Emerson Rosemount FCL, Reference Manual

Page: 64 / 108

1. ±0.4 °C accuracy is not acceptable.
2. The temperature measurement is suspected of being in error. Calibrate
temperature by making the transmitter reading match the temperature measured
with a standard thermometer.
Procedure
1. Remove the sensor from the flow cell. Place it in an insulated container of water
along with a calibrated thermometer. Submerge at least the bottom two inches of
the sensor.
2. Allow the sensor to reach thermal equilibrium.
The time constant for the sensor is about five minutes, so it may take as long as
thirty minutes for equilibration.
3. Press MENU .
The main Menu screen appears. The cursor is on Calibrate.
4. Press ENTER .
5. Choose the sensor you wish to calibrate.
Sensor 1 is the chlorine sensor. Sensor 2 (if present) is the pH sensor.
6. Choose Temperature.
7. Change the display to match the temperature read from the calibrated
thermometer. Press ENTER .
If the present temperature is more than 5 °C different from the value entered, an
error message appears.
8. To force the transmitter to accept the calibration, choose Yes. To repeat the
calibration, choose No.
For troubleshooting assistance, see
Troubleshooting when no error message is
showing .
9. To return to the main display, press
MENU
and then
EXIT
.
6.3 Calibration - free chlorine
6.3.1 Purpose
As Figure 6-1 shows, a free chlorine sensor generates a current directly proportional to the
concentration of free chlorine in the sample. Calibrating the sensor requires exposing it to
a solution containing no free chlorine (zero standard) and to a solution containing a known
amount of free chlorine (full-scale standard).
Calibrate Reference Manual
May 2019 00809-0100-3412
64 Emerson.com/Rosemount