Operational Guide
27
pH
Calibration
Calibration
Messages
•
If the buffer temperature exceeds the temperature limits of the buffer,
“WRONG BUFFER TEMPERATURE” will be displayed.
•
Press
CLR
after entering calibration to clear previous calibrations stored on
probe. “CLEAR CALIBRATION” message will be displayed. Press
CFM
. The
instrument will return to measurement mode displaying the “CAL DUE”
message.
•
If measured value differs more than expected “CHECK ELECTRODE CHECK
BUFFER“ will be displayed. Take appropriate action, cleaning the probe if
necessary or refreshing the pH buffer.
pH Buffer Temperature Dependence
Calibration buffers are affected by temperature. During calibration with standard
pH buffers (not Custom), the instrument will display the pH buffer value at 25 ºC,
however, it will use the appropriate value for that buffer at the temperature of
the buffer for the calibration. Immediately after exiting calibration, the buffer
will read its value at the temperature of measurement.
TEMP
pH BUFFERS
ºC
ºF
1.679
3.000
4.010
6.862
7.010
9.177
10.010
12.454
0
32
1.670
3.072
4.007
6.982
7.130
9.459
10.316
13.379
5
41
1.670
3.051
4.002
6.949
7.098
9.391
10.245
13.178
10
50
1.671
3.033
4.000
6.921
7.070
9.328
10.180
12.985
15
59
1.673
3.019
4.001
6.897
7.046
9.273
10.118
12.799
20
68
1.675
3.008
4.004
6.878
7.027
9.222
10.062
12.621
25
77
1.679
3.000
4.010
6.862
7.010
9.177
10.010
12.450
30
86
1.683
2.995
4.017
6.851
6.998
9.137
9.962
12.286
35
95
1.688
2.991
4.026
6.842
6.989
9.108
9.919
12.128
40
104
1.693
2.990
4.037
6.837
6.983
9.069
9.881
11.978
45
113
1.700
2.990
4.049
6.834
6.979
9.040
9.847
11.834
50
122
1.707
2.991
4.062
6.834
6.978
9.014
9.817
11.697
55
131
1.715
2.993
4.076
6.836
6.979
8.990
9.793
11.566
60
140
1.724
2.995
4.091
6.839
6.982
8.969
9.773
11.442
65
149
1.734
2.998
4.107
6.844
6.987
8.948
9.757
11.323
70
158
1.744
3.000
4.123
6.850
6.993
8.929
9.746
11.211
75
167
1.755
3.002
4.139
6.857
7.001
8.910
9.740
11.104
80
176
1.767
3.003
4.156
6.865
7.010
8.891
9.738
11.003
85
185
1.780
3.002
4.172
6.873
7.019
8.871
9.740
10.908
90
194
1.793
3.000
4.187
6.880
7.029
8.851
9.748
10.819
95
203
1.807
2.996
4.202
6.888
7.040
8.829
9.759
10.734
The Calibration Check™ feature may flag diagnostic messages during a
calibration. As electrode aging is normally a slow process, substantial changes
from previous calibrations are likely due to a temporary problem with the probe
or buffers that can be addressed easily. These messages are seen in Standard
and Basic modes.
Wrong Buffer
This message appears when the difference between
the pH reading and the value of the selected buffer
is too great. If this error message is displayed, check
if you have selected the proper calibration buffer and
have poured the desired buffer.
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