Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 42 of 118
This document is uncontrolled when printed.
The Output Opto Board allows connection for up to 8 signalling outputs.
Each output is a voltage free contact that can drive nominally 120 mA
(E.g. a Q-type relay ).
Dimensions are 100 mm (l) x 76 mm (w). The PCB is held in a green
plastic circuit board module with mounting feet which clip on to TS32
(Klippon) rail or TS35 (DIN) rail. Identifying features of the board
are:
(a)1 x 8 way ( Green ) connector and 1 x 2 way ( Green ) connector.
(b)Integrated circuits have a black coloured
casing (National/Matsushita AQV214)
(c)Row of 8 indicating LEDs
(d)1 x D15 Female connectors (labelled 'I/P 1' )
Refer to drawing M08-871 Layout., M08-872 Circuit, M08-873 cable.
3.6.2 Function
The Output Opto Board allows connection for up to 8 signalling
outputs to be driven by the Level Crossing Monitor. Each output is a
voltage free contact that can drive nominally 120 mA DC (e.g. two
Q-type relay or 5 LEDs). The Output Opto Board is protected
against back EMF and is suitable for driving relays directly without
any additional protection.
3.6.3 Operation
The level crossing monitor drives circuits 1 to 8 respectively through
pins 1 to 8 of the D15F connector. All 8 circuits are identical and have
consecutive component numbering.
When +5V is applied to pin 1 of the D15 connector, the indicator
LED (LD1) is illuminated and current flows across pins 1 & 2 of the
AQV214H optoisolator (U1) and illuminates the internal LED which
turns on the internal phototransistor and enables the output. The
output is a voltage free contact (i.e. it can be likened to a relay
contact). When enabled the contact is closed and a 'short' exists
across pins 5 & 6 of U1 (actually the resistance between the pins is
about 10 Ohms).
When 0 VDC is applied to pin 1 of the D15 connector, the indicator
LED (LD1) is extinguished and no current flows across pins 1 & 2 of
the AQV214H optoisolator, the internal LED is turned off and the
phototransistor is turned off, so that the output of U1 is disabled (i.e.
an open circuit exists between the output pins).
Each output circuit can drive (nominally) up to 120 mA at voltages
up to 120 VDC. This means an output can drive, for example, a non-
vital relay, two Q-type relays, up to 5 LEDs, or a sonalert.
This particular Output Optoisolator Board cannot switch AC voltages.