Procedure - Zeroing The Sensor - Emerson Rosemount MCL-220 Manual

Calibration
7.3.2

Procedure - zeroing the sensor

Complete the following steps to calibrate the sensor with the zero standard.
1.
2.
3.
4.
5.
6.
7.
50
Remove the sensor from the flow cell and place it in the zero standard (deionized
water). Be sure no air bubbles are trapped against the membrane.
The sensor current drops rapidly at first and then gradually reaches a stable zero
value.
To monitor the sensor current, press DIAG.
Choose Sensor 1 (monochloramine).
The input current is the first line in the display. Note the units: nA is nanoamps; uA is
microamps. Typical zero current for the new sensor is between -10 and 15 nA. A new
sensor or a sensor in which the electrolyte solution has been replaced may require
several hours (occasionally as long as overnight) to reach a minimum zero current.
Important
Do not start the zero routine until the sensor has been in the zero solution for at least two
hours.
Press MENU.
The main Menu screen appears. The cursor is on Calibrate.
Press ENTER.
Choose Sensor 1.
Choose Monochloramine.
Rosemount MCL