMP & LOGIC.
A status indication with LOGIC flashing once per second indicates that
the monitor has had its reporting of status changes disabled
temporarily (called maintenance mode). When in this state the monitor
will not report changes of status to the Control Centre via modem. This
state, is entered by holding the Fault Reset button pressed for 5
seconds. It is cancelled by a momentary push of the Fault Reset button
or after a time delay of 45 minutes. This function is provided so that
maintenance staff can conduct maintenance activities at the level
crossing without causing unnecessary faults and warning to be reported
back to the Control Centre. All Faults and Warnings must be cleared
before cancelling this maintenance mode otherwise they will be
reported to the Control Centre.
2.2 Control and Interrogation
The control, interrogation, and reporting facilities are provided via the
RS232 serial ports labelled channel A, and channel B. Normally a dial-
up modem is connected to channel A.
Maintenance staff may Control and interrogate the Monitor using a
Personal Computer and one of two programs. Either the MS-DOS V6.2
based program named LX_MAINT.exe or the MS-WINDOWS
3.1/WIN95 based programme named ‘Cerberus’.
The dial-up modem is connected to serial channel A. Serial channel B is
available for on-site maintenance staff. The maintainers PC is directly
connected to the Level Crossing Monitor serial channel B via a null
modem serial cable. The cable must include loopbacks on the Level
Crossing Monitor end. These are DTR to CD, and RTS to CTS. See
section 4.2 for further details of the cable configuration. Normally the
Laptop PC end of the cable is plugged into serial port 1.
The level crossing monitors have a default set-up of: