14
A
dvanced
S
ensor
T
echnologies,
I
nc. U.S.A.
Website:
www.astisensor.com
IOTRON
TM
Trademark of ASTI
IOTRON
TM
pH / ORP / ISE / DO / Conductivity Measurement Products Lines
“Manual Calibrate pH Offset”
The manual calibration pH offset can be performed with
a pH buffer or else used to allow for agreement between
the inline process reading and an offline grab sample
determination.
Such adjustments to a grab sample
value should always be done in the ‘Offset’ mode after
all pH buffer calibrations are performed.
The current pH reading and temperature are shown for
the selected channel in this screen along with the
existing current used asymmetric potential offset
calibration as well as the time since this calibration was
last performed.
Enter the value to which you wish to adjust the reading
of the pH sensor. In the case that a pH buffer is used the
exact value at the current temperature should be entered
(see appenix “A” and “B” for further details).
After pressing the “Calibrate” button the screen will
display “Calibrating”. If the calibration is successful it
will show “Calibrationg Complete”. The calibration
might not be successful if the calibration limits are
exceeded or else is a communication error occurs.
Finally after the dampener time is expired the new
calibration results will be shown and the time since
calibration will show as 0.00 days. The basic sequence of
events after pressing the calibrate button also occurs for
the autobuffer calibrations screens as well as the manual
calibration screens.
It is important to recall that the acid slope and base slope
calibrations for pH sensors should always be done after
performing the offset calibration first. For any type of
calibrations to force agreement between the inline
process reading and an offline determined value this
should ALWAYS be done in the manual offset
calibration mode and never in the manual slope
calibration mode. Contact factory for assistance if the
best practice calibration procedures are in doubt.