Thermo Fisher Scientific Alpha DO 500 - Manual (Page 20)

Instruction Manual Alpha DO 500
14
4.2 Calibration in mg/l or ppm of Oxygen
The DO Transmitter is capable of calibration of up to 2 points for dissolved
oxygen. All new calibration values will automatically override existing
calibration data. Make sure the unit of measurement is set to mg/l or ppm.
(Refer Section 5.2 for switching unit of measurements).
If you wish to abort the DO calibration, press Ÿ and ź keys simultaneously
and the DO Transmitter reverts to measurement mode.
4.2.1 1-Point Calibration
The 1-point calibration is done at high-point using 8.24 mg/l of dissolved
oxygen solution.
Measured value should be
within +/- 50 % of high-point
Calibration error occurs if measured value
is not within +/- 50% of high-point
during 1-point calibration
2
CAL
HOLD
1
ENT ENT ENT
CAL
HOLD
2
CAL
HOLD
2
CAL
HOLD
3
mg/l
MEAS
mg/l
°C
ATC
READY
4
CAL
HOLD
mg/l
READY
ERR
+
1 1
From measurement mode press CAL key to enter calibration mode as
described in section 4.1. The LCD shows ‘CAL Do’. Press ENT key to
begin calibration.
2
Select 1-point calibration: The display shows ‘1Pt CAL’. If ‘2Pt CAL’ is
shown, press Ÿ or ź key to select ‘1Pt CAL’.
Press ENT key to confirm the selection.
3
The buffer annunciator appears in LCD. The lower display shows ‘HI’,
indicating the high-point is being calibrated. Immerse the electrode in
8.24 mg/l dissolved oxygen solution. Immerse the temperature probe in
the solution if ATC is enabled. The upper display shows the measured
value of dissolved oxygen of the solution. Allow the reading to stabilize.
LCD shows ‘READY’ annunciator when the reading is stable.
Press Ÿ or ź key to adjust the reading to 8.24 mg/l. The Transmitter
allows adjusting up to
r50% of the measured value.
Press ENT key to confirm the reading.
NOTE: The transmitter does not accept the calibration and shows
calibration error if the displayed (measured) value is more than
r50% of the high-point value.
4
The calibration is completed. The DO Transmitter reverts to
measurement mode.