Emerson Rosemount TupHFET TF396, Quick Start Manual, Page: 26 / 36

4 Start up and calibrate
4.1 Prepare sensor
In most cases, you can simply install the pH sensor as shipped and obtain
readings with an accuracy of ±0.6 pH. To obtain greater accuracy or to verify
proper operation, calibrate the sensor as a loop with its compatible
transmitter.
4.2 pH calibration
After establishing a temporary connection between the sensor and the
transmitter, you may perform a buffer calibration.
Consult the appropriate pH transmitter reference manual for specific
calibration and standardization procedures or see below for recommended
two-point buffer calibration.
4.2.1 Recommended two-point buffer calibration
Prerequisites
Select two stable buffer solutions, preferably pH 4.0 and 10.0. pH buffers
other than pH 4.0 and pH 10.0 can be used as long as the pH values are at
least two pH units apart.
Note
A pH 7.0 buffer solution reads an mV value of zpprozimately zero, and pH
buffers read approximately 59.1 mV for each pH unit above or below 7.0.
Check the pH buffer manufacturer specifications for millivolt values at
various temperatures, since it may affect the actual value of the buffer
solution mV/pH values.
Procedure
1. Immerse sensor in the first buffer solution. Allow sensor to adjust to
the buffer temperature (to avoid errors due to temperature
differences between the buffer solution and sensor temperature) and
wait for reading to stabilize.
The transmitter can now acknowledge the value of the buffer.
2. Rinse the buffer solution off of the sensor with distilled or deionized
water.
3. Repeat Step 1 and Step 2 using the second buffer solution.
Once the transmitter has acknowledged both buffer solutions, a sensor
slope (mV/pH) is established. You can find the slope value within the
transmitter.
Quick Start Guide March 2020
26 Emerson.com/Rosemount