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APPENDIX B Supplemental Compliance Information
Instrument Engineering Bulletin
The Hach EC1000 shows an accuracy shift when exposed to radio frequency interference
of 3 and 10 volts per meter. What this means to you is that if the displayed data is not
stable (within the accuracy and repeatability specifications) and other interferences are
not suspected as the cause, inspect the area for portable phones, paging service tower/
antennas, or any other transmitting communication device. For example, if the user of the
instrument detects a measurement deviation while using a hand-held radio communication
device to relay information to a base station, the interference is clearly caused by the
hand-held radio communication device. To resolve the interference problem, move the
hand-held radio communication device at least 3 to 4 meters from the instrument to
provide isolation.
As shown in the following table, the instrument reading may deviate slightly at specific
frequencies. Any electronic instrument is sensitive to radio waves if the power is great
enough. However typical transmitting power is limited by regulatory controls and field
strengths greater than 3 to 10 volts per meter are seldom experienced.
Frequency
Display w/o RF
(MHz)
(pH)
30
9.3
36
9.12
38
9.12
50
9.12
57
9.12
65
9.12
76
9.3
82
9.12
90
9.3
115
9.12
120
9.12
124
9.3
125
9.12
142
9.12
176
9.12
181
9.3
200
9.12
220
9.12
229
9.3
260
9.12
265
9.3
271
9.3
300
9.12
304
9.3
322
9.31
326
9.12
328
9.31
348
9.12
361
9.28
Display w/10V RF
Temperature w/o RF
(pH)
8.29
8.12
8.12
7.47
6.51
8.59
7.47
6.31
7.94
-1.66
4.70
7.58
8.52
2.63
8.83
7.23
8.29
8.69
4.17
8.42
7.49
7.1
8.33
4.48
7.33
8.81
6.9
8.98
8.99
117
Temperature w/10 V/m
(°C)
(°C)
23.3
26.9
21.3
18.00
21.3
18.00
21.3
18.30
21.3
17020
21.3
20.20
23.8
21.5
21.3
16.90
23.8
28.6
21.3
3.50
21.3
1.40
23.9
29.6
21.3
20.00
21.3
10.00
21.3
20.60
24
22.2
21.3
19.40
21.3
20.20
24
13
21.3
20.10
24.1
19.7
24.1
20.00
21.3
19.10
24.2
15.7
24.2
20.2
21.3
20.40
24.2
21.8
21.3
—
21.8
—
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