
For example, start with a simulated resistance of 103.9
Ω
, which corresponds to 10.0 °C
(50 °F). Assume that the offset from the sensor calibration was -0.3
Ω
. Because of the
offset, the analyzer calculates temperature using 103.6
Ω
. The result is 9.2 °C. Now change
the resistance to 107.8
Ω
, which corresponds to 20.0 °C (68 °F). The analyzer uses 107.5
Ω
to calculate the temperature, so the display reads 19.2 °C. Because the difference between
the displayed temperatures (10.0 °C) is the same as the difference between the simulated
temperatures, the analyzer is working correctly.
Temp
Pt 100 (
Ω)
22k NTC (k
Ω)
1 °C (34 °F)
100.0
64.88
10 °C (50 °F)
103.9
41.33
20 °C (68 °F)
107.8
26.99
25 ° C (77 °F)
109.7
22.00
30 °C (86 °F)
111.7
18.03
40 °C (104 °F)
115.5
12.31
50 °C (122 °F)
119.4
8.565
60 °C (140 °F)
123.2
6.072
70 °C (150 °F)
127.1
4.378
80 °C (176 °F)
130.9
3.208
85 °C (185 °F)
132.8
2.761
90 °C (194 °F)
134.7
2.385
100 (212 °F)
138.5
1.796
8.4.13
Measuring reference voltage
Some processes contain substances that poison or shift the potential of the reference
electrode. Sulfide is a good example. Prolonged exposure to sulfide converts the reference
electrode from a silver/silver chloride electrode to a silver/silver sulfide electrode. The
change in reference voltage is several hundred millivolts. A good way to check for
poisoning is to compare the voltage of the reference electrode with a silver/silver chloride
electrode known to be good. The reference electrode from a new sensor is best. See
. If the reference electrode is good, the voltage difference should be no more
than about 20 mV. A poisoned reference electrode usually requires replacement.
Diagnostics and troubleshooting
118
Rosemount 5081
Содержание Rosemount5081
Страница 1: ...Instruction Manual LIQ MAN 5081 Rev A September 2017 Rosemount 5081 Explosion Proof Transmitter ...
Страница 4: ......
Страница 10: ...Contents vi Rosemount 5081 ...
Страница 12: ...Startup procedure 2 Rosemount 5081 ...
Страница 23: ...Mounting 5081 on a pipe Figure 3 2 Installation Instruction Manual 13 ...
Страница 24: ...Installation 14 Rosemount 5081 ...
Страница 28: ...Wiring 18 Rosemount 5081 ...
Страница 50: ...Programming basics 40 Rosemount 5081 ...
Страница 130: ...Diagnostics and troubleshooting 120 Rosemount 5081 ...
Страница 136: ...Digital communications 126 Rosemount 5081 ...
Страница 138: ...NOTICE Consult the factory for additional information regarding service or repair Return of material 128 Rosemount 5081 ...
Страница 140: ...Engineering drawings 130 Rosemount 5081 ...
Страница 141: ...Engineering drawings Instruction Manual 131 ...
Страница 142: ...Engineering drawings 132 Rosemount 5081 ...
Страница 143: ...Engineering drawings Instruction Manual 133 ...
Страница 144: ...Engineering drawings 134 Rosemount 5081 ...
Страница 145: ...Engineering drawings Instruction Manual 135 ...
Страница 146: ...Engineering drawings 136 Rosemount 5081 ...
Страница 151: ...EU Declarations of Conformity 138 Rosemount 5081 ...