Hanna Instruments HI 8510 User Manual
Page 19
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pH DIAGNOSTIC TESTS
HI 8510, HI 8710 and HI 8711 are provided
with autodiagnostic functions that allow to
check and troubleshoot any malfunctioning.
The functions are made via front panel keys
to isolate the cause of malfunction whether it
is due to pH electrode contamination, internal
offset circuit or amplifier circuit.
Follow the procedure described below.
First press the MEASURE
key, then one of the following
keys.
A) Sensor Test
Immerse the electrode in
pH 7.01 buffer solution
(HI 7007), press SENSOR
TEST key and the display
shows the mV response
of the electrode.
If the electrode is in good working condi-
tion, the value should be within ±30 mV.
A value between 30 and 60 mV or -60 and
-30 mV, indicates some contamination of
the electrode.
If the value is higher than 60 mV or lower
than -60 mV, the contamination is too
high and the electrode should be replaced.
COARSE
SET
FINE
MEA
SURE
4 cm
(1½")
HI 7007
pH VALUES AT VARIOUS
TEMPERATURE
Temperature has an effect on the pH. The
calibration buffer solutions are affected by
temperature changes to a lesser degree than
normal solutions.
Please refer to the following chart to perform
the pH calibration:
For instance, if the buffer temperature is 25°C
(77°F), calibrate to read on the display pH
4.01 or 7.01 or 10.01.
If the buffer temperature is 20°C, calibrate to
read on the display pH 4.00 or 7.03 or 10.06.
If the buffer temperature is 50°C, calibrate to
read on the display pH 4.06 or 6.98 or 9.82.
TEMP
pH VALUE
°C
°F
4.01
6.86
7.01
9.18
10.01
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
32
41
50
59
68
77
86
95
104
113
122
131
140
149
158
4.01
4.00
4.00
4.00
4.00
4.01
4.02
4.03
4.04
4.05
4.06
4.07
4.09
4.11
4.12
6.98
6.95
6.92
6.90
6.88
6.86
6.85
6.84
6.84
6.83
6.83
6.84
6.84
6.85
6.85
7.13
7.10
7.07
7.04
7.03
7.01
7.00
6.99
6.98
6.98
6.98
6.98
6.98
6.99
6.99
9.46
9.39
9.33
9.27
9.22
9.18
9.14
9.10
9.07
9.04
9.01
8.99
8.97
8.95
8.93
10.32
10.24
10.18
10.12
10.06
10.01
9.96
9.92
9.88
9.85
9.82
9.79
9.77
9.76
9.75
SENSOR
TEST
mV