
Instruction Manual
α
lpha-pH 550
Eutech Instruments
17
NOTES:
•
To exit from pH calibration mode without confirming calibration, press
▲
and
▼
keys together.
•
When confirming the buffer measurement, if measured pH value is not
within
±
1.00pH from selected buffer value, the electrode annunciator
blinks and
ERR
indicator appears in the display. This error can also occur if
non-standard buffers are used or the electrode has worn out. If this
happens, press both
▲
and
▼
keys together to restart the calibration
beginning from Step1.
•
When calibrating with manual temperature compensation, the meter
automatically changes from the preset ‘process temperature’ to the
‘calibration temperature’. After leaving the calibration mode, the pH Monitor
reverts back to ‘process temperature’.
4.3.2 For NIST Buffer
Make sure that the pH Monitor is set to accept NIST standard buffer in the
Setup mode. (Refer Section 5.4 for Buffer Selection Settings) The factory
default is USA standard. It is recommended that you perform 2-point
calibration at room temperature (25
o
C), starting with the first buffer at pH
6.86 followed by any other buffer value. (pH 4.01, 1.68, 9.18 or 12.45)
1-Point Calibration:
CAL
HOLD
ENT
CAL
pH
READY
HOLD
pH
CAL
CAL
mV
pH
HOLD
MEAS
PH
°C
ATC
READY
ENT
1
2
3
4
From pH measurement mode
press CAL key
to enter calibration mode
as described in section
1
1
4.2. The LCD shows ‘
CAL PH
’.
Press ENT key
to begin calibration.
Place the electrode in pH 6.86 buffer. Immerse the temperature probe in
the buffer solution if ATC mode is enabled. Immerse the potential
matching pin in the buffer if symmetrical mode is enabled. The buffer
annunciator
2
appears in LCD. Lower display shows pH 6.86 (NIST
standard buffer). Upper display shows the current uncalibrated pH
reading. Allow the reading to stabilize. LCD shows ‘
READY
’ annunciator
when the reading is stable.
Press CAL key
to confirm the reading.
The calibration is completed. The pH Monitor re-calculates electrode
properties based on the calibration. The new slope (in mV) is shown in
the upper display and pH reading at 0mV (pH7.00
±
offset) is shown in
the lower display.
3
Press ENT key
to exit from the calibration.
The pH Monitor reverts to pH measurement mode.
4