©
2008
Gastech
Australia
Pty
Ltd
Page
14
2.3.3
Optional
Relay
Board
The
D
‐
Guard
TM
can
be
ordered
with
an
optional
relay
board
(Part
number:
65
‐
1011
‐
xxx)
which
allows
the
D
‐
Guard
TM
to
operate
as
a
independent
unit.
WARNING:
If
the
D
‐
Guard
is
used
with
the
relay
board,
the
unit
is
no
longer
Intrinsically
Safe,
even
if
used
in
conjunction
with
an
IS
barrier.
The
image
below
shows
various
connectors
on
the
relay
PCB.
The
function
of
the
various
connectors
is
as
follows:
Feature
Description
24V
Connect
this
to
the
positive
side
of
the
power
supply.
Supplies
power
to
the
relay
board
as
well
as
the
D
‐
Guard
TM
main
PCB.
FB
(feedback)
Current
source
loop
output,
for
connection
to
an
external
controller
0V
Connect
this
to
negative
side
of
the
power
supply
DG+
This
needs
to
be
connected
to
the
+
connector
on
the
D
‐
Guard
TM
main
PCB.
DG
‐
This
needs
to
be
connected
to
the
‐
connector
on
the
D
‐
Guard
TM
main
PCB.
AL1
Low
Alarm
This
relay
is
energized
when
AL1
is
active.
This
alarm
point
is
adjustable
in
software
as
described
in
the
next
section.
AL2
High
Alarm
This
relay
is
energized
when
AL2
is
active.
This
alarm
point
is
adjustable
in
software
as
described
in
the
next
section.
Fault
Relay
This
relay
is
normally
energized.
It
becomes
de
‐
energized
when
there
is
a
sensor
failure,
power
failure
or
when
the
D
‐
Guard
TM
is
in
Isolate
mode.
Jumper
This
jumper
connects
the
FB
and
0V
lines
together.
It
allows
the
D
‐
Guard
TM
main
PCB
to
operate
in
standalone
mode
where
a
system
controller
is
not
present
Connection
to
power
source
and
a
4
‐
20mA
loop
(optional)
Power
for
D
‐
G
uard
TM
main
PCB
AL1
Low
Alarm
AL2
High
Alarm
Fault
relay
Wire
harness
to
D
‐
G
uard
TM
main
PCB
Jumper
Summary of Contents for D-Guard
Page 2: ......
