
Instruction Manual
α
lpha-pH 550
Eutech Instruments
14
4. Calibration Mode
4.1 Preparing the Monitor & Electrode for Calibration
Before starting calibration, make sure that the pH Monitor is in appropriate
measurement mode (pH or ORP). When the monitor is switched on, it starts
up with the measurement mode last used. For example, if the pH Monitor is
switched off in ORP measurement mode, it starts up in ORP mode when it is
switched on. (Refer Section 5.5 for switching measurement modes)
Be sure to remove the protective electrode storage bottle or rubber cap of the
electrode before calibration or measurement. If the electrode has been stored
dry, wet the electrode in tap water for 10 minutes before calibrating or taking
readings to saturate the pH electrode surface and minimize drift.
Rinse the electrode in de-ionized water after use, and store in electrode
storage solution. If storage solution is not available, use pH 4.01 or 7.00
buffer solution.
Do not reuse buffer solutions after calibration. Contaminants in the solution
can affect the calibration, and the accuracy of the measurements.
The pH Monitor features two internationally recognized pH buffer standards.
Select the buffer standard you require in the setup mode. (Refer Section 5.4)
Available buffer options are:
•
USA buffers --- pH 4.01, 1.68, 7.00, 10.01 and 12.45
•
NIST buffers --- pH 4.01, 1.68, 6.86, 9.18 and 12.45
4.2 Entering pH/ORP Calibration Mode
While in measurement mode, press the
CAL
key to access calibration mode.
LCD indicates ‘
CAL PH
’ (when measurement mode is pH) or ‘
CAL OrP
’
(when measurement mode is ORP).
pH Calibration
OPR Calibration
Temp. Calibration
Calibration Mode
- See Section 4.3
- See Section 4.4
- See Section 4.5
CAL
HOLD
CAL
MEAS
pH
°C
ATC
READY
&
To quit Calibration Mode
ENT
NOTES:
•
To exit calibration mode at any time during calibration,
press
▲
and
▼
keys simultaneously
(escape). The pH Monitor returns to the
measurement mode and the old calibration values remain active
•
The calibration is always carried out in the units of measurement (pH
or mV), selected in setup mode