Thermo Fisher Scientific Alpha DO 500 - Manual (Page 24)

Instruction Manual Alpha DO 500
18
NOTES:
x If the displayed value is not within 50% to 150%, the Transmitter
indicates a calibration error by showing ‘ERR’ and blinking electrode
annunciator. If this happens, press Ÿ and ź keys together to return to
measurement mode. Restart the calibration from Step1.
x To exit from calibration mode without confirming calibration, press Ÿ
and ź keys together.
x When calibrating with manual temperature compensation, the
Transmitter automatically changes from preset ‘process temperature’ to
‘calibration temperature’. After leaving calibration mode, the transmitter
switches back to the ‘process temperature’. (Refer section 5.4 for
temperature settings)
4.3.2 2-Point Calibration:
The 2-point calibration is carried out with standard DO buffer of 0% oxygen
saturation and then in air (100% oxygen saturation)
Measured value should be
<10 % of high-point
Calibration error occurs
if measured value is
<10% of high-point
during 1st point calibration
or
if measured value is not
within +/-50% of high-point
during 2nd point calibration
2
CAL
HOLD
1
ENT
ENT
ENT
CAL
HOLD
2
CAL
HOLD
2
CAL
HOLD
MEAS
°C
ATC
READY
4
CAL
HOLD
READY
ERR
CAL
HOLD
3
READY
5
ENT
ENT
% %
% %
+
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 first calibration point.
2
Select 2-point calibration: The display shows ‘1Pt CAL’. Press Ÿ or ź
key to select ‘2Pt CAL’.
Press ENT key to confirm the selection.
3
The buffer annunciator appears in LCD. The lower display shows
‘0.0’. Immerse the electrode in 0% standard DO buffer 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.