OXY5500 Gas Analyzer Operating Instructions
Endress+Hauser 51
The Mode of Port1 and Port2 can be set to one of the following:
• Off: No input reading or output writing.
• Linear: High and low value that has been set to correspond to 4mA and 20ma. Values between these two
settings will be calculated linearly. Values outside this range will initiate the error trigger level.
• Bilinear: High, mid, and low value set to correspond to 4mA, 12mA, and 20mA respectively. This mode allows
higher resolution in a certain range. Refer to Figure 65 for an example.
Figure 65. Bilinear current output vs oxygen value
The first example (gray line) in Figure 65 shows high resolution in a low oxygen environment. The second example
(yellow line) shows a high resolution in high oxygen environment. This also shows the behavior for measurement
values that lie outside the value range (oxygen values over a maximum of 50 will be shown as 20mA).
In the event of any error, the Error Trigger Level (2mA or 22mA) will be applied to the currently selected port. For
the input, any value outside the 4-20mA range will be interpreted as “not valid”.
5.15.2 4-20mA values
In the 4-20mA VALUES screen, enter the values that correspond to 4mA, 12mA, or 20mA depending on the
currently selected mode.
Modes that can be selected include:
• Off: No values can be entered. Refer to Figure 66.
• Linear: The high and low value can be entered. Refer to Figure 67. The unit depends on the selected output and
oxygen sensor. If the output is set to Temperature, the unit is always °C. Otherwise, the output depends on the
oxygen sensor (the oxygen unit selected in the measurement screen will explicitly NOT be used):
o OP-3: %O2
o OP-6: %O2
o OP-9: ppmv
The values will be used for calculating the output or input value on the next measurement.
Figure 66. Analogues - 4-20mA values for mode “Off”
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