
GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 24
INITIAL
SETUP
Once
installed,
apply
power
to
the
GASMAX
CX
and
verify
that
the
LCD
display
is
active.
Certain
sensors
may
initially
indicate
off
‐
scale
high
or
low
values,
but
should
quickly
return
to
zero
if
no
target
gas
is
present.
During
this
warm
‐
up
delay
period,
the
4
‐
20mA
output
is
held
at
4.0
mA
to
eliminate
false
alarms
in
any
receiving
devices.
Warm
‐
up
delay
is
one
of
the
user
‐
adjustable
parameters.
Once
operational,
the
user
should
verify
the
following
settings
prior
to
initial
calibration:
Local
time
and
date:
Check
date
value
and
adjust
time
for
proper
time
zone.
Tag
name
or
Engineering
Units
settings:
Edit
values
as
necessary.
CAL
SPAN
GAS
value:
Set
to
match
concentration
of
calibration
gas
cylinder.
CAL
MARKER
value:
Adjust
desired
output
mA
during
calibration.
ALARM
1,
ALARM
2,
ALARM
3
settings:
Set
for
desired
levels.
NOTE:
If
relays
are
not
installed,
GASMAX
CX
programmable
alarm
levels
affect
operation
of
display
color
only
(Sec
7
‐
3).
Allow
the
GASMAX
CX
to
stabilize
for
at
least
four
hours,
preferably
overnight
if
possible.
This
will
allow
all
sensors
to
reach
stable
equilibrium
with
respect
to
environmental
conditions
such
as
ambient
temperature,
humidity,
and
barometric
pressure
as
well
as
applied
“reference”
and
“counter”
voltages
generated
by
the
GASMAX
CX
electronics.
At
this
point,
the
GASMAX
CX
can
be
calibrated
and
made
operational.
NORMAL
OPERATING
MODE
During
normal
operation,
the
GASMAX
display
shows
the
current
gas
reading
in
direct
calibrated
engineering
units.
If
the
reading
goes
above
the
Alarm
1
or
Alarm
2
values,
the
display
will
change
color
and
flash,
and
the
internal
relays,
if
installed
and
programmed
properly,
will
activate.
The
4
‐
20mA
outputs
will
transmit
values
that
represent
the
%
of
scale
shown
on
the
display.
If
the
sensor
malfunctions,
or
is
removed,
the
display
will
turn
red
and
the
message
FAULT
will
appear
on
the
screen.
ALARM
OPERATION
–
ALARM
1,
2
AND
3
Each
channel
can
be
programmed
for
up
to
three
independent
alarm
levels,
and
can
be
set
to
alarm
ABOVE
the
target
value
for
BELOW
the
target
value.
All
programming
is
done
in
engineering
units
that
correspond
to
the
channels
ZERO
and
SPAN
settings.
Alarm
processing
will
trigger
an
alarm
condition
when
the
input
exceeds
the
programmed
value,
and
includes
hysteresis
to
keep
the
alarm
from
rapidly
switching
ON
and
OFF
if
the
input
remains
close
to
the
programmed
alarm
value.
NOTE:
ALARM
RELAYS
ARE
NORMALLY
TRIGGERED
IF
EITHER
CHANNEL
1
OR
CHANNEL
2
ALARM
THRESHOLDS
ARE
EXCEEDED.