Emerson Rosemount5081 Instruction Manual page 125

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Instruction Manual
The second line of the display shows the pH. The pH should be approximately
7.00. Because calibration data stored in the analyzer may be offsetting the input
voltage, the displayed pH may not be exactly 7.00
If a standard millivolt source is available, disconnect the jumper wire between the
pH IN and REF IN terminals and connect the voltage source as shown in
Figure 8-13: Simulate pH
Calibrate the transmitter. Use 0.0 mV for Buffer 1 (pH 7.00) and -177.4 mV for Buffer
2 (pH 10.00).
If the analyzer is working properly, it should accept the calibration. The slope should
be 59.16 mV/pH, and the offset should be zero.
To check linearity, set the voltage source to the values shown in the table verify that
the pH and millivolt readings match the values in the table.
Diagnostics and troubleshooting
Figure 8-13.
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