YOKOGAWA PH71, User Manual

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IM 12B03D01-01E
4-3
4. Calibration
4.1 Automatic Calibration
In automatic calibration the Model PH71 Personal pH Meter automatically recognizes
standard solutions being used and calibrates itself using values of Table 4.1. Two types
of standard solutions are preprogrammed: NIST (solutions prepared in accordance with
Japanese standards, factory default) and US (solutions prepared in accordance with the
U.S. standards). If NIST is selected, the meter recognizes standard solutions with pH 2,
4, 7, 9, and 12. The meter recognizes standard solutions with pH 4, 7, and 10 if US is
selected.
Table 4.1 pH-Temperature Relationship in pH Standard Solutions
0 5 10 15 20 25 30 35 40 45 50
pH2
pH4
pH7
pH9
pH12
-
4.003
6.984
9.464
13.423
1.668
3.999
6.951
9.395
13.207
1.670
3.998
6.923
9.332
13.003
1.672
3.999
6.900
9.276
12.810
1.675
4.002
6.881
9.225
12.627
1.679
4.008
6.865
9.180
12.454
1.683
4.015
6.856
9.139
12.289
1.688
4.024
6.844
9.102
12.133
1.694
4.035
6.838
9.068
11.984
1.700
4.047
6.834
9.038
11.841
1.707
4.060
6.833
9.011
11.705
55 60 70 80
1.715
4.075
6.834
8.985
11.574
1.723
4.091
6.836
8.962
11.449
1.743
4.126
6.845
8.921
-
1.766
4.164
6.859
8.885
-
Std. Solution
d
NIST
Temperature
8
C
0 5 10 15 20 25 30 35 40 45 50
pH4
pH7
pH10
4.000
7.120
10.317
3.998
7.090
10.245
3.997
7.060
10.179
3.998
7.040
10.118
4.001
7.020
10.062
4.005
7.000
10.012
4.010
6.990
9.966
4.018
6.980
9.926
4.027
6.980
9.889
4.038
6.978
9.856
4.050
6.970
9.828
55 60
4.064
6.980
9.828
4.080
6.980
9.828
Std. Solution
Temperature
8
C
d
US
T0402.EPS
Before Automatic Calibration
Make sure that the correct type of standard solutions to be used for automatic calibration
has been selected. (Refer to Section 5.3 (9), “Standard solution setting (Std) panel.”)