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

2.2.2 SCADA 2000 A I/O Board

S-2000 A/2.0 I/O Board is a general purpose micro controller board with 64 digital inputs

and/or outputs. These 64 I/O can be configured as either Inputs or Output in groups of 8.

These are configured as 56 Inputs and 8 Outputs for the level crossing monitor.

The I/O Board also has two serial communications ports at the front, and a Bitbus

communications port which is connected to the Backplane.

Dimensions of the I/O Board are 261 mm (length of face plate) x 220 mm (d) x 20 mm

(width of face plate). These are the standard dimensions for a 6U high x 220 mm deep

extended Eurocard.

The major features of the I/O Board are:

b) The 8044 BitBus Enhanced Micro controller (BEM) which is the heart of the I/O

Board, controlling all its functions.

c) EPROM socket (U5) which allows a 64 KByte (27512) EPROM containing the

software to be installed.

d) RAM sockets (U6 & U7) which each contain a 32 Kbyte SRAM chip.

e) Two D9 Male serial ports (Channel A & Channel B) which are controlled by the

82530 serial communications chip.

f) 14 x Indication LEDs on the front of the board (LEDs 1 - 2 are for the micro

controller status, LEDs 3 - 6 are general purpose LEDs, and LEDs 7 - 14 show

the I/O Port Configuration).

g) Two 64 way IEC Male connectors mounted on the rear of the board. These

connectors contain the power supply pins, BitBus pins, I/O pins and Address

pins. The top connector is known as 'IOJ1' (it has I/O Bit Nos. 1 to 32) and the

bottom connector is known as 'IOJ2' (it has I/O Bit Nos. from 33 to 64).

Drawing M08-723 shows the physical dimensions and component layout of the I/O Board.

Drawing M08-724 shows a block diagram of the I/O Board.

2.2.2.1 Function

The I/O Board is responsible for controlling the functions of the Level Crossing Monitor

and storing the logged information.

2.2.2.2 Operation

The microprocessor on the I/O Board executes a software program which resides in the

EPROM plugged into the I/O board. The program determines the functionality and

configuration of the Level Crossing Monitor.

If the program is not executed correctly then a Watch Dog IC will reset the board. The

Watch Dog IC also monitors the 5 volt power supply and will reset the microprocessor

and hold it reset while the 5 volts bus is not greater than 4.7 volts. There have been some

cases where a slightly high resistance connection between the power supply and the I/O

board supply pins has resulted in the Watch Dog resetting the microprocessor and

stopping the monitor from operating.

For complete details on the operation of the SCADA 2000 board refer to the source code

of the level crossing monitor and the SCADA 2000 A/2.0 Technical manual.