User guide

I-E67-84-1B February,2002 6-5
4) If the reading was stable, enter the NEW
VAL (i.e., new process variable) that
reflects the difference between the grab
sample value and the indicated value when
the grab sample was taken (i.e., Current
TB84PH Indication + [Grab Sample Value -
TB84PH Indication at the time the grab
sample was taken]). Use the Key to
increment the digit value and the Key
to move to the next digit. Press the
ENTER Key to enter the new value.
Invalid calibration values will generate the
text string BAD.CAL, and the calibration value
will not be accepted. If the new value is
valid, the Efficiency (i.e., slope value shown
as a percentage of theoretical) will be shown.
Pressing the NEXT Smart Key displays the
Offset value. At this point, the user can
return to the Process Sensor Calibrate State
by pressing the NEXT Smart Key or to the
Measure Mode by pressing the Exit To MEASURE
Smart Key.
Note: If a Hold condition is present, the TB84PH
Advantage Series analyzer inquires if this
condition should be released.
For more information on sensor calibration
techniques and troubleshooting, refer to TP90-
2.
Two-Point Calibrate State
The Two-Point Calibrate State conducts offset
and slope adjustments on the sensor input to
determine its response characteristics. This
calibration is typically conducted before
installation into its final location and
periodically during the life of the sensor
when the response of the sensor begins to
decrease. This calibration procedure uses
buffers or standards depending on the type of
sensor (e.g., pH versus pION, respectively).
When conducting a Two-Point Calibration, the
TB84PH Advantage Series analyzer initiates an
automatic Hold All condition. The Hold icon
will begin to flash, and the Hold All
condition will remain active until the
calibration is complete.