
GDS-68XP Operation & Maintenance Manual, Revision 3.5
Page 26
GASMAX
CONTROLS
AND
DISPLAY
There
are
four
magnetic
switches
on
the
face
of
the
GASMAX
CX,
arranged
in
a
quadrant
around
the
LCD
display.
Starting
in
the
upper
left
and
proceeding
clockwise
these
are
labeled
UP,
NEXT,
EDIT
and
DN/CAL.
To
activate,
or
“press”
a
magnetic
switch,
swipe
the
magnet
near
the
switch.
For
the
balance
of
this
manual,
the
term
“press”
will
be
used
to
describe
activation
of
any
key
via
the
magnetic
wand.
Below
the
LCD
display,
two
LEDs
monitor
the
MODBUS
RS
‐
485
or
Ethernet
network
interface.
Flashing
indicates
sent
or
received
data.
The
EDIT
key
activates
the
USER
MENU
mode
(See
Chapter
8).
During
USER
MENU
mode,
the
UP,
DN
and
NEXT
keys
are
used
to
select
and
confirm
menu
entries.
The
USER
MENU
allows
the
operator
to
view
the
Event
Log
and
channel
parameters
and
change
system
settings
such
as
alarm
levels
and
real
time
clock
day
and
date.
Pressing
the
DOWN/CAL
key,
followed
by
the
EDIT
key,
initiates
calibration
mode.
For
a
detailed
description
of
calibration,
see
Chapter
6.
Pressing
the
NEXT
key
momentarily
causes
the
GDS
‐
68XP
display
to
sequence
display
screens
between
DUAL
DISPLAY,
RAW
SENSOR
TREND,
PPM
OUTPUT
TREND,
RAW
SENSOR,
and
PPM
OUTPUT.
Figure 6-4: GDS-68XP GASMAX Display Sequence
RAW
SENSOR
displays
the
calibrated
gas
value
being
read
by
the
sensor
at
any
moment.
As
such,
it
will
increase
when
the
3
‐
way
valve
opens
to
allow
sample
gas
into
the
unit,
and
will
then
drop
back
to
zero
during
purge
and
purge
/
hold.
Use
the
Raw
Sensor
Trend
screen
to
monitor
the
sensor’s
response
to
sample
gas.
PPM
OUTPUT
displays
and
holds
the
maximum
value
found
during
the
most
recent
sample
sequence.
Its
value
is
updated
each
time
the
sequencer
identifies
a
new
maximum
ppm
value.
DUAL
DISPLAY
shows
both
RAW
SENSOR
and
PPM
OUPTUT
values
on
a
single
screen.