GDS-68XP Operation & Maintenance Manual, Revision 3.5
Page 29
CALIBRATION
PROCEDURE
(CAL
PORT
SAMPLE)
Calibration
using
the
built
‐
in
calibration
port
is
the
fastest
and
most
convenient
method.
When
the
GASMAX
enters
CAL
MODE,
the
purge
air
pump
automatically
turns
on
to
provide
zero
air
flow
from
ambient
air;
sample
air
flow
is
provided
by
the
fixed
flow
regulator
connected
to
the
calibration
gas
cylinder.
CALIBRATION
PROCEDURE
–
CALIBRATION
PORT
OBTAIN
THE
FOLLOWING
ITEMS:
1)
CYLINDER
OF
CALIBRATION
GAS
WITH
FIXED
FLOW
REGULATOR
AND
LENGTH
OF
FLEXIBLE
TUBING
2)
CYLINDER
OF
‘ZERO
AIR’
IF
NECESSARY
IF
NOT
PREVIOUSLY
DONE:
1)
VERIFY
THAT
THE
CHANNEL
1
CAL
SPAN
VALUE
MATCHES
THE
CALIBRATION
GAS
TO
BE
USED
2)
VERIFY
THAT
THE
CALIBRATION
GAS
IS
NOT
EXPIRED
ENTER
CAL
MODE:
WAIT
UNTIL
THE
SEQUENCER
IS
IN
PURGE/HOLD
MODE
AS
INDICATED
BY
“L2”
(GREEN)
FLASH
PRESS
THE
“CAL”
KEY
FOLLOWED
BY
THE
“EDIT”
KEY
ATTEMPTING
TO
CALIBRATE
THE
GASMAX
DURING
A
SAMPLE
SEQUENCE
WILL
RESULT
IN
A
CALIBRATION
ERROR
THE
“APPLY
ZERO
GAS”
SCREEN
WILL
APPEAR;
L2
WILL
CHANGE
TO
SINGLE
FLASH
PURGE
AIR
PUMP
WILL
TURN
ON
AND
AMBIENT
(“ZERO”)
AIR
WILL
FLOW
INTO
THE
SENSOR
FLOW
CELL
SET
THE
ZERO
VALUE:
ALLOW
THE
READING
TO
STABILIZE
AND
PRESS
THE
“EDIT”
KEY
TO
ACCEPT
THE
CURRENT
READING
AS
‘ZERO’
IF
THERE
IS
A
POSSIBILITY
THAT
TARGET
GAS
MAY
BE
PRESENT
IN
AMBIENT
AIR,
USE
A
CYLINDER
OF
ZERO
AIR
IN
PLACE
OF
PURGE
AIR
IF
ZERO
READING
IS
WITHIN
LIMITS,
THE
ZERO
CAL
SUCCESS
SCREEN
WILL
MOMENTARILY
APPEAR
THE
“APPLY
SPAN
GAS”
SCREEN
WILL
APPEAR
SET
THE
SPAN
VALUE:
CONNECT
THE
SPAN
GAS
AS
SHOWN
ABOVE,
SET
THE
RUN/CAL
VALVE
TO
“CAL”
AND
TURN
ON
THE
REGULATOR.
VERIFY
FLOW
ON
THE
FLOW
METER.
ALLOW
THE
READING
TO
STABILIZE
AND
PRESS
THE
“EDIT”
KEY
TO
ACCEPT
THE
CURRENT
READING
AS
‘SPAN’
ALLOW
THE
GAS
TO
FLOW
FOR
ABOUT
AS
LONG
AS
IT
DOES
DURING
A
NORMAL
SEQUENCE,
USUALLY
BETWEEN
THREE
AND
FOUR
MINUTES.
IF
SPAN
READING
IS
WITHIN
LIMITS,
THE
SPAN
CAL
SUCCESS
SCREEN
WILL
MOMENTARILY
APPEAR
THE
GASMAX
DUAL
SCREEN
WILL
REAPPEAR
SHOWING
CHANNEL
1
IN
PURPLE
(CAL
DELAY)
COMPLETE
CALIBRATION:
DISCONNECT
THE
SPAN
GAS
CYLINDER
AND
SET
THE
RUN/CAL
VALVE
BACK
TO
“RUN”
ONCE
CAL
PURGE
DELAY
IS
COMPLETE,
THE
SEQUENCER
WILL
RETURN
TO
THE
PURGE/HOLD
MODE
Figure 7-1: Calibration Procedure (Cal Port)