Section 4: Calibration; Calibration - Emerson Rosemount 3200HP Instruction Manual

Instruction Manual
LIQ-MAN-3200HP

Section 4: Calibration

4.1

Calibration

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Calibration
Select two stable buffer solutions. Ideally, the calibration buffers should bracket the
expected pH of the sample and be at least two pH units apart. Use the ring at the bottom
of the back plate to hold the beaker containing the buffer.
Most pH meters offer automatic buffer recognition. Automatic buffer recognition means
the instrument automatically calibrates using the correct pH for the buffer temperature.
(The pH of a buffer, particularly one with alkaline pH, changes as the temperature changes.)
If the meter does not have automatic buffer recognition, refer to the label on the buffer
bottle for a table of pH versus temperature.
Remove the sensor from the flow cell and rinse it with deionized water. Immerse it in the
first buffer. Be sure the capillary disc is completely submerged. Gently swirl the sensor in
the buffer for a few seconds. Allow the sensor and buffer to reach the same temperature.
Once pH readings are stable, start the calibration. Follow the procedure in the transmitter
instruction manual.
After the sensor has been calibrated in the first buffer, remove and rinse it with deionized
water. Place the sensor in the second buffer and complete the calibration.
After the calibration is complete, check the slope and intercept of the sensor. The slope
should be between 56 and 60 mV/pH and the offset should be between -20 and 20 mV.
Calibration
April 2017
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