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Appendix, 2 ph temperature dependency – KROHNE OPTISENS PAS 2000 EN User Manual

Page 39

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APPENDIX

8

39

OPTISENS PAS 2000

www.krohne.com

11/2008 • MA PAS 2000 R04 en

8.2 pH temperature dependency

The output from a pH-electrode varies with the temperature in a predictable way. The size of the
variation depends on both the temperature and the pH being measured.

At pH 7 or 78°F the temperature error is zero. If temperature or pH changes the temperature
error is calculated using the following formula: 0.03 pH-difference / pH / 10°C. PAS 2000 pH has
a built in compensation for the temperature error provided that the correct temperature of
calibration buffers and measured media is entered.

°C

°F

pH

pH

pH

pH

pH

pH

pH

pH

pH

pH

pH

pH

5

41

2.30

3.24

4.18

5.12

6.06

7.00

8.06

9.12

10.18 11.24 12.30 13.36

15

59

2.15

3.12

4.09

5.06

6.03

7.00

8.03

9.06

10.09 11.12 12.15 13.18

25

77

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00 11.00 12.00 13.00

35

95

1.85

2.88

3.91

4.94

5.97

7.00

7.97

8.94

9.91

10.88 11.85 12.82

45

113

1.70

2.76

3.82

4.88

5.94

7.00

7.94

8.88

9.82

10.76 11.70 12.64

55

131

1.55

2.64

3.73

4.82

5.91

7.00

7.91

88.2

9.73

10.64 11.55 12.46

65

149

1.40

2.52

3.64

4.76

5.88

7.00

7.88

8.76

9.64

10.52 11.40 12.28

75

167

1.25

2.40

3.55

4.70

5.85

7.00

7.85

8.70

9.55

10.40 11.25 12.10

85

185

1.10

2.28

3.46

4.64

5.82

7.00

7.82

8.64

9.46

10.28 11.10 11.92

95

203

0.95

2.16

3.37

4.58

5.79

7.00

7.79

8.58

9.37

10.16 10.95 11.74

.book Page 39 Friday, November 28, 2008 2:32 PM