20
Thermo Scientific Alpha pH 560
calibration mode, the pH Controller reverts back to ‘process
temperature’.
Make sure that the pH Controller is set to accept NIST standard buffer
in the Setup mode. (Refer Page 16) 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)
Figure 4–17.
NIST Buffer Single-Point Calibration
1
1
From pH measurement mode p
press CAL key to enter
calibration mode as described in page 16. The LCD shows
‘C
CAL PH’. P
Press ENT key to begin calibration.
2
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
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 ‘R
READY’ annunciator when the reading is
stable.
Press CAL key to confirm the reading.
3
The calibration is completed. The pH Controller 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
r
offset) is shown in the lower
display.
Press ENT key to exit from the calibration.
4
The pH Controller reverts to pH measurement mode.
For NIST Buffer
1-Point Calibration:
2-Point Calibration:
www.
GlobalTestSupply
.com
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